Sheared Edge Bend Crack Evaluation in Press-Formed Steel Parts
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Solution Overview
Problem
Current methods lack an effective evaluation technique for bending cracks at the sheared end face of high strength steel sheets during press forming, which is crucial for ensuring the quality and safety of press-formed components in automobiles.
Innovation Solution
A method and system for evaluating bending cracks by determining the relationship between bend outer side strain and stress gradient at the sheared end face, using shape information and forming conditions, to assess the bendability and potential for cracking in metal sheets before press forming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high strength steel sheets are used for press forming, then vehicle weight reduction and collision safety are improved, but bending cracks occur at the sheared end face
Solution Approach 1:
The patent performs preliminary evaluation of bending crack risk before press forming by calculating bend outer side strain and stress gradient from shape information and forming conditions. This allows selection of appropriate metal sheets or adjustment of forming parameters in advance to prevent crack occurrence during actual manufacturing
Solution Approach 2:
The patent replaces physical trial-and-error testing with a computational evaluation system that uses mathematical models to calculate bend outer side strain and stress gradient. This computational approach substitutes mechanical experimentation with theoretical analysis based on shape information and forming conditions
2Measurement precision
If evaluation methods for stretch flange cracks are used, then stretch flange crack prediction is improved, but bending crack evaluation at sheared end face cannot be performed
Solution Approach 1:
The patent changes the evaluation parameters from those used for stretch flange cracks to parameters specific for bending cracks at sheared end faces. It introduces bend outer side strain and stress gradient as key parameters, which are calculated based on shape information and forming conditions, making the evaluation method adaptable to bending crack scenarios
Solution Approach 2:
The patent segments the crack evaluation problem into two distinct types: stretch flange crack evaluation and bending crack evaluation. By separating these evaluation methods, it allows each to use optimized parameters and models specific to its crack type, improving both precision and adaptability
Data Source
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AI summary
Provided is a technology for, when press forming into a desired press-formed component, evaluating forming allowance for a bending crack at a sheared end face of the press-formed component from shape information of an actual component and the like. It is a method for, when applying press forming including bending deformation to a metal sheet subjected to shearing to manufacture a desired press-formed component, evaluating forming allowance for a bending crack at a sheared end face being an end face subjected to the shearing. A crack index value for evaluating the bending crack at the sheared end face of the press-formed component is obtained from a bend outer side strain at or near the sheared end face acquired on a basis of a component shape of the press-formed component and a press die bend radius at a portion forming the sheared end face in a press die used in the press forming, and the forming allowance for the bending crack is evaluated by the obtained crack index value.