Ceramic Panel Insert Fastening for Gas Turbine Engines
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Solution Overview
Problem
Attaching ceramic panels to metallic structures in gas turbine engines is challenging due to differing thermal expansion rates and the relative weakness of ceramic materials, leading to potential cracking and weakened areas.
Innovation Solution
A ceramic panel assembly with a slot and insert configuration, where a metallic or ceramic insert is slidably received within the slot, providing a female fastening element aligned with a hole, and secured using a threaded male fastening element, which includes an anti-rotation feature to prevent damage during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If typical attachment configurations are used to secure ceramic panels to metallic structures, then the ceramic panels can be attached, but the ceramic panels may crack or have weakened areas due to different thermal expansion rates and low ceramic strength
Solution Approach 1:
A metallic insert is introduced as an intermediary component between the ceramic panel and the fastening system. The insert is received within a slot in the ceramic panel and provides threaded features for fastening. This intermediary protects the ceramic material from direct fastening operations that could cause cracking, while still enabling secure attachment to the metallic structure.
Solution Approach 2:
The attachment system is divided into separate functional components: the ceramic panel with slot, the metallic insert with threaded features, and the fastening element. This segmentation allows each component to be optimized for its specific function - the ceramic provides thermal resistance, the insert provides mechanical fastening features, and the fastener provides secure attachment - while reducing stress concentrations in the ceramic material.
2Temperature
If ceramic panels are used to enable higher temperatures, then engine efficiency is improved, but attachment to metallic structures becomes difficult due to different thermal expansion rates
Solution Approach 1:
The metallic insert acts as a mediator between the ceramic panel and the external fastening system. It absorbs the thermal expansion differential stresses that would otherwise be transmitted to the ceramic material, enabling the use of high-temperature ceramic materials without compromising the attachment process or the integrity of the ceramic panel during thermal cycling.
3Ease of manufacture
If typical attachment configurations are used, then fastening can be achieved, but expensive formed features are required or the ceramic is weakened
Solution Approach 1:
The metallic insert serves as a cost-effective intermediary that eliminates the need for expensive formed features in the ceramic panel. The insert can be manufactured using standard metal forming processes and provides the necessary threaded features for fastening, while the ceramic panel only requires a simple slot to receive the insert, significantly reducing manufacturing complexity and cost.
Solution Approach 2:
The metallic insert is a relatively inexpensive component compared to the cost of forming complex features directly in the ceramic panel. By using this sacrificial or replaceable metallic component, the system avoids the high costs associated with precision ceramic forming operations, making the overall attachment system more economically viable.
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 configuration effectively secures ceramic panels to metallic structures while accommodating thermal expansion differences, enhancing structural strength and preventing cracking, thereby improving the durability and efficiency of gas turbine engine components.
Implementation Method 1
difficult to attach the dissimilar materials of the ceramic panels and the metallic support structure due to the different rates of thermal expansion
Data Source
AI summary
A gas turbine engine ceramic panel assembly includes a ceramic liner that has a slot and includes a hole. An insert is received in the slot and provides a female fastening element aligned with the hole. A method of manufacturing a ceramic panel assembly includes the steps of forming a ceramic liner with a slot, installing an insert into the slot, and securing the ceramic liner to a structure using a fastening assembly.