EP-4420804-B1 - PRESS-FORMING ANALYSIS METHOD, PRESS-FORMING ANALYSIS APPARATUS, AND PRESS-FORMING ANALYSIS PROGRAM

Inventors

• OGAWA, TAKESHI
• SUMIKAWA, SATOSHI
• YAMASAKI, YUJI
• SHINMIYA, TOYOHISA

Dates

Publication Date

20260506

Application Date

20221108

Claims (11)

1. A computer implemented press forming analysis method for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank, comprising: a first shape acquisition step (S1) of acquiring a shape of a press formed part after die release as a first shape by performing press forming analysis in a case where press forming is performed with a predetermined tool-of-press-forming model by using a flat blank model having a flat shape; a generation step (S3) of generating a shape variation blank model corresponding to the shape variation; a second shape acquisition (S5) of acquiring a shape of a press formed part after die release as a second shape by performing press forming analysis in a case where press forming is performed with the predetermined tool-of-press-forming model by using the shape variation blank model; and a deviation amount acquisition step (S7) of acquiring a portion where both of the first shape and the second shape deviate from each other and a deviation amount by comparing the first shape and the second shape.
2. The press forming analysis method according to claim 1, wherein the shape variation blank model generated in the generation step has a cyclic waveform having a predetermined pitch and a predetermined amplitude.
3. The press forming analysis method according to claim 1, wherein the shape variation blank model generated in the generation step is generated by measuring a shape of an actual blank taken from a metal sheet having a shape variation and referring to a measurement result.
4. The press forming analysis method according to any one of claims 1 to 3, wherein, in the deviation amount acquisition step, a difference between a springback amount of a predetermined portion in the first shape and a springback amount of a same portion as the predetermined portion of the first shape in the second shape is acquired as the deviation amount.
5. The press forming analysis method according to any one of claims 1 to 4, further comprising an identification step of identifying a portion where the deviation amount exceeds a preset threshold as a portion requiring a countermeasure.
6. A press forming analysis apparatus for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank, comprising: a first shape acquisition unit (23) configured to acquire a shape of a press formed part after die release as a first shape by performing press forming analysis in a case where press forming is performed with a predetermined tool-of-press-forming model by using a flat blank model having a flat shape; a generation (25) configured to generate a shape variation blank model corresponding to the shape variation; a second shape acquisition unit (27) configured to acquire a shape of a press formed part after die release as a second shape by performing press forming analysis in a case where press forming is performed with the predetermined tool-of-press-forming model by using the shape variation blank model; and a deviation amount acquisition unit (29) configured tc acquire a portion where both of the first shape and the second shape deviate from each other and a deviation amount by comparing the first shape and the second shape .
7. The press forming analysis apparatus according to claim 6, wherein the shape variation blank model generated by the generation unit has a cyclic waveform having a predetermined pitch and a predetermined amplitude.
8. The press forming analysis apparatus according to claim 6, wherein the shape variation blank model generated by the generation unit is generated based on a measured value of a shape of an actual blank taken from a metal sheet having a shape variation.
9. The press forming analysis apparatus according to any one of claims 6 to 8, wherein the deviation amount acquisition unit is configured to acquire, as the deviation amount, a difference between a springback amount of a predetermined portion in the first shape and a springback amount of a same portion as the predetermined portion of the first shape in the second shape.
10. The press forming analysis apparatus according to any one of claims 6 to 9, further comprising an identification unit configured to identify a portion where the deviation amount exceeds a preset threshold as a portion requiring a countermeasure.
11. A press forming analysis program causing a computer to function as the press forming analysis apparatus according to any one of claims 6 to 10.

Description

Field The present invention relates to a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank. Background In the progress of improvement of collision safety of an automotive body due to tightening of an automobile collision safety standard, weight reduction of automotive body is also required in order to achieve improvement of fuel efficiency of an automobile in response to recent carbon dioxide emission regulations. In order to achieve both the collision safety performance and the weight reduction of automotive body, a growing number of metal sheets having higher strength than before are adopted in automotive bodies. An actual metal sheet from which a blank for obtaining a press formed part is taken has not been completely flat, but has a waveform (shape variation). Therefore, an actual blank taken from the metal sheet is not necessarily flat, and may have a shape variation. When a metal sheet having such a waveform is used as a blank and press-formed into an automotive part, the press formed part obtained after the press forming may deviate from targeted dimensional accuracy due to the shape variation. For example, Patent Literatures 1 and 2 are disclosed as techniques for selecting a press formed part deviating from the targeted dimensional accuracy from press formed parts after press forming. Citation List Patent Literature Patent Literature 1: JP S62-047504 APatent Literature 2: JP 2019-002834 A In addition, JP 6 683269 B1 discloses a press forming analysis method of a shape variation of a blank taken from a metal sheet. According to this method, a shape variation blank model corresponding to the shape variation is generated and a shape of a press formed part after die release is acquired by performing press forming analysis using the blank model. Summary Technical Problem The techniques disclosed in Patent Literature 1 or 2 compares the shapes of the press formed parts after press forming with each other, and cannot predict an influence of the shape variation of a blank before the press forming on the press formed parts after the press forming. The influence of the shape variation of a blank on the shape of a press formed part has not been predicted. Furthermore, a portion of the press formed part susceptible to the influence of the shape variation of the blank has not been identified. The present invention has been made to solve the above-described problems, and an object thereof is to provide a press forming analysis method, a press forming analysis apparatus, and a press forming analysis program for predicting an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank. Solution to Problem A press forming analysis method according to the present invention predicts an influence of a shape variation of a blank taken from a metal sheet having the shape variation in a case where press forming is performed by using the blank, and includes: a first shape acquisition step of acquiring a shape of a press formed part after die release as a first shape by performing press forming analysis in a case where press forming is performed with a predetermined tool-of-press-forming model by using a flat blank model having a flat shape; a generation step of generating a shape variation blank model corresponding to the shape variation; a second shape acquisition step of acquiring a shape of a press formed part after die release as a second shape by performing press forming analysis in a case where press forming is performed with the predetermined tool-of-press-forming model by using the shape variation blank model; and a deviation amount acquisition step of acquiring a portion where both of the first shape and the second shape deviate from each other and a deviation amount by comparing the first shape and the second shape. The shape variation blank model generated in the generation step may have a cyclic waveform having a predetermined pitch and a predetermined amplitude. The shape variation blank model generated in the generation step may be generated by measuring a shape of an actual blank taken from a metal sheet having a shape variation and referring to a measurement result. In the deviation amount acquisition step, a difference between a springback amount of a predetermined portion in the first shape and a springback amount of a same portion as the predetermined portion of the first shape in the second shape may be acquired as the deviation amount. The press forming analysis method may further include an identification step of identifying a portion where the deviation amount exceeds a preset threshold as a portion requiring a countermeasure. A press forming analysis apparatus according to the pre