Thin Plate Armrest Structure for Side Impact Force Management
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Solution Overview
Problem
Motor vehicle armrests face a challenge in balancing vertical strength with lateral collapsibility to minimize injury risk during side impacts, as existing designs either provide insufficient lateral flexibility or excessive stiffness, which can increase the risk of injury to occupants.
Innovation Solution
A motor vehicle armrest structure featuring a matrix of structural cells with acute and obtuse angles, where the obtuse angles span perpendicular to the door's interior face and beams are non-parallel, coupled with varying cross-sectional area struts to control lateral stiffness, allowing for increased collapsibility and reduced force transmission during side impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the armrest uses a traditional rigid structure, then vertical strength is improved, but lateral stiffness increases causing higher injury risk in side impacts
Solution Approach 1:
The armrest structure is divided into multiple structural cells arranged in a matrix pattern, creating discrete compartments that can deform independently during side impacts while maintaining overall vertical support capability
Solution Approach 2:
Different regions of the armrest structure have different cell configurations and beam orientations optimized for their specific functions - vertical load-bearing regions maintain stronger configurations while side-impact-prone areas have more collapsible designs
2Object-affected harmful factors
If the armrest uses an open cellular construction, then lateral collapsibility is improved, but vertical strength decreases
Solution Approach 1:
The structural cells feature asymmetric beam arrangements with specific acute and obtuse angles, where beams are oriented at non-parallel angles to create directional strength - stronger in vertical loading direction while more compliant in lateral impact direction
Solution Approach 2:
The acute angles of the structural cells are specifically designed to be small, which mathematically increases collapsibility during side impacts while the obtuse angles spanning perpendicular to the door face maintain vertical load support
3Strength
If the armrest uses hexagonally arranged cell walls, then vertical strength is improved, but lateral stiffness remains too high
Solution Approach 1:
The patent moves away from symmetric hexagonal cells to asymmetric quadrilateral cells with specific acute and obtuse angles, where the beam orientations are non-parallel and specifically angled to reduce lateral stiffness while maintaining vertical strength
Solution Approach 2:
By changing the cell geometry parameters - specifically making acute angles smaller and orienting beams at non-parallel angles - the structure achieves reduced lateral stiffness while preserving vertical load-bearing capacity
Data Source
AI summary
A motor vehicle door and armrest assembly using a thin plate that is vertically strong while laterally collapsible. The plate is comprised of a matrix of intersecting parallel struts forming four sided cells having a first set of opposing acute angles and a second set of opposing obtuse angles. The obtuse angles span a direction normal to the motor vehicle door and allow the plate to more easily limit force transmission from a side impact force. The struts are coupled to a frame, the coupling struts variable in cross sectional area to further determine the lateral stiffness of the plate.