JP2008216082A - Dynamic tensile test method and device - Google Patents

Dynamic tensile test method and device Download PDF

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JP2008216082A
JP2008216082A JP2007054772A JP2007054772A JP2008216082A JP 2008216082 A JP2008216082 A JP 2008216082A JP 2007054772 A JP2007054772 A JP 2007054772A JP 2007054772 A JP2007054772 A JP 2007054772A JP 2008216082 A JP2008216082 A JP 2008216082A
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bar
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wave
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JP4830913B2 (en
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Kazuo Shimamura
和夫 島村
Masanari Okuda
将成 奥田
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IHI Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein compressive stress acts on a test piece. <P>SOLUTION: A test piece 3 having a parallel section 8 between gripper sections 9a and 9b on the input rod side and output rod side is arranged between an input rod 1 and output rod 2 arranged in series. The gripper section 9a on the input rod side is connected to the tip of the input rod 1 via a stress wave transmission adjusting tool 10 that permits the relative displacement to the input rod 1 side and can restrain the relative displacement to the output rod 2 side. The gripper section 9b on the other end side is attached to the base end of the output rod 2. A color 12 is interposed between the stress wave transmission adjusting tool 10 and the base end surface of the output rod side 2. Compression wave entered from the base end side of the input rod 2 by collision of a striking rod 7 is transmitted to the output rod 2 via the stress wave transmission adjusting tool 10 and the color 21. At this time, the stress wave transmission adjusting tool 10 pressed to the output rod 2 side is permitted to be relatively displaced to the input rod 1 side of the gripper section 9a on the input rod side, and the transmission of the compression wave to the test piece 3 is prevented. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、材料が動的負荷を受ける場合の材料特性を取得すべく、試験片に動的な引張荷重を作用させて引張試験を行うために用いる動的引張試験方法及び装置に関するものである。   The present invention relates to a dynamic tensile test method and apparatus used for performing a tensile test by applying a dynamic tensile load to a test piece in order to acquire material characteristics when the material is subjected to a dynamic load. .

自動車や航空宇宙の分野、あるいは、ガスタービンやジェットエンジンや発電機のような高速回転機器の分野等では、高速衝突等により衝撃荷重が発生する問題を扱うことがあり、このような衝撃荷重に対する各種機器や構造物の安全設計のために、使用材料が動的負荷を受ける場合の材料特性に関するデータが必要とされることがある。   In the field of automobiles and aerospace, or in the field of high-speed rotating equipment such as gas turbines, jet engines, and generators, the problem of impact loads generated by high-speed collisions may be handled. For the safety design of various devices and structures, data on the material properties when the material used is subjected to a dynamic load may be required.

上記のような動的負荷の下での材料特性データを得るための各種試験法のうち、たとえば、構造用鋼の動的強度特性を取得するための動的引張試験法(高速引張試験法)としては、油圧サーボ法、ホプキンソン棒法、ワンバー法(One−Bar法)、検力ブロック法が主として用いられている(たとえば、非特許文献1参照)。   Among various test methods for obtaining material property data under dynamic load as described above, for example, dynamic tensile test method (high speed tensile test method) for obtaining dynamic strength properties of structural steel For example, a hydraulic servo method, a Hopkinson bar method, a one bar method (One-Bar method), and a force detection block method are mainly used (see, for example, Non-Patent Document 1).

このうち、油圧サーボ法は、油圧サーボ式の高速引張試験機を用いるもので、一端側を固定した試験片の他端側を、油圧シリンダにより所定の速度まで助走させたチャックによって引張るようにして試験を行い、試験片に貼った歪ゲージにより荷重を検出するようにしてある。   Of these, the hydraulic servo method uses a hydraulic servo type high-speed tensile tester, and the other end of the test piece with one end fixed is pulled by a chuck that has been run to a predetermined speed by a hydraulic cylinder. A test is performed, and the load is detected by a strain gauge attached to the test piece.

ホプキンソン棒法による動的引張試験としては、カラーを用いる方式と、ヨークを用いる方式が主として用いられている。このうち、カラーを用いる方式のホプキンソン棒法による動的引張試験を行うための装置は、図8(イ)(ロ)に示す如き構成としてある。すなわち、同一の断面積で且つ同一の長さ寸法としてある細長い2本の応力棒としての入力棒1と出力棒2とを直列(一直線上)に配置し、該入力棒1の先端部となる一端部と、出力棒2の基端部となる他端部との間に、試験片3を挟み込むように配置すると共に、該試験片3の両端部を、上記入力棒1の先端面の中心部と、出力棒2の基端面の中心部にそれぞれ取り付けてある。更に、2個一組の半円筒形状のカラー4を、上記試験片3の外周を取巻くようにして上記入力棒1の先端面と出力棒2の基端面との間に介装させて、該カラー4により、上記入力棒1と出力棒2の互いに近接する方向への相対変位のみを拘束できるようにしてある。更に、図示してはいないが、上記入力棒1の基端側の外部位置に、所要の加速手段(撃ち出し手段)で加速して上記入力棒1の基端部に衝突させるための打撃棒を備えた構成としてある。これにより、上記図示しない打撃棒を上記入力棒1の基端部に衝突させて負荷を与えることにより、入射波としての圧縮波を上記入力棒1の基端部より入射させると、この圧縮波が、該入力棒1中を基端側から先端部まで伝播された後、上記試験片3の取付部分では、試験片3の外周に配されているカラー4を介して上記入力棒1の先端面より出力棒2の基端面へ透過されて、透過波としての圧縮波が該出力棒2中を基端側より先端側へ伝播され、その後、上記圧縮波が、自由端としてある出力棒2の先端に達して反射されることで反射波としての引張波が生じるようにしてあり、この反射引張波を、上記出力棒2を先端側から基端部まで伝播させた後、該出力棒2の基端部と入力棒1の先端部との間に取り付けられている上記試験片3に伝えることで、該試験片3に引張力(引張負荷)を作用させるようにしてある。そして、上記入力棒1と出力棒2の長手方向の所要個所、たとえば、入力棒1と出力棒2の長手方向中間部付近にそれぞれ取り付けてある歪ゲージ(図示せず)により、該入力棒1及び出力棒2中を伝播される圧縮波と、該圧縮波の反射波である反射引張波をそれぞれ検出して、その時間履歴を記録し、該記録されたデータに基いて上記入力棒1と出力棒2の運動解析を行うことにより、該入力棒1と出力棒2の間で高速変形される上記試験片3の応力−歪関係を求めることができるとされている。   As a dynamic tensile test by the Hopkinson bar method, a system using a collar and a system using a yoke are mainly used. Among these, the apparatus for performing the dynamic tensile test by the Hopkinson rod method using the collar is configured as shown in FIGS. That is, the input bar 1 and the output bar 2 as two elongated stress bars having the same cross-sectional area and the same length are arranged in series (on a straight line) and become the tip of the input bar 1. The test piece 3 is disposed so as to sandwich the one end and the other end serving as the base end of the output rod 2, and both ends of the test piece 3 are arranged at the center of the distal end surface of the input rod 1. And a central portion of the base end face of the output rod 2. Further, two sets of semi-cylindrical collars 4 are interposed between the distal end surface of the input rod 1 and the proximal end surface of the output rod 2 so as to surround the outer periphery of the test piece 3, The collar 4 can restrain only the relative displacement of the input bar 1 and the output bar 2 in the directions close to each other. Further, although not shown, a striking bar for accelerating by a required acceleration means (shooting means) to an external position on the base end side of the input bar 1 and colliding with the base end of the input bar 1 It is set as the structure provided with. Thus, when a compression wave as an incident wave is incident from the proximal end portion of the input rod 1 by applying a load by causing the hitting rod (not shown) to collide with the proximal end portion of the input rod 1, the compression wave Is propagated through the input rod 1 from the proximal end side to the distal end portion, and at the mounting portion of the test piece 3, the distal end of the input rod 1 is interposed via the collar 4 arranged on the outer periphery of the test piece 3. The transmission wave is transmitted from the surface to the base end surface of the output rod 2, and the compressed wave as the transmitted wave is propagated through the output rod 2 from the base end side to the front end side, and then the compression wave is the free end as the output rod 2. A tensile wave is generated as a reflected wave by being reflected by reaching the tip of the output rod, and after propagating the reflected tensile wave from the tip side to the base end portion, the output rod 2 Is transmitted to the test piece 3 attached between the base end portion of the input rod 1 and the tip end portion of the input rod 1. In Rukoto, it is to exert a tensile force (tensile load) on the test piece 3. Then, the input rod 1 and the output rod 2 are provided at required positions in the longitudinal direction, for example, strain gauges (not shown) attached in the vicinity of the intermediate portions in the longitudinal direction of the input rod 1 and the output rod 2, respectively. And a compressed wave propagating through the output bar 2 and a reflected tensile wave, which is a reflected wave of the compressed wave, are recorded respectively, and the time history is recorded. Based on the recorded data, the input bar 1 and It is said that the stress-strain relationship of the test piece 3 that is deformed at high speed between the input bar 1 and the output bar 2 can be obtained by performing a motion analysis of the output bar 2.

又、ヨークを用いる方式のホプキンソン棒法による動的引張試験の装置は、図9に示す如く、上記と同様に、直列に配置した入力棒1と出力棒2との間に試験片3を取り付けた構成において、入力棒1と出力棒2との間にカラー4を介装する構成に代えて、入力棒1の基端部に、外周方向へ突出する鍔状のヨーク5を一体に取り付け、更に、上記入力棒1の周りに円筒型の打撃棒6を遊嵌させた構成としてある。これにより、上記打撃棒6を、所要の加速手段で加速して、上記入力棒1に沿わせて該入力棒1の先端側から基端側へスライドさせて、入力棒1の基端部に一体に設けてある上記ヨーク5へ衝突させることで、上記入力棒1に、直接引張負荷を入力(入射)できるようにしてある。   In addition, as shown in FIG. 9, a dynamic tensile test apparatus using a Hopkinson bar method using a yoke is provided with a test piece 3 between an input bar 1 and an output bar 2 arranged in series as shown above. In this configuration, instead of the configuration in which the collar 4 is interposed between the input rod 1 and the output rod 2, a hook-shaped yoke 5 protruding in the outer peripheral direction is integrally attached to the base end portion of the input rod 1, Further, a cylindrical hitting rod 6 is loosely fitted around the input rod 1. As a result, the hitting bar 6 is accelerated by a required acceleration means, and is slid along the input bar 1 from the front end side of the input bar 1 to the base end side. A tensile load can be directly input (incident) to the input rod 1 by colliding with the yoke 5 provided integrally.

更に、上記いずれのホプキンソン棒法によっても、細長い入力棒1及び出力棒2中を伝播される応力波(圧縮波や反射引張波)は、該各応力棒1,2の長手方向に沿う方向にのみ伝播される一次元の波として取り扱うことができるとされている。   Furthermore, in any of the above Hopkinson bar methods, the stress wave (compression wave or reflected tensile wave) propagated through the elongated input bar 1 and output bar 2 is in a direction along the longitudinal direction of the stress bars 1 and 2. It can be treated as a one-dimensional wave that is only propagated.

ワンバー法は、原理的には、上記ホプキンソン棒法の一種であり、上記ホプキンソン棒法における出力棒と同様の細長い出力棒の基端部に、試験片の一端を取り付けると共に、該試験片の他端側には、大質量の打撃ブロック(衝撃ブロック)を取り付けて、この打撃ブロックを、所要のハンマーで打撃することで上記試験片の引張試験を行うようにしてある。   The One-Bar method is a kind of the Hopkinson bar method in principle. One end of a test piece is attached to the base end of an elongated output bar similar to the output bar in the Hopkinson bar method. A large-mass striking block (impact block) is attached to the end side, and the striking test of the test piece is performed by striking the striking block with a required hammer.

検力ブロック法は、検力ブロック式高速材料試験機を用いて行うもので、これは、ベースブロックに該ベースブロックの大きさと比べて十分に小さい小突起を設けて、該小突起に試験片を取り付け、該試験片に、負荷ブロックに該負荷ブロックの大きさと比べて十分に小さいサイズとなるよう設けてあるブレードを衝突させるようにしてあり、これにより、上記試験片に負荷される動荷重が、負荷ブロックの振動のない状態で直接作用し、又、試験片に発生した動荷重が、ベースブロック中を伝播することによる応力波の乱れや、そのブロック外の振動の影響も受けない状態で十分長時間の計測がなされるとされている。   The power block method is performed using a power block type high-speed material testing machine, which is provided with a small protrusion on the base block that is sufficiently smaller than the size of the base block, and a test piece on the small protrusion. And the test piece is made to collide with a blade that is provided on the load block so that the size is sufficiently smaller than the size of the load block. However, the load block acts directly in the absence of vibration, and the dynamic load generated in the test piece is not affected by the disturbance of the stress wave caused by propagation through the base block or the vibration outside the block. It is said that measurement will be made for a sufficiently long time.

谷村,「動的応力計測技術(1)−今後のものづくりのための基盤整備−」,機械の研究,株式会社養賢堂,2006年9月1日,第58巻,第9号,p.913−921Tanimura, “Dynamic Stress Measurement Technology (1)-Infrastructure Development for Future Manufacturing”, Research on Machinery, Yokendo Co., Ltd., September 1, 2006, Vol. 58, No. 9, p. 913-921

ところが、上記従来の動的引張試験法のうち、油圧サーボ法では、油圧サーボ式高速引張試験機の固有振動に起因して荷重が振動してしまうという問題が生じる。   However, among the conventional dynamic tensile testing methods, the hydraulic servo method has a problem that the load vibrates due to the natural vibration of the hydraulic servo type high-speed tensile testing machine.

上記ホプキンソン棒法のうち、カラーを用いる方式のものでは、試験片3の取付部分にて、入力棒1側からの圧縮波をカラー4を介して出力棒2側へ透過させるときに、上記試験片3に一時的に圧縮力が作用することを避けられないという問題がある。そのために、試験片3に非常に大きい歪速度を与えようとして、打撃棒の入力棒1への衝突速度を大とすると、上記試験片3に一時的に作用する圧縮力も非常に大きくなってしまい、そのために、該試験片3が塑性座屈する虞が生じるというのが実状である。一方、ヨークを用いる直接引張方式のホプキンソン棒法によれば、試験片3に圧縮力が作用する虞は防止できる。しかし、従来提案されているいずれのホプキンソン棒法においても、入力棒1に打撃棒6を衝突させるときに生じる圧縮波(入射波)は、急峻に立ち上がる矩形波形となるため、この波形の急峻な立ち上がりに起因して、最終的に応力−歪曲線を得ようとすると、図7に示す如く、特に変形初期の領域に大きな振動がのってしまうという問題が生じる。しかも、上記圧縮波が急峻に立ち上がる矩形波形となることにより、高周波成分が重畳し易くなってしまうため、1次元波動論の近似精度が低くなり、そのために、従来のホプキンソン棒法による動的引張試験は、数値シミュレーションが難しい。   Of the above-mentioned Hopkinson bar method, in the method using a collar, when the compression wave from the input bar 1 side is transmitted to the output bar 2 side through the collar 4 at the mounting portion of the test piece 3, the test is performed. There is a problem that it is inevitable that a compressive force acts on the piece 3 temporarily. Therefore, if the impact velocity of the striking rod to the input rod 1 is increased to give a very high strain rate to the test piece 3, the compressive force that temporarily acts on the test piece 3 also becomes very large. For this reason, the actual condition is that the test piece 3 may be plastically buckled. On the other hand, according to the direct tension type Hopkinson bar method using a yoke, the possibility that a compressive force acts on the test piece 3 can be prevented. However, in any of the conventionally proposed Hopkinson bar methods, the compression wave (incident wave) generated when the striking bar 6 collides with the input bar 1 has a steeply rising rectangular waveform. If an attempt is made to finally obtain a stress-strain curve due to the rise, there is a problem that a large vibration is caused particularly in the initial deformation region as shown in FIG. In addition, since the compression wave becomes a rectangular waveform that rises steeply, high-frequency components are easily superimposed, so that the approximation accuracy of the one-dimensional wave theory is lowered. Therefore, the dynamic tension by the conventional Hopkinson bar method is reduced. The test is difficult to perform numerical simulation.

上記ワンバー法では、衝突ブロックを打撃して発生させる衝突力の制御ができないという問題がある。   The one bar method has a problem that it is impossible to control the collision force generated by hitting the collision block.

上記検力ブロック法は、装置構成が複雑で、高価なものとなってしまうという問題がある。しかも、該検力ブロック法でも衝突力の制御ができず、更には、誤差の程度を定量的に把握することができないという問題もある。   The power detection block method has a problem that the apparatus configuration is complicated and expensive. In addition, there is a problem in that the collision force cannot be controlled even by the detection block method, and further, the degree of error cannot be quantitatively grasped.

そこで、本発明は、打撃棒の衝突時の衝突力の形を制御でき、且つ試験片に圧縮力が作用する虞を解消でき、しかも、機構が単純で試験自体を数値シミュレーションで表現できて、結果を検証することが可能な動的引張試験方法及び装置を提供しようとするものである。   Therefore, the present invention can control the shape of the collision force at the time of collision of the striking rod and can eliminate the possibility of compressive force acting on the test piece, and the mechanism is simple and the test itself can be expressed by numerical simulation. It is an object of the present invention to provide a dynamic tensile test method and apparatus capable of verifying the results.

本発明は、上記課題を解決するために、入力棒の先端側に出力棒を直列に配置し、該入力棒の先端部と出力棒の基端部との間に試験片を配置して、上記入力棒の基端側より打撃棒の衝突による圧縮波を入射させて、該圧縮波を、該入力棒中を基端側より先端側へ伝播させた後、該入力棒の先端部より試験片に作用させることなく出力棒へ伝えるようにし、次いで、該出力棒の基端部に伝えられた圧縮波を、出力棒中を先端まで伝播させて反射させることで反射引張波を生じさせた後、該引張波を、出力棒の先端側から基端部まで伝播させてから上記試験片の出力棒側端部に伝えて、該試験片の出力棒側端部と、試験片の入力棒側端部との間に引張力を作用させて、該試験片の引張試験を行うようにする動的引張試験方法及び装置とする。   In order to solve the above-mentioned problem, the present invention arranges an output rod in series on the distal end side of the input rod, arranges a test piece between the distal end portion of the input rod and the proximal end portion of the output rod, A compression wave caused by the impact of a striking rod is made incident from the base end side of the input rod, and after the propagating wave is propagated through the input rod from the base end side to the tip end side, the test is performed from the tip end portion of the input rod. It was transmitted to the output rod without acting on the piece, and then the reflected tensile wave was generated by propagating the compression wave transmitted to the base end portion of the output rod to the tip through the output rod and reflecting it. Thereafter, the tensile wave is propagated from the distal end side to the proximal end portion of the output rod and then transmitted to the output rod side end portion of the test piece, and the output rod side end portion of the test piece and the input rod of the test piece are transmitted. A dynamic tensile test method and apparatus for performing a tensile test of the test piece by applying a tensile force to the side end portion.

より具体的には、上記構成における応力波伝達調整治具を、試験片の入力棒側端部の外周に取り付ける内筒部材と、該内筒部材の外周に配置して上記内筒部材の入力棒側へのみ相対変位を許容できる外筒部材とを備えてなる構成とする。   More specifically, the stress wave transmission adjusting jig in the above configuration is attached to the outer periphery of the input rod side end portion of the test piece, and the inner cylinder member is arranged on the outer periphery of the inner cylinder member. The outer cylinder member is allowed to allow relative displacement only to the rod side.

又、上記各構成において、入力棒の基端部における打撃棒の衝突個所に、打撃棒の衝突時に潰れて変形できる波形調整部材を配設して、該波形調整部材に打撃棒を衝突させることで上記入力棒の基端部より、立ち上がりの緩和された圧縮波を入射させるようにし、更に、上記入力棒及び出力棒中を伝播される上記圧縮波及び反射引張波を、上記入力棒及び出力棒の各長手方向の複数個所に所要間隔を隔てて取り付けてある歪ゲージで計測するようにする方法及び装置とする。   Further, in each of the above configurations, a wave adjusting member that can be crushed and deformed at the time of collision of the hitting bar is disposed at the hitting point of the hitting bar at the base end portion of the input bar, and the hitting bar is caused to collide with the wave adjusting member. Then, a compression wave whose rise is relaxed is made incident from the base end portion of the input bar, and the compression wave and the reflected tensile wave propagated through the input bar and the output bar are further converted into the input bar and the output. A method and apparatus for measuring with a strain gauge attached to a plurality of positions in the longitudinal direction of the rod at predetermined intervals.

更に、上記構成において、入力棒の基端部における打撃棒の衝突個所に配設する波形調整部材として、円柱形状の波形調整部材を用いるようにする。   Further, in the above configuration, a cylindrical corrugated adjusting member is used as the corrugated adjusting member disposed at the collision portion of the striking rod at the base end portion of the input rod.

本発明によれば、以下のような優れた効果を発揮する。
(1)入力棒の先端側に出力棒を直列に配置し、該入力棒の先端部と出力棒の基端部との間に試験片を配置して、上記入力棒の基端側より打撃棒の衝突による圧縮波を入射させて、該圧縮波を、該入力棒中を基端側より先端側へ伝播させた後、該入力棒の先端部より試験片に作用させることなく出力棒へ伝えるようにし、次いで、該出力棒の基端部に伝えられた圧縮波を、出力棒中を先端まで伝播させて反射させることで反射引張波を生じさせた後、該引張波を、出力棒の先端側から基端部まで伝播させてから上記試験片の出力棒側端部に伝えて、該試験片の出力棒側端部と、試験片の入力棒側端部との間に引張力を作用させて、該試験片の引張試験を行うようにする動的引張試験方法及び装置、より具体的には、上記構成における応力波伝達調整治具を、試験片の入力棒側端部の外周に取り付ける内筒部材と、該内筒部材の外周に配置して上記内筒部材の入力棒側へのみ相対変位を許容できる外筒部材とを備えてなる構成としてあるので、打撃棒の衝突により入力棒の基端側より入射させる圧縮波は、該入力棒と出力棒の間の試験片取付部分では、上記応力波伝達調整部材とカラーを介して出力棒へ伝えることができ、この際、上記圧縮波によって出力棒側へ押される応力波伝達調整部材に対し、上記試験片の入力棒側端部は入力棒側への相対変位が許容されているため、該試験片の入力棒側端部に上記圧縮波が作用することはない。このため上記試験片にいかなる歪み速度を与える条件の下においても、純粋な動的引張試験を実施することが可能になる。
(2)入力棒の基端部における打撃棒の衝突個所に、打撃棒の衝突時に潰れて変形できる波形調整部材を配設して、該波形調整部材に打撃棒を衝突させることで上記入力棒の基端部より、立ち上がりの緩和された圧縮波を入射させるようにし、更に、上記入力棒及び出力棒中を伝播される上記圧縮波及び反射引張波を、上記入力棒及び出力棒の各長手方向の複数個所に所要間隔を隔てて取り付けてある歪ゲージで計測するようにすることにより、最終的に得られる応力−歪曲線における変形初期の領域に、大きな振動がのってしまうという問題を回避することができて、荷重振動の少ない滑らかな応力−歪曲線を得ることができる。又、入力棒に入射される圧縮波の立ち上がりを緩和させることで、上記圧縮波及び反射引張波を、いずれも1次元波動論で良好に近似することが可能となる。このために、上記入力棒及び出力棒の複数個所に設けた各歪ゲージにて計測される上記圧縮波と反射引張波の合成された波形から、1次元波動論に基いて、上記入力棒と出力棒を伝播される圧縮波と反射引張波を、良好に分離することができて、動的引張試験を、数値シミュレーションすることも可能になる。
(3)入力棒の基端部における打撃棒の衝突個所に配設する波形調整部材として、円柱形状の波形調整部材を用いるようにすることにより、製作コストが安価になると共に、該波形調整治具の解析的検討が可能で、理論的取り扱いが容易となる効果が期待できる。
According to the present invention, the following excellent effects are exhibited.
(1) An output rod is arranged in series on the distal end side of the input rod, and a test piece is disposed between the distal end portion of the input rod and the proximal end portion of the output rod, and is hit from the proximal end side of the input rod. A compression wave caused by the collision of the rod is made incident, and the compression wave is propagated in the input rod from the proximal end side to the distal end side, and then from the distal end portion of the input rod to the output rod without acting on the test piece. Then, after the compression wave transmitted to the base end portion of the output rod is propagated through the output rod to the tip to generate a reflected tensile wave, the tensile wave is output to the output rod. Is transmitted from the tip end side to the base end portion and then transmitted to the output rod side end portion of the test piece, and the tensile force between the output rod side end portion of the test piece and the input rod side end portion of the test piece And a dynamic tensile test method and apparatus for performing a tensile test on the test piece, more specifically, stress wave propagation in the above configuration. An inner cylinder member that attaches the adjustment jig to the outer periphery of the input rod side end of the test piece, and an outer cylinder member that is arranged on the outer periphery of the inner cylinder member and can allow relative displacement only to the input rod side of the inner cylinder member Therefore, the compression wave incident from the base end side of the input rod due to the collision of the striking rod is the stress wave transmission adjusting member at the test piece mounting portion between the input rod and the output rod. It can be transmitted to the output rod through the collar. At this time, relative to the stress wave transmission adjusting member pushed to the output rod side by the compression wave, the input rod side end of the test piece is relatively displaced to the input rod side. Therefore, the compression wave does not act on the input rod side end of the test piece. For this reason, it is possible to carry out a pure dynamic tensile test under the condition that gives any strain rate to the test piece.
(2) A wave adjusting member that can be crushed and deformed at the time of the collision of the hitting bar is disposed at the hitting point of the hitting bar at the base end portion of the input bar, and the hitting bar is caused to collide with the corrugated adjusting member, whereby the input bar From the base end of the input rod, a rising compression wave is made incident, and further, the compression wave and the reflected tensile wave propagated through the input rod and the output rod are applied to the longitudinal lengths of the input rod and the output rod. By measuring with strain gauges attached at multiple intervals in the direction with a certain interval, there is a problem that large vibrations are placed in the initial region of deformation in the finally obtained stress-strain curve. It can be avoided and a smooth stress-strain curve with little load vibration can be obtained. Further, by relaxing the rise of the compression wave incident on the input rod, both the compression wave and the reflected tensile wave can be satisfactorily approximated by a one-dimensional wave theory. For this purpose, based on the one-dimensional wave theory, the input bar and the input bar are obtained from the combined waveform of the compression wave and the reflected tension wave measured by the strain gauges provided at a plurality of positions of the input bar and the output bar. The compression wave propagating through the output bar and the reflected tension wave can be well separated, and the dynamic tensile test can be numerically simulated.
(3) The use of a cylindrical waveform adjusting member as the waveform adjusting member disposed at the impact point of the striking rod at the base end of the input rod reduces the manufacturing cost and reduces the waveform adjusting process. Analytical examination of tools is possible, and the effect of facilitating theoretical handling can be expected.

以下、本発明を実施するための最良の形態を図面を参照して説明する。   The best mode for carrying out the present invention will be described below with reference to the drawings.

図1(イ)(ロ)乃至図3は本発明の動的引張試験方法及び装置の実施の一形態を示すもので、従来のホプキンソン棒法と同様に、2本の応力棒である入力棒1と出力棒2とを直列に配置して、上記入力棒1の先端部と、出力棒2の基端部との間に試験片3を連結し、更に、上記入力棒1の基端面より所要寸法離れた一直線上位置に、図示しない所要の加速手段(撃ち出し手段)によって加速させて上記入力棒1の基端側に衝突させることで負荷を与えるための打撃棒7を備えた構成において、上記試験片3を、図1(ロ)及び図2に示す如く、長手方向中間部に所要断面積で長手方向に所要寸法延びる平行部8を有し、且つ該平行部8の両側となる長手方向の両端部に、上記平行部8よりも大径として外周面に雄ねじを刻設してなる入力棒側つかみ部9aと出力棒側つかみ部9bをそれぞれ設けてなる構成とする。   1 (a), (b) to FIG. 3 show an embodiment of a dynamic tensile test method and apparatus according to the present invention. As in the conventional Hopkinson bar method, an input bar which is two stress bars. 1 and the output rod 2 are arranged in series, the test piece 3 is connected between the distal end portion of the input rod 1 and the proximal end portion of the output rod 2, and further, from the proximal end surface of the input rod 1 In a configuration provided with a striking rod 7 for applying a load by accelerating by a required acceleration means (shooting means) (not shown) and colliding with the proximal end side of the input rod 1 at a position on a straight line separated by a required dimension. 1 and 2, the test piece 3 has a parallel portion 8 having a required cross-sectional area and a required dimension extending in the longitudinal direction at the intermediate portion in the longitudinal direction, and on both sides of the parallel portion 8. An input rod having a larger diameter than the parallel part 8 at both ends in the longitudinal direction and engraved male threads on the outer peripheral surface The gripping portion 9a and the output bar side gripping portion 9b and comprising respectively configured.

上記試験片3は、上記入力棒側つかみ部9aを、該入力棒側つかみ部9aの入力棒1側への相対変位は許容できる一方、出力棒側への相対変位は拘束できるようにしてある応力波伝達調整治具10を介して上記入力棒1の先端部に連結すると共に、上記出力棒側つかみ部9bを、上記出力棒2の基端面の中心部に設けてあるねじ孔11に螺着させて取り付けるようにする。更に、上記試験片3の入力棒側つかみ部9aに取り付けてある上記応力波伝達調整治具10の出力棒2に臨む先端面と、上記出力棒側つかみ部9bが連結してある出力棒2の基端面との間に、1対の半円筒形状のカラー12を介装して、該各カラー12が、上記試験片3の平行部8の外周を非接触で取巻くようにする。これにより、上記試験片3の入力棒側つかみ部9aに取り付けてある上記応力波伝達調整治具10の先端面と、上記出力棒2の基端面との互いに近接する方向への相対変位を拘束できるようにしてあり、よって、上記入力棒1の基端部への打撃棒7の衝突により該入力棒1に基端側より入射された圧縮波が、該入力棒1の先端部まで伝播されると、該圧縮波を、入力棒1の先端面より上記応力波伝達調整治具10とカラー12のみを介して上記出力棒2の基端面まで伝えることができ、一方、上記圧縮波が出力棒2の先端で反射されることで生じる反射引張波は、出力棒2の基端部より上記試験片3の出力棒側つかみ部9bへ伝えることで、上記応力波伝達調整治具10を介して上記入力棒1の先端部に取り付けてある該試験片3の入力棒側つかみ部9aとの間の平行部8に対して、引張力を作用させることができるようにしてある。   The test piece 3 allows the input rod side grip portion 9a to be allowed to be relatively displaced toward the input rod 1 side of the input rod side grip portion 9a, while restricting the relative displacement toward the output rod side. It is connected to the distal end portion of the input rod 1 via a stress wave transmission adjusting jig 10, and the output rod side grip portion 9 b is screwed into a screw hole 11 provided in the central portion of the base end surface of the output rod 2. Wear it and attach it. Further, the output rod 2 connected to the output rod 2 gripping portion 9b is connected to the distal end surface of the stress wave transmission adjusting jig 10 attached to the input rod gripping portion 9a of the test piece 3. A pair of semi-cylindrical collars 12 are interposed between the base end surfaces of the test pieces 3 so that each collar 12 surrounds the outer periphery of the parallel portion 8 of the test piece 3 in a non-contact manner. As a result, the relative displacement in the direction in which the distal end surface of the stress wave transmission adjusting jig 10 attached to the input rod side grip portion 9a of the test piece 3 and the proximal end surface of the output rod 2 are close to each other is restrained. Therefore, the compression wave incident on the input rod 1 from the proximal end side by the collision of the striking rod 7 with the proximal end portion of the input rod 1 is propagated to the distal end portion of the input rod 1. Then, the compression wave can be transmitted from the front end surface of the input bar 1 to the base end surface of the output bar 2 only through the stress wave transmission adjusting jig 10 and the collar 12, while the compression wave is output. The reflected tensile wave generated by being reflected at the tip of the rod 2 is transmitted from the base end portion of the output rod 2 to the output rod side grip portion 9b of the test piece 3 so that the stress wave transmission adjusting jig 10 is used. The input bar side of the test piece 3 attached to the tip of the input bar 1 Against the parallel portion 8 between the hair portion 9a, it is as a tensile force can be applied.

更に、上記入力棒1の基端面における打撃棒7の衝突個所には、波形調整治具13を配設する。これにより、上記入力棒1の基端側に上記打撃棒7を衝突させて負荷を与える際には、上記打撃棒7が入力棒1の基端面に配設してある上記波形調整治具13に衝突するようにして、この衝突時に該波形調整治具13が潰れるように大変形することで、上記打撃棒7の衝突によって上記入力棒1の基端部に入射される圧縮波(入射波)の立ち上がりを、従来の打撃棒を入力棒1の基端部に直接衝突させていた場合に生じていた矩形波形の入射波(圧縮波)の立ち上がりに比して緩和できるようにしてある。   Further, a waveform adjusting jig 13 is disposed at the collision point of the hitting bar 7 on the base end surface of the input bar 1. Thereby, when the impact rod 7 is caused to collide with the proximal end side of the input rod 1 and a load is applied, the corrugation adjusting jig 13 disposed on the proximal end surface of the input rod 1 is applied. And the waveform adjusting jig 13 is deformed so as to be crushed at the time of the collision, so that a compression wave (incident wave) incident on the base end portion of the input rod 1 due to the collision of the striking rod 7. ) Can be relaxed in comparison with the rising of the incident wave (compressed wave) having a rectangular waveform that occurs when the conventional striking rod is directly collided with the base end of the input rod 1.

更に又、上記入力棒1と出力棒2には、それぞれ長手方向に所要の間隔を隔てた2個所ずつに、歪ゲージ14a,14bと15a,15bを取り付けるようにする。   Furthermore, the strain gauges 14a, 14b and 15a, 15b are attached to the input rod 1 and the output rod 2, respectively, at two positions spaced apart in the longitudinal direction.

詳述すると、上記応力波伝達調整治具10は、図1(ロ)及び図2に示す如く、上記試験片3の入力棒側つかみ部9aの外周面に設けてある雄ねじに螺着させるための内筒部材16と、上記内筒部材16の外周に配置して該内筒部材16の入力棒1側への相対変位のみを許容できるようにした外筒部材17と、該外筒部材17の入力棒側端部を入力棒1の先端部に連結するための連結部材18とからなる3分割構造としてある。   More specifically, the stress wave transmission adjusting jig 10 is screwed onto a male screw provided on the outer peripheral surface of the input rod side grip portion 9a of the test piece 3 as shown in FIGS. An inner cylinder member 16, an outer cylinder member 17 disposed on the outer periphery of the inner cylinder member 16 so as to allow only a relative displacement of the inner cylinder member 16 toward the input rod 1, and the outer cylinder member 17. The input rod side end portion of the input rod 1 is connected to the tip end portion of the input rod 1 to form a three-part structure.

より具体的には、上記内筒部材16は、上記試験片3の入力棒側つかみ部9aの外径に対応する内径を有し、且つ該入力棒側つかみ部9aと同等か若しくはやや短い軸心方向寸法を有する円筒形状として、その内周面に、試験片3の入力棒側つかみ部9aの雄ねじに螺着させるための雌ねじ19が刻設してある。   More specifically, the inner cylinder member 16 has an inner diameter corresponding to the outer diameter of the input rod side grip portion 9a of the test piece 3 and has a shaft that is equal to or slightly shorter than the input rod side grip portion 9a. As a cylindrical shape having a dimension in the center direction, a female screw 19 for engraving the male screw of the input rod side grip portion 9a of the test piece 3 is engraved on the inner peripheral surface thereof.

上記外筒部材17は、軸心方向中間部の内側に、上記内筒部材16の外径よりもわずかに大きい内径で、上記試験片3の入力棒側つかみ部9aの軸心方向寸法よりもやや長い寸法で軸心方向に延びる内筒収納部20を備え、且つ該内筒収納部20よりも出力棒2寄りに配されることとなる軸心方向一端部の内周面部を、上記試験片3の出力棒側つかみ部9bの外径よりもわずかに大きい内径寸法となるまで縮径させて縮径部21とし、該縮径部21と上記内筒収納部20との間に、上記内筒部材16の軸心方向一端面を当接させて係止させるための段差部22を形成するようにしてある。更に、上記内筒収納部20よりも入力棒1寄りに配されることとなる該外筒部材17の軸心方向他端部の内周面には、ねじ山先端部の内側の径が上記内筒部材16の外径よりも大となる雌ねじ23が刻設してある。   The outer cylinder member 17 has an inner diameter slightly larger than the outer diameter of the inner cylinder member 16 on the inner side in the axial center direction, and is larger than the axial dimension of the input rod side grip portion 9a of the test piece 3. The inner peripheral surface portion at one end in the axial direction that is provided with the inner cylinder storage portion 20 having a slightly longer dimension and extending in the axial direction and that is disposed closer to the output rod 2 than the inner cylinder storage portion 20 is The diameter is reduced to an inner diameter dimension slightly larger than the outer diameter of the output rod side grip portion 9b of the piece 3 to form a reduced diameter portion 21. Between the reduced diameter portion 21 and the inner cylinder storage portion 20, the above-mentioned A stepped portion 22 is formed for contacting and locking one end surface of the inner cylinder member 16 in the axial direction. Further, on the inner peripheral surface of the other axial end portion of the outer cylinder member 17 that is disposed closer to the input rod 1 than the inner cylinder storage portion 20, the inner diameter of the screw thread tip portion is the above-described diameter. A female screw 23 larger than the outer diameter of the inner cylinder member 16 is engraved.

上記連結部材18は、上記外筒部材17寄りとなる軸心方向の一端部に、該外筒部材17の軸心方向他端部内周面の雌ねじ23に螺着させる雄ねじ部24を備え、且つ、軸心方向の他端部に、入力棒1の先端面の中心部に設けたねじ孔26に螺着させるための入力棒連結用雄ねじ部25を備えた構成としてある。これにより、上記内筒部材16を、試験片3の入力棒側つかみ部9aの外周の雄ねじに螺着させた後、該内筒部材16が取り付けてある上記試験片3を、上記外筒部材17の内側に、該外筒部材17の軸心方向他端側から挿入して、該試験片3の出力棒側つかみ部9bを、上記外筒部材17の縮径部21を通して該外筒部材17の軸心方向一端側の外部へ突出させるようにすることで、上記内筒部材16の軸心方向一端面が該外筒部材17の段差部22に当接されるようにする。更に、この状態で上記外筒部材17の軸心方向他端部内周面の雌ねじ17に、上記連結部材18の軸心方向一端部の雄ねじ部24を螺着させることで、上記試験片3への応力波伝達調整治具の取り付けを行い、この際、上記試験片3の入力棒側つかみ部9aの端面と、上記連結部材18の軸心方向一端側の雄ねじ部24の端面との間に、所要の隙間27を形成できるようにしてある。よって、上記試験片3の入力棒側つかみ部9aに取り付けてある内筒部材16の軸心方向一端面が外筒部材17の段差部22に接している初期状態から、上記試験片3の入力棒側つかみ部9aが、応力波伝達調整治具10内で入力棒1側へ移動しようとする相対変位は、該入力棒側つかみ部9aに取り付けてある内筒部材16を外筒部材17の内筒収納部20の内側でスライドさせることで許容できる一方、上記初期状態から、上記試験片3の入力棒側つかみ部9aが、応力波伝達調整治具10内で出力棒2側へ移動しようとする相対変位は、上記内筒部材16の軸心方向一端面と外筒部材17の段差部22が既に接していることで拘束できるようにしてある。   The connecting member 18 includes a male screw portion 24 that is screwed into a female screw 23 on the inner peripheral surface of the other end portion in the axial direction of the outer cylinder member 17 at one end portion in the axial direction near the outer cylinder member 17, and The input rod connecting male screw portion 25 for screwing into the screw hole 26 provided in the center portion of the front end surface of the input rod 1 is provided at the other end portion in the axial direction. As a result, after the inner cylinder member 16 is screwed onto the male screw on the outer periphery of the input rod side grip portion 9a of the test piece 3, the test piece 3 to which the inner cylinder member 16 is attached is attached to the outer cylinder member. The outer cylinder member 17 is inserted from the other axial end side of the outer cylinder member 17, and the output rod side grip portion 9 b of the test piece 3 is inserted into the outer cylinder member 17 through the reduced diameter portion 21 of the outer cylinder member 17. By projecting to the outside at one end side in the axial direction of 17, one end surface in the axial direction of the inner cylinder member 16 is brought into contact with the stepped portion 22 of the outer cylinder member 17. Further, in this state, the male screw portion 24 at one end in the axial direction of the connecting member 18 is screwed to the female screw 17 at the inner peripheral surface of the other end in the axial direction of the outer cylinder member 17, thereby the test piece 3. The stress wave transmission adjusting jig is attached, and at this time, between the end surface of the input rod side grip portion 9a of the test piece 3 and the end surface of the male screw portion 24 on one end side in the axial direction of the connecting member 18. The required gap 27 can be formed. Therefore, from the initial state in which one axial end surface of the inner cylinder member 16 attached to the input rod side grip portion 9a of the test piece 3 is in contact with the stepped portion 22 of the outer cylinder member 17, the input of the test piece 3 is performed. The relative displacement of the rod side grip portion 9a to move to the input rod 1 side within the stress wave transmission adjusting jig 10 causes the inner cylinder member 16 attached to the input rod side grip portion 9a to move to the outer cylinder member 17. On the other hand, the input rod side grip portion 9a of the test piece 3 will move from the initial state to the output rod 2 side in the stress wave transmission adjusting jig 10 while allowing it to slide inside the inner cylinder storage portion 20. The relative displacement is set such that the one end surface in the axial direction of the inner cylinder member 16 and the step portion 22 of the outer cylinder member 17 are already in contact with each other.

上記波形調整治具13は、上記入力棒1及び打撃棒7に比して十分柔らかい材質、たとえば、純アルミニウムにより、図3に示す如く、所要の半径寸法Rで且つ軸心方向に所要の長さ寸法Lを有する円柱形状に形成してある。このように上記波形調整治具13を単純な円柱形状としたのは、塑性歪と体積との積が緩衝に重要であるという本発明者等の考察と、製作が安価となるためであることに加えて、該波形調整治具13を円柱形状とすることで、解析的検討が可能で、理論的取り扱いが容易となるためである。   The waveform adjusting jig 13 is made of a material that is sufficiently softer than the input rod 1 and the striking rod 7, for example, pure aluminum, and has a required radial dimension R and a required length in the axial direction as shown in FIG. It is formed in a cylindrical shape having a thickness L. The reason why the waveform adjusting jig 13 is formed in a simple columnar shape is that the inventors consider that the product of the plastic strain and the volume is important for buffering, and that the manufacturing is inexpensive. In addition to this, by making the waveform adjusting jig 13 into a cylindrical shape, an analytical study is possible, and theoretical handling becomes easy.

このことは、本発明者等が、上記波形調整治具13について、半径寸法R及び長さ寸法Lを種々変更させた場合に得られる入射波(圧縮波)の立ち上がり波形について実施した、図4(イ)に示す如き理論解析結果と、図4(ロ)に示す如き数値シミュレーションの結果(なお、上記いずれの結果も、上記波形調整治具13の半径寸法R[mm]と長さ寸法L[mm]についてはそれぞれ図中に記載してある)との比較からも明らかである。すなわち、図5(ロ)に示した数値シミュレーションの結果にて、半径寸法R及び長さ寸法Lを種々変更させた場合に得られる入射波の立ち上がり波形の勾配の傾向は、図4(イ)に示した理論解析結果における同条件の下で得られる入射波の立ち上がり波形の勾配によく一致していることから、上記数値シミュレーションの有効性が確認できるのである。よって、所要の試験片3の動的引張試験を行う際に打撃棒7の衝突により入力棒1へ入射させるべき圧縮波の強度が定まると、該圧縮波の立ち上がりをどの程度緩和させればよいかが定まるため、その緩和量が得られるように、数値シミュレーションの結果を考慮して上記波形調整治具13の半径寸法Rや長さ寸法L、更には、該波形調整治具13に用いる材料の硬度(加工硬化も考慮した硬度)を適宜選択するようにすればよい。   This was performed by the inventors on the rising waveform of the incident wave (compressed wave) obtained when the radius dimension R and the length dimension L were variously changed in the waveform adjusting jig 13 shown in FIG. The theoretical analysis results as shown in (a) and the results of numerical simulation as shown in FIG. 4 (b) (note that both the above results are the radial dimension R [mm] and the length dimension L of the waveform adjusting jig 13). It is clear from comparison with [mm] that is described in each figure. That is, in the result of the numerical simulation shown in FIG. 5B, the gradient tendency of the rising waveform of the incident wave obtained when the radius dimension R and the length dimension L are variously changed is shown in FIG. Therefore, the effectiveness of the numerical simulation can be confirmed because the slope of the rising waveform of the incident wave obtained under the same conditions in the theoretical analysis result shown in FIG. Therefore, when the strength of the compression wave to be incident on the input rod 1 is determined by the collision of the striking rod 7 when the required dynamic tensile test of the test piece 3 is performed, how much the rising of the compression wave should be relaxed. In order to obtain the amount of relaxation, the radius dimension R and the length dimension L of the waveform adjusting jig 13 as well as the material used for the waveform adjusting jig 13 are taken into consideration in order to obtain the relaxation amount. Hardness (hardness considering work hardening) may be selected as appropriate.

なお、上記波形調整治具13を用いて入力棒1に対して入射する圧縮波の立ち上がりを緩和させる場合の緩和時間としては、該波形調整治具13を用いないで入力棒1の基端面に打撃棒を直接衝突させるときに該入力棒1に入射されることとなる圧縮波の矩形波形の急峻な立ち上がりに比して、100マイクロ秒程度の緩和時間が取れるようにすればよい。このように、立ち上がりの緩和時間を100マイクロ秒程度としたのは、100マイクロ秒程度の緩和時間を取ると、上記波形調整治具13への打撃棒7の衝突によって上記入力棒1へ入射されることとなる圧縮波に対し、1次元波動論による近似が十分妥当となるためである。   The relaxation time when the rising of the compression wave incident on the input bar 1 is relaxed by using the waveform adjusting jig 13 is not applied to the base end surface of the input bar 1 without using the waveform adjusting jig 13. Compared to the steep rise of the rectangular waveform of the compression wave that is incident on the input rod 1 when the striking rod is directly collided, a relaxation time of about 100 microseconds may be taken. As described above, the rise relaxation time is set to about 100 microseconds. When the relaxation time is about 100 microseconds, it is made incident on the input rod 1 by the collision of the striking rod 7 with the waveform adjusting jig 13. This is because the approximation by the one-dimensional wave theory is sufficiently valid for the compression wave to be obtained.

ところで、上記のようにして入力棒1へ入射される圧縮波の立ち上がり時間を緩和させると、この立ち上がり時間を緩和させた分だけ該圧縮波の継続時間が長くなる。このように入力棒1に入射される圧縮波の継続時間が長くなると、入力棒1に入射した圧縮波が、上記入力棒1の基端側から、応力波伝達調整治具10及びカラー12を透過させて上記出力棒2の先端まで伝播される間に、該出力棒2の先端で上記圧縮波が反射されることで生じた後、該出力棒2の先端側から試験片3及び応力波伝達調整治具10を経て上記入力棒1の基端側へ戻る反射引張波が重畳することが避けられなくなり、このために、上記入力棒1と、出力棒2に取り付けられている個々の歪ゲージ14a,14b,15a,15bでは、上記圧縮波と反射引張波が合成された波形が計測されるようになる。   By the way, if the rise time of the compression wave incident on the input rod 1 is relaxed as described above, the duration of the compression wave becomes longer by the amount of the relaxation of the rise time. When the duration time of the compression wave incident on the input rod 1 becomes longer in this way, the compression wave incident on the input rod 1 causes the stress wave transmission adjusting jig 10 and the collar 12 from the base end side of the input rod 1. While being transmitted and propagated to the tip of the output rod 2, the compression wave is reflected at the tip of the output rod 2, and then the test piece 3 and the stress wave from the tip side of the output rod 2. It is unavoidable that the reflected tensile wave returning to the base end side of the input bar 1 through the transmission adjusting jig 10 is unavoidable, and for this reason, the individual strains attached to the input bar 1 and the output bar 2 are inevitable. The gauges 14a, 14b, 15a, and 15b measure a waveform obtained by combining the compression wave and the reflected tension wave.

そのため、本発明では、上記したように、上記入力棒1の基端面に波形調整治具13を設けることにより、打撃棒7の衝突により上記入力棒1に入射させる上記圧縮波の立ち上がりを緩和させて、1次元波動論により近似して取り扱うことに十分な妥当性が生じるようにしてある。このことに鑑みて、本発明では、更に、上記入力棒1と出力棒2に、それぞれ長手方向に所要の間隔を隔て2個ずつの歪ゲージ14a,14bと15a,15bを取り付けてなる構成として、図5(イ)に示す如き上記各歪ゲージ14a,14b,15a,15bでそれぞれ計測される波形と、該入力棒1と出力棒2の2個所ずつに配設してある歪ゲージ14aと14b同士、及び、15aと15b同士の間の距離を上記圧縮波及び反射引張波が進むのに要する時間とから、1次元波動論を用いて連立方程式を構築し、これを解くことで、図5(ロ)に示す如く、上記入力棒1と出力棒2について、たとえば、上記入力棒1における歪ゲージ14bの設置個所での圧縮波と反射引張波の波形、及び、上記出力棒2における歪ゲージ15bの設置個所での圧縮波と反射引張波の波形を、それぞれ分離して求めることができるようにしてある。   Therefore, in the present invention, as described above, the waveform adjusting jig 13 is provided on the base end surface of the input rod 1 to alleviate the rising of the compression wave incident on the input rod 1 due to the collision of the striking rod 7. Therefore, sufficient validity arises in the approximation and handling by one-dimensional wave theory. In view of this, in the present invention, the input rod 1 and the output rod 2 are further provided with two strain gauges 14a, 14b and 15a, 15b, respectively, spaced apart from each other in the longitudinal direction. 5 (a), the waveforms measured by the strain gauges 14a, 14b, 15a and 15b, and the strain gauges 14a disposed at the two positions of the input bar 1 and the output bar 2, respectively. By constructing simultaneous equations using one-dimensional wave theory from the time required for the compression wave and reflected tension wave to travel, the distance between 14b and between 15a and 15b, and solving this, As shown in FIG. 5 (b), for the input rod 1 and the output rod 2, for example, the waveform of the compression wave and the reflected tensile wave at the installation location of the strain gauge 14b in the input rod 1, and the strain in the output rod 2 Installation of gauge 15b Reflection tensile wave waveform and compression waves at the point, are to be able to determine in isolation, respectively.

したがって、その後、従来のホプキンソン棒法と同様に、上記入力棒1と出力棒2中をそれぞれ伝播する応力波の時間履歴を記録し、上記各入力棒1と2の運動解析を行うことにより、上記2本の入力棒1と出力棒2の間で作用する引張力によって高速変形する試験片3の時々刻々の平均応力、歪及び歪速度を求めて、応力−歪関係を、たとえば、図7に示す如き応力−歪曲線図として得ることができるようにしてある。   Therefore, after that, similarly to the conventional Hopkinson bar method, by recording the time history of the stress wave propagating through the input bar 1 and the output bar 2, respectively, and performing the motion analysis of the input bars 1 and 2, The average stress, strain, and strain rate of the test piece 3 that is deformed at high speed by the tensile force acting between the two input rods 1 and the output rod 2 are obtained, and the stress-strain relationship is shown in FIG. It can be obtained as a stress-strain curve diagram as shown in FIG.

なお、図示してはいないが、上記入力棒1及び出力棒2は、摩擦抵抗の少ない支持部材、たとえば、ポリテトラフルオロエチレン樹脂製のリング等を用いた支持部材により、軸心方向への変位のみが許容された状態で支持してあるものとする。   Although not shown, the input rod 1 and the output rod 2 are displaced in the axial direction by a support member having a low frictional resistance, for example, a support member using a polytetrafluoroethylene resin ring or the like. Only in an allowed state.

以上の構成としてある本発明の動的引張試験装置を用いて動的引張試験を行う場合は、先ず、試験片3の入力棒側つかみ部9aに応力波伝達調整治具10を取り付ける。   When performing a dynamic tensile test using the dynamic tensile testing apparatus of the present invention having the above-described configuration, first, the stress wave transmission adjusting jig 10 is attached to the input rod side grip portion 9a of the test piece 3.

次に、上記応力波伝達調整治具10の連結部材18における入力棒連結用雄ねじ部25を、入力棒1の先端面中心部のねじ孔26に取り付けると共に、上記応力波伝達調整治具10より出力棒2側に突出させてある上記試験片3の出力棒側つかみ部9bを、出力棒2の基端面中心部のねじ孔11に取り付け、更に、上記応力波伝達調整治具10の先端面となる外筒部材17の軸心方向一端面と、出力棒2の基端面との間に、1対の半円筒形状のカラー12を介装する。   Next, the input rod connecting male screw portion 25 in the connecting member 18 of the stress wave transmission adjusting jig 10 is attached to the screw hole 26 at the center of the distal end surface of the input rod 1, and from the stress wave transmission adjusting jig 10. The output rod side grip portion 9b of the test piece 3 protruding to the output rod 2 side is attached to the screw hole 11 at the center of the proximal end surface of the output rod 2, and the distal end surface of the stress wave transmission adjusting jig 10 is further attached. A pair of semi-cylindrical collars 12 are interposed between one axial end surface of the outer cylinder member 17 and the proximal end surface of the output rod 2.

又、上記入力棒1と出力棒2の長手方向に所要間隔を隔てた2個所ずつには、歪ゲージ14a,14b,15a,15bをそれぞれ取り付けておく。   Further, strain gauges 14a, 14b, 15a, and 15b are respectively attached to the input bar 1 and the output bar 2 at two positions spaced apart in the longitudinal direction.

更に、上記入力棒1の基端面に、所要の波形調整治具13を取り付ける。この場合、上記波形調整治具13の軸心方向の一端面を、たとえば、グリス等を用いて上記入力棒1の基端面の中心部に貼り付けるようにすればよい。   Further, a required waveform adjusting jig 13 is attached to the base end face of the input rod 1. In this case, one end face in the axial direction of the waveform adjusting jig 13 may be attached to the center of the base end face of the input rod 1 using, for example, grease.

その後、上記のように入力棒1の基端側の外方位置に配置してある打撃棒7を、図示しない所要の加速手段で所要速度に加速して、上記入力棒1の基端部に配設してある波形調整治具13に衝突させるようにする。   After that, the striking rod 7 arranged at the outer position on the base end side of the input rod 1 as described above is accelerated to a required speed by a required acceleration means (not shown), and is applied to the base end portion of the input rod 1. It is made to collide with the waveform adjustment jig | tool 13 currently arrange | positioned.

この打撃棒7の衝突により、上記波形調整治具13は潰れるように大変形され、これにより、上記入力棒1の基端側より、立ち上がりの緩和された圧縮波が入射され、この入射された圧縮波は、該入力棒1中を先端側へ向けて伝播される。上記圧縮波が入力棒1の先端まで達すると、該圧縮波は、入力棒1の先端部より応力波伝達調整治具10の連結部材18と外筒部材17を順に経た後、該外筒部材17の先端面と出力棒の基端面との間に介装してあるカラー12を経て出力棒2の基端部へ伝えられるようになる。この際、上記応力波伝達調整治具10では、上記連結部材18より圧縮波を受ける上記外筒部材17に対し、上記試験片3の入力棒側つかみ部9aに取り付けてある内筒部材16の入力棒1側への相対変位が許容されており、しかも、上記試験片3の入力棒側つかみ部9aの端面と、これに対面する上記連結部材18の雄ねじ部24の端面との間には隙間27が形成してあって両者が互いに接触することはないため、上記外筒部材17に伝えられた圧縮波が上記試験片3へ伝えられることはなく、よって、該試験片3に圧縮力が作用することはない。   Due to the collision of the striking rod 7, the waveform adjusting jig 13 is deformed so as to be crushed, and as a result, a compression wave whose rise is relaxed is incident from the base end side of the input rod 1 and is incident. The compression wave is propagated through the input rod 1 toward the tip side. When the compression wave reaches the tip of the input rod 1, the compression wave passes through the connecting member 18 and the outer tube member 17 of the stress wave transmission adjusting jig 10 from the tip of the input rod 1 in order, and then the outer tube member. It is transmitted to the base end portion of the output rod 2 through the collar 12 interposed between the tip end surface 17 and the base end surface of the output rod. At this time, in the stress wave transmission adjusting jig 10, the inner tube member 16 attached to the input rod side grip portion 9 a of the test piece 3 with respect to the outer tube member 17 receiving the compression wave from the connecting member 18. Relative displacement to the input rod 1 side is allowed, and between the end surface of the input rod side grip portion 9a of the test piece 3 and the end surface of the male thread portion 24 of the connecting member 18 facing the input rod 1 side. Since the gap 27 is formed and the two do not come into contact with each other, the compression wave transmitted to the outer cylindrical member 17 is not transmitted to the test piece 3. Will not work.

その後、上記出力棒2の基端部へ伝えられた圧縮波は、該出力棒2中を先端側へ伝播された後、自由端としてある出力棒2の先端に達した時点で反射されて反射引張波となり、この反射引張波が、該出力棒2中を、先端側から基端側へ伝播される。その後、該反射引張波が出力棒2の基端部に達すると、該反射引張波は、出力棒2の基端部に取り付けられている上記試験片3の出力棒側つかみ部9bへ伝えられ、この際、該試験片3の入力棒側つかみ部9aは、その外周に取り付けられている内筒部材16が、外筒部材17の段差部22に係止されていて出力棒2側への相対変位が拘束されているため、試験片3における上記出力棒側つかみ部9bと入力棒側つかみ部9aとの間に形成されている平行部8に対して、上記反射引張波の作用による引張力が作用されるようになる。   Thereafter, the compression wave transmitted to the base end portion of the output rod 2 is propagated through the output rod 2 to the distal end side, and then reflected and reflected when reaching the distal end of the output rod 2 as a free end. The reflected tension wave is propagated through the output rod 2 from the distal end side to the proximal end side. Thereafter, when the reflected tensile wave reaches the base end of the output bar 2, the reflected tensile wave is transmitted to the output bar side grip 9b of the test piece 3 attached to the base end of the output bar 2. At this time, the input rod side grip portion 9a of the test piece 3 has the inner cylinder member 16 attached to the outer periphery thereof locked to the step portion 22 of the outer cylinder member 17 so that the output rod 2 side is connected. Since the relative displacement is constrained, the tensile force by the action of the reflected tensile wave is applied to the parallel portion 8 formed between the output rod side grip portion 9b and the input rod side grip portion 9a in the test piece 3. Force is applied.

その後、上記反射引張波は、該試験片3から、上記応力波伝達調整治具10の外筒部材17及び連結部材18を介して入力棒1の先端部へ伝えられて、該入力棒1中を基端側へ伝播されるようになる。   Thereafter, the reflected tensile wave is transmitted from the test piece 3 to the tip of the input bar 1 through the outer cylinder member 17 and the connecting member 18 of the stress wave transmission adjusting jig 10, Is propagated to the proximal side.

更に、上記のようにして試験片3の平行部8に引張力を作用させる際に上記入力棒1と出力棒2の2個所ずつに取り付けてある歪ゲージ14a,14bと15a,15bによって計測される波形を基に、1次元波動論を用いた連立方程式を構築した後、これを、各歪ゲージ14aと14b同士、及び、15aと15b同士の間の距離と、上記入力棒1中及び出力棒2中での圧縮波及び反射引張波の進行速度とを用いて解いて上記入力棒1と出力棒2の所要個所に作用している圧縮波と反射引張波の波形を分離して求め、該分離された上記入力棒1と出力棒2中をそれぞれ伝播される圧縮波と反射引張波の時間履歴を記録して、入力棒1と出力棒2の運動解析を行う。このようにして、該入力棒1と出力棒2の間で上記引張力の作用により試験片3が高速変形するときの時々刻々の平均応力、歪及び歪速度等を応力−歪関係として求めて、たとえば、図6に示す如き示す応力−歪曲線図を得るようにすればよい。   Further, when a tensile force is applied to the parallel portion 8 of the test piece 3 as described above, it is measured by the strain gauges 14a, 14b and 15a, 15b attached to the input bar 1 and the output bar 2 respectively. After constructing simultaneous equations using the one-dimensional wave theory based on the waveform, the distance between the strain gauges 14a and 14b and between the strain gauges 14a and 15b, the input rod 1 and the output Solved using the compression wave and the traveling speed of the reflected tension wave in the rod 2 and separately obtained the waveform of the compression wave and the reflected tension wave acting on the required portions of the input rod 1 and the output rod 2, The time history of the compressed wave and the reflected tensile wave propagated through the separated input bar 1 and output bar 2 is recorded, and the motion analysis of the input bar 1 and the output bar 2 is performed. In this manner, the average stress, strain, strain rate, and the like when the test piece 3 is deformed at high speed between the input rod 1 and the output rod 2 by the action of the tensile force are obtained as a stress-strain relationship. For example, a stress-strain curve diagram as shown in FIG. 6 may be obtained.

このように、本発明の動的引張試験方法及び装置によれば、上記応力波伝達調整治具10とカラー12を用いることで、打撃棒7の衝突により入力棒1の基端部より入射させる圧縮波が試験片3へ伝えられる虞を解消できる。このため該試験片3にいかなる歪み速度を与える条件の下においても、純粋な動的引張試験を実施することが可能になる。   As described above, according to the dynamic tensile test method and apparatus of the present invention, the stress wave transmission adjusting jig 10 and the collar 12 are used so that the impact is caused to enter from the base end portion of the input bar 1 by the collision of the hitting bar 7. The possibility that the compression wave is transmitted to the test piece 3 can be eliminated. For this reason, it is possible to carry out a pure dynamic tensile test under the condition of giving any strain rate to the test piece 3.

更に、上記入力棒1の基端面部に波形調整治具13を配設して、該波形調整治具13に打撃棒7を衝突させることによって上記入力棒1へ入射させる圧縮波の立ち上がりを緩和させることができる。これにより、従来のホプキンソン棒法で生じていたような、最終的に得られる応力−歪曲線における変形初期の領域に、大きな振動がのってしまうという問題を回避することができて、荷重振動の少ない滑らかな応力−歪曲線を得ることができる。このことは、後述するように図6の応力−歪曲線と、図7の応力−歪み曲線との比較からも明らかである。   Further, a waveform adjusting jig 13 is disposed on the base end surface portion of the input bar 1, and the rising of the compression wave incident on the input bar 1 is reduced by colliding the hitting bar 7 with the waveform adjusting jig 13. Can be made. This avoids the problem that large vibrations are applied to the initial deformation region in the finally obtained stress-strain curve, which was caused by the conventional Hopkinson bar method. A smooth stress-strain curve with a small amount can be obtained. As will be described later, this is apparent from a comparison between the stress-strain curve of FIG. 6 and the stress-strain curve of FIG.

更に、上記入力棒1に入射される圧縮波の立ち上がりを緩和させることができることから、上記圧縮波、及び、該圧縮波が出力棒の先端で反射されて生じる反射引張波を、いずれも1次元波動論で良好に近似することが可能となる。よって、上記入力棒1及び出力棒2について、それぞれ2個所ずつで歪ゲージ14a,14b及び15a,15bによって計測される圧縮波と反射引張波の合成された波形から、1次元波動論に基いて、上記入力棒1と出力棒2を伝播される圧縮波と反射引張波を、良好に分離することができる。更には、本発明の動的引張試験方法及び装置を用いた動的引張試験を、数値シミュレーションすることが可能になる。   Furthermore, since the rising of the compression wave incident on the input rod 1 can be relaxed, both the compression wave and the reflected tensile wave generated by reflecting the compression wave at the tip of the output rod are one-dimensional. It becomes possible to approximate well by wave theory. Therefore, the input bar 1 and the output bar 2 are based on the one-dimensional wave theory from the combined waveform of the compression wave and the reflected tension wave measured by the strain gauges 14a, 14b and 15a, 15b at two locations respectively. The compression wave and the reflected tensile wave propagated through the input bar 1 and the output bar 2 can be well separated. Furthermore, it is possible to perform a numerical simulation of a dynamic tensile test using the dynamic tensile test method and apparatus of the present invention.

なお、実際の動的引張試験を実施すると、歪速度は一定ではないため、試験結果から直ちに強度の歪速度依存性は決定できない。しかし、実用上は、厳密性は欠いても、簡単な構成則(スケーリング則)が構築できれば便利である。よって、構成則を仮定した数値シミュレーションを、実際の動的引張試験と全く同様にデータ処理して応力−歪関係を求めるよう行い、その数値シミュレーションの結果と、実際の動的引張試験とで、歪みエネルギー密度と平均歪み速度の差を最小化できるようにすれば、構成則のパラメータを求めることが可能になる。   Note that when the actual dynamic tensile test is performed, the strain rate is not constant, so the strain rate dependency of the strength cannot be determined immediately from the test results. However, in practice, it is convenient if a simple constitutive law (scaling law) can be constructed even if strictness is lacking. Therefore, a numerical simulation assuming a constitutive law is performed to determine the stress-strain relationship by processing data in exactly the same way as in an actual dynamic tensile test, and with the result of the numerical simulation and the actual dynamic tensile test, If the difference between the strain energy density and the average strain rate can be minimized, the parameters of the constitutive law can be obtained.

更には、上記波形調整治具13を、円柱形状とすることにより、該円柱形状の半径寸法R、長さ寸法L、及び、該波形調整治具13の硬度と、該波形調整治具13が打撃棒7の衝突位置に存在することで上記入力棒1に入射されるようになる圧縮波が立ち上がるときの緩和量とを、解析的検討することが可能になって、理論的な取り扱いができることから、上記入力棒1に入射させるべき圧縮波の強度と、該圧縮波に所望される立ち上がりの緩和時間を、たとえば、100マイクロ秒とするために必要とされる波形の立ち上がりの緩和量から、上記入力棒1の基端面部に配設すべき上記波形調整治具13の半径寸法R及び長さ寸法Lや、硬度を適宜設定することも可能になる。   Furthermore, by making the waveform adjusting jig 13 into a cylindrical shape, the radial dimension R, the length dimension L of the cylindrical shape, the hardness of the waveform adjusting jig 13, and the waveform adjusting jig 13 The amount of relaxation when the compression wave that enters the input rod 1 rises due to the presence of the hitting rod 7 at the collision position can be analyzed analytically and theoretically handled. From the intensity of the compression wave to be incident on the input bar 1 and the amount of relaxation of the rise of the waveform required to set the rise relaxation time desired for the compression wave to, for example, 100 microseconds, It is also possible to set the radius dimension R and the length dimension L of the waveform adjusting jig 13 to be disposed on the base end face portion of the input rod 1 and the hardness as appropriate.

なお、本発明は、上記実施の形態にのみ限定されるものではなく、図1(イ)(ロ)乃至図3に示した入力棒1及び出力棒2、打撃棒7、試験片3、応力波伝達調整治具10、波形調整治具13のそれぞれの寸法は、図示するための便宜上の寸法であって、これらの部材の実際の寸法を反映するものではない。更に各部材同士の寸法の比は適宜変更してもよい。   In addition, this invention is not limited only to the said embodiment, The input rod 1, the output rod 2, the striking rod 7, the test piece 3, and stress shown in FIG. 1 (A) (B) thru | or FIG. The dimensions of the wave transmission adjusting jig 10 and the waveform adjusting jig 13 are dimensions for convenience of illustration, and do not reflect actual dimensions of these members. Furthermore, you may change suitably the ratio of the dimension of each member.

応力波伝達調整治具10は、その外径が入力棒1や出力棒2と異なる径であってもよい。既存の入力棒を利用できるようにするという観点、及び、衝撃を受ける部分を容易に交換可能にするという観点からは、応力波伝達調整治具10に連結部材18を備えて、外筒部材17を、上記連結部材18を介して入力棒1の先端面中心部に設けてあるねじ孔26に取り付ける構成とすることが望ましいが、上記連結部材18は省略してもよい。この場合は、上記入力棒1の先端部に、上記応力波伝達調整治具10の外筒部材17の入力棒側端部の内側に形成してある雌ねじ23に螺着可能な雄ねじ部を設けて、該入力棒1の先端部を、上記外筒部材17に直接連結するようにすればよい。   The stress wave transmission adjusting jig 10 may have an outer diameter different from that of the input bar 1 and the output bar 2. From the viewpoint of making it possible to use an existing input rod and making it possible to easily replace a portion that receives an impact, the stress wave transmission adjusting jig 10 is provided with a connecting member 18 and an outer cylinder member 17. Is preferably attached to the screw hole 26 provided at the center of the distal end surface of the input rod 1 via the connecting member 18, but the connecting member 18 may be omitted. In this case, a male screw portion that can be screwed to a female screw 23 formed on the inner side of the input rod side end portion of the outer tube member 17 of the stress wave transmission adjusting jig 10 is provided at the tip portion of the input rod 1. Thus, the distal end portion of the input rod 1 may be directly connected to the outer cylinder member 17.

その他本発明の要旨を逸脱しない範囲内で種々変更を加え得ることは勿論である。   Of course, various modifications can be made without departing from the scope of the present invention.

以下、本発明者等が実施した本発明の動的引張試験方法及び装置の有効性を検証した結果について示す。   Hereinafter, the results of verifying the effectiveness of the dynamic tensile test method and apparatus of the present invention conducted by the present inventors will be described.

(1)
図3に示した如き円柱形状の波形調整治具13の半径寸法Rと長さ寸法Lをそれぞれ変化させた場合に、該波形調整治具13の存在下で入力棒1に入射されることとなる応力波(圧縮波)の波形の立ち上がりの緩和量の変化について、理論解析と数値シミュレーションをそれぞれ行った。理論解析結果を図4(イ)に、又、数値シミュレーションの結果を図4(ロ)にそれぞれ示す。なお、上記波形調整治具13の半径寸法R[mm]と長さ寸法L[mm]の設定値は、それぞれ図中に記載してある。
(1)
When the radial dimension R and the length dimension L of the cylindrical waveform adjusting jig 13 as shown in FIG. 3 are changed, they are incident on the input rod 1 in the presence of the waveform adjusting jig 13. Theoretical analysis and numerical simulation were performed on the change in the amount of relaxation at the rise of the stress wave (compression wave). The theoretical analysis results are shown in FIG. 4 (a) and the numerical simulation results are shown in FIG. 4 (b). The set values of the radius dimension R [mm] and the length dimension L [mm] of the waveform adjusting jig 13 are shown in the drawing.

図4(イ)(ロ)のいずれの結果からも、波形調整治具13を用いることで、入力棒1に入射される応力波(圧縮波)の波形の立ち上がりを緩和できることが分かる。   4A and 4B, it can be seen that the rise of the waveform of the stress wave (compression wave) incident on the input rod 1 can be alleviated by using the waveform adjusting jig 13.

更に、図4(イ)の理論解析結果と、図4(ロ)の数値シミュレーションの結果の比較から、波形調整治具13の半径寸法Rと長さ寸法Lをそれぞれ変化させたいずれの場合においても、数値シミュレーション結果として得られる波形の全体的な勾配が、理論解析結果の勾配とよく一致していることが分かる。よって、このことから、上記波形調整治具13を円柱形状とすることで、解析的検討が可能で、理論的取り扱いが容易となることが判明した。   Furthermore, from the comparison of the theoretical analysis result of FIG. 4 (a) and the numerical simulation result of FIG. 4 (b), in each case where the radius dimension R and the length dimension L of the waveform adjusting jig 13 are changed, respectively. It can also be seen that the overall slope of the waveform obtained as a result of the numerical simulation is in good agreement with the slope of the theoretical analysis result. Therefore, it has been found that by making the waveform adjusting jig 13 a cylindrical shape, an analytical study is possible and the theoretical handling becomes easy.

(2)
図1(イ)(ロ)乃至図3に示した本発明の動的引張試験装置を用いて、SUS304材による試験片3を対象とする動的引張試験を行った。
(2)
Using the dynamic tensile testing apparatus of the present invention shown in FIGS. 1 (a) to 1 (b) to FIG. 3, a dynamic tensile test was performed on the test piece 3 made of SUS304 material.

入力棒1に取り付けた2つの歪ゲージ14a,14bと、出力棒2に取り付けた2つの歪ゲージ15a,15bでそれぞれ計測された波形を、図5(イ)に示す。線28、線29、線30、線31は、それぞれ歪ゲージ14a,14b,15a,15bで計測された波形である。   The waveforms measured by the two strain gauges 14a and 14b attached to the input bar 1 and the two strain gauges 15a and 15b attached to the output bar 2 are shown in FIG. Lines 28, 29, 30 and 31 are waveforms measured by the strain gauges 14a, 14b, 15a and 15b, respectively.

上記のように入力棒1に取り付けられた2つの歪ゲージ14a,14bで得られた波形、及び、出力棒2に取り付けられた2つの歪ゲージ15a,15bで得られた波形を基に、1次元波動論を用いて入力棒1へ入射された圧縮波、及び、該圧縮波が出力棒2の先端で反射されて生じる反射引張波についての連立方程式を構築し、これを、各歪ゲージ14a,14b同士の間の距離データ及び各歪ゲージ15a,15bの間の距離データと、上記圧縮波及び反射引張波が入力棒1中及び出力棒2中を進行する速度に関するデータとを用いて解くことで、上記入力棒1における歪ゲージ14bの取付位置での圧縮波(入射波)と反射引張波の波形を分離すると共に、同様に、出力棒2における歪ゲージ15bの取付位置での圧縮波と反射引張波の波形を分離した。その結果を図5(ロ)に示す。図5(ロ)における線32と線33は、入力棒1の歪ゲージ14bの取付位置での圧縮波(入射波)と反射引張波の分離した波形をそれぞれ示す。又、線34と線35は、出力棒2の歪ゲージ15bの取付位置での圧縮波(入射波)と反射引張波を分離した波形をそれぞれ示す。   Based on the waveform obtained by the two strain gauges 14a and 14b attached to the input rod 1 as described above and the waveform obtained by the two strain gauges 15a and 15b attached to the output rod 2, 1 Using the dimensional wave theory, a simultaneous equation is constructed for the compression wave incident on the input rod 1 and the reflected tensile wave that is generated when the compression wave is reflected at the tip of the output rod 2, and this is expressed by each strain gauge 14a. , 14b, distance data between the strain gauges 15a, 15b, and data on the speed at which the compression wave and reflected tensile wave travel in the input bar 1 and the output bar 2 are solved. Thus, the compression wave (incident wave) and the reflected tensile wave at the position where the strain gauge 14b is attached to the input bar 1 are separated, and similarly, the compression wave at the position where the strain gauge 15b is attached to the output bar 2 And reflected tension wave To separate the waveform. The result is shown in FIG. A line 32 and a line 33 in FIG. 5B respectively show the separated waveforms of the compression wave (incident wave) and the reflected tension wave at the position where the strain gauge 14b of the input bar 1 is attached. Lines 34 and 35 respectively indicate waveforms obtained by separating the compression wave (incident wave) and the reflected tensile wave at the position where the strain gauge 15b of the output rod 2 is attached.

図5(ロ)の結果から、上記入力棒1及び出力棒2を伝播される圧縮波と反射引張波の波形は、いずれも立ち上がりが十分に緩和されていることが分かる。又、図5(イ)に示した各歪ゲージ14a,14b,15a,15bによる計測波形では、上記入力棒1及び出力棒2を伝わる圧縮波と反射引張波を分離して判別することはできないが、該計測波形を基に、上記したような1次元波動論に基く分離操作を行うことで、図5(ロ)に示す如く、圧縮波と反射引張波とを良好に分離可能であることが明らかとなった。   From the result of FIG. 5 (b), it can be seen that the rising of the compression wave and the reflected tensile wave propagated through the input bar 1 and output bar 2 is sufficiently relaxed. Further, in the measurement waveforms by the strain gauges 14a, 14b, 15a, and 15b shown in FIG. 5 (a), the compression wave and the reflected tensile wave transmitted through the input bar 1 and the output bar 2 cannot be separately determined. However, by performing the separation operation based on the one-dimensional wave theory as described above on the basis of the measured waveform, the compression wave and the reflected tension wave can be satisfactorily separated as shown in FIG. Became clear.

上記図5(ロ)に示したようにそれぞれ分離される入力棒1中を伝播される圧縮波(線32)と反射引張波(線33)、及び、出力棒2中を伝播される圧縮波(線34)と反射引張波(線35)の時間履歴を記録して、各入力棒1と出力棒2の運動解析を行い、その運動解析結果を基に、上記入力棒1と出力棒2との間に連結されている試験片3が、作用する引張力によって高速変形するときの入力棒側応力、出力棒側応力、平均応力、歪速度及び歪速度の平均値を求めた。その結果を図6の応力−歪曲線図として示す。線36は入力棒側応力、線37は出力棒側応力、線38は平均応力、線39は歪速度、線40は歪速度の平均値をそれぞれ示す。比較として、図7に、上記と同様の条件の下で、波形調整治具13を用いずに動的引張試験を行った場合に得られる応力−歪曲線図を示す。各線の符号は、図6に示したものと同様としてある。   As shown in FIG. 5 (b), the compression wave (line 32) and reflected tensile wave (line 33) propagated through the input rod 1 and the compression wave propagated through the output rod 2 are separated. (Line 34) and reflected tensile wave (line 35) are recorded in time history, the motion analysis of each input bar 1 and output bar 2 is performed, and based on the motion analysis result, the input bar 1 and output bar 2 The average value of the input bar side stress, the output bar side stress, the average stress, the strain rate, and the strain rate when the test piece 3 connected between the test piece 3 is deformed at high speed by the acting tensile force was obtained. The result is shown as a stress-strain curve diagram of FIG. A line 36 indicates an input bar side stress, a line 37 indicates an output bar side stress, a line 38 indicates an average stress, a line 39 indicates a strain rate, and a line 40 indicates an average value of the strain rate. As a comparison, FIG. 7 shows a stress-strain curve diagram obtained when a dynamic tensile test is performed without using the waveform adjusting jig 13 under the same conditions as described above. The reference numerals of the respective lines are the same as those shown in FIG.

図6と図7を比較すると、図7に示した応力−歪曲線図では、変形初期の領域に大きな荷重振動が生じているが、図6の応力−歪曲線図では、変形初期の領域においても大きな荷重振動が生じずに、滑らかな応力−歪曲線が得られることが分かる。したがって、上記波形調整治具13を用いることの有効性が確認された。   6 and 7, in the stress-strain curve diagram shown in FIG. 7, a large load vibration is generated in the initial deformation region. In the stress-strain curve diagram of FIG. It can be seen that a smooth stress-strain curve can be obtained without causing large load vibration. Therefore, the effectiveness of using the waveform adjusting jig 13 was confirmed.

本発明の動的引張試験方法及び装置の実施の一形態を示すもので、(イ)は装置全体を示す概要図、(ロ)は試験片の取付部分を拡大して示す切断側面図である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of a dynamic tensile test method and apparatus according to the present invention, where FIG. . (イ)は、図1(ロ)の試験片の取付部分を分解した状態を示す図、(ロ)は、カラーを軸心方向から見た図である。(A) is a figure which shows the state which decomposed | disassembled the attachment part of the test piece of FIG. 1 (b), (b) is the figure which looked at the collar from the axial center direction. 図1の装置における波形調整治具を拡大して示す斜視図である。It is a perspective view which expands and shows the waveform adjustment jig in the apparatus of FIG. 波形調整治具の半径寸法と長さ寸法をそれぞれ変化させた場合に得られる、入力棒に入射される圧縮波の波形の立ち上がりの変化について示すもので、(イ)は理論解析による結果を、(ロ)は数値シミュレーションの結果をそれぞれ示すものである。This shows the change in the rise of the waveform of the compression wave incident on the input bar, obtained when the radius dimension and length dimension of the waveform adjustment jig are changed. (A) shows the result of theoretical analysis. (B) shows the result of the numerical simulation. 本発明者等が図1の装置を用いて実施した動的引張試験により得られた結果を示すもので、(イ)は入力棒と出力棒にそれぞれ取り付けてある各歪ゲージによる計測波形を、(ロ)は(イ)の計測波形を分離操作して得られた入力棒と出力棒を伝播される圧縮波と反射引張波の波形を示す図である。1 shows the results obtained by the dynamic tensile test conducted by the inventors using the apparatus of FIG. 1, wherein (a) shows the measurement waveforms by the strain gauges attached to the input bar and the output bar, (B) is a figure which shows the waveform of the compression wave and reflection tension wave which are propagated through the input bar and the output bar obtained by separating the measurement waveform of (A). 本発明者等が図1の装置を用いて実施した動的引張試験により試験片が高速変形するときの応力と歪の関係を示す図である。It is a figure which shows the relationship between the stress and distortion when a test piece deform | transforms at high speed by the dynamic tensile test implemented by the present inventors using the apparatus of FIG. 本発明者等が図1の装置構成から波形調整治具を除いた装置構成を用いて実施した動的引張試験により試験片が高速変形するときの応力と歪の関係を示す図である。It is a figure which shows the relationship between the stress and distortion when a test piece deform | transforms at high speed by the dynamic tensile test implemented by the present inventors using the apparatus structure except the waveform adjustment jig from the apparatus structure of FIG. 従来のカラーを用いる方式のホプキンソン棒法による動的引張試験を行うための装置を示す概要図である。It is the schematic which shows the apparatus for performing the dynamic tensile test by the Hopkinson stick | rod method of the system using the conventional color | collar. 従来のヨークを用いる方式のホプキンソン棒法による動的引張試験を行うための装置を示す概要図である。It is the schematic which shows the apparatus for performing the dynamic tensile test by the Hopkinson stick | rod method of the system using the conventional yoke.

符号の説明Explanation of symbols

1 入力棒
2 出力棒
3 試験片
7 打撃棒
10 応力波伝達調整治具
12 カラー
13 波形調整治具
14a,14b 歪ゲージ
15a,15b 歪ゲージ
16 内筒部材
17 外筒部材
DESCRIPTION OF SYMBOLS 1 Input rod 2 Output rod 3 Test piece 7 Impact rod 10 Stress wave transmission adjustment jig 12 Collar 13 Waveform adjustment jig 14a, 14b Strain gauge 15a, 15b Strain gauge 16 Inner cylinder member 17 Outer cylinder member

Claims (6)

入力棒の先端側に出力棒を直列に配置し、該入力棒の先端部と出力棒の基端部との間に試験片を配置して、上記入力棒の基端側より打撃棒の衝突による圧縮波を入射させて、該圧縮波を、該入力棒中を基端側より先端側へ伝播させた後、該入力棒の先端部より試験片に作用させることなく出力棒へ伝えるようにし、次いで、該出力棒の基端部に伝えられた圧縮波を、出力棒中を先端まで伝播させて反射させることで反射引張波を生じさせた後、該引張波を、出力棒の先端側から基端部まで伝播させてから上記試験片の出力棒側端部に伝えて、該試験片の出力棒側端部と、試験片の入力棒側端部との間に引張力を作用させて、該試験片の引張試験を行うようにする動的引張試験方法。   An output rod is arranged in series on the distal end side of the input rod, a test piece is arranged between the distal end portion of the input rod and the proximal end portion of the output rod, and the impact rod strikes from the proximal end side of the input rod. The compression wave is caused to enter, and after the propagating wave is propagated in the input rod from the proximal end side to the distal end side, it is transmitted from the distal end portion of the input rod to the output rod without acting on the test piece. Then, after the compression wave transmitted to the base end portion of the output rod is propagated through the output rod and reflected to generate a reflected tensile wave, the tensile wave is moved to the distal end side of the output rod. Is propagated from the base end to the output bar side end of the test piece, and a tensile force is applied between the output bar side end of the test piece and the input bar side end of the test piece. A dynamic tensile test method for performing a tensile test on the test piece. 入力棒の基端部より立ち上がりの緩和された圧縮波を入射させるようにし、更に、上記入力棒及び出力棒中を伝播される圧縮波及び反射引張波を、上記入力棒及び出力棒の各長手方向の複数個所に所要間隔を隔てて取り付ける歪ゲージで計測させるようにする請求項1記載の動的引張試験方法。   A compression wave whose rise is relaxed from the base end portion of the input bar is made incident, and further, the compression wave and the reflected tensile wave propagated through the input bar and the output bar are applied to each longitudinal direction of the input bar and the output bar. The dynamic tensile test method according to claim 1, wherein measurement is performed by strain gauges attached at a plurality of positions in the direction with a predetermined interval. 入力棒の先端側に出力棒を直列に配置すると共に、上記入力棒の基端側の外部位置に、上記入力棒の基端部に衝突させることで負荷を与えるための打撃棒を備え、且つ上記入力棒の先端部と出力棒の基端部との間に試験片を配置して、該試験片の出力棒側端部を、上記出力棒の基端部に取り付けると共に、試験片の入力棒側端部を、該試験片の入力棒側端部の入力棒側への相対変位は許容でき且つ出力棒側への相対変位は拘束できるようにしてある応力波伝達調整治具を介して上記入力棒の先端部に取り付け、更に、上記応力波伝達調整治具の出力棒に臨む先端面と、上記出力棒の基端面との間にカラーを介装してなる構成を有することを特徴とする動的引張試験装置。   An output rod is arranged in series on the distal end side of the input rod, and provided with a striking rod for applying a load by colliding with the proximal end portion of the input rod at an external position on the proximal end side of the input rod, and A test piece is arranged between the tip of the input bar and the base end of the output bar, and the output bar side end of the test piece is attached to the base end of the output bar, and the test piece is input. Through a stress wave transmission adjusting jig that allows the relative displacement of the end of the rod side to the input rod side of the input rod side of the test piece and allows the relative displacement to the output rod side to be restrained. It is attached to the distal end portion of the input rod, and further has a configuration in which a collar is interposed between the distal end surface facing the output rod of the stress wave transmission adjusting jig and the proximal end surface of the output rod. Dynamic tensile testing equipment. 応力波伝達調整治具を、試験片の入力棒側端部の外周に取り付ける内筒部材と、該内筒部材の外周に配置して上記内筒部材の入力棒側へのみ相対変位を許容できる外筒部材とを備えてなる構成とした請求項3記載の動的引張試験装置。   An inner cylinder member that attaches a stress wave transmission adjusting jig to the outer periphery of the input rod side end of the test piece, and is disposed on the outer periphery of the inner cylinder member so that relative displacement can be allowed only to the input rod side of the inner cylinder member. The dynamic tensile testing apparatus according to claim 3, wherein the dynamic tensile testing apparatus is configured to include an outer cylinder member. 入力棒の基端部における打撃棒の衝突個所に、打撃棒の衝突により潰れて変形できるようにしてある波形調整部材を配設する共に、上記入力棒及び出力棒の各長手方向の複数個所に所要間隔を隔てて歪ゲージを取り付けるようにした請求項4記載の動的引張試験装置。   A corrugated adjustment member arranged so as to be able to be crushed and deformed by the collision of the striking bar is disposed at the impact point of the striking bar at the base end portion of the input bar, and at the plurality of positions in the longitudinal direction of the input bar and the output bar. 5. The dynamic tensile testing apparatus according to claim 4, wherein strain gauges are attached at a required interval. 入力棒の基端部における打撃棒の衝突個所に配設する波形調整部材を、円柱形状とした請求項5記載の動的引張試験装置。   6. The dynamic tensile testing apparatus according to claim 5, wherein the corrugated adjusting member disposed at the impact portion of the striking rod at the base end portion of the input rod has a cylindrical shape.
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CN111579409A (en) * 2020-04-28 2020-08-25 杭州电子科技大学 Device and method for testing dynamic rheological mechanical properties of fresh metal surface layer
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KR101727405B1 (en) 2015-10-28 2017-05-02 전북대학교산학협력단 Modification of Hoek triaxial cell for SHPB tests and its application to dynamic shear strength measurement of brittle materials
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CN111855419A (en) * 2020-06-28 2020-10-30 东南大学 Laboratory experiment system and method for dynamic stability of surrounding rock of cavern under action of stress wave
CN112014247A (en) * 2020-08-12 2020-12-01 中国人民解放军空军工程大学 Universal test piece supporting and positioning device of Hopkinson pressure bar and using method
CN115493950A (en) * 2022-10-27 2022-12-20 西南石油大学 Rock dynamic mechanical property testing device

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