Aircraft Duct Assembly Using Preform Body and Sacrificial Mandrel
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Solution Overview
Problem
The manufacturing of duct assemblies for aircraft engines is limited by manufacturing capabilities and costs, leading to increased weight and inefficient designs due to the complexity and spacing requirements of turbine engines, which can result in duct assemblies that are not adequately robust for high-pressure, high-temperature, and vibration environments.
Innovation Solution
A method of forming a duct assembly using a preform body and a sacrificial mandrel, where a metallic layer is deposited over both to create a unitary metallic tubular element, allowing for structural integrity and reduced weight by optimizing material distribution and eliminating stress risers, with the mandrel being removed after deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If traditional manufacturing methods are used for duct assemblies, then manufacturing capabilities and costs are constrained, but the duct assemblies suffer from increased weight and reduced structural robustness
Solution Approach 1:
The duct assembly is divided into multiple preform bodies that are positioned at different locations within the duct. Each preform body serves as a localized reinforcement element, allowing weight reduction in non-critical areas while maintaining structural integrity at stress-critical locations. The preform bodies are segmented and distributed throughout the duct structure rather than using a uniform thick-walled design.
Solution Approach 2:
Reinforcement is applied locally at specific high-stress areas using preform bodies positioned at critical locations such as bends, joints, and support attachment points. The duct walls in non-critical areas can be thinner, optimizing weight while maintaining structural robustness where needed. This local quality approach allows differential wall thickness and material distribution based on stress requirements.
2Device complexity
If traditional duct designs are used, then spacing requirements for turbine engine components are difficult to accommodate, but complex ducting paths increase manufacturing complexity
Solution Approach 1:
The duct assembly is segmented into multiple sections with preform bodies positioned at different locations, allowing each segment to be optimized for its specific function and stress conditions. This segmentation enables complex ducting paths to be constructed from simpler modular sections that can be adapted to accommodate various engine component spacing requirements.
Solution Approach 2:
Preform bodies are pre-positioned at critical locations within the duct before final assembly or during the manufacturing process. This preliminary action allows for pre-planned reinforcement at anticipated stress points and simplifies the overall manufacturing process by preparing reinforcement elements in advance rather than adding them later.
3Strength
If conventional reinforcement methods are used, then additional brazing or welding is required, but this increases manufacturing complexity and potential stress risers
Solution Approach 1:
The preform bodies are integrated directly into the duct wall structure through a single extrusion process, merging the reinforcement elements with the duct body into a unified structure. This eliminates the need for separate brazing or welding operations to attach reinforcement elements, reducing manufacturing complexity and eliminating potential stress risers at joints between separate components.
Solution Approach 2:
The mechanical joining methods of brazing or welding are replaced by a monolithic extrusion process that creates an integrated structure. The preform bodies and duct wall are formed as one continuous piece through extrusion, substituting complex mechanical joining operations with a single forming process that eliminates joint-related stress concentrations.
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 duct assembly with superior structural strength at critical areas while reducing the overall mass, enhancing reliability and efficiency by minimizing unnecessary material usage and eliminating the need for additional reinforcement methods like brazing or welding.
Implementation Method 1
disposing the preform body adjacent a sacrificial mandrel such that at least a portion of the preform body abuts an outer surface of the sacrificial mandrel
Implementation Method 2
depositing metal on the exposed outer surface of the sacrificial mandrel and the preform body to define a unitary metallic tubular element where depositing metal occurs at a temperature that does not damage the sacrificial mandrel
Implementation Method 3
removing the sacrificial mandrel to define the duct assembly
Data Source
AI summary
Duct assembly and method of forming a duct assembly, the method including providing a preform body having an outer surface, disposing the preform body adjacent a sacrificial mandrel such that at least a portion of the preform body abuts an outer surface of the sacrificial mandrel, forming the duct assembly by depositing metal on the outer surface of the sacrificial mandrel and the preform body to define a unitary metallic tubular element with integral preform body and where depositing metal occurs at a temperature that does not damage the sacrificial mandrel, and removing the sacrificial mandrel to define the duct assembly.