Press Forming Die Stiffness Design for Lower Forming Loads
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Solution Overview
Problem
Existing methods for designing press forming dies for high-tensile steel sheets require extensive calculation time due to finite element analysis using solid models, and the increased press forming load necessitates process line changes or part division, hindering the application of high-tensile steel sheets in automotive bodies.
Innovation Solution
Designing press forming dies using a shell model with nonrigid two-dimensional elements and varying boundary conditions to reduce stiffness distributions, allowing for rapid press forming load estimation without solid modeling, and adjusting stiffness distributions until the load falls within predetermined limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If solid model (three-dimensional element) is used for FEM analysis of press forming die, then analysis accuracy is improved, but calculation time and modeling time increase significantly
Solution Approach 1:
The patent creates a simplified two-dimensional shell model that copies the essential structural characteristics of the three-dimensional press forming die. This shell model includes key structural elements such as ribs, thickness variations, and support regions, allowing FEM analysis to be performed with significantly reduced calculation and modeling time while maintaining sufficient accuracy for design optimization purposes
Solution Approach 2:
The patent extracts only the critical structural features from the complete three-dimensional die model to create the two-dimensional shell model. By taking out and representing only the essential load-bearing elements (such as rib structures, thickness distributions, and support regions) in a simplified format, the analysis achieves adequate accuracy without the computational burden of full 3D modeling
2Force
If press forming die structure is designed to reduce press forming load, then load on die is reduced, but design time increases due to iterative solid modeling and FEM analysis
Solution Approach 1:
The patent uses a simplified two-dimensional shell model that copies the essential structural behavior of the press forming die, enabling rapid iterative design modifications and FEM analysis. This allows multiple design iterations to be performed in a fraction of the time required by solid modeling, facilitating optimization of die structure to reduce press forming load without excessive design time investment
Solution Approach 2:
The patent enables rapid modification of structural parameters in the two-dimensional shell model, such as rib thickness, rib spacing, die thickness distribution, and support region locations. These parameter changes can be quickly implemented and analyzed through FEM to determine their effect on press forming load, allowing efficient optimization of the die structure to reduce loading while maintaining adequate design time
3Strength
If high-tensile steel sheet is used for automotive body, then fuel efficiency and collision safety are improved, but press forming load increases requiring process line changes or part division
Solution Approach 1:
The patent applies local quality optimization to the press forming die structure by varying thickness, adding ribs, or modifying support regions in specific areas where they are most needed. This localized structural reinforcement or modification allows the die to handle the high press forming loads of high-tensile steel sheets without requiring complete process line changes or part division, maintaining system simplicity while adapting to the stronger material
Data Source
Figure 1
Figure 2~3
Figure 4(A)~4(E)
AI summary
A designing method of a press forming die according to the present invention is a method capable of reducing a press forming load, and includes a die model making step S1, a die model stiffness distribution setting step S3, a press forming load acquiring step S5, a press forming load determining step S7, and a press forming die design stiffness determining step S9 of determining stiffness distributions of a die model as design stiffness distributions of a press forming die when it is determined in the press forming load determining step S7 that a press forming load is within a predetermined range of the press forming load.