Interlocking Flange Assembly for Shear-Resistant Turbine Cases
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Solution Overview
Problem
Existing gas turbine engine component mounting methods lack effective interlocking mechanisms to securely attach adjacent components, particularly in axial and rotational directions, which can lead to movement and stress issues during operation.
Innovation Solution
The use of annular cases with flanges and ramped surfaces that interlock through axial and rotational movement, allowing for secure attachment with fasteners, and incorporating inserts to enhance stability and resistance to shear waves and stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fastening methods are used to attach adjacent engine components, then the components can be connected, but the connection lacks effective interlocking mechanisms allowing movement in axial and rotational directions
Solution Approach 1:
The patent employs ramped surfaces with curved geometries that guide axial movement and convert it into rotational interlocking. The ramped surfaces create a wedge effect where axial compression forces generate rotational locking, providing secure attachment while maintaining structural integrity.
Solution Approach 2:
The mounting mechanism allows dynamic movement during assembly where components can move axially into position and then rotate to lock. The design accommodates thermal expansion and operational stresses through controlled movement capabilities while maintaining secure attachment in the locked position.
2Reliability
If secure interlocking mechanisms are implemented to prevent movement, then connection reliability improves, but manufacturing complexity and costs increase
Solution Approach 1:
The mounting mechanism is divided into separate functional elements: flanges for positioning, ramped surfaces for interlocking, and fastener receptacles for securing. This segmentation allows each component to be manufactured independently using standard processes, then assembled through simple alignment and fastening operations.
Solution Approach 2:
Instead of using complex mechanical interlocks that require precision machining, the patent inverts the approach by using simple ramped surfaces that guide components into their locked position through axial movement, converting a complex locking problem into a simple guiding and wedging mechanism.
3Object-affected harmful factors
If traditional flange attachments are used, then components can be connected, but they are susceptible to shear waves and foreign object debris impacts
Solution Approach 1:
The ramped surfaces are designed to convert harmful shear forces and impact loads into beneficial compressive forces along the fastener axes. When subjected to shear waves or FOD impacts, the ramped geometry redirects these forces into the receptacles and fasteners, transforming potential failure modes into load paths that strengthen the connection.
Solution Approach 2:
The ramped surfaces act as pre-positioned load distribution elements that cushion against sudden impacts from foreign object debris. The gradual slope of the ramps allows impact energy to be dissipated through controlled deformation and force redistribution before reaching the fasteners, protecting the structural integrity of the connection.
Data Source
AI summary
An assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a first annular case that has a first body extending from a first end portion and a second annular case that has a second body extending along a longitudinal axis from a second end portion. The first end portion has a first flange. The first flange has at least one mounting assembly. The at least one mounting assembly has a first aperture dimensioned to receive a fastener and a first ramped surface that extends axially from the first aperture. The second end portion includes at least one flange that defines a receptacle dimensioned to receive the first end portion and a second aperture dimensioned to receive the fastener and a second ramped surface. The first annular case is moveable in an axial direction relative to the longitudinal axis through an axial opening of the receptacle such that the first end portion is received in the receptacle, and is rotatable about the longitudinal axis to define an interface between the first and second ramped surfaces to interlock the first end portion in the receptacle and limit movement of the first annular case relative to the longitudinal axis. A method of assembly for a gas turbine engine is also disclosed.