JP2005337784A

JP2005337784A - Breakage determination method in impact simulation

Info

Publication number: JP2005337784A
Application number: JP2004154365A
Authority: JP
Inventors: Hideyuki Inaba; 英之稲葉
Original assignee: Asahi Kasei Chemicals Corp
Current assignee: Asahi Kasei Chemicals Corp
Priority date: 2004-05-25
Filing date: 2004-05-25
Publication date: 2005-12-08

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method capable of calculating the value of a strain by which a resin material required for executing impact simulation of a resin product is broken without performing a tensile test in accordance with a strain speed of an actual product, and calculating prediction of an experimental condition reaching breakage only by the impact simulation in the small, two or three, number of times. <P>SOLUTION: This method is characterized as follows: a relation equation 1 between the strain speed and the breakage strain is determined from a tensile test result acquired by changing several kinds of tensile speeds; an optional strain speed is substituted for the equation 1 to predict the breakage strain; a relation equation 2 is determined, between the breakage strain acquired by substituting a strain speed at the maximum strain spot acquired from impact simulation results of the product acquired by changing the several kinds of experimental conditions and the experimental condition at that time; a relation equation 3 between the maximum strain acquired from the impact simulation result and the experimental condition is determined; and it is determined that a crossing point between the equation 2 and the equation 3 shows a breakage generation condition and the breakage strain. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は産業上広く応用範囲のあるＣＡＥによる衝撃シミュレーションに関するものである。 The present invention relates to impact simulation by CAE which has a wide range of applications in industry.

樹脂は粘弾性体であり、早く変形すればするほど硬くなるという性質を持つ。樹脂はこの性質を持っているために、シミュレーションの際に、変形の際の歪み速度がわからないと正確な破壊歪みが予想できない。特許文献１，２によると、破壊する落下高さ等の実験条件を正確に予測するには、実験条件を与えて計算し、その時の最大歪みが発生する個所の歪み速度で、材料の破壊歪みを測定し、そのデータより破壊の有無を判断し、破壊しない様なら実験条件を変えて、一連の解析、実験をやり直し、また実験条件を変更するといったことを何回も何十回もしなくてはならない。このような従来の方法では予測に膨大な時間と手間がかかるため、事実上実施不可能に近い。
特開平０２−２２８５６６号公報特開平０２−２９６１６４号公報 Resin is a viscoelastic body and has the property of becoming harder as it deforms faster. Since the resin has this property, an accurate fracture strain cannot be predicted unless the strain rate at the time of deformation is known during simulation. According to Patent Documents 1 and 2, in order to accurately predict the experimental conditions such as the drop height to be destroyed, the experimental conditions are given and calculated, and the fracture strain of the material is calculated at the strain rate where the maximum strain occurs at that time. If you do not destroy it, change the experimental conditions, repeat the series of analyzes and experiments, and change the experimental conditions several times and dozens of times. Must not. In such a conventional method, since it takes a lot of time and labor to make a prediction, it is practically impossible to implement.
Japanese Patent Laid-Open No. 02-228666 Japanese Patent Laid-Open No. 02-296164

本発明の第一の目的は、樹脂製品の衝撃シミュレーションを実施するに際し必要とされる樹脂材料が破壊する歪みの値を、実際の製品の歪み速度に合わせた引張試験を行わなくても算出できることであり、更に第二の目的は、２回から３回の少ない衝撃シミュレーションをするだけで、破壊に至る実験条件の予想を容易に算出できることである。 The first object of the present invention is to be able to calculate the value of the strain that the resin material that is required when performing the impact simulation of the resin product, without performing a tensile test in accordance with the strain rate of the actual product. In addition, the second object is to easily calculate the prediction of the experimental conditions leading to the fracture with only a few impact simulations two to three times.

上記目的を達成すべく成された本発明の衝撃シミュレーション方法は、その一実施形態を示す図１〜図３を用いて説明すると、数種類の引張速度を変えた引張試験結果のうち、歪み速度をｘ軸、破壊歪みをｙ軸にプロットして、その関係方程式（１）を求め、その方程式（１）に任意の歪み速度を代入することによって、破壊歪みを予測し、また数種類の実験条件を変えた製品の衝撃シミュレーション結果より得た最大歪み個所の歪み速度を方程式（１）に代入して得られる破壊歪みをｙ軸、その時の実験条件をｘ軸にプロットして、その関係方程式（２）を求め、また衝撃シミュレーション結果より得た最大歪みをｙ軸、実験条件をｘ軸にプロットして関係方程式（３）を求め、方程式（２）と方程式（３）の交差する点が破壊が発生する実験条件と破壊歪みであると判断することを特徴とするものである。
本発明者は、樹脂製品の衝撃シミュレーションについて鋭意検討を重ねた結果、実験条件と破壊歪みに関係方程式を当てはめることができることを見い出し、本発明に至ったものである。 The impact simulation method of the present invention, which has been achieved to achieve the above object, will be described with reference to FIGS. 1 to 3 showing an embodiment thereof. By plotting the x-axis and fracture strain on the y-axis, obtaining the relational equation (1), substituting an arbitrary strain rate into the equation (1), the fracture strain is predicted, and several experimental conditions are set. The fracture strain obtained by substituting the strain rate of the maximum strain location obtained from the impact simulation result of the changed product into the equation (1) is plotted on the y-axis and the experimental conditions at that time are plotted on the x-axis. ), And the maximum strain obtained from the impact simulation result is plotted on the y-axis and the experimental condition is plotted on the x-axis to obtain the relational equation (3), and the point where equation (2) and equation (3) intersect is broken Occur It is characterized in that it is determined that the test conditions to be destructive distortion.
As a result of intensive studies on the impact simulation of resin products, the present inventor has found that a relational equation can be applied to the experimental conditions and the fracture strain, leading to the present invention.

樹脂の歪み速度に対する特性と、実験条件に依存する衝撃シミュレーション結果を方程式化することを工夫したため、今までほとんど不可能だった精度の高い破壊が発生する実験条件の予測を容易に出来る。 Since we devised equations for impact characteristics that depend on the strain rate of the resin and the experimental conditions, we can easily predict the experimental conditions that cause high-precision fracture that was almost impossible until now.

以下、本発明の一実施形態を示す図１〜図３を参照して本発明を詳細に説明する。なお、図１は歪み速度と破壊歪みとの関係を表す方程式の求め方の図、図２は実験条件と破壊歪みとの関係を表す方程式の求め方の図、図３は実験条件と発生する最大歪みとの関係を表す方程式の求め方の図である。
本発明は自動車部品、家電製品、ＯＡ製品、工業製品等、ＣＡＥによる衝撃シミュレーションを行うすべての製品に有効である。
図１〜図３で示した関係方程式は一例のため１次方程式であるが、データによって２次方程式、指数方程式等如何なる方程式を用いることが出来る。方程式の精度を高めるため、可能な限り、データ点数は多い方がよい。またｘ軸に使用するデータ（歪み速度と実験条件）はそれぞれの値が近すぎない方がよい。また図１〜図３のように方程式を求めるためにグラフを使用したが、方程式が別な方法で求めることができるならば、グラフを書くこと自体は特に本発明を限定しない。 Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 3 showing an embodiment of the present invention. 1 is a diagram of how to obtain an equation representing the relationship between strain rate and fracture strain, FIG. 2 is a diagram of how to obtain an equation representing the relationship between experimental conditions and fracture strain, and FIG. It is a figure of how to obtain | require the equation showing the relationship with maximum distortion.
The present invention is effective for all products that perform impact simulation by CAE, such as automobile parts, home appliances, OA products, and industrial products.
The relational equations shown in FIGS. 1 to 3 are linear equations as an example, but any equation such as a quadratic equation or an exponential equation can be used depending on the data. To increase the accuracy of the equation, it is better to have as many data points as possible. In addition, it is better that the data used for the x-axis (strain rate and experimental conditions) are not too close to each other. In addition, although the graph is used to obtain the equations as shown in FIGS. 1 to 3, if the equations can be obtained by another method, writing the graph itself does not limit the present invention.

本発明でいう実験条件とは、製品の使用目的によって、衝突速度、落下高さ、衝突エネルギー等のことであるが、数値化できるものであれば如何なる条件も使用することが出来る。ただし方程式（２）を求める実験条件と方程式（３）を求める実験条件は同じものにする必要がある。方程式（２）及び（３）を求めるのに、実験条件は２水準以上変える必要があるが、好ましくは３水準以上変えて行うことが好ましい。
衝撃シミュレーションを行う樹脂としてはポリエチレン、ポリプロピレン、ポリスチレン、ＡＢＳ、ポリ塩化ビニル、ポリアミド、ポリアセタール、ポリカーボネート、変性ポリフェニレンエーテル、ポリエチレンテレフタレート、ポリブチレンテレフタレート、ポリフェニレンスルフィド、ポリイミド、ポリアミドイミド、ポリアリレート、ポリサルフォン、ポリエーテルサルフォン、ポリエーテルエーテルケトン、液晶ポリマー、ポリテトラフルオロエチレン、熱可塑性エラストマー等の様々な樹脂又はこれらの樹脂混合物が挙げられ、更には、これらの樹脂又は樹脂混合物に充填材、難燃剤、安定剤等の添加剤を添加した樹脂組成物に用いることができる。
衝撃シミュレーションを行うソフトウエアはＬＳ−ＤＹＮＡ、ＲＡＤＩＯＳＳ、ＭＡＳＹＭＯ、ＭＳＣ．ｄｙｔｏｒａｎ、ＰＡＭ−ＣＬＡＳＨ等が挙げられるが本発明の目的に適うものであれば如何なるソフトウエアも用いることができる。 The experimental conditions referred to in the present invention are the collision speed, the drop height, the collision energy, etc. depending on the purpose of use of the product, but any conditions can be used as long as they can be quantified. However, the experimental condition for obtaining equation (2) and the experimental condition for obtaining equation (3) must be the same. In order to obtain the equations (2) and (3), it is necessary to change the experimental conditions by two or more levels, but it is preferable to change the experiment conditions by three or more levels.
The resin for impact simulation is polyethylene, polypropylene, polystyrene, ABS, polyvinyl chloride, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyimide, polyamideimide, polyarylate, polysulfone, poly Various resins such as ether sulfone, polyether ether ketone, liquid crystal polymer, polytetrafluoroethylene, thermoplastic elastomer and the like, and a mixture of these resins, and further, a filler, a flame retardant, It can be used for a resin composition to which an additive such as a stabilizer is added.
Software for performing impact simulation is LS-DYNA, RADIUS, MASYMO, MSC. dytoran, PAM-CLASH, etc., but any software can be used as long as it meets the object of the present invention.

以下に実施例を挙げて本発明を更に詳細に説明するが、これは本発明を限定するものではない。
（実施例１）
図４に本実施例を示す。製品形状は箱型で、幅５０ｍｍ、高さ１００ｍｍ、奥行き３５ｍｍ、肉厚はすべて５ｍｍである。図４の矢印方向に製品を剛体床面に落とした際の破壊発生実験条件を求める。使用樹脂はガラス繊維を１０重量％添加して強化した変性ポリフェニレンエーテルを用いる。使用ソフトウエアはＬＳ−ＤＹＮＡ（ＬｉｖｅｒｍｏｒｅＳｏｆｔｗａｒｅＴｅｃｈｎｏｌｏｇｙ社製）である。実験条件は床面に当たる直前の落下速度である。
使用樹脂の歪み速度と破壊歪みの関係は図５のようになり、関係方程式（１）はｙ＝−０．０００１２９ｘ＋０．０３１３となる。
製品を１０００ｍｍ／ｓ、２０００ｍｍ／ｓ、４０００ｍｍ／ｓの落下速度で剛体に衝突した際のシミュレーションを行う。それぞれの実験条件での最大歪みが発生する個所の歪み速度を方程式（１）に代入し、落下速度と破壊歪みの関係方程式（２）は図６に示すようにｙ＝−０．００００１７２ｘ＋０．０３１９となる。また落下速度とシミュレーションで求めた最大歪みとの関係方程式（３）は図７に示すようにｙ＝０．００００００９３９ｘ−０．０００１８０となる。方程式（２）と方程式（３）の連立方程式を解くことにより、破壊が発生する落下速度は１７６０ｍｍ／ｓであることがわかる。 The present invention will be described in more detail with reference to the following examples, but it is not intended to limit the present invention.
(Example 1)
FIG. 4 shows this embodiment. The product shape is box-shaped, width 50 mm, height 100 mm, depth 35 mm, and wall thickness are all 5 mm. The experimental conditions for fracture occurrence when the product is dropped on the rigid floor surface in the direction of the arrow in FIG. The resin used is a modified polyphenylene ether reinforced by adding 10% by weight of glass fiber. The software used is LS-DYNA (manufactured by Livermore Technology). The experimental condition is the drop speed just before hitting the floor.
The relationship between the strain rate and the fracture strain of the resin used is as shown in FIG. 5, and the relational equation (1) is y = −0.000129x + 0.0313.
A simulation is performed when the product collides with a rigid body at a drop speed of 1000 mm / s, 2000 mm / s, and 4000 mm / s. The strain rate at which the maximum strain occurs under each experimental condition is substituted into equation (1), and the relational equation (2) between the drop rate and the fracture strain is y = −0.0000172x + 0.0319 as shown in FIG. It becomes. The relational equation (3) between the drop speed and the maximum strain obtained by the simulation is y = 0.000000939x−0.000180 as shown in FIG. By solving the simultaneous equations of Equation (2) and Equation (3), it can be seen that the drop speed at which fracture occurs is 1760 mm / s.

樹脂の歪み速度と破壊歪みの関係方程式を表す一例である。It is an example showing the relational equation between the strain rate of resin and the fracture strain. 実験条件と破壊歪みの関係方程式を表す一例である。It is an example showing the relational equation between experimental conditions and fracture strain. 実験条件と最大発生歪みの関係方程式を表す一例である。It is an example showing the relational equation of experimental conditions and the maximum generation distortion. 本発明の実施例１の製品形状と落下方向を示す斜視図である。It is a perspective view which shows the product shape and fall direction of Example 1 of this invention. 本発明の実施例１の樹脂の特性を示す歪み速度と破壊歪みの関係方程式を表す図である。It is a figure showing the relational equation of the strain rate which shows the characteristic of resin of Example 1 of this invention, and a fracture | rupture strain. 本発明の実施例１の落下速度と破壊歪みの関係方程式を表す図である。It is a figure showing the relational equation of the fall speed and fracture | rupture distortion of Example 1 of this invention. 本発明の実施例１の落下速度と最大発生歪みの関係方程式を表す図である。It is a figure showing the relational equation of the fall speed of Example 1 of this invention, and the largest generation | occurrence | production distortion.

Claims

When performing a CAE simulation for predicting fracture due to impact of a resin product, first, a tensile test is performed using a test piece made of a resin composition that is a material molded into the resin product, and three types of strain rates are set. A plurality of stress-strain curves are obtained by measuring at the above speed, and second, an equation is obtained by calculating the relationship between the value of the fracture strain and the strain rate at each strain rate obtained from the stress-strain curve by approximate calculation. On the other hand, the maximum strain εmax that occurs when the resin product is subjected to an impact under an initial condition and the maximum strain rate Vmax at the location where the maximum strain occurs are calculated by CAE simulation, and the maximum The fracture strain εcalc. Calculated by substituting the strain rate Vmax as the strain rate value in the equation (1). For the fracture strain εcalc. And the maximum strain εmax obtained by simulation are compared, and the fracture strain εcalc. A method for determining the presence or absence of destruction in an impact simulation that determines that the product is destroyed when the maximum strain εmax is larger.

In performing the CAE simulation for predicting the fracture due to the impact of the resin product according to claim 1, as a result of calculation by changing the experimental condition of 2 level or more and 8 level or less, the strain rate Vmax of the maximum strain occurrence point is The relationship between the fracture strain calculated by substituting into equation (1) and the experimental condition is approximated to equation (2), and the relationship between the maximum strain and the experimental condition is approximated to equation (3) to determine the equation ( A method for determining a destructive experiment condition of an impact simulation that determines that the intersection of 2) and equation (3) is an experimental condition that causes a destructive phenomenon.

3. A method for determining a destructive experiment condition for an impact simulation according to claim 2, wherein the test condition for the destructive shock simulation is changed in three or more levels.