Retaining Ring End Gap Scalloped Surface Stress Distribution
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Solution Overview
Problem
Retaining rings for gas turbine engines often cause stress concentrations at the end gap location, leading to contact stress and cracking in the cover plate during operation.
Innovation Solution
A split ring retaining ring with scalloped surfaces and axially extending faces is used to reduce stress concentrations by distributing forces more evenly between the rotating disc and cover plate, preventing axial motion and providing radial support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a split ring construction is used to retain the cover plate, then the retaining ring can be assembled and retained, but stress concentrations form at the end gap location causing contact stress and cracking
Solution Approach 1:
The patent applies curvature by replacing the traditional flat end gap surface with a scalloped surface featuring multiple curved segments. This curvature distributes the contact stress from the cover plate across the scalloped profile, preventing stress concentration at any single point and eliminating cracking while maintaining the split ring's assembly capability
Solution Approach 2:
The patent modifies only the local region at the end gap by introducing the scalloped surface, while the rest of the retaining ring maintains its original structure. This localized modification addresses the stress concentration problem at the end gap without changing the overall split ring construction or assembly process
2Reliability
If the end gap is minimized to improve retention, then the retaining ring holds the cover plate more securely, but stress concentrations increase at the gap location
Solution Approach 1:
The scalloped surface with its curved profile allows the end gap to remain small for secure retention while distributing the contact stress across multiple curved segments. This prevents stress concentration even when the gap is minimized, solving both the retention security and stress reduction requirements simultaneously
Data Source
Figure 1
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AI summary
A gas turbine engine (10) and a retaining ring (110) are disclosed. The gas turbine engine includes a rotating disc assembly (35), including a rotating disc (102), a cover plate (104), and a retaining ring (110) disposed between the rotating disc and the cover plate, wherein the retaining ring axially retains the rotating disc and the cover plate, the retaining ring including a rotating disc face (112) to interface with the rotating disc; a cover plate face (114) to interface with the cover plate; and an end gap portion (120) defining an end gap, wherein at least one of the rotating disc face, the cover plate face, and the end gap portion includes a stress reducing feature.