Press-Formed Part Fracture Timing via Stress State Reproduction
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Solution Overview
Problem
Existing methods cannot distinguish between fractures occurring during press forming and those occurring during springback in press formed parts, making it difficult to implement effective countermeasures.
Innovation Solution
A method that involves reproducing the stress state of the fracture occurrence portion using a test piece and determining the presence of micro cracks through microscopic observation to differentiate between fractures caused by press forming and springback, allowing for targeted countermeasures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing fracture evaluation methods are used, then fracture prediction capability is provided, but the ability to distinguish between press forming fractures and springback fractures is lost
Solution Approach 1:
The invention segments the fracture determination process into two distinct evaluation stages: (1) press forming process evaluation by reproducing bending deformation stress states, and (2) springback process evaluation by reproducing stress release conditions. This segmentation allows independent assessment of each process stage, enabling precise identification of when fractures occur without losing critical timing information.
Solution Approach 2:
The invention performs preliminary stress state reproduction tests on test pieces before final product evaluation. By conducting micro crack occurrence determination tests under controlled reproduction conditions that mirror the actual press forming and springback processes, the method proactively identifies potential fracture risks and their timing, enabling preventive countermeasures before actual production.
2Reliability
If fracture countermeasures are implemented without accurate fracture timing determination, then general fracture suppression may be achieved, but effective targeted countermeasures cannot be decided
Solution Approach 1:
The invention establishes a feedback loop where fracture determination results from stress state reproduction tests directly inform countermeasure decisions. The system evaluates micro crack occurrence under reproduced press forming and springback conditions, then feeds this information back to select appropriate countermeasures, ensuring that countermeasure complexity matches the actual fracture risk profile rather than applying uniform complex solutions to all cases.
Solution Approach 2:
The invention changes the evaluation parameters based on fracture timing determination. When press forming fractures are identified, parameters such as bending radius, material strength, and forming pressure are optimized. When springback fractures are identified, parameters such as springback restraint conditions and stress release control are adjusted. This parameter adaptation simplifies countermeasure decisions by focusing on specific critical parameters rather than comprehensively modifying all process variables.
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
Enables effective suppression of fractures by distinguishing between press forming and springback-related fractures, improving the performance of press formed parts through preliminary countermeasure decisions at the design stage.
Implementation Method 1
bending deformation of a metal sheet material
Implementation Method 2
press forming of a metal sheet
Implementation Method 3
springback of the press formed part 21 after die release of the part from a press-forming die
Data Source
AI summary
A press formed part fracture determination method decides a countermeasure for a fracture occurring in a press formed part in which a fracture has occurred or a fracture is predicted to occur by press forming of a metal sheet, and includes: reproducing a stress state in a press forming process of a fracture occurrence portion where a fracture has occurred or a fracture is predicted to occur, in the press formed part, and determining occurrence/non-occurrence of a micro crack in a stress state reproduction portion of the test piece; and determining, when a micro crack has occurred, that there is a fracture occurred in the press formed part in the press forming process, and determining, when there is no micro crack in the stress state reproduction portion of the test piece, that there is a fracture occurred in springback of the press formed part after press forming.