Landing Gear Shock Absorber Crumple Element for Overload Detection
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Solution Overview
Problem
Current aircraft landing gear shock absorbers face challenges in detecting excessive extension loads without disassembly, as recoil elements may not function during brief compression periods or in malfunction scenarios, leading to potential overload conditions that require costly and time-consuming inspections.
Innovation Solution
Incorporating a crumple element that plastically deforms at a lower load threshold than the rest of the shock absorber, allowing for detection of excessive loads by measuring changes in shock absorber length, thereby indicating an extension event without disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a crumple element is added to detect excessive loads, then detection capability is improved, but device complexity increases
Solution Approach 1:
The crumple element serves dual purposes: it acts as both the detection mechanism and the sacrificial component that deforms under excessive load. The element's own deformation serves as the indication signal, eliminating the need for separate sensors or detection devices. This self-service approach improves detection capability while avoiding additional complexity from external monitoring systems.
Solution Approach 2:
The crumple element is designed as a disposable, sacrificial component that is intentionally made to deform or fail when subjected to excessive extension loads. This deliberate use of a short-living element provides clear detection of overload events without requiring complex reusable sensing systems. The element's deformation or failure serves as the detection signal, trading the element itself for detection information.
2Reliability
If the shock absorber is designed to withstand high extension loads, then reliability is improved, but the shock absorber size increases
Solution Approach 1:
The shock absorber is segmented into two functional zones: a crumple element designed to deform at lower extension loads for detection purposes, and the main shock absorber structure designed to withstand higher loads. This segmentation allows the main structure to be optimized for its load-bearing function without being oversized for detection purposes, while the crumple element handles the detection function with minimal size requirements.
Solution Approach 2:
Different parts of the shock absorber have different mechanical properties tailored to their specific functions. The crumple element has local quality characteristics (lower strength, designed deformation behavior) optimized for detection, while the main shock absorber structure has characteristics optimized for withstanding high extension loads. This local differentiation allows each component to be sized appropriately for its function rather than the entire assembly being oversized.
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
Enables non-destructive detection of excessive loads, reducing the need for costly inspections and ensuring safe operation by identifying extension events through measurable length changes, allowing the landing gear to function safely without additional components.
Implementation Method 1
A shock absorber for aircraft landing gear may have a piston (10) mounted for movement within a cylinder (8) and a crumple element configured to undergo plastic deformation in the event that it is subjected to a load exceeding a predetermined threshold
Data Source
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Figure 3(a)
AI summary
A shock absorber (6) for an aircraft landing gear (4) is disclosed. The shock absorber comprises a stop surface (44) arranged to limit extension of the shock absorber (6) and a crumple element (48) configured to deform in the event that the extension load on the stop surface (44) exceeds a predetermined threshold. The crumple element (48) may form part of the out-stop tube (46) of the shock absorber (6). Deformation of the crumple element (48) may be identified by measuring the length of the fully extending landing gear, through non-destructive testing or by measuring the change in conductance of the crumple element (48).