Airbag Cover Panel Stress Riser Placement
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Solution Overview
Problem
Existing airbag cover panels in luxury vehicles face challenges in maintaining aesthetic integrity while ensuring the airbag can be released effectively during a crash, as current methods require pre-cuts that weaken the material and compromise the panel's structural integrity.
Innovation Solution
A seamless cover panel with a rigid structure and elastic covering material featuring a stress raiser tear or cutting direction that intersects the hinge line of the openable door, allowing the panel to tear efficiently without visible pre-cuts, and optionally incorporating a rigid ornament aligned with the tear direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pre-cuts are made in the elastic covering material to promote panel breaking during airbag expansion, then the airbag can be released effectively, but the aesthetic appearance of the visible surface is compromised due to visible cuts and grooves
Solution Approach 1:
The stress raisers are placed exclusively in the concealed portion of the elastic covering material, creating a local differentiation where the visible surface remains intact and aesthetic while the concealed portion contains the breaking features. This spatial separation allows the visible area to maintain smooth appearance while the hidden area performs the breaking function.
Solution Approach 2:
The breaking features (stress raisers) are extracted from the visible surface and relocated to the concealed portion of the material. By removing the cuts and grooves from the aesthetic zone and placing them only where they cannot be seen, the invention separates the functional requirement (breaking) from the aesthetic requirement (smooth surface).
2Strength
If the elastic covering material is made thicker to maintain structural integrity and aesthetic appearance, then the panel strength is improved, but the airbag expansion time increases beyond safety standards
Solution Approach 1:
Stress raisers are pre-formed in the concealed portion of the elastic covering material during manufacturing. These pre-formed stress concentration points are positioned to initiate tearing at specific locations when the airbag expands, ensuring that the material breaks along predetermined paths without requiring thinning of the visible surface material.
Solution Approach 2:
The stress raisers create localized weak points in the concealed portion of the material, allowing controlled breaking in specific areas while the rest of the panel maintains its full thickness and structural strength. This local weakening enables timely airbag deployment without compromising overall panel integrity or aesthetic appearance.
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 solution ensures rapid and effective opening of the airbag door while maintaining the panel's aesthetic appearance, meeting safety standards for airbag deployment without compromising the material's strength or visibility.
Implementation Method 1
at least one stress raiser tear or cutting concerning the whole thickness of the elastic covering material
Data Source
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AI summary
A seamless cover panel for airbags having an improved breaking feature and method of manufacturing the same in which a stress raiser tear of the covering layer of the panel is provided in the form of a partial tear in a zone concealed from sight and close to the weakened zone of the panel where the breaking is promoted upon the airbag bursting.