Springback Stress Difference Mapping for Press-Formed Parts
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Solution Overview
Problem
Existing methods for press forming analysis, such as CAE analysis, often fail to accurately reproduce the stress state before the press-formed product is released from the die, leading to discrepancies in springback amounts between analysis and actual products, necessitating adjustments in die and forming conditions.
Innovation Solution
A method and apparatus that identify the portion of the press-formed product causing discrepancies in springback amounts by comparing stress distributions between CAE analysis and actual products, involving three-dimensional shape measurement, mechanical analysis, and stress difference calculations to adjust die and forming conditions effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If CAE analysis is used to predict springback, then springback can be estimated before die manufacture, but the analysis often fails to accurately reproduce the actual stress state, leading to discrepancy between predicted and actual springback amounts
Solution Approach 1:
The patent performs preliminary actions by measuring the actual three-dimensional shape of the press-formed product and conducting mechanical analysis to obtain the actual stress distribution before die adjustment. This preliminary characterization of actual stress state enables more accurate springback prediction in subsequent CAE analyses, reducing the need for iterative die adjustments.
Solution Approach 2:
The patent changes key parameters in the CAE analysis by replacing the originally assumed stress distribution with the actual stress distribution obtained from mechanical analysis of the measured product shape. This parameter change aligns the CAE model with reality, significantly improving springback prediction accuracy while maintaining the time-saving benefits of CAE.
2Manufacturing precision
If die adjustment operations are performed to ensure form accuracy, then springback can be reduced, but the process requires extensive trial and error to identify discrepancy-causing portions
Solution Approach 1:
The patent implements feedback by using the measured three-dimensional shape of the actual press-formed product to inform and refine the CAE analysis. The actual product geometry feeds back into the mechanical analysis to determine real stress distribution, which then feeds back into improving the CAE model for more accurate predictions, creating a closed-loop system that reduces trial-and-error adjustments.
Solution Approach 2:
The patent performs preliminary mechanical analysis on the actual measured product to identify the true stress distribution before any die adjustment occurs. This preliminary insight into actual stress states allows for targeted die modifications based on real data rather than theoretical assumptions, streamlining the adjustment process.
3Productivity
If the CAE analysis uses assumed forming loads and standard die shapes, then analysis can be performed quickly, but it cannot accurately reproduce the actual stress state when forming conditions differ from assumptions
Solution Approach 1:
The patent dynamically changes the stress distribution parameters in the CAE analysis based on actual measured data. Instead of using fixed assumed loads and standard die shapes, the analysis adapts its parameters to match the actual forming conditions by incorporating real three-dimensional product geometry and derived stress distributions, maintaining both speed and reliability.
Solution Approach 2:
The patent introduces dynamics into the CAE analysis by making the stress distribution adaptive rather than static. The analysis evolves from using fixed assumed parameters to using dynamically determined parameters based on actual product measurements, allowing the model to adapt to real forming conditions while preserving computational efficiency.
Data Source
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AI summary
Provided are springback amount discrepancy factor portion identification method and apparatus for identifying a portion that is a factor causing a discrepancy in springback amount between a press-formed product and a CAE analysis. The present invention includes a formed product driving stress distribution acquisition step of acquiring a driving stress distribution of a press-formed product, an analysis driving stress distribution acquisition step of acquiring a driving stress distribution of a springback analysis, a stress difference distribution setting step of setting a stress difference distribution between an analysis driving stress distribution and a formed product driving stress distribution to the shape of a formed product at the bottom dead center, a stress difference springback amount acquisition step of acquiring a springback amount based on the stress difference distribution, a changed stress difference springback amount acquisition step of acquiring a springback amount by changing a value in a region of the stress difference distribution, and a springback amount discrepancy factor portion identification step of identifying a portion that is a factor causing a discrepancy in springback amount by comparing the acquired springback amounts.