Polygonal Impact Absorber with Reinforced Center Sheet
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Solution Overview
Problem
Impact absorbing members made from metal sheets face challenges in securing absorption energy while minimizing weight, as reducing the sheet thickness leads to decreased energy absorption due to out-of-plane deformation.
Innovation Solution
The design involves a main body with a polygonal cross-section and a center sheet with a greater thickness, where the center sheet is joined to the long sides, causing buckling deformation differing in phase, thereby increasing absorption energy and energy per unit mass without increasing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the sheet thickness of the main body is reduced to minimize weight, then the weight of the impact absorbing member decreases, but the energy absorption capability deteriorates due to out-of-plane deformation
Solution Approach 1:
A center sheet is nested inside the hollow main body along the axial direction, creating a nested structure where the center sheet reinforces the main body from the interior. This allows the main body to use thinner sheet material while the center sheet provides additional structural support to prevent out-of-plane deformation and maintain energy absorption capability.
Solution Approach 2:
The impact absorbing member uses a composite structure combining the main body and center sheet made from metal sheets of different thicknesses. The center sheet with greater thickness is strategically positioned inside the hollow main body, creating a composite system where the two components work together to provide both weight reduction and structural reinforcement.
2Use of energy by moving object
If a center sheet is added inside the hollow main body to reinforce structure, then the energy absorption capability improves, but the weight of the impact absorbing member increases
Solution Approach 1:
Instead of uniformly increasing the thickness of the entire main body, the center sheet is strategically placed only in specific regions inside the hollow main body where reinforcement is most needed. The center sheet has greater thickness than the main body and is positioned to provide local reinforcement that maximizes energy absorption while minimizing additional weight.
3Stability of the object's composition
If the center sheet has greater thickness than the main body to prevent deformation, then the structural stability improves, but the manufacturing complexity increases
Solution Approach 1:
The impact absorbing member is segmented into two distinct components: the hollow main body and the internal center sheet. This segmentation allows each component to be manufactured separately with optimized thickness for its specific function, then assembled together. The center sheet is formed from a single metal sheet that is folded and joined to create the internal reinforcement structure.
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
This design enhances energy absorption and energy per unit mass by reducing out-of-plane deformation and promoting continuous buckling, allowing for thinner main body sheet thickness while maintaining or improving energy absorption.
Implementation Method 1
the center sheet is joined to each of the long sides of the polygonal shape of the main body, and causing buckling deformation differing in phase
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
An impact absorbing member 10 able to secure absorption energy while lightening weight by absorbing the impact load applied in the axial direction by periodic buckling, wherein the impact absorbing member 10 is provided with a main body 20 comprised of metal sheet and having a polygonal shape in cross-section vertical to an axial direction and a center sheet 30 comprised of metal sheet and provided at a hollow part in the main body along the axial direction, the polygonal shape of the main body 20 includes a pair of long side (20a, 20b) facing each other, the center sheet 30 is joined to each of the long sides (20a, 20b) of the polygonal shape of the main body 20, and the sheet thickness t1 (mm) of the main body 20 and the sheet thickness t2 (mm) of the center sheet 30 satisfy 1.3×t1≤t2.