Conical Washer Structure for Visual Load Imbalance Indication
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Solution Overview
Problem
Existing washers used in aerospace applications fail to effectively indicate load imbalances, leading to stress concentrations and potential failure modes in aircraft panels, as they require removal for paint-based alignment checks and are prone to smearing during installation or removal.
Innovation Solution
A conical washer with a viscoelastic material-filled cavity that protrudes when subjected to load imbalances, providing a visual indication of misalignment or excessive load without requiring fastener removal, utilizing a conical design with an outer and inner wall and an end wall to form a cavity, where the viscoelastic material, such as rubber cement or silicone, is compressed and visible when load imbalances occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If paint-based alignment checks are used, then load imbalance detection is possible, but the washer requires removal and is prone to smearing
Solution Approach 1:
The washer itself serves the dual function of both fastening and load imbalance indication. The viscoelastic material integrated into the washer body automatically deforms and protrudes when subjected to imbalanced loads, eliminating the need for separate paint-based indication methods and washer removal for inspection.
Solution Approach 2:
The viscoelastic material is formulated with a distinct color that contrasts with surrounding components. When the material protrudes due to compression from imbalanced loads, the color change provides an immediate visual indication of the problem without requiring removal or additional marking materials.
2Reliability
If fastener removal is required for alignment checks, then load imbalance can be detected, but productivity is reduced
Solution Approach 1:
The washer provides self-indication of load imbalance through the protrusion of viscoelastic material, allowing inspection to be performed without removing the fastener or washer. This maintains assembly integrity while enabling rapid visual inspection during production and maintenance operations.
Solution Approach 2:
The viscoelastic material is pre-positioned and pre-compressed during normal assembly, so that any subsequent load imbalance immediately causes protrusion. This preliminary setup eliminates the need for separate inspection steps or fastener removal, enabling continuous productivity while maintaining detection accuracy.
3Strength
If traditional washers are used, then fastening is achieved, but load imbalance indication capability is lost
Solution Approach 1:
The washer is designed to perform multiple functions simultaneously: providing mechanical fastening support through its rigid structure and distributing load, while also serving as a load imbalance indicator through the integrated viscoelastic material that deforms and protrudes when subjected to uneven forces.
Solution Approach 2:
The washer combines rigid structural material for fastening strength with viscoelastic material for indication capability. This composite construction allows the single component to maintain mechanical integrity while simultaneously providing visual feedback about load distribution through the contrasting viscoelastic material that protrudes under imbalanced conditions.
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 provides a quick and effective visual indication of load imbalances, enhancing safety, reliability, and panel life by detecting misalignment and excessive loads without disrupting the fastening process, and can remain in place to indicate panel fatigue over time.
Implementation Method 1
a viscoelastic material disposed in the cavity, the viscoelastic material to protrude from the opening when the outer conical wall and the inner conical wall are moved toward each other
Data Source
AI summary
Washers for indicating imbalanced loading and methods of making the same are disclosed herein. An example washer includes an outer conical wall having a first end and a second end opposite the first end, and an inner conical wall concentric with the outer conical wall. The inner conical wall is spaced apart from the outer conical wall. The inner conical wall has a first end and a second end opposite the first end. The inner conical wall defines a central bore through the washer. The washer also includes an end wall between the second ends of the outer conical wall and the inner conical wall, such that a cavity is formed between the outer conical wall, the inner conical wall, and the end wall. An opening to the cavity is formed between the first ends. A viscoelastic material is disposed in the cavity that can protrude from the opening.