Resin Vehicle Door Panel Attenuated Portions for Crack Control
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Solution Overview
Problem
Vehicle doors with outer panels made of resin or fiber-reinforced resin face challenges in preventing separation and crack propagation during side collisions, leading to unintended movement of the door lock wire due to deformation, as traditional hemming work and welding methods are not applicable and crack locations are difficult to predict.
Innovation Solution
A vehicle door structure with attenuated portions along boundary lines dividing the outer door panel into regions, including the outer door handle and other areas, to control crack propagation and separation, thereby preventing unintended movement of the door lock wire by designating specific paths for deformation and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the outer door panel is made of resin or fiber-reinforced resin, then the door structure can be lighter and more design-flexible, but traditional hemming work and welding cannot be applied making it difficult to prevent panel separation during side collisions
Solution Approach 1:
The outer door panel is divided into multiple regions by providing attenuated portions along boundary lines. This segmentation allows the panel to be divided into a first region containing the door handle and a second region, enabling controlled separation along predetermined lines during collision while maintaining overall structural integrity
Solution Approach 2:
The attenuated portions are provided with different strength characteristics compared to other portions of the panel. By creating local variations in strength along boundary lines, the panel is designed to preferentially fail at these weakened sections during collision, preventing uncontrolled cracking while maintaining light weight
2Ease of manufacture
If the outer door panel is made of resin, etc., then manufacturing flexibility is improved, but the panel tends to generate cracks due to collision load and it is difficult to predict with accuracy the location of generated cracks
Solution Approach 1:
Attenuated portions are pre-formed during the molding process of the outer door panel. These predetermined weak sections are created in advance along boundary lines, guiding crack propagation to specific locations during collision before the actual collision event occurs
Solution Approach 2:
The strength parameters of the panel are deliberately modified at specific locations by creating attenuated portions with reduced material thickness or density. This changes the stress distribution and crack propagation paths, making crack locations predictable and controllable while maintaining ease of manufacturing through integrated molding
3Loss of energy
If the outer door panel deforms during side collision, then energy absorption is improved, but the region around the outer door handle may be dragged and moved causing the wire for operating the door lock device to move in an unintended direction
Solution Approach 1:
By dividing the panel into separate regions through attenuated portions, the deformation during collision is confined to specific areas. The first region containing the door handle can deform independently from the second region, preventing dragged movement that would displace the wire while still absorbing collision energy
Solution Approach 2:
The attenuated portions effectively extract or isolate the door handle region from the main panel structure. This separation allows the handle region to move or deform independently during collision without dragging the wire, while the main panel continues to absorb collision energy
Data Source
AI summary
A vehicle door structure includes an outer door panel made of resin, etc. The outer door panel has an attenuated portion. The attenuated portion is provided along a boundary line that divides the outer door panel into at least a first region that includes the outer door handle and other regions.