Press-Formed Sheet Rigidity Planning for Springback Suppression
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Solution Overview
Problem
Conventional methods for reducing springback in press-forming of high strength steel sheets are inadequate, especially for components with low rigidity, as they fail to effectively specify positions for rigidity improvement and may introduce new stresses, leading to incomplete springback suppression.
Innovation Solution
A press-forming method that involves repeatedly performing springback analysis on a virtually rigidified analysis model to identify positions for rigidity improvement, allowing for efficient suppression of springback by restricting stretch and shrink deformation while permitting rotation, and applying rigidity measures to these specified positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional springback reduction methods (emboss crushing, excess bead formation, concave-and-convex portion addition) are applied, then residual stress uniformity is improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent replaces complex mechanical springback reduction methods (emboss crushing, excess bead formation, concave-and-convex portion addition) with a computational approach using springback analysis software. The system uses finite element analysis to calculate residual stress distribution and automatically determine optimal rigidity improvement positions, substituting mechanical process complexity with computational modeling and automated position specification.
Solution Approach 2:
The patent creates a virtual model (analysis model) that copies the geometric shape and material properties of the actual press-formed product. This virtual model is used to perform springback analysis and identify rigidity improvement positions without requiring physical prototypes or trial-and-error manufacturing, thereby reducing device complexity while maintaining precision.
2Strength
If high strength steel sheets are used to increase body strength and rigidity, then collision energy absorption is improved, but springback increases due to higher material strength
Solution Approach 1:
The patent performs springback analysis and identifies rigidity improvement positions before the actual press-forming process. By pre-calculating the residual stress distribution and determining where rigidity enhancement is needed, the system prepares a plan that compensates for the increased springback tendency of high strength steel, allowing the final product to achieve both high strength and good shape fixability.
Solution Approach 2:
The patent applies rigidity improvement measures selectively at specific positions identified through springback analysis, rather than uniformly across the entire sheet. The system determines local regions where additional rigidity is needed based on residual stress distribution patterns, applying measures such as increased material thickness or structural reinforcement only where necessary to control springback while maintaining overall strength.
3Manufacturing precision
If shape optimization analysis or topology optimization analysis is performed to detect rigidity contributory positions, then springback suppression effectiveness is improved, but analysis time and computational resources increase
Solution Approach 1:
The patent extracts only the essential information needed for springback control from complex optimization analyses. Instead of performing full shape optimization or topology optimization that analyzes all possible design variations, the system focuses specifically on calculating residual stress distribution and identifying positions where rigidity improvement will have the greatest impact on springback reduction, thereby reducing analysis time while maintaining effectiveness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables precise specification of positions for rigidity improvement, effectively reducing springback in press-formed products without requiring complex optimization analyses, thus enhancing shape fixability and dimensional accuracy.
Implementation Method 1
restricting a stretch and shrink deformation while permitting rotation with respect to a specific position of a formed-product model
Implementation Method 2
The springback is caused by elastic recovery generated when a bending moment due to a non-uniform residual stress is released at the removal of the press-formed product from the die
Implementation Method 3
crushing the emboss to apply a compressive stress to the stretch flange portion and a tensile stress to the shrink flange portion
Data Source
Figure 1~2
Figure 3~4
AI summary
It is an object to provide a press-forming method that can efficiently suppress springback and easily specify a position where a springback reduction effect by rigidity improvement is large, and the press-forming method used in producing a press-formed product having a predetermined shape by press-forming a sheet material, the method comprising: a first process that repeatedly performs a springback analysis, while changing a position to be restricted, with an analysis model on which processing of virtually improving rigidity has been performed by restricting a stretch and shrink deformation while permitting rotation with respect to a specific position of a formed-product model having the predetermined shape, to specify a position where a springback reduction effect by rigidity improvement is large; a second process that performs a rigidity improvement measure on a position of the sheet material corresponding to the position of the formed-product model specified in the first process; and a third process that produces the press-formed product by press-forming the sheet material on which the rigidity improvement measure has been performed.