JP2004050253A

JP2004050253A - Press formation analysis method of pressed part by means of computer simulation, and characteristic analysis method of structure including pressed part

Info

Publication number: JP2004050253A
Application number: JP2002212742A
Authority: JP
Inventors: Koji Tanaka; 田中　康治; Koji Hashimoto; 橋本　浩二; Akihiro Uenishi; 上西　朗弘; Hiroshi Yoshida; 吉田　博司; Hitoshi Suga; 菅　仁志
Original assignee: Nippon Steel Corp; Toyota Motor Corp
Current assignee: Nippon Steel Corp; Toyota Motor Corp
Priority date: 2002-07-22
Filing date: 2002-07-22
Publication date: 2004-02-19
Anticipated expiration: 2022-07-22
Also published as: JP3979492B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a press formation analysis method of a pressed part by means of a simple and highly accurate computer simulation based on a final shape of the pressed part, and a characteristic analysis method of anti-collision performance characteristics, strength performance characteristics, rigidity characteristics, vibration and acoustic characteristics, etc. with high accuracy of a structure including the pressed part. <P>SOLUTION: Data 5 on a shape in which a hole part included in the pressed part is filled, and a flange or a flange having a draw bead is added to an outer circumferential part is prepared based on data 1 on the final part shape of the pressed part, and the press formation analysis is performed by the inverse analysis method based on data 5 of the shape. Characteristic analysis is performed in a coupling manner on anti-collision performance characteristic, strength performance characteristic, rigidity characteristic, vibration and acoustic characteristics, etc. by mapping inverse analysis result data 8 obtained by this method. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、プレス成形により製作される部品のコンピュータシミュレーションによるプレス成形解析法及び自動車等のプレス部品を含む構造体の耐衝突性能特性や強度性能特性や剛性特性や振動・音響特性等の特性解析法に関するものである。
【０００２】
【従来の技術】
従来より、自動車車両等のプレス成形金属部品を含む構造体の設計においては、コンピュータシミュレーションによりその構造体の耐衝突性能、強度、剛性や振動・音響特性等の特性に関する各種性能の解析が行なわれている。
【０００３】
プレス成形された金属部品はプレス前の母材（ブランク）と比較して、板厚、残留ひずみ、残留応力等の特性が変化する。また残留ひずみが変化することによる金属部品の加工硬化等により応力−歪み特性も大きく変化する。さらにこれらの変化は同一部品内においても部位によって異なる。従って、プレス成形金属部品を含む構造体の耐衝突性能、強度、剛性や振動・音響特性等の特性に関する解析を精度よく行なうためには、個々の部品のプレス成形による厚さ分布、残留歪み分布、応力−歪み特性の変化等を考慮したコンピュータシミュレーションモデルを作成し、解析する必要がある。
【０００４】
プレス成形される金属部品の成形性や成形後の板厚、残留歪み、応力分布等については、既にコンピュータシミュレーションによる成形解析法が提案されている。その代表的なものは、インクレメンタル（Ｉｎｃｒｅｍｅｎｔａｌ）法である。インクレメンタル法は、ブランク、金型、ホルダー、パンチ等の形状、材料特性、潤滑条件や押え力等のプレス条件をもとに、プレス加工の工程を微小なタイムステップに区切り、タイムステップ毎の微小変形について順次計算を積み重ねて行く解法であり、比較的高い計算精度が得られる。
【０００５】
このインクレメンタル法によりプレス成形される金属部品のコンピュータシミュレーションによる成形解析を行なうためには、まず金型、ホルダー、パンチ等の金型設計を行い、潤滑条件や押え力等のプレス条件を設定しなければならない。ところが通常の自動車の設計業務では、コンピュータシミュレーションによる耐衝突性能や強度等に関する解析評価を行ないながら部品形状を決定して行く。そして部品形状を決定した後で、プレスのための金型設計に入るのが普通である。従って、設計段階においては金型形状やプレス条件が決定されておらず、インクレメンタル法によるプレス成形解析が出来ない段階で耐衝突性能や強度等に関するコンピュータシミュレーションを行なう必要がある。またインクレメンタル法は一つのプレス部品の解析計算に数時間から数十時間という非常に長時間を要という問題もある。このためインクレメンタル法は主に個々のプレス部品の成型性検討や金型設計等には用いられているが、非常に多くのプレス部品からなる自動車等の構造体の設計段階での耐衝突性能や強度等の検討のためのコンピュータシミュレーションによる解析においてはほとんど行なわれていない。
【０００６】
このほか、プレス後の形状をベースとして解析を行うインバース（Ｉｎｖｅｒｓｅ）法がある。この方法はプレス後の最終形状からブランクの初期平面形状を逆解析し、プレスによる各部分の形状変化から板厚、残留歪み、残留応力等の特性を求める方法であり、インクリメンタル法と比較して非常に短時間で解析可能である。製品形状をもとにインバース解析を行えば、金型設計が不要であるうえ長い計算時間を要しないので、インクレメンタル法とは異なり通常の自動車等の構造体の設計段階での耐衝突性能や強度等の検討のためのコンピュータシミュレーション解析に取り入れることが可能である。しかしこの製品形状をもとにしたインバース法はあまりにも計算精度が低いため、実用性がないとされている。
【０００７】
上記したように、既存のコンピュータシミュレーション法にはそれぞれ欠点があり、実用的には用いられていない。そこで一般的には、プレス成形される部品の設計段階ではプレス成形に起因する板厚減少や加工硬化等の特性変化を無視し、プレス成形部材がプレス前の母材と同一の板厚であり、残留歪みもないものとして耐衝突性能や強度等に関する解析評価を行なっている。その結果、大きな解析誤差が生じており、コンピュータシュミレーションだけでは十分な精度での設計が行えないため、実験による耐衝突性能や強度等の確認と設計修正を何度も繰り返すことが必要になり設計を行なう上でのコスト増、設計工期増等の要因となっていた。
【０００８】
【発明が解決しようとする課題】
本発明は上記した従来の問題点を解決し、コンピュータシミュレーションにより、金型設計を必要とせずかつ短時間で部品の最終形状から精度よくプレス成形部品の板厚、残留歪み、残留応力等の特性を求めることができるコンピュータシミュレーションによるプレス部品の成形解析法と、さらに構造体の耐衝突性能特性や強度性能特性や剛性特性や振動・音響特性等の特性解析を高精度に行うことができるプレス部品を含む構造体の特性解析法を提供するためになされたものである。
【０００９】
【課題を解決するための手段】
上記の課題を解決するために本発明者等は検討を重ねた結果、製品形状をもとにしたインバース解析の計算精度が低いのことの主たる原因は、プレス成形の過程での金属の流れに対する移動抵抗が実際の現象と大きく異なっている点にあるのではないかと考えた。そして部品の最終形状の外周部に移動抵抗力を付加して解析を行なえば、短時間で精度の高いプレス成形解析が行なえることを究明した。
【００１０】
本発明は上記の知見に基づいて完成されたものであって、請求項１の発明のコンピュータシミュレーションによる部品のプレス成形解析法は、金属材料をプレス成形して製作されるか、もしくはプレス成形と合わせて穴明け加工やトリム加工や曲げ加工等の一つもしくは複数の加工を行って製作されるプレス部品の板厚分布や残留ひずみ分布等の特性をコンピュータシミュレーションにより解析するにあたって、プレス部品の加工後の最終部品形状のデータをもとに、その最終部品形状の外周部にフランジもしくはドロービードを有しているフランジを追加したフランジ追加形状のデータを作成し、このフランジ追加形状のデータについてインバース解析法によりプレス成形解析を行なうことを特徴とするものである。
【００１１】
また、請求項２の発明のコンピュータシミュレーションによる部品のプレス成形解析法は、金属材料をプレス成形と合わせて穴明け加工やトリム加工や曲げ加工等の一つもしくは複数の加工を行って製作されるプレス部品の内その加工工程としてプレス成形後に穴明け加工を行うプレス部品の板厚分布や残留ひずみ分布等の特性をコンピュータシミュレーションにより解析するにあたって、プレス部品の加工後の最終部品形状のデータをもとにそのプレス成形後にあけられた穴部を埋めた穴埋め形状のデータを作成し、その穴埋め形状の外周部にフランジもしくはドロービードを有しているフランジを追加したフランジ追加形状のデータを作成し、このフランジ追加形状のデータについてインバース解析法によりプレス成形解析を行なうことを特徴とするものである。
【００１２】
なお、請求項３、４に示すように、最終形状の外周部もしくは穴埋め形状の外周部に追加されるフランジもしくはドロービードを有しているフランジの方向を、部品のプレス方向に対して垂直もしくは、最終形状の外周部もしくは穴埋め形状の外周部の延長方向とすることができる。
【００１３】
また請求項５の発明のコンピュータシミュレーションによる構造体の耐衝突性能や強度性能や剛性特性や振動・音響特性等の特性解析法は、構造体に含まれるプレス部品の全てもしくは一部について請求項１、２、３または４に記載のプレス成形解析法により得られたプレス後の板厚分布や残留歪み分布を含むデータを用い、構造体の耐衝突性能特性や強度性能特性や剛性特性や振動・音響特性等の特性解析を連成的に行なうことを特徴とするものである。
【００１４】
請求項１，２，３，４の発明によれば、インバース解析法によりプレス成形解析を短時間で精度良く行なうことができ、プレス後の板厚分布や残留歪み分布を正確に知ることができる。また請求項５の発明によれば、インバース解析法の結果を利用して連成解析を行ない、構造体の耐衝突性能特性、強度性能特性、剛性特性または振動・音響特性等の特性を精度良く求めることができる。従って本発明によれば、構造体の設計段階において、耐衝突性能特性、強度性能特性剛性特性または振動・音響特性等に関する解析評価を実用的なレベルで行なうことができる。
以下に本発明をその実施形態とともに更に詳細に説明する。
【００１５】
【発明の実施の形態】
図１は本発明の実施形態のフローを示すブロック図である。また図３は本発明の工程中で作成される形状データを、画像として模式的に示す斜視図である。図３の形状は画面上に表示されるだけのものであって、実物が存在するわけではない。なお、本発明において解析の対象とするのは、プレス成形によりもしくはプレス成形あわせてトリム加工及や穴開け加工により最終形状とされる金属部品であり、自動車の金属部品の多くはこれに該当する。この実施形態では、自動車ボディに用いられる図３Ａに示す形状１１の部品を解析対象とする。
【００１６】
最終形状のデータ１による形状を図３Ａに示す。ここで形状データとしてはＣＡＤデータを用いてもまたＦＥＭのメッシュデータを用いることが出来る。図３Ａから分かるように、この部品１１はプレス後に複数の穴部１２を加工されたものである。本発明では穴開け前のプレス成形解析を行なうのであるから、最終形状のデータ１から穴部１２を埋めた穴埋め形状のデータ３を作成する。その形状を図３Ｂに示す。
【００１７】
次にこのデータ３にはプレス成形中における金属の流れによる移動抵抗の要素が含まれていないため、穴埋め形状の外周部にドロービード１４を含むフランジ部１３を追加する処理４を行いフランジを追加した形状データ５を得る。
【００１８】
また、もしプレス部品がプレス成形後に穴あけされていなければ、穴埋め処理２を省略して、最終製品形状１に直接フランジもしくはドロービードを含むフランジを追加すればよく、この場合の実施形態のフローを図２に示す。
【００１９】
この実施形態ではフランジの方向を、部品のドロービードを含むプレス方向に対して垂直とすることにより図３Ｃに示す様な形状を得たが、フランジの方向を最終形状の外周部もしくは穴埋め形状の外周部の延長方向とした図３ｄに示す様な形状をしてもよい。またドロー含むフランジ部の代わりにドロービードの無いフランジとしてもよい。このようなにフランジを付けることにより、プレス成形中の金属流れの移動抵抗を形状に置き換えることができる。
【００２０】
フランジの長さやドロービードのサイズ、位置については、部品サイズに対して一定割合とするか、部品サイズに応じて一定量とするか、構造断面の縦・横長さに応じて設定する方法等がある。データの蓄積によりフランジ長さの最適な決定法を確立できるが、解析者が経験的に設定を行なうようにしてもよい。この実施形態では、穴埋め形状の外周部に一定長さのフランジを設定しその中央にドロービードを設定している。
【００２１】
ここで、最終形状に対しておこなう穴埋め、フランジやドロービードの追加などの形状修正はＣＡＤデータベースでおこなっても、ＦＥＭのメッシュデータベースで行ってもよい。
【００２２】
このようにして金属の流れに対する移動抵抗を考慮するためのフランジ追加形状データ５を作成したうえ、このフランジ追加形状データ５に材料特性６を加えたインバース解析モデル７を作成し、公知のインバース解析法によりプレス成形解析を行なう。前記したようにインバース解析法は金型データ等を必要とせず、部品形状からブランクの初期平面形状を逆算し、板厚、残留歪み、残留応力等の特性を求める方法である。本発明では部品の最終形状ではなく、フランジ追加形状をもとにインバース解析を行なうため、短時間でしかも精度よくプレス後の板厚、残留歪み、残留応力等の解析結果データ８を求めることができる。
【００２３】
構造体の耐衝突性能や強度性能や剛性特性や振動・音響特性等の性能特性解析を行なう請求項５の発明においては、構造体のを構成する個々のプレス部品に対し、それぞれ上記のようにしてプレス成形解析法により得られたプレス後の板厚分布や残留歪み分布を含む解析結果データ８を、特性解析モデル９の個々のプレス部品にマッピングして、公知特性解析を連成的に行なう。この特性解析プログラム自体は既存のものであるが、特性解析モデル９の個々のプレス部品に板厚分布や残留歪み分布等が正確にマッピングされているため、従来に比較して精度の高い衝突強度の解析が可能となる。
【００２４】
また、構造体を構成する全てのプレス部品に対しプレス後の板厚分布や残留歪み分布を考慮する必要が無い場合は、全てのプレス部品に対してプレス成形解析を行う必要はなく、板厚分布や残留歪み分布の考慮が必要な部材についてのみプレス成形解析と解析データのマッピングを行って連成連成解析を行えばよい。
【００２５】
また図４のような２つのプレス部品からなる潰れビードを持つ箱形構造の落重による耐衝突特性について、実験と本発明による解析結果を表１に示す。本発明による解析では２つのプレス部材のそれぞれの製品形状の外周に４０ｍｍのフランジを外周部の延長方向に追加して形状データを作成し、このフランジをインバース解析して板厚分布および残留ひずみ分布を求めて耐衝突性能特性モデルにマッピングして特性解析を行った。表１から判るように、プレス部材のプレスによる板厚分布や残留ひずみ分布を無視した耐衝突特性は実験値に比べ大きな誤差が生じているが、本発明による解析の結果は実験値に非常近い値となっており、特性解析の大幅な精度向上がはかられている。なお図４のモデルは、高さ２１６ｍｍ×幅１２０ｍｍ×奥行き６０ｍｍのサイズのもので、材質は板厚１．６ｍｍ、最大強度５９０Ｍｐａの冷延鋼板であり、落重衝突条件は落重質量１１０ｋｇｆ、落重速度１２．９ｍ／ｓである。
【００２６】
【表１】

【００２７】
【発明の効果】
以上に説明したように、本発明の部品のプレス成形解析法によれば、最終部品形状にフランジもしくはドロービードを有しているフランジを追加することによって金属の流れの移動抵抗を考慮し、それをインバース法により解析することによって、部品の最終形状のデータから金型設計を必要とせずかつ非常に短時間でプレス成形部品の板厚、残留歪み、残留応力等の特性を求めることができる。
【００２８】
また本発明の構造体の耐衝突性能特性、強度性能特性剛性特性または振動・音響特性等部品の特性解析法によれば、プレス後の板厚分布や残留歪み分布を含むデータをマッピングした特性解析モデルを用いて衝突解析を連成的に行なうので、従来に比較して精度の高い特性解析が可能となる。
【００２９】
このように本発明によれば、自動車等のプレス部品を含む構造体の設計業務において、金型設計等の膨大な追加業務を伴うことなく、コンピュータシミュレーションによってプレス部品を含む構造体の特性に関する解析評価を非常に高精度で行なうことができるので、実験による耐衝突性能や強度等の確認や設計修正を大幅に減らすことができ、自動車等の構造体の設計を行なう上での低コスト化や設計工期短縮をはかることが可能になる。
【図面の簡単な説明】
【図１】本発明の実施形態のフローを示すブロック図である。
【図２】本発明の実施形態のフローを示すブロック図である。
【図３】本発明の工程中で作成される形状データの画像を示す斜視図である。
【図４】本発明の実施例で行った落重による衝突モデルである。
【符号の説明】
１　最終部品形状データ
２　穴埋め処理
３　穴埋め形状データ
４　フランジもしくはドロービードを含むフランジを追加する処理
５　フランジ追加形状データ
６　材料特性
７　インバース解析モデル
８　インバース解析結果
９　特性解析モデル
１０　連成特性解析
１１　最終部品形状
１２　穴部
１３　フランジ
１４　ドロービード[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a press forming analysis method by computer simulation of parts manufactured by press forming, and a characteristic analysis such as a collision resistance characteristic, a strength performance characteristic, a rigidity characteristic and a vibration / acoustic characteristic of a structure including a pressed part such as an automobile. It is about the law.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in the design of a structure including a press-formed metal part such as an automobile vehicle, a computer simulation has been used to analyze various performances of the structure, such as collision resistance, strength, rigidity, vibration and acoustic characteristics. ing.
[0003]
A metal part formed by press molding changes in properties such as plate thickness, residual strain, and residual stress as compared with a base material (blank) before pressing. In addition, the stress-strain characteristics also change greatly due to work hardening of the metal component due to the change in the residual strain. Further, these changes are different from part to part even in the same part. Therefore, in order to accurately analyze the impact resistance, strength, rigidity, vibration and acoustic characteristics, etc. of the structure including the press-formed metal parts, the thickness distribution and residual strain distribution of the individual parts by press forming are required. It is necessary to create and analyze a computer simulation model in consideration of changes in stress-strain characteristics and the like.
[0004]
With respect to the formability and the thickness, residual strain, stress distribution, and the like of a metal part to be press-formed, a forming analysis method by computer simulation has already been proposed. A typical example is an incremental method. The incremental method divides the pressing process into minute time steps based on the pressing conditions such as the shapes of blanks, dies, holders, and punches, material characteristics, lubrication conditions, and pressing force. This is a solution in which calculations are sequentially accumulated for small deformations, and relatively high calculation accuracy can be obtained.
[0005]
In order to perform a molding analysis of a metal part press-formed by the incremental method by computer simulation, first, a mold such as a mold, a holder and a punch is designed, and press conditions such as lubrication conditions and pressing force are set. There must be. However, in the usual design work of an automobile, the shape of a part is determined while performing an analysis and evaluation on collision resistance, strength and the like by computer simulation. After determining the part shape, it is usual to enter a mold design for a press. Therefore, at the design stage, the shape of the mold and the pressing conditions are not determined, and it is necessary to perform computer simulation on the impact resistance, strength and the like at the stage where the press forming analysis by the incremental method cannot be performed. In addition, the incremental method has a problem that it takes a very long time of several hours to several tens of hours for the analysis calculation of one pressed part. For this reason, the incremental method is mainly used for examining the moldability of individual pressed parts and designing dies, but the impact resistance at the design stage of automobiles and other structures consisting of a large number of pressed parts Is hardly performed in the analysis by computer simulation for studying the strength and the like.
[0006]
In addition, there is an inverse method for performing analysis based on the shape after pressing. This method reversely analyzes the initial plane shape of the blank from the final shape after pressing, and obtains properties such as plate thickness, residual strain, residual stress, etc. from the shape change of each part by pressing, compared with the incremental method. It can be analyzed in a very short time. Performing an inverse analysis based on the product shape eliminates the need for mold design and requires a long calculation time. It can be incorporated into computer simulation analysis for studying strength and the like. However, the inverse method based on this product shape is considered to be impractical because the calculation accuracy is too low.
[0007]
As described above, each of the existing computer simulation methods has a drawback and is not used practically. Therefore, in general, at the design stage of parts to be press-formed, changes in properties such as thickness reduction and work hardening caused by press-forming are ignored, and the press-formed member has the same thickness as the base material before pressing. Assuming that there is no residual strain, analysis and evaluation on collision resistance, strength and the like are performed. As a result, large analysis errors occur, and computer simulation alone cannot be used to design with sufficient accuracy. However, this has led to an increase in cost and an increase in the design period for the implementation.
[0008]
[Problems to be solved by the invention]
The present invention solves the above-mentioned conventional problems and, by computer simulation, does not require a mold design, and quickly and precisely from the final shape of the part to the characteristics such as plate thickness, residual strain, residual stress, etc. of the pressed part. Parts that can be obtained by computer simulation that can determine the shape of the pressed parts, and the pressed parts that can analyze the collision resistance, strength, rigidity, vibration and acoustic characteristics of the structure with high accuracy. The purpose of the present invention is to provide a method for analyzing the characteristics of a structure including:
[0009]
[Means for Solving the Problems]
As a result of repeated studies by the present inventors to solve the above-described problems, the main cause of the low calculation accuracy of the inverse analysis based on the product shape is mainly due to the metal flow in the process of press forming. We thought that the movement resistance might be significantly different from the actual phenomenon. Then, it was clarified that accurate press forming analysis can be performed in a short time by applying a movement resistance to the outer peripheral portion of the final shape of the part and performing the analysis.
[0010]
The present invention has been completed based on the above findings, and the method for analyzing the press forming of parts by computer simulation according to the invention of claim 1 is a method for manufacturing by pressing a metal material, When analyzing by computer simulation the characteristics such as plate thickness distribution and residual strain distribution of a pressed part manufactured by performing one or more processing such as drilling, trimming, bending, etc. Based on the data of the final part shape, the data of the additional flange with additional flange or draw bead on the outer periphery of the final part shape is created, and inverse analysis is performed on the data of the additional flange shape. It is characterized by performing press forming analysis by the method.
[0011]
The method of analyzing press forming of a part by computer simulation according to the second aspect of the present invention is manufactured by performing one or more processes such as drilling, trimming, bending, and the like on a metal material together with press forming. When analyzing the characteristics such as the thickness distribution and residual strain distribution of a pressed part that performs drilling after press forming as a processing step of the pressed part by computer simulation, the data of the final part shape after processing of the pressed part is also used. Create data of a hole filling shape that fills the hole that was drilled after the press molding, and create data of a flange addition shape in which a flange having a flange or a draw bead is added to the outer periphery of the hole filling shape, Perform press forming analysis on the data of this additional flange shape by the inverse analysis method. It is an feature.
[0012]
In addition, as shown in Claims 3 and 4, the direction of the flange having a flange or a draw bead added to the outer peripheral portion of the final shape or the outer peripheral portion of the filled-in shape is perpendicular to the pressing direction of the part, or The extension direction may be the outer peripheral portion of the final shape or the outer peripheral portion of the filled shape.
[0013]
The method for analyzing characteristics such as collision resistance, strength performance, rigidity characteristics, and vibration / acoustic characteristics of a structure by computer simulation according to the invention of claim 5 is directed to all or a part of the pressed parts included in the structure. Using the data including the thickness distribution and residual strain distribution after pressing obtained by the press forming analysis method described in 2, 3 or 4, the impact resistance characteristics, strength performance characteristics, rigidity characteristics, vibration, Characteristic analysis such as acoustic characteristics is performed in a coupled manner.
[0014]
According to the first, second, third, and fourth aspects of the present invention, the press forming analysis can be accurately performed in a short time by the inverse analysis method, and the thickness distribution and the residual strain distribution after the pressing can be accurately known. . According to the fifth aspect of the present invention, a coupled analysis is performed using the result of the inverse analysis method, and the characteristics of the structure such as the collision resistance characteristics, the strength performance characteristics, the rigidity characteristics, and the vibration / acoustic characteristics are accurately determined. You can ask. Therefore, according to the present invention, in the design stage of a structural body, it is possible to perform an analysis and evaluation on a crash resistance characteristic, a strength performance characteristic, a rigidity characteristic, a vibration / acoustic characteristic, and the like at a practical level.
Hereinafter, the present invention will be described in more detail with reference to embodiments thereof.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a block diagram showing a flow of an embodiment of the present invention. FIG. 3 is a perspective view schematically showing, as an image, shape data created in the process of the present invention. The shape in FIG. 3 is only displayed on the screen, and there is no real thing. In the present invention, an object to be analyzed is a metal part whose final shape is formed by press forming or trimming and drilling together with press forming, and many metal parts of an automobile correspond to this. . In this embodiment, a part having a shape 11 shown in FIG. 3A used for an automobile body is to be analyzed.
[0016]
FIG. 3A shows a shape based on data 1 of the final shape. Here, as the shape data, mesh data of FEM can be used even if CAD data is used. As can be seen from FIG. 3A, the component 11 has a plurality of holes 12 formed after pressing. In the present invention, since the press-forming analysis before drilling is performed, the data 3 of the hole filling shape in which the hole 12 is filled is created from the data 1 of the final shape. The shape is shown in FIG. 3B.
[0017]
Next, since the data 3 does not include the element of the movement resistance due to the flow of the metal during the press forming, the processing 4 for adding the flange portion 13 including the draw bead 14 to the outer peripheral portion of the fill-in shape was performed, and the flange was added. The shape data 5 is obtained.
[0018]
Also, if the pressed part is not drilled after press forming, the filling process 2 may be omitted and a flange or a flange including a draw bead may be added directly to the final product shape 1. FIG. It is shown in FIG.
[0019]
In this embodiment, the shape as shown in FIG. 3C is obtained by making the direction of the flange perpendicular to the pressing direction including the draw bead of the part. However, the direction of the flange is changed to the outer periphery of the final shape or the outer periphery of the filled shape. The shape may be as shown in FIG. Further, a flange without a draw bead may be used instead of the flange portion including the draw. By providing such a flange, the movement resistance of the metal flow during press forming can be replaced with a shape.
[0020]
There are methods such as setting the length of the flange and the size and position of the draw bead to a fixed ratio to the component size, a fixed amount according to the component size, or setting according to the vertical and horizontal length of the structural cross section . Although an optimal method for determining the flange length can be established by accumulating data, an analyst may make an empirical setting. In this embodiment, a flange of a fixed length is set at the outer peripheral portion of the fill-in shape, and a draw bead is set at the center of the flange.
[0021]
Here, shape correction such as filling of holes and addition of flanges and draw beads to the final shape may be performed using a CAD database or a FEM mesh database.
[0022]
In this way, the flange additional shape data 5 for considering the movement resistance to the metal flow is created, and the inverse analysis model 7 in which the material characteristics 6 are added to the flange additional shape data 5 is created. Press molding analysis is performed by the method. As described above, the inverse analysis method does not require mold data or the like, but is a method of calculating the initial plane shape of the blank from the component shape and calculating characteristics such as plate thickness, residual strain, and residual stress. In the present invention, inverse analysis is performed based on the additional shape of the flange, not the final shape of the part. Therefore, it is possible to quickly and accurately obtain the analysis result data 8 such as the thickness, residual strain, and residual stress after pressing in a short time. it can.
[0023]
In the invention according to claim 5, the performance characteristics of the structure such as collision resistance, strength performance, rigidity characteristics, vibration and acoustic characteristics are analyzed. Analysis data 8 including the thickness distribution and residual strain distribution after pressing obtained by the press forming analysis method are mapped to individual pressed parts of the characteristic analysis model 9 to perform a known characteristic analysis in a coupled manner. . Although the characteristic analysis program itself is an existing program, since the thickness distribution, the residual strain distribution, and the like are accurately mapped on the individual pressed parts of the characteristic analysis model 9, the collision strength is higher than in the past. Can be analyzed.
[0024]
When it is not necessary to consider the thickness distribution and residual strain distribution after pressing for all the pressed parts constituting the structure, it is not necessary to perform the press forming analysis for all the pressed parts. Press-forming analysis and mapping of the analysis data may be performed only on members for which distribution and residual strain distribution need to be considered, and coupled-coupling analysis may be performed.
[0025]
Table 1 shows the results of an experiment and the analysis of the present invention with regard to the collision resistance characteristics of a box-shaped structure having a crushed bead made of two pressed parts as shown in FIG. In the analysis according to the present invention, a shape data is created by adding a 40 mm flange to the outer periphery of each product shape of the two press members in the extension direction of the outer periphery, and the flange is subjected to inverse analysis to obtain a thickness distribution and a residual strain distribution. The characteristic analysis was performed by mapping to the collision performance model. As can be seen from Table 1, the collision resistance of the press member ignoring the thickness distribution and the residual strain distribution due to pressing has a larger error than the experimental value, but the result of the analysis according to the present invention is very close to the experimental value. Value, which greatly improves the accuracy of characteristic analysis. The model in FIG. 4 has a size of 216 mm in height × 120 mm in width × 60 mm in depth. The material is a cold-rolled steel plate having a thickness of 1.6 mm and a maximum strength of 590 Mpa. The falling speed is 12.9 m / s.
[0026]
[Table 1]

[0027]
【The invention's effect】
As described above, according to the press forming analysis method of the present invention, the movement resistance of the metal flow is considered by adding a flange or a flange having a draw bead to the final part shape, and it is taken into consideration. By analyzing by the inverse method, it is possible to obtain the characteristics such as the plate thickness, residual strain, residual stress and the like of the press-formed component in a very short time without the need of a mold design from the data of the final shape of the component.
[0028]
In addition, according to the method for analyzing the characteristics of components such as the collision resistance characteristics, the strength performance characteristics, the rigidity characteristics, and the vibration / acoustic characteristics of the structure of the present invention, the characteristic analysis is performed by mapping the data including the thickness distribution and the residual strain distribution after pressing. Since the collision analysis is performed jointly using the model, it is possible to perform a characteristic analysis with higher accuracy than in the past.
[0029]
As described above, according to the present invention, in the design work of a structure including a pressed part of an automobile or the like, the analysis on the characteristics of the structure including the pressed part is performed by computer simulation without involving a huge amount of additional work such as die design. Since the evaluation can be performed with very high precision, it is possible to significantly reduce the number of verifications and verifications of collision resistance and strength by experiments, and to reduce costs in designing structures such as automobiles. It is possible to shorten the design period.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a flow of an embodiment of the present invention.
FIG. 2 is a block diagram showing a flow of an embodiment of the present invention.
FIG. 3 is a perspective view showing an image of shape data created in the process of the present invention.
FIG. 4 is a collision model due to falling weight performed in the embodiment of the present invention.
[Explanation of symbols]
1 Final part shape data 2 Filling process 3 Filling shape data 4 Processing to add a flange including a flange or draw bead 5 Additional flange data 6 Material properties 7 Inverse analysis model 8 Inverse analysis result 9 Characteristic analysis model 10 Coupled characteristic analysis 11 Final Part shape 12 Hole 13 Flange 14 Draw bead

Claims

Thickness distribution and residual strain of pressed parts that are manufactured by pressing metal materials or that are manufactured by performing one or more processes such as drilling, trimming, bending, etc. together with press forming In analyzing the characteristics such as distribution by computer simulation, based on the data of the final part shape after processing of the pressed part, a flange with a flange or a draw bead on the outer periphery of the final part shape added A forming analysis method for a pressed part by computer simulation, wherein shape data is created and press forming analysis is performed on the data of the added shape of the flange by an inverse analysis method.

Among the pressed parts manufactured by performing one or more processes such as drilling, trimming, bending, etc. in conjunction with press forming of metal materials, of the pressed parts that perform drilling after press forming as a processing step When analyzing the characteristics such as thickness distribution and residual strain distribution by computer simulation, based on the data of the final part shape after processing of the pressed part, the data of the hole filling shape that filled the hole drilled after press forming was used. It is characterized by creating a flange addition shape data by adding a flange or a draw bead that has a flange or a draw bead on the outer periphery of the fill-in shape, and performing press forming analysis by inverse analysis method on the data of this flange addition shape. Forming analysis method of pressed parts by computer simulation.

3. The part by computer simulation according to claim 1 or 2, wherein the direction of the flange added to the outer peripheral part of the final shape or the outer peripheral part of the filled-in shape or the flange having a draw bead is perpendicular to the pressing direction of the part. Press forming analysis method.

The direction of the flange added to the outer peripheral portion of the final shape or the outer peripheral portion of the filled-in shape or the direction of the flange having the draw bead is defined as the extension direction of the outer peripheral portion of the final shape or the outer peripheral portion of the filled-in shape. A forming analysis method for a pressed part by the computer simulation described above.

Analyzes performance characteristics such as collision resistance, strength performance, rigidity characteristics, vibration and acoustic characteristics of a structure composed of one or more pressed parts or including one or more pressed parts In doing so, for all or a part of the pressed parts included in the structure, data including the thickness distribution and the residual strain distribution of the pressed parts obtained by the press forming analysis method according to claim 1, 2, 3, or 4 is used. A method of analyzing the characteristics of structures including pressed parts by computer simulation, which analyzes characteristics such as collision resistance, strength, rigidity, and vibration / acoustic characteristics of the structure.