Variable Stiffness Bearing Housing for Turbine Engines
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Solution Overview
Problem
Mechanical structures, such as those in turbine engines, often have static members with limited stiffness ranges, which restrict their operational flexibility in response to varying loads and deflections, necessitating improved stiffness properties.
Innovation Solution
The integration of a variable stiffness element, such as a shape memory alloy or spring, within a bearing housing that adjusts its stiffness based on load conditions, allowing the gap between housing portions to change, thereby adapting to different operational parameters and enhancing the engine's stiffness properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single linear stiffness structural member is used, then the structure is simple and reliable, but the operational flexibility and adaptability to varying loads are limited
Solution Approach 1:
The bearing housing transitions from a static single-stiffness structure to a dynamic variable stiffness structure by incorporating a variable stiffness element that can adjust its mechanical properties in response to changing operational conditions, allowing the housing to adapt its load-bearing characteristics throughout the engine operating range
Solution Approach 2:
The patent changes the stiffness parameter of the bearing housing from a fixed value to a variable value that can be adjusted based on operational requirements. The variable stiffness element modifies the overall stiffness characteristic of the bearing housing to match different load and deflection conditions during engine operation
2Adaptability or versatility
If a variable stiffness element is integrated into the bearing housing, then stiffness adaptability to varying loads is improved, but the device complexity increases
Solution Approach 1:
The variable stiffness element is designed to automatically adjust the stiffness of the bearing housing in response to changing load conditions without requiring external control systems. The element self-regulates its mechanical properties based on the operational state, reducing the need for complex control mechanisms while maintaining adaptability
Solution Approach 2:
The bearing housing becomes a composite structure combining traditional rigid housing materials with a variable stiffness element that may utilize shape memory alloys or other advanced materials. This composite approach enables the housing to exhibit both structural integrity and variable mechanical properties
3Strength
If the bearing housing stiffness is increased, then the structural strength and stability are improved, but the ability to accommodate thermal expansion and centrifugal growth is reduced
Solution Approach 1:
The bearing housing stiffness is made dynamic rather than static, allowing it to adjust its rigidity characteristics in response to thermal and centrifugal loads. This enables the housing to provide high strength when needed while accommodating dimensional changes during operation through controlled stiffness variation
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
This solution improves engine operation by mitigating rotor unbalance, tightening clearances, and reducing startup times, leading to increased efficiency and adaptive responses to varying load conditions.
Implementation Method 1
the variable stiffness element includes a shape memory alloy
Implementation Method 2
The variable stiffness element defines a spring
Data Source
AI summary
A turbine engine including a bearing element coupled to a rotor assembly and a bearing housing disposed substantially concentric to the axial centerline of the turbine engine. The bearing housing includes a first member coupled to the bearing element. The first member defines a groove at which a variable stiffness element is coupled to the first member and disposed within the groove. The bearing housing defines a first portion and a second portion adjacent to the first portion along a load direction. The first portion and the second portion together selectively define a gap therebetween based at least on a change in load along the load direction.