Fire Resistant APU Mount Yoke for Load Distribution
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Solution Overview
Problem
Aircraft auxiliary power unit (APU) assemblies secured with direct mounts to lightweight housings are prone to failure during fires due to concentrated load distribution, which can lead to structural failure and operational issues, as existing mounting systems do not adequately distribute forces over a sufficient area to meet stringent airworthiness standards.
Innovation Solution
A mount yoke assembly comprising a main hanger bracket and an anchor bracket with a receiving portion and anchor holes, which secures the APU mount to a component of the APU assembly, distributing forces over a larger area and providing a hingeable connection to absorb inertial and operational loads, thereby enhancing fire resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If mounts are fixed directly to the APU housing to transfer loads, then the mounting structure is simple and lightweight, but the housing may be weakened or fail during a fire concentrated near one of the mounts
Solution Approach 1:
The patent introduces a mount yoke assembly as an intermediary component between the APU housing and the mounting struts. This yoke assembly distributes the concentrated loads from multiple mounts across a larger area of the housing, preventing localized heat concentration and structural failure during fires while maintaining overall system simplicity
Solution Approach 2:
The mount yoke assembly extends the mounting structure in multiple dimensions, creating a three-dimensional load distribution network. The yoke assembly includes horizontal and vertical components that spread forces across the housing surface, transforming point loads into distributed loads over a larger thermal management area
2Weight of moving object
If mounts are fixed directly to the APU housing, then the weight is reduced, but the support footprint is insufficient to distribute forces over a larger area
Solution Approach 1:
The mount yoke assembly extends the mounting structure in multiple dimensions, creating a three-dimensional load distribution network. The yoke assembly includes horizontal and vertical components that spread forces across the housing surface, transforming point loads into distributed loads over a larger thermal management area
Solution Approach 2:
The mounting system is segmented into multiple components: individual mounts, mount yoke assemblies, and supporting struts. This segmentation allows each component to be optimized for its specific function while collectively achieving weight reduction through the use of lightweight materials and distributed load paths
3Weight of moving object
If the APU housing uses lightweight materials, then weight is reduced and efficiency is improved, but the housing may be weakened or fail during a fire
Solution Approach 1:
The mount yoke assembly serves as a protective intermediary between the lightweight housing and the mounting loads. It distributes forces across a larger area of the housing, preventing localized stress concentration that could lead to failure during fires, thereby enabling the use of lightweight materials without compromising fire resistance
Solution Approach 2:
The mount yoke assembly provides beforehand cushioning by distributing loads across multiple mounting points and a larger housing area. This pre-distribution of forces protects the lightweight housing from concentrated thermal and mechanical stresses during fire events, allowing the use of lighter materials
Data Source
AI summary
A mount yoke assembly comprises a first main hanger bracket and a first anchor bracket. The first main hanger bracket includes a first receiving portion for a first auxiliary power unit (APU) mount with first and second hanger arms. The first hanger arm includes a first hanger flange extending proximate a distal end of the first hanger arm. The first anchor bracket includes a first plurality of anchor holes and a first anchor flange. The first plurality of anchor holes are disposed substantially along a length of the first anchor bracket for securing the mount yoke assembly to a component of an APU assembly. The first anchor flange extends from the first anchor bracket for hingeably securing the first anchor bracket to the first main hanger bracket.