Door Trim Armrest Varying Wall Thickness Energy Absorption
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Solution Overview
Problem
Existing vehicle door designs fail to effectively localize and absorb energy from occupant impacts during vehicle collisions, particularly above the pelvis, leading to undesirable energy absorption by the rib cage.
Innovation Solution
A door trim panel assembly with an armrest having varying wall thicknesses, where the middle portion initially receives and transfers impact force to thicker bottom and thinner top portions, guiding energy absorption to the pelvis area while minimizing force transfer to the rib cage, using materials like 10% talc filled polypropylene and incorporating a foam body for additional energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the door structure uses uniform thickness design, then manufacturing is simple, but energy absorption is ineffective and rib cage injury risk increases
Solution Approach 1:
The armrest is designed with non-uniform wall thickness, featuring a thicker bottom portion and a thinner top portion. This local variation in thickness allows the structure to absorb impact energy more effectively by concentrating deformation in specific zones, thereby reducing the risk of rib cage injury while maintaining manufacturing feasibility through extrusion processes.
2Object-affected harmful factors
If the armrest bottom portion is made thicker for energy absorption, then occupant safety improves, but device complexity increases
Solution Approach 1:
The armrest is segmented into distinct portions with different wall thicknesses - a thicker bottom portion for energy absorption and a thinner top portion for reduced complexity. This segmentation allows each zone to serve its specific function while maintaining overall structural integrity and manufacturability through standard extrusion techniques.
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
The design effectively absorbs and redirects impact energy to the pelvis, reducing the risk of rib cage injury by focusing force on the armrest's thicker bottom portion and utilizing foam for supplementary energy absorption, thus enhancing occupant safety within logistical and cost constraints.
Implementation Method 1
incorporating a foam body for additional energy absorption
Implementation Method 2
The middle portion 22 may initially receive the impact force. The wall thickness 56 and the wall thickness 58 of the middle portion 22 facilitates transfer of the energy created from the impact force to the top portion 18 and the bottom portion 20
Implementation Method 3
using materials like 10% talc filled polypropylene
Data Source
AI summary
A door trim panel assembly includes a door trim panel and an armrest supported by the door trim panel. The armrest includes a top portion and a bottom portion each extending from the door trim panel, and a middle portion extending from the top portion to the bottom portion. The bottom portion has a wall thickness greater than a wall thickness of the top portion and greater than a wall thickness of the middle portion. The wall thickness of the top portion is less than the wall thickness of the middle portion.