Sheared Edge Crack Evaluation in Press-Formed Steel Bending
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Solution Overview
Problem
Current methods lack a reliable evaluation technique for bending cracks at the sheared end face of press-formed components, particularly for high-strength steel sheets, which are critical for weight reduction and collision safety 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 press die bend radius to calculate a crack index value, enabling the selection of metal sheets that minimize bending cracks during 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 applies preliminary action by calculating a crack index value before press forming to predict bending crack occurrence. The system computes the crack index using bend outer side strain and press die bend radius, then determines forming allowance in advance, allowing preventive measures to be taken before actual forming occurs
Solution Approach 2:
The patent replaces direct mechanical testing with computational evaluation. Instead of physically testing metal sheets through forming processes, the system uses mathematical calculations involving bend outer side strain, stress gradient, and crack index values to predict crack behavior and determine forming allowance
2Measurement precision
If a crack evaluation method for bending crack is developed, then forming allowance can be determined accurately, but no such method has been developed yet
Solution Approach 1:
The patent introduces a crack index value as an intermediary parameter that bridges the relationship between bend outer side strain, stress gradient, and bending crack occurrence. This intermediate calculation simplifies the evaluation process by providing a standardized metric that can be computed from existing forming parameters
Solution Approach 2:
The patent utilizes parameter changes by establishing relationships between bend outer side strain, stress gradient, and crack index value. The system determines forming allowance by analyzing how these parameters change and interact during the press forming process, enabling predictive evaluation without complex physical testing
Data Source
AI summary
A technology for evaluating forming allowance for a bending crack at a sheared end face of the press-formed component from shape information of an actual component. The method includes applying press forming including bending deformation to a metal sheet being sheared to manufacture a 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.