Nested Structural Member Layout to Suppress Crash Cross-Section Collapse
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Solution Overview
Problem
Structural members in mobile bodies, such as automobile bumper reinforcements, face a reduction in withstand load performance due to early-stage cross-sectional collapse during crashes, leading to decreased crash resistance.
Innovation Solution
A structural member design featuring a first member and a second member with a restricting portion, where the second member's vertical walls are disposed along the first member's vertical walls and include beads to restrict inward tilting, dispersing the crash load and maintaining the structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the structural member uses a simple hat-shaped cross section, then the weight is reduced, but the withstand load performance decreases due to early-stage cross-sectional collapse
Solution Approach 1:
The structural member is divided into multiple segments: a first member with a hat-shaped cross section and a second member (closing plate) that closes the opening. This segmentation allows the first member to maintain lightweight structure while the second member provides additional support to prevent cross-sectional collapse, thereby improving withstand load performance without significantly increasing weight.
Solution Approach 2:
The second member is disposed inside the first member, forming a nested configuration where the closing plate is positioned within the hat-shaped structure. This nesting arrangement allows the second member to reinforce the first member's cross section and prevent inward tilting of vertical walls during crashes, improving strength while maintaining a compact, lightweight overall structure.
2Loss of energy
If the vertical walls tilt inward during crash deformation, then the structural member absorbs impact energy, but the height in transverse cross section reduces causing cross-sectional collapse
Solution Approach 1:
The second member (closing plate) is pre-positioned inside the first member before crash occurs. During deformation, the second member's vertical walls and flanges provide preliminary resistance to the inward tilting of the first member's vertical walls, preventing excessive height reduction and cross-sectional collapse before they can occur.
Solution Approach 2:
The second member acts as an intermediary element between the external crash load and the first member's vertical walls. It mediates the deformation process by providing internal support that prevents direct contact and excessive tilting of the vertical walls, thereby maintaining the height in transverse cross section while still allowing controlled energy absorption.
3Ease of manufacture
If the second member is designed as a closing plate without internal structure, then the manufacturing is simplified, but the deformation control capability is insufficient
Solution Approach 1:
The second member is segmented into distinct functional components: vertical walls for structural support, flanges for joining and lateral support, and ridge portions for connecting vertical walls to flanges. This segmentation allows each component to perform its specific function in controlling deformation while maintaining a relatively simple overall structure that can be manufactured efficiently.
Solution Approach 2:
The second member features local quality variations with vertical walls providing structural support, flanges providing lateral support and joining capability, and ridge portions providing connection. This localized functional differentiation allows the second member to effectively control deformation at critical locations while maintaining manufacturing simplicity through a modular design approach.
Data Source
AI summary
A structural member includes a first member, a second member, and a restricting portion. The first member includes a top plate, vertical walls, flanges, and ridge portions. The second member includes a top plate, vertical walls, flanges, and ridge portions. The vertical walls of the second member are disposed along the vertical walls of the first member inside of the vertical walls. The flanges of the second member are joined to the flanges of the first member, respectively. The restricting portion is provided between the vertical walls of the second member. The restricting portion restricts deformation in which portions of the vertical walls of the first member close to the flanges approach each other.