CMC Turbine Component Pin Assembly for Edge-Chipping Control
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Solution Overview
Problem
CMC materials used in gas turbine engines face issues such as low tensile ductility, edge chipping, and thermal expansion mismatch with metal components, leading to assembly challenges and durability problems.
Innovation Solution
A stepped pin design with chamfered edges is used to connect CMC engine components to metal hangers, providing a controlled interference fit that reduces edge chipping and improves assembly and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If CMC materials are used in turbine components, then temperature resistance and weight reduction are improved, but tensile ductility is reduced and edge chipping occurs
Solution Approach 1:
The patent uses ceramic matrix composite (CMC) materials for the shroud assembly, which combine ceramic fibers in a matrix to achieve both high temperature resistance and improved toughness. This composite structure allows the material to maintain strength at elevated temperatures while reducing the brittleness inherent in monolithic ceramics, thereby addressing the tensile ductility issue while preserving temperature resistance.
2Weight of moving object
If CMC materials are used in turbine components, then weight is reduced, but thermal expansion mismatch with metal components increases assembly difficulty
Solution Approach 1:
The patent addresses thermal expansion mismatch by modifying geometric parameters of the assembly interface. The shroud assembly includes features such as clearance gaps and adjustable mounting configurations that compensate for differential thermal expansion between CMC and metal components. This allows the assembly to accommodate dimensional changes during thermal cycling without creating excessive assembly complexity.
3Ease of manufacture
If conventional pin design is used to connect CMC components, then manufacturing is simple, but edge chipping and durability problems occur
Solution Approach 1:
The patent applies local quality by providing enhanced protection specifically at the edge regions of the CMC shroud assembly where chipping is most likely to occur. This includes features such as reinforced edge structures, protective coatings applied selectively to edge areas, and chamfered or rounded edge geometries that reduce stress concentration. These local modifications improve durability without significantly complicating the overall manufacturing process.
4Productivity
If CMC shroud assembly is used, then weight is reduced and efficiency is improved, but maintenance costs increase due to durability issues
Solution Approach 1:
The patent incorporates protective features during the design and manufacturing stages to prevent durability issues before they occur. This includes built-in edge protection structures, stress-relief geometries, and quality control measures during manufacturing that preemptively address potential failure points. By cushioning against potential damage beforehand, the design reduces maintenance requirements and costs while preserving the efficiency benefits of CMC materials.
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 pin design enhances the durability and ease of assembly of CMC components by minimizing edge chipping and maintaining a precise interface, thereby improving the efficiency and reducing maintenance costs in gas turbine engines.
Implementation Method 1
A stepped pin design with chamfered edges is used to connect CMC engine components to metal hangers, providing a controlled interference fit that reduces edge chipping and improves assembly and durability.
Data Source
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AI summary
A turbine engine component assembly includes a first part comprising a ceramic matrix composite material and having a first flange defining a first borehole, a second part defining a second borehole, and a pin inserted, in an axial direction, through the first borehole and the second borehole to connect the first part to the second part. The pin includes a first contact portion positioned at a first axial location of the pin corresponding to the first borehole and an elongated portion extending axially from the first contact portion. The first contact portion includes a first chamfered section, a second chamfered section, and a first contact surface between the first chamfered section and the second chamfered section. The first chamfered section and the second chamfered section slope away from the first contact surface with decreasing diameters.