Automotive Structural Member Groove Flange Design
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Solution Overview
Problem
Structural members for automotive bodies with groove-like depressions in the hat top do not effectively enhance energy absorption efficiency, leading to buckling under impact loads, which limits their load transfer capability and rigidity.
Innovation Solution
A structural member with a press-formed steel sheet having a gutter-shaped cross section, featuring a groove in the top plate and an outward flange at the ridge, where the groove depth is set within a specific range relative to the groove width and sheet thickness, enhancing energy absorption and preventing buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a groove-like depression is formed in the hat top of a structural member with gutter-shaped cross section, then the number of load-bearing ridgelines increases and energy absorption capacity should improve, but the structural member buckles downward under impact load due to insufficient rigidity in the region along the ridge
Solution Approach 1:
The invention introduces asymmetry by forming an outward flange only in the region along the ridge, creating an asymmetric structural configuration. This asymmetric design reinforces the ridge area specifically, preventing buckling in the direction toward the opening while preserving the groove-induced load-bearing ridgelines for energy absorption.
Solution Approach 2:
The outward flange is formed in advance during press forming, creating a preliminary reinforcement structure that prevents buckling before impact loads are applied. This preliminary structural preparation ensures that the ridge region maintains its rigidity and resists downward buckling when subjected to axial impact forces.
2Use of energy by moving object
If the groove depth is increased to enhance energy absorption, then more energy can be absorbed during collision, but the press forming process becomes more difficult and manufacturing complexity increases
Solution Approach 1:
The invention optimizes the groove depth parameter within a specific range (0.05t ≤ h ≤ 0.3t, where t is sheet thickness) to achieve the best balance between energy absorption and manufacturability. This parameter optimization ensures sufficient energy absorption capability while avoiding excessive press forming difficulty that would occur with deeper grooves.
Solution Approach 2:
The outward flange is formed locally in the region along the ridge, providing localized reinforcement that compensates for the structural weakening caused by the groove. This local quality enhancement allows for effective energy absorption through the groove while maintaining overall structural integrity and ease of manufacture.
Data Source
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AI summary
[Object] Provided is a structural member for an automotive body, which is excellent in load transfer capability and rigidity by effectively enhancing energy absorption efficiency provided by disposing a groove in the structural member having a substantially gutter-shaped cross section and a groove in the top plate. [Solution] The structural member for an automotive body, the structural member consisting of a press-formed product made of a steel sheet, the press-formed product extending in a predetermined direction, including a top plate, a ridge continuing to the top plate, and a vertical wall continuing to the ridge, and having a substantially gutter-shaped cross section intersecting the predetermined direction, includes at least one groove formed in the top plate, and extending in the predetermined direction, and an outward flange formed at least in a region of the ridge in an end in the predetermined direction. The groove having a depth set according to a width of the groove and a sheet thickness of the steel sheet.