CMC Airfoil Assembly Load Transfer via Metallic Sleeve
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Solution Overview
Problem
Gas turbine engine airfoils face challenges in withstanding high temperatures and transferring loads due to the difference in thermal expansion coefficients and strength between ceramic matrix composite materials and metallic components, making it difficult to effectively manage thermal stresses and maintain structural integrity.
Innovation Solution
The airfoil assembly incorporates a ceramic matrix composite vane with a metallic support spar and sleeve, featuring load-transfer tabs and a bias member to transmit force loads from the vane to the sleeve, which are then directed to a metallic support structure, controlling the orientation and distributing loads efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic matrix composite materials are used for airfoils to withstand high temperatures, then temperature resistance is improved, but structural integrity and load transfer capability deteriorate due to differences in thermal expansion coefficients and strength compared to metallic components
Solution Approach 1:
The patent employs a hybrid composite structure combining ceramic matrix composite (CMC) vane material with metallic support components (spar and sleeve). The CMC provides high-temperature resistance while the metallic components provide structural strength and load transfer capability. This composite construction resolves the contradiction by allowing each material to perform its optimal function within the assembly.
Solution Approach 2:
The metallic sleeve acts as an intermediary component between the CMC vane and the metallic support structure. It facilitates load transfer from the CMC material to the metallic components while accommodating differences in thermal expansion coefficients, thereby maintaining structural integrity at high temperatures.
2Temperature
If ceramic matrix composite materials are used for airfoils, then temperature resistance is improved, but load transfer capability worsens due to difficulty in effectively managing thermal stresses
Solution Approach 1:
The hybrid CMC-metallic composite structure enables effective load transfer by combining the high-temperature capability of CMC with the superior load-bearing and thermal stress management properties of metallic materials. The metallic components serve as load paths that can effectively transmit forces away from the hot section.
Solution Approach 2:
The design accounts for parameter changes in thermal expansion coefficients between CMC and metallic materials by incorporating flexible metallic components that can accommodate these differences, thereby maintaining effective load transfer capability across varying temperature conditions.
3Temperature
If composite materials are used to manufacture vanes, then temperature resistance is improved, but device complexity increases due to geometry and strength limitations of composite materials
Solution Approach 1:
The airfoil assembly is segmented into distinct functional components: CMC vane for high-temperature exposure, metallic spar for structural support, and metallic sleeve for load transfer. This segmentation allows each component to be manufactured using appropriate processes for its material properties, reducing overall manufacturing complexity despite using composite materials.
Solution Approach 2:
The metallic sleeve serves multiple functions simultaneously: it provides structural support, facilitates load transfer from the CMC vane, accommodates thermal expansion differences, and simplifies the assembly process. This multi-functionality reduces the need for additional specialized components, thereby managing device complexity.
Data Source
AI summary
An airfoil assembly includes a vane that includes an outer platform, an inner platform, and an airfoil. The outer platform defines an outer boundary of a gas path. The inner platform is spaced apart axially from the outer platform relative to an axis and defines an inner boundary of the gas path. The airfoil extends axially between and interconnects the outer platform and the inner platform. Force loads caused by gases interacting with the airfoil are configured to be transmitted from the airfoil assembly to a case arranged around the airfoil assembly.