JP2013130429A - Panel evaluation method - Google Patents

Panel evaluation method Download PDF

Info

Publication number
JP2013130429A
JP2013130429A JP2011278964A JP2011278964A JP2013130429A JP 2013130429 A JP2013130429 A JP 2013130429A JP 2011278964 A JP2011278964 A JP 2011278964A JP 2011278964 A JP2011278964 A JP 2011278964A JP 2013130429 A JP2013130429 A JP 2013130429A
Authority
JP
Japan
Prior art keywords
curvature
panel
load
displacement
curvature radius
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP2011278964A
Other languages
Japanese (ja)
Other versions
JP5382104B2 (en
Inventor
Kinya Nakagawa
欣哉 中川
Takashi Iwama
隆史 岩間
Yuji Yamazaki
雄司 山▲崎▼
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
JFE Steel Corp
Original Assignee
JFE Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by JFE Steel Corp filed Critical JFE Steel Corp
Priority to JP2011278964A priority Critical patent/JP5382104B2/en
Priority to PCT/JP2012/008061 priority patent/WO2013094176A1/en
Priority to TW101148404A priority patent/TWI505955B/en
Publication of JP2013130429A publication Critical patent/JP2013130429A/en
Application granted granted Critical
Publication of JP5382104B2 publication Critical patent/JP5382104B2/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01MTESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M5/00Investigating the elasticity of structures, e.g. deflection of bridges or air-craft wings

Landscapes

  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Strength Of Materials By Application Of Mechanical Stress (AREA)
  • Body Structure For Vehicles (AREA)

Abstract

PROBLEM TO BE SOLVED: To easily and more accurately evaluate tensile rigidity of a panel component.SOLUTION: According to a panel evaluation method for evaluating tensile rigidity of a panel component which protrudes to one surface side as a whole, a curvature ratio is determined which is a ratio of a first curvature radius that is a maximum curvature radius of the panel component at an evaluation position set to the panel component, and a second curvature radius that is a curvature radius in a direction orthogonal to a curvature direction of that maximum curvature radius. Furthermore, thickness of the panel component at the evaluation position is determined. By using the determined curvature ratio and thickness, load-displacement characteristics at the evaluation position are then determined.

Description

本発明は、自動車用パネル部品など、全体として一方の面側に凸形状となっているパネル部品の張り剛性を評価するパネル評価方法に関する。   The present invention relates to a panel evaluation method for evaluating the tension rigidity of panel components that are convex on one side as a whole, such as automotive panel components.

自動車用のパネル部品(ドア、フード、ルーフ等)に求められる特性の一つとして、張り剛性が挙げられる。従来、その張り剛性は、実際に張り剛性を測定する測定器を使用した試験によって求めたり、モデルの解析手法によって求めたりして算出する。
上記張り剛性を高めるためには、パネルの部品形状を最適化することが有効な手段である。特にパネルの曲率は張り剛性に対して大きな影響を与える。
これに対し、特許文献1には、パネル上の任意の位置の最大曲率と最小曲率の和を一定とすることで、パネル上の張り剛性が一定となるように設計をすることが記載されている。
また特許文献2では、ルーフパネル中央の車体左右方向の曲率半径と車体前後方向の曲率半径との積、ヤング率、及び板厚から張り剛性を算出する方法が記載されている。
One of the characteristics required for automotive panel parts (doors, hoods, roofs, etc.) is tension rigidity. Conventionally, the tension stiffness is calculated by a test using a measuring instrument that actually measures the tension stiffness or by a model analysis method.
In order to increase the tension rigidity, it is an effective means to optimize the part shape of the panel. In particular, the curvature of the panel has a great influence on the stiffness.
On the other hand, Patent Document 1 describes that the tension stiffness on the panel is designed to be constant by making the sum of the maximum curvature and the minimum curvature at any position on the panel constant. Yes.
Patent Document 2 describes a method of calculating the tension rigidity from the product of the curvature radius in the vehicle body left-right direction and the curvature radius in the vehicle longitudinal direction at the center of the roof panel, the Young's modulus, and the plate thickness.

特許第3229399号公報Japanese Patent No. 3229399 特開2004−17682号公報JP 2004-17682 A

特許文献1の実施例では、5kgfの荷重をかけた際の変位で張り剛性を整理している。しかしながら、最大曲率と最小曲率の和が一定の条件では、荷重が5kgfに至るまでの荷重−変位曲線の経路は様々に異なる。このため、特許文献1に記載のように、最大曲率と最小曲率の和が等しければ張り剛性は等しいとは必ずしも言えない。
一方、特許文献2については、該特許文献2に記載されている式から、車体前後方向の曲率半径と車体左右方向の曲率半径との積が等しければ張り剛性は等しいことが読み取れる。しかし特許文献1の場合と同様に、車体前後方向の曲率半径と車体左右方向の曲率半径の積が等しいという条件では荷重−変位曲線の経路は様々に異なるため、車体前後方向の曲率半径と車体左右方向の曲率半径の積が等しくても、張り剛性が等しいとは必ずしも言えない。
In the Example of patent document 1, tension rigidity is arranged by the displacement at the time of applying a 5 kgf load. However, under the condition where the sum of the maximum curvature and the minimum curvature is constant, the path of the load-displacement curve until the load reaches 5 kgf is variously different. For this reason, as described in Patent Document 1, if the sum of the maximum curvature and the minimum curvature is equal, the tension stiffness is not necessarily equal.
On the other hand, for Patent Document 2, it can be seen from the formula described in Patent Document 2 that the tension stiffness is equal if the product of the curvature radius in the longitudinal direction of the vehicle body and the curvature radius in the lateral direction of the vehicle body are equal. However, as in the case of Patent Document 1, the path of the load-displacement curve is different under the condition that the product of the curvature radius in the longitudinal direction of the vehicle body and the curvature radius in the lateral direction of the vehicle body are equal. Even if the products of the curvature radii in the left-right direction are equal, the tension stiffness is not necessarily equal.

例えば図11に示すように、ある荷重αに達したときの変位βが等しくても、曲線A,曲線Bのようにそこに至るまでの「荷重−変位」の経路が異なれば、実際にパネルを押した際の感触は全く異なり、張り剛性が等しいとは限らない。つまり、パネルの各位置における、荷重が負荷される場所の荷重−変位関係を精度良く得ることが出来なければ、所定の精度をもってパネル部品の張り剛性を評価することが出来ない。
本発明は、上記のような点に着目したもので、簡便に且つより精度良くパネル部品の張り剛性を評価することを目的としている。
For example, as shown in FIG. 11, even if the displacement β when reaching a certain load α is equal, if the “load-displacement” path to reach the load β is different as in the curves A and B, the panel is actually The feeling when pressing is completely different, and the tension stiffness is not always the same. In other words, unless the load-displacement relationship at the position where the load is applied at each position of the panel can be obtained with high accuracy, the stiffness of the panel component cannot be evaluated with a predetermined accuracy.
The present invention pays attention to the above points, and aims to evaluate the rigidity of panel components in a simple and more accurate manner.

ここで、特許文献2に記載されている式を用いて得られるのは、荷重−変位曲線における荷重負荷開始の際の最初の傾きだけである。張り剛性の荷重−変位曲線は、通常、上に凸の形状を示すことが多く、変位が大きくなるに従って、特許文献2に記載されている式から得られた値と、実際の張り剛性値との乖離は大きくなる。特に、求められる張り剛性は評価対象の部品や部位によって条件が様々であり、荷重−変位曲線の初めの傾きのみでは、張り剛性の評価が不十分となる。   Here, only the initial slope at the start of load loading in the load-displacement curve is obtained using the formula described in Patent Document 2. The tension-rigidity load-displacement curve usually shows a convex shape upward, and as the displacement increases, the value obtained from the equation described in Patent Document 2 and the actual tension stiffness value The divergence of becomes larger. In particular, the required tension stiffness has various conditions depending on the part or part to be evaluated, and the tension stiffness evaluation is insufficient only with the initial slope of the load-displacement curve.

これに対し、発明者らは、評価位置での最小曲率での曲率半径とそれに直交する方向での曲率半径との曲率半径の比である曲率比によって、荷重−変位曲線の経路が異なるという知見を得た。なお最小曲率に直交する方向は、最大曲率の方向の場合が多い。すなわち、発明者らは、様々な形状のパネルの張り剛性の調査を通じて、パネル上の最小曲率方向と、それに直交する方向の二つの曲率の比、及び板厚の組み合わせで、パネルに荷重を加えた時の荷重−変位曲線をより精度良く算出することが可能であるという知見を得た。   In contrast, the inventors have found that the path of the load-displacement curve differs depending on the curvature ratio, which is the ratio of the curvature radius between the curvature radius at the minimum curvature at the evaluation position and the curvature radius in the direction orthogonal thereto. Got. The direction orthogonal to the minimum curvature is often the direction of the maximum curvature. That is, the inventors applied a load to the panel by examining the rigidity of the panel having various shapes and combining the minimum curvature direction on the panel, the ratio of the two curvatures in the direction perpendicular to the direction, and the plate thickness. It was found that the load-displacement curve can be calculated with higher accuracy.

このような知見に基づき、上記のような課題を解決するために、本発明のうち請求項1に記載した発明は、全体として一方の面側に凸形状となっているパネル部品の張り剛性を評価するパネル評価方法であって、
パネル部品に設定した評価位置における、パネル部品の最大曲率半径である第1曲率半径と、その最大曲率半径の曲率方向に直交する方向の曲率半径である第2曲率半径とを求め、その求めた第1曲率半径と第2曲率半径との比である曲率比を求めると共に、上記評価位置におけるパネル部品の板厚を求め、上記求めた曲率比と板厚を用いて、上記評価位置における荷重−変位特性を求めることを特徴とする。
Based on such knowledge, in order to solve the above-mentioned problems, the invention described in claim 1 of the present invention has the rigidity of the panel component that is convex on one side as a whole. A panel evaluation method to evaluate,
The first curvature radius that is the maximum curvature radius of the panel component at the evaluation position set for the panel component and the second curvature radius that is the curvature radius in the direction orthogonal to the curvature direction of the maximum curvature radius are obtained and obtained. While calculating | requiring the curvature ratio which is ratio of a 1st curvature radius and a 2nd curvature radius, the plate | board thickness of the panel component in the said evaluation position is calculated | required, The load in the said evaluation position-using the calculated | required curvature ratio and plate | board thickness- The displacement characteristic is obtained.

次に、請求項2に記載した発明は、請求項1に記載した構成に対し、上記曲率比と板厚を用いて求める荷重−変位特性は、曲率比および変位を変数とした4次関数で表される式によって求めることを特徴とする。
次に、請求項3に記載した発明は、請求項1又は請求項2に記載のパネル評価方法によって複数の評価位置を評価することで、補強位置を決定することを特徴とする。
Next, in the invention described in claim 2, with respect to the configuration described in claim 1, the load-displacement characteristic obtained using the curvature ratio and the plate thickness is a quartic function with the curvature ratio and displacement as variables. It is calculated | required by the type | formula represented.
Next, the invention described in claim 3 is characterized in that the reinforcing position is determined by evaluating a plurality of evaluation positions by the panel evaluation method according to claim 1 or claim 2.

本発明によれば、簡便にパネルの張り剛性を評価する事が可能となる。   According to the present invention, it is possible to easily evaluate the stiffness of a panel.

本発明に基づく実施形態に係る評価方法を説明するフローチャート図である。It is a flowchart figure explaining the evaluation method which concerns on embodiment based on this invention. パネルに設定した評価位置の例を示す模式図である。It is a schematic diagram which shows the example of the evaluation position set to the panel. 解析モデル形状を示す図である。It is a figure which shows an analysis model shape. 1mm変位させるのに必要な荷重とy方向曲率との関係を示す図である。It is a figure which shows the relationship between a load required in order to displace 1 mm, and a y direction curvature. 回帰計算結果と有限要素解析結果とを比較した図である。It is the figure which compared the regression calculation result and the finite element analysis result. ドアモデルを示す図である。It is a figure which shows a door model. 板厚と2mm変位させるのに必要な荷重との関係を示す図である。It is a figure which shows the relationship between plate | board thickness and the load required to be displaced 2 mm. 評価試験装置の断面模式図である。It is a cross-sectional schematic diagram of an evaluation test apparatus. 実施例における評価位置を示す図である。It is a figure which shows the evaluation position in an Example. 評価結果を示す図である。It is a figure which shows an evaluation result. 荷重−変位の関係を説明する模式図である。It is a schematic diagram explaining the relationship of load-displacement.

次に、本発明の実施形態について図面を用いて説明する。
(評価対象)
本実施形態では、全体として一方の面側に凸形状となっているパネル部品として、自動車用パネル部品であるルーフパネル(以下単にパネルと呼ぶ)を評価対象とする。評価対象は、ドアパネルでも良いし、自動車パネル部品以外のパネル部品でも良い。全体として一方の面側に凸形状となっているパネル部品であれば、つまり一部に凹の曲率が存在していても、全体の輪郭形状としては凸の曲率で形成されていれば適用可能である。なお、凸側から荷重負荷を行う場合とする。
また、以下の方法で評価するパネルには、レインフォースメントやリブなどの補強部材が設けられていない状態とする。若しくは、補強部材が設けられていても補強部材による影響が低い位置を評価位置とする。
Next, embodiments of the present invention will be described with reference to the drawings.
(Target of evaluation)
In the present embodiment, a roof panel (hereinafter simply referred to as a panel), which is an automotive panel component, is an evaluation object as a panel component that is convex on one side as a whole. The evaluation object may be a door panel or a panel component other than an automobile panel component. If it is a panel part that has a convex shape on one side as a whole, that is, even if there is a concave curvature in part, it can be applied if it is formed with a convex curvature as a whole contour shape It is. It is assumed that load is applied from the convex side.
Moreover, the panel evaluated by the following method is in a state where reinforcement members such as reinforcement and ribs are not provided. Alternatively, a position where the influence of the reinforcing member is low even if the reinforcing member is provided is set as the evaluation position.

(パネル設計方法)
図1は、本実施形態の張り剛性評価方法を使用したパネル設計方法の手順を説明する概略フローチャート図である。
まず、ステップS10にて、評価するパネルの形状を初期設定して、パネルのモデルを決定する。パネル形状として具体的に、パネルの曲率半径、板厚を設定する。ここで、パネルの曲率半径はパネル上で一律である必要はなく、分布を持っていてもよい。
(Panel design method)
FIG. 1 is a schematic flowchart illustrating a procedure of a panel design method using the tension stiffness evaluation method of the present embodiment.
First, in step S10, the panel shape to be evaluated is initialized and a panel model is determined. Specifically, the radius of curvature and thickness of the panel are set as the panel shape. Here, the curvature radius of the panel does not need to be uniform on the panel, and may have a distribution.

次に、ステップS20にて、図2のように、上記評価するパネル1上に対して複数の評価位置Hを設定する。
次に、ステップS30にて、ステップS20で設定した複数の評価位置についてそれぞれ、以下の曲率半径、板厚の値を求める。
各評価位置において、最小曲率の向きを求め、更にその最小曲率の曲率半径である最大曲率半径を求めて、その曲率半径を第1曲率半径として設定する。更に、上記最小曲率の向きに直交する方向での曲率半径を求め、その求めた曲率半径を第2曲率半径として設定する。また、各評価位置における板厚を求める。
Next, in step S20, as shown in FIG. 2, a plurality of evaluation positions H are set on the panel 1 to be evaluated.
Next, in step S30, the following curvature radii and plate thickness values are obtained for the plurality of evaluation positions set in step S20.
At each evaluation position, the direction of the minimum curvature is obtained, the maximum curvature radius that is the curvature radius of the minimum curvature is obtained, and the curvature radius is set as the first curvature radius. Further, a curvature radius in a direction orthogonal to the direction of the minimum curvature is obtained, and the obtained curvature radius is set as a second curvature radius. Further, the plate thickness at each evaluation position is obtained.

ここで、上記各曲率半径は、初期設定したパネル形状の形状情報に基づき、表計算ソフトその他のソフトを利用して算出しても良いし、実際に測定して求めても良い。
測定する際は、3点ゲージを用いる、3次元形状測定器を用いる、等の手段により曲率半径を測定することができる。板厚は、マイクロメータや超音波板厚計等の手段により求めることができる。
Here, the respective radii of curvature may be calculated using spreadsheet software or other software based on the shape information of the initially set panel shape, or may be obtained by actual measurement.
When measuring, the radius of curvature can be measured by means such as using a three-point gauge or a three-dimensional shape measuring instrument. The plate thickness can be obtained by means such as a micrometer or an ultrasonic plate thickness meter.

次に、ステップS40にて、下式に基づき、上記求めた第1曲率半径及び第2曲率半径とに基づき、各評価位置での曲率比を求める。
曲率比 =(第2曲率半径/第1曲率半径)
次に、ステップS50にて、各評価位置毎に、ステップS40にて求めた曲率比、ステップS30にて求めた板厚を、下記式に代入して、各評価位置での荷重−変位曲線をそれぞれ求める。
P =P×Pr(d)×(2.9438×t+0.1875) ・・・(1)
但し、
Next, in step S40, based on the following formula, the curvature ratio at each evaluation position is obtained based on the obtained first and second curvature radii.
Curvature ratio = (2nd radius of curvature / 1st radius of curvature)
Next, in step S50, for each evaluation position, the curvature ratio obtained in step S40 and the plate thickness obtained in step S30 are substituted into the following equation, and a load-displacement curve at each evaluation position is obtained. Ask for each.
P = P 1 × Pr (d) × (2.9438 × t 3 +0.1875) (1)
However,

Figure 2013130429
Figure 2013130429

ここで、P:荷重(N)、d:変位(mm)、Rx:第2曲率半径(mm)、Ry:第1曲率半径(最大曲率半径)(mm)、aa、ab、ac、bb、bc、cc、ka、kb、la、lb、ma、mb、na、nbは定数である。   Here, P: load (N), d: displacement (mm), Rx: second radius of curvature (mm), Ry: first radius of curvature (maximum radius of curvature) (mm), aa, ab, ac, bb, bc, cc, ka, kb, la, lb, ma, mb, na, nb are constants.

次に、ステップS60にて、ステップS50で求めた各評価位置での荷重−変位曲線に基づき、パネル上の張り剛性の低い位置を求める。そして、補強が必要な位置を決定する。
なお、張り剛性の低い位置が、目標とする最低張り剛性よりも低い場合には、その張り剛性の低い位置が目標とする最低張り剛性以上となる曲率比を、上記式から逆算して求め、上記初期設定を更新して、上記ステップS10〜S60の処理を繰り返しても良い。
ここで、上記処理は、一連のソフトとしてコンピュータに組み込んでおいても良い。
上記処理のように、評価位置の曲率半径から簡易かつ所定の精度をもって張り剛性の評価を行うことが出来る。この結果、パネルに対する補強が必要な位置を決定することも出来る。
Next, in step S60, based on the load-displacement curve at each evaluation position obtained in step S50, a position with low tension rigidity on the panel is obtained. And the position which needs reinforcement is determined.
If the position where the tension stiffness is low is lower than the target minimum tension stiffness, the curvature ratio at which the position where the tension stiffness is lower than the target minimum tension stiffness is calculated by back-calculating from the above formula, The initial setting may be updated, and the processes in steps S10 to S60 may be repeated.
Here, the above processing may be incorporated in a computer as a series of software.
As in the above-described process, the tension stiffness can be evaluated easily and with a predetermined accuracy from the radius of curvature at the evaluation position. As a result, it is also possible to determine the position where the panel needs to be reinforced.

そして、本実施形態の方法を用いれば、パネル上の任意の位置の荷重−変位特性を簡便に得ることが可能となるため、任意の荷重を与えた際の変位、任意の変位を与えた際の荷重をパネル上の任意の点において算出する事が可能となる。そのため例えばごく小さい荷重をかけた時のパネルの変位や、大きく変位した時の荷重等、条件が異なる場合の張り剛性も同じ式で簡便に求める事が可能となる。
なお、上記式における、各定数は、一度、実際にパネル上の測定点の曲率半径を測定し、測定点に変位を与え荷重を測定する作業を複数点に行う実験、もしくは前記実験と同様の手法を用いた解析により求めておけば良い。
If the method of this embodiment is used, it is possible to easily obtain the load-displacement characteristic at an arbitrary position on the panel. Therefore, when an arbitrary load is applied, an arbitrary displacement is applied. Can be calculated at any point on the panel. Therefore, for example, it is possible to easily obtain the tension stiffness when the conditions are different, such as the displacement of the panel when a very small load is applied and the load when the displacement is large.
In addition, each constant in the above formula is an experiment in which the radius of curvature of the measurement point on the panel is actually measured once, and the load is measured by applying displacement to the measurement point. What is necessary is just to obtain | require by the analysis using a method.

ここで、上記(1)式の「P×Pr(d)」の項は、曲率比及び変位を変数とした4次式の関数として纏めることが出来る。後述のように、曲率比及び変位を変数とした4次以上の関数で纏める方が精度が良いが、上記(1)式を、曲率比により荷重−変位曲線の形状が決定されるという考えに基づき、曲率比および変位を変数とした1次式、2次式若しくは3次式に纏めてもよい。4次式の場合に比べて精度は多少落ちる。また、曲率比及び変位を変数とした5次以上の関数で纏めても良い。但し、その分、計算が煩雑となる。 Here, the term “P 1 × Pr (d)” in the above equation (1) can be summarized as a function of a quartic equation with the curvature ratio and displacement as variables. As will be described later, it is more accurate to use a function of the fourth or higher order with the curvature ratio and displacement as variables, but the above equation (1) is based on the idea that the shape of the load-displacement curve is determined by the curvature ratio. On the basis of this, a linear expression, a quadratic expression, or a cubic expression with the curvature ratio and displacement as variables may be summarized. The accuracy is somewhat lower than in the case of the quartic equation. Moreover, you may summarize by the function of the 5th order or more which used the curvature ratio and the displacement as variables. However, the calculation is complicated accordingly.

また、上記荷重−変位特性の式は、曲率比と変位の他に板厚を変数とする式となっている。板厚が一定と仮定した場合には、曲率比と変位だけを変数とした式となる。従って、複数の評価位置の各曲率比を比較することで、パネルの張り剛性の分布を評価することも可能である。すなわち、複数の評価位置の曲率比によって、パネル上の張り剛性の状態を評価することも可能である。   In addition, the equation of the load-displacement characteristic is an equation using the plate thickness as a variable in addition to the curvature ratio and the displacement. If the plate thickness is assumed to be constant, the equation is based on only the curvature ratio and displacement. Therefore, it is possible to evaluate the distribution of the panel stiffness by comparing the curvature ratios at a plurality of evaluation positions. That is, it is possible to evaluate the state of the tension rigidity on the panel based on the curvature ratios at a plurality of evaluation positions.

(式の妥当性について)
次に、上記式の妥当性について補足説明する。
発明者らは、張り剛性に与える形状の効果を調査するため、有限要素解析にて調査、検討を行った。
方法としては、図3に示すような、投影面積が500mm×500mmのパネルであり、x方向及びy方向にそれぞれ一律な曲率半径を持った上側に凸のパネルのモデルを作製した。図3では、横方向にx軸を縦方向にy軸を設定した。そして、上記モデルの中央を点負荷で垂直下方に変位させることで荷重−変位曲線を得て、x方向,y方向それぞれの曲率半径と荷重−変位関係とを整理した。
(Validity of the formula)
Next, the validity of the above formula will be supplementarily described.
Inventors investigated and examined by the finite element analysis in order to investigate the effect of the shape given to tension rigidity.
As a method, a model of a panel having a projection area of 500 mm × 500 mm as shown in FIG. 3 and having a uniform curvature radius in each of the x direction and the y direction was produced. In FIG. 3, the x axis is set in the horizontal direction and the y axis is set in the vertical direction. Then, a load-displacement curve was obtained by displacing the center of the model vertically downward with a point load, and the curvature radii in the x and y directions and the load-displacement relationship were organized.

ここで、有限要素解析に用いたソフトはLS−DYNA(Livermore Software Technology Corporation製)ver971d R3.2.1であり、そのメッシュサイズは約5mm×5mm、板厚は0.65mmである。各モデルは四辺を完全拘束とした。また、解析には静的陰解法を用いた。
またこのとき、材料特性は、弾性率(ヤング率):210GPa、YP(降伏強度):285MPa、TS(引張強度):345MPa、 uEL(一様伸び):20.1%とした。
なお、モデルの四辺の拘束は、500mm×500mmのサイズの場合、変位が2mmまでの解析であれば中央部の荷重−変位関係に殆ど影響を及ぼさないことを確認した。
Here, the software used for the finite element analysis is LS-DYNA (manufactured by Livermore Software Technology Corporation) ver971d R3.2.1, the mesh size is about 5 mm × 5 mm, and the plate thickness is 0.65 mm. Each model was completely constrained on all four sides. The static implicit method was used for the analysis.
At this time, the material properties were as follows: elastic modulus (Young's modulus): 210 GPa, YP (yield strength): 285 MPa, TS (tensile strength): 345 MPa, uEL (uniform elongation): 20.1%.
It was confirmed that the constraints on the four sides of the model had little influence on the load-displacement relationship in the central part if the analysis was up to 2 mm when the size was 500 mm × 500 mm.

上記各モデルのx方向の曲率半径(Rx)、y方向の曲率半径(Ry)の組み合わせは、次の8通りから重複を許した全ての組合せで行った。また、与える変位の上限は2mmとした。
曲率半径:500mm,1000mm,1500mm,2000mm,5000mm,10000mm,15000mm,20000mmの8通り。
まず、発明者らは、ある変位を与えた際に生じる荷重について整理を行った。すなわち、各設定したx方向曲率半径(Rx)毎に、y方向曲率半径(Ry)を変更して、そのRyと1mm変位時の荷重の関係を求めたところ、図4に示す関係を得た。なお、図4の横軸は、後の整理のため、曲率を1000倍したρy(=1000/Ry)としている。
The combinations of the curvature radii (Rx) in the x direction and the curvature radii (Ry) in the y direction of each model described above were performed in all combinations that allowed overlapping from the following eight types. The upper limit of displacement applied was 2 mm.
Curvature radius: 8 types of 500mm, 1000mm, 1500mm, 2000mm, 5000mm, 10000mm, 15000mm, 20000mm.
First, the inventors organized the load that occurs when a certain displacement is applied. That is, for each set x-direction radius of curvature (Rx), the y-direction radius of curvature (Ry) was changed, and the relationship between the Ry and the load at the time of 1 mm displacement was obtained. The relationship shown in FIG. 4 was obtained. . Note that the horizontal axis in FIG. 4 is ρy (= 1000 / Ry) obtained by multiplying the curvature by 1000 for the purpose of later arrangement.

そして図4から、発明者らは、「ρと1mm変位時の荷重との関係」はほぼ一次線形の関係であり、1mm変位させるのに必要な荷重は曲率半径によって整理出来るという知見を得た。
さらに、発明者らは、図4に示される曲線について、Rx,Ryを使用して、以下の式によって表現できるという知見を得た。
ρ =1000/R
ρ =1000/R
(ρ)=aa・ρ +ab・ρ +ac
(ρ)=ab・ρ +bb・ρ +bc
(ρ)=ac・ρ +bc・ρ +cc
=f(ρ)・ρ +f(ρ)・ρ+f(ρ
ここでaa〜ccは、表1に示される定数である。
は、負荷する荷重を示す。また、表2は、有限要素解析で求めた値である。
From FIG. 4, the inventors obtained the knowledge that “the relationship between ρ y and the load at the time of 1 mm displacement” is a substantially linear relationship, and the load necessary to displace 1 mm can be arranged by the radius of curvature. It was.
Furthermore, the inventors have found that the curve shown in FIG. 4 can be expressed by the following equation using Rx and Ry.
ρ x = 1000 / R x
ρ y = 1000 / R y
f 1x ) = aa · ρ x 2 + ab · ρ x + ac
f 2x ) = ab · ρ x 2 + bb · ρ x + bc
f 3x ) = ac · ρ x 2 + bc · ρ x + cc
P 1 = f 1x ) · ρ y 2 + f 2x ) · ρ y + f 3x )
Here, aa to cc are constants shown in Table 1.
P 1 denotes a load applied. Table 2 shows values obtained by finite element analysis.

Figure 2013130429
Figure 2013130429

Figure 2013130429
Figure 2013130429

上記の式にRx、Ryを代入して得られた解と、表2に示される有限要素解析で得られた1mm変位時の荷重をプロットすると、図5となる。図5から分かるように、回帰式によって得られる解は、ほぼ有限要素解析解と等しいことが分かる。
以上のように、Rx、Ryを用いて1mm変位時の荷重を回帰することができた。
FIG. 5 is a plot of the solution obtained by substituting Rx and Ry into the above equation and the load at the time of 1 mm displacement obtained by the finite element analysis shown in Table 2. As can be seen from FIG. 5, the solution obtained by the regression equation is almost equal to the finite element analysis solution.
As described above, it was possible to regress the load at the time of 1 mm displacement using Rx and Ry.

次に、上記結果から得られる1mm変位時の荷重、およびRx、Ryから、荷重−変位曲線を回帰することを考えた。
様々な試行と解析の結果から、荷重−変位曲線の形状は、RxとRyの比率に対し相関が強いという知見を得た。更に、荷重−変位曲線は、曲率比及び変位を変数とした4次関数以上の次数の式で近似することで、より精度の良い近似が可能であるという知見を得た。
以上をまとめると、曲率の付いたパネルの荷重(P)−変位(d)曲線は、直交する二つのRをRx、Ryとすると、下記式で表現することができる。
P =P×Pr(d) ・・・(2)
ただし、
Next, it was considered to regress a load-displacement curve from the load at the time of 1 mm displacement obtained from the above results, and Rx and Ry.
From the results of various trials and analyses, it was found that the shape of the load-displacement curve has a strong correlation with the ratio of Rx and Ry. Furthermore, the load-displacement curve was found to be able to be approximated with higher accuracy by approximating it with an expression of an order of a quartic function or more with the curvature ratio and displacement as variables.
In summary, the load (P) -displacement (d) curve of the panel with curvature can be expressed by the following equation, where two orthogonal Rs are Rx and Ry.
P = P 1 × Pr (d) (2)
However,

Figure 2013130429
Figure 2013130429

ここで、P:荷重(N)、d:変位(mm)、Rx:曲率半径(mm)、Ry:曲率半径(mm)、aa、ab、ac、bb、bc、cc、ka、kb、la、lb、ma、mb、na、nbは定数である。
aa〜nbを表1および表3に示す。
また、(Rx/Ry)≦1とする。
Here, P: load (N), d: displacement (mm), Rx: radius of curvature (mm), Ry: radius of curvature (mm), aa, ab, ac, bb, bc, cc, ka, kb, la , Lb, ma, mb, na, nb are constants.
Tables 1 and 3 show aa to nb.
Further, (Rx / Ry) ≦ 1.

Figure 2013130429
Figure 2013130429

上記解析においてRx、Ryはそれぞれパネルの最大曲率半径と最小曲率半径に相当する。発明者らはさらに解析により、測定点における最小曲率半径と最大曲率半径の組合せ以外の組合せでの荷重―変位曲線の近似について検討を行い、最大曲率半径と最大曲率半径と直交する方向の曲率半径の比を用いて荷重−変位曲線を近似することが最もよい近似を得られることを知見した。
なお、表1および表3に記載の係数は、板厚0.65mmの鋼板の場合での値である。すなわち、目的のパネルの材質に応じて、予め上記定数aa〜nbの値を求めておけば良い。
In the above analysis, Rx and Ry correspond to the maximum curvature radius and the minimum curvature radius of the panel, respectively. The inventors further investigated the approximation of the load-displacement curve by a combination other than the combination of the minimum and maximum curvature radii at the measurement point, and analyzed the curvature radius in the direction orthogonal to the maximum curvature radius and the maximum curvature radius. It was found that the best approximation can be obtained by approximating the load-displacement curve using the ratio of
The coefficients shown in Tables 1 and 3 are values in the case of a steel plate having a thickness of 0.65 mm. That is, the values of the constants aa to nb may be obtained in advance according to the target panel material.

さらに発明者らは、式(2)に対して板厚で補正をかけることにより、様々な板厚に対して式(1)を適用できると考えた。
ここで、一般に材料力学的な見地から、張り剛性は板厚の3乗にほぼ比例する事が知られている。
そこで、図6のドアのモデルに対して、アウターパネルの板厚を変化させ、張り剛性の解析を行った。
Furthermore, the inventors considered that the formula (1) can be applied to various plate thicknesses by correcting the formula (2) with the plate thickness.
Here, it is generally known from the viewpoint of material dynamics that the tension stiffness is substantially proportional to the cube of the plate thickness.
Therefore, the stiffness of the outer panel was changed with respect to the door model shown in FIG.

モデル作製については、三次元形状測定器によって実際のドアの形状を測定して、そのデータを基にAltair社のHyperMeshを用いて有限要素解析モデルを作製した。その際、メッシュサイズは、アウターパネルは15mm、インナーパネル及びその他構造部材は10mmとした。要素はシェル要素を用い、全要素数は20762、内アウターパネルの要素数は4113である。インナーパネルの板厚は1.2mm、インパクトビーム、及びパネル下部に配置されているパイプの肉厚は2.3mm、アウターパネルの板厚は0.7mmとした。拘束条件は、ドアとして車両に取り付けられる際に車体フレームに固定される位置を完全固定とした。要素タイプは多直線近似等方弾塑性体モデルを用いた。解析にはLS−DYNA ver971d R3.2.1(Livermore Software Technology Corporation製)を用い、静的陰解法で行った。   For model production, an actual door shape was measured with a three-dimensional shape measuring instrument, and a finite element analysis model was produced using HyperMesh from Altair based on the data. At that time, the mesh size was 15 mm for the outer panel and 10 mm for the inner panel and other structural members. The element is a shell element, the total number of elements is 20762, and the number of elements of the inner and outer panels is 4113. The plate thickness of the inner panel was 1.2 mm, the thickness of the impact beam and the pipe disposed at the bottom of the panel was 2.3 mm, and the plate thickness of the outer panel was 0.7 mm. The restraint condition was such that the position fixed to the vehicle body frame when attached to the vehicle as a door was completely fixed. The element type used was a multi-line approximate isotropic elasto-plastic model. The analysis was performed by static implicit method using LS-DYNA ver971d R3.2.1 (manufactured by Livermore Software Technology Corporation).

アウターパネルの板厚を0.7mm,0.65mm、0.60mmとした場合の張り剛性の解析結果から、板厚と張り剛性の関係を求めた。上記3種の板厚での解析結果から、図6に示される位置の2mm変位時の荷重をそれぞれの板厚についてプロットすると図7となる。図7から、張り剛性の値は板厚の3乗にほぼ比例する事がわかる。
ここで、板厚0.65mmのときに予め設定した量だけ変位させるのに必要な荷重をP(0.65)、同じ位置を板厚t(mm)とした場合の、予め設定した量だけ変位させるのに必要な荷重をP(t)とすると、P(t)はP(0.65)を用いて以下の式で表すことが出来る。
The relationship between the plate thickness and the stiffness was obtained from the analysis results of the stiffness when the thickness of the outer panel was 0.7 mm, 0.65 mm, and 0.60 mm. From the analysis results of the above three types of plate thicknesses, the load at the time of displacement of 2 mm at the position shown in FIG. From FIG. 7, it can be seen that the value of the tension stiffness is substantially proportional to the cube of the plate thickness.
Here, when the plate thickness is 0.65 mm, the load required to be displaced by a preset amount is P (0.65), and the same position is the plate thickness t (mm). Assuming that the load necessary for displacement is P (t), P (t) can be expressed by the following equation using P (0.65).

P(t)=P(0.65)×(2.9438×t+0.1875)
・・・(3)
式(3)中のP(0.65)は式(2)中のPと同一である。このため、最終的に曲率半径、板厚を用いて荷重(P)−変位(d)曲線を特定する式は、下記式となる。
P=P(0.65)×(2.9438×t+0.1875)
=P×Pr(d)×(2.9438×t+0.1875)
・・・(4)
となる。
この(4)式は、曲率比と変位を変数とした4次式の関数となっている。
P (t) = P (0.65) × (2.9438 × t 3 +0.1875)
... (3)
P (0.65) in the formula (3) is the same as P in the formula (2). For this reason, the formula which finally specifies the load (P) -displacement (d) curve using the radius of curvature and the plate thickness is the following formula.
P = P (0.65) × (2.9438 × t 3 +0.1875)
= P 1 × Pr (d) × (2.9438 × t 3 +0.1875)
... (4)
It becomes.
This equation (4) is a function of a quartic equation with the curvature ratio and displacement as variables.

次に、上記実施形態に基づく実施例について説明する。
本実施例は、評価するパネルとして自動車用のドアパネルの場合である。
(評価方法)
図8は、評価試験を説明する断面模式図である。
張り剛性試験は、試験装置に対し対象とするドアパネルを水平に固定し、図8に示すように、ドアパネルのアウターパネル側からインナーパネル側に向かう方向に高さ16mm、φ45mmのゴム圧子を用いて荷重を負荷し、ドア裏側から接触式変位計を測定位置に当て変位を測定することで、各測定位置における荷重−変位曲線を得た。このとき、試験装置へのドアパネルの設置はアウターパネル測定位置に対して圧子が垂直に当たるように行い、アウターパネルのほぼ四隅にあたる点を万力で固定して行った。
Next, examples based on the above embodiment will be described.
This embodiment is a case of a door panel for an automobile as a panel to be evaluated.
(Evaluation method)
FIG. 8 is a schematic cross-sectional view illustrating an evaluation test.
In the tension stiffness test, a target door panel is fixed horizontally with respect to a test apparatus, and a rubber indenter having a height of 16 mm and a diameter of 45 mm is used in the direction from the outer panel side to the inner panel side of the door panel as shown in FIG. A load-displacement curve at each measurement position was obtained by applying a load and measuring the displacement by applying a contact displacement meter to the measurement position from the back side of the door. At this time, the door panel was installed in the test apparatus so that the indenter was perpendicular to the outer panel measurement position, and the points corresponding to the four corners of the outer panel were fixed with a vise.

一方、曲率半径Rx,Ryは三次元形状測定データから算出した。
比較対象とした評価位置は、インパクトビームによる補強がほとんど影響しないであろう「A」、「B」の2点とした(図9参照)。
Aの位置の曲率半径はそれぞれRx=3000mm、Ry=5000mmであり、Bの位置の曲率半径はRx=3500mm、Ry=50000mmである。アウターパネルの板厚は0.7mmである。Rxが第2曲率半径、Ryが第1曲率半径である。
図10に、上記評価試験による測定結果、上記実施形態によって求めたグラフを示す。
図10に示す結果から分かるように、本発明技術を適用することで、曲率、板厚のみにより、精度良く、荷重−変位曲線が表現出来ていることが分かる。
On the other hand, the curvature radii Rx and Ry were calculated from the three-dimensional shape measurement data.
The evaluation positions used as comparison targets were “A” and “B”, which would hardly be affected by the impact beam reinforcement (see FIG. 9).
The curvature radii at the position A are Rx = 3000 mm and Ry = 5000 mm, respectively, and the curvature radii at the position B are Rx = 3500 mm and Ry = 50000 mm. The thickness of the outer panel is 0.7 mm. Rx is the second radius of curvature and Ry is the first radius of curvature.
FIG. 10 shows a measurement result obtained by the evaluation test and a graph obtained by the embodiment.
As can be seen from the results shown in FIG. 10, it can be seen that by applying the technique of the present invention, a load-displacement curve can be accurately expressed only by the curvature and the plate thickness.

また図10には、比較例1として、最大曲率半径から+45度、および−45度ずらした2方向の各曲率半径を、上記(4)式に代入して得た結果を併記している。
図10から分かるように、最大曲率半径、及びそれと直交する方向の曲率半径をもって計算を行ったほうが、より精度良く実験結果を予測していることが分かる。
また図10中に特許文献2に記載の式に上記曲率半径、板厚を代入して得た曲線を比較例2として併記する。比較例2では、荷重−変位曲線の初めの傾きは再現できているが、変位が大きくなるに従って実験結果との乖離が大きくなり、張り剛性を精度よく予測できているとは言えない。
In FIG. 10, as Comparative Example 1, results obtained by substituting the curvature radii in two directions shifted by +45 degrees and −45 degrees from the maximum curvature radius into the above equation (4) are also shown.
As can be seen from FIG. 10, it is understood that the experimental result is predicted with higher accuracy when the calculation is performed with the maximum curvature radius and the curvature radius in the direction orthogonal thereto.
In FIG. 10, a curve obtained by substituting the radius of curvature and the plate thickness into the formula described in Patent Document 2 is also shown as Comparative Example 2. In Comparative Example 2, the initial slope of the load-displacement curve can be reproduced, but the deviation from the experimental result increases as the displacement increases, and it cannot be said that the tension stiffness can be accurately predicted.

1 パネル
H 評価位置
Rx、Ry 曲率半径
1 Panel H Evaluation position Rx, Ry Curvature radius

Claims (3)

全体として一方の面側に凸形状となっているパネル部品の張り剛性を評価するパネル評価方法であって、
パネル部品に設定した評価位置における、パネル部品の最大曲率半径である第1曲率半径と、その最大曲率半径の曲率方向に直交する方向の曲率半径である第2曲率半径とを求め、その求めた第1曲率半径と第2曲率半径との比である曲率比を求めると共に、上記評価位置におけるパネル部品の板厚を求め、
上記求めた曲率比と板厚を用いて、上記評価位置における荷重−変位特性を求めることを特徴とするパネル評価方法。
A panel evaluation method for evaluating the stiffness of panel components that are convex on one side as a whole,
The first curvature radius that is the maximum curvature radius of the panel component at the evaluation position set for the panel component and the second curvature radius that is the curvature radius in the direction orthogonal to the curvature direction of the maximum curvature radius are obtained and obtained. While calculating | requiring the curvature ratio which is ratio of the 1st curvature radius and the 2nd curvature radius, calculating | requiring the plate | board thickness of the panel component in the said evaluation position,
A panel evaluation method characterized in that a load-displacement characteristic at the evaluation position is determined using the calculated curvature ratio and plate thickness.
上記曲率比と板厚を用いて求める荷重−変位特性は、曲率比および変位を変数とした4次関数で表される式によって求めることを特徴とする請求項1に記載したパネル評価方法。   2. The panel evaluation method according to claim 1, wherein the load-displacement characteristic obtained by using the curvature ratio and the plate thickness is obtained by an expression represented by a quartic function having the curvature ratio and the displacement as variables. 請求項1又は請求項2に記載のパネル評価方法によって複数の評価位置を評価することで、補強位置を決定することを特徴とするパネル評価方法。
A panel evaluation method, wherein a reinforcing position is determined by evaluating a plurality of evaluation positions by the panel evaluation method according to claim 1.
JP2011278964A 2011-12-20 2011-12-20 Panel evaluation method Active JP5382104B2 (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP2011278964A JP5382104B2 (en) 2011-12-20 2011-12-20 Panel evaluation method
PCT/JP2012/008061 WO2013094176A1 (en) 2011-12-20 2012-12-18 Panel evaluation method
TW101148404A TWI505955B (en) 2011-12-20 2012-12-19 Evaluation method for panel

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2011278964A JP5382104B2 (en) 2011-12-20 2011-12-20 Panel evaluation method

Publications (2)

Publication Number Publication Date
JP2013130429A true JP2013130429A (en) 2013-07-04
JP5382104B2 JP5382104B2 (en) 2014-01-08

Family

ID=48668094

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2011278964A Active JP5382104B2 (en) 2011-12-20 2011-12-20 Panel evaluation method

Country Status (3)

Country Link
JP (1) JP5382104B2 (en)
TW (1) TWI505955B (en)
WO (1) WO2013094176A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015063235A (en) * 2013-09-25 2015-04-09 Jfeスチール株式会社 Method for reinforcing panel component, and panel component reinforced by the same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7207547B2 (en) * 2019-07-22 2023-01-18 Jfeスチール株式会社 Quality prediction model generation method, quality prediction model, quality prediction method, metal material manufacturing method, quality prediction model generation device, and quality prediction device

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3229399B2 (en) * 1992-01-10 2001-11-19 トヨタ自動車株式会社 Panel structure
JP2004017682A (en) * 2002-06-12 2004-01-22 Kobe Steel Ltd Automobile roof panel and method of designing automobile roof panel
JP2006240448A (en) * 2005-03-02 2006-09-14 Mitsubishi Fuso Truck & Bus Corp Method for arranging reinforcing member of panel structure
JP2009115775A (en) * 2007-10-16 2009-05-28 Jfe Steel Corp Indenter, method and system for measuring bracing rigidity
JP2011089167A (en) * 2009-10-22 2011-05-06 Nippon Steel Corp Composite panel having excellent stretch rigidity

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002016122A1 (en) * 2000-08-25 2002-02-28 Massachusetts Institute Of Technology A panel with two-dimensional curvature

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3229399B2 (en) * 1992-01-10 2001-11-19 トヨタ自動車株式会社 Panel structure
JP2004017682A (en) * 2002-06-12 2004-01-22 Kobe Steel Ltd Automobile roof panel and method of designing automobile roof panel
JP2006240448A (en) * 2005-03-02 2006-09-14 Mitsubishi Fuso Truck & Bus Corp Method for arranging reinforcing member of panel structure
JP2009115775A (en) * 2007-10-16 2009-05-28 Jfe Steel Corp Indenter, method and system for measuring bracing rigidity
JP2011089167A (en) * 2009-10-22 2011-05-06 Nippon Steel Corp Composite panel having excellent stretch rigidity

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015063235A (en) * 2013-09-25 2015-04-09 Jfeスチール株式会社 Method for reinforcing panel component, and panel component reinforced by the same

Also Published As

Publication number Publication date
TWI505955B (en) 2015-11-01
JP5382104B2 (en) 2014-01-08
WO2013094176A1 (en) 2013-06-27
TW201328909A (en) 2013-07-16

Similar Documents

Publication Publication Date Title
EP1985989B1 (en) Fracture prediction method
US10444732B2 (en) Blank shape determining method, blank, press formed product, press forming method, computer program, and recording medium
JP5919782B2 (en) Dent resistance evaluation method
KR20150042837A (en) Springback suppression component and method for manufacturing same
Souto et al. Material parameter identification within an integrated methodology considering anisotropy, hardening and rupture
JP5098800B2 (en) Method for analyzing collision characteristics or rigidity of thin plate structure, analysis processing apparatus, analysis processing program, and recording medium
JP5382104B2 (en) Panel evaluation method
CN104685338B (en) The manufacture method of board member evaluation method, board member evaluating apparatus and automobile sheetsteel part
JP5827778B2 (en) Nonlinear structural load transfer analyzer
JP5505295B2 (en) Surface shape design method for automotive outer plate parts with excellent dent resistance and the parts
JP5073611B2 (en) Method for evaluating collision-resistant reinforcing material for vehicle using finite element method, computer program, and computer-readable storage medium
JP6246074B2 (en) Tensile compression test method for high strength steel sheet
US11731187B2 (en) Press forming method, rigidity-improvement-position specifying method, press forming system, and press-formed product
JP5757224B2 (en) Structural member design method
Esener et al. Analytical evaluation of plasticity models for anisotropic materials with experimental validation
JP5673636B2 (en) Panel component evaluation method, panel component evaluation apparatus, and automotive panel component manufacturing method
JP5949719B2 (en) Springback amount evaluation method
JP6414138B2 (en) Body design support apparatus and method
JP5673635B2 (en) Panel component evaluation method, panel component evaluation apparatus, and automotive panel component manufacturing method
Yoshida et al. Material Modeling for Accuracy Improvement of the Springback Prediction of High Strength Steel Sheets
Iwata et al. Numerical prediction of the spring-back behavior of stamped metal sheets
JP2014048886A (en) Method and device for detecting optimal local reinforcing position of component constituting structure and method for reinforcing component based on method for detecting optimal local reinforcing position
KR20240054303A (en) Method for predicting shape change of press molded products
Chen et al. Springback Prediction on Slit‐Ring Test
Liewald et al. Chances and risks when using high strength steel sheets in structural parts of modern car bodies

Legal Events

Date Code Title Description
A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20130731

A871 Explanation of circumstances concerning accelerated examination

Free format text: JAPANESE INTERMEDIATE CODE: A871

Effective date: 20130731

TRDD Decision of grant or rejection written
A975 Report on accelerated examination

Free format text: JAPANESE INTERMEDIATE CODE: A971005

Effective date: 20130827

A01 Written decision to grant a patent or to grant a registration (utility model)

Free format text: JAPANESE INTERMEDIATE CODE: A01

Effective date: 20130903

A61 First payment of annual fees (during grant procedure)

Free format text: JAPANESE INTERMEDIATE CODE: A61

Effective date: 20130916

R150 Certificate of patent or registration of utility model

Ref document number: 5382104

Country of ref document: JP

Free format text: JAPANESE INTERMEDIATE CODE: R150

Free format text: JAPANESE INTERMEDIATE CODE: R150

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250

R250 Receipt of annual fees

Free format text: JAPANESE INTERMEDIATE CODE: R250