Thermal Barrier Coating Test Piece for Compression Stress Evaluation
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Solution Overview
Problem
Existing methods fail to accurately evaluate damage to thermal barrier coatings (TBC) on bending parts of gas turbines and combustors subjected to compression stress, due to the difficulty in applying and maintaining uniform TBC quality on these parts.
Innovation Solution
A testing method and test piece design that includes a pair of arm parts with a bending part in between, a TBC layer on the bending surface, and round holes for pin attachment to a compression testing device, allowing for controlled compression stress application to simulate the stress conditions on real machine parts, thereby reducing bending moment influence and enabling accurate damage assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If compression stress is applied to evaluate TBC on bending parts, then measurement precision is improved, but device complexity increases due to the need for specialized test piece geometry and attachment mechanisms
Solution Approach 1:
The test piece is divided into distinct functional segments: arm parts for attachment, a bending part for stress application, and a TBC layer for evaluation. This segmentation allows each component to be optimized for its specific function while simplifying the overall testing system.
Solution Approach 2:
The test piece geometry parameters (curvature radius R, TBC thickness hc, bending part thickness hs) are carefully controlled within specific ranges to accurately replicate the stress conditions of real machine bending parts while maintaining manufacturability and test reliability.
2Reliability
If TBC is applied to bending parts, then thermal barrier property is improved, but manufacturing precision deteriorates due to difficulty in maintaining uniform TBC quality
Solution Approach 1:
The test piece is designed with a specific bending geometry (curvature radius R within 3-7mm) that locally concentrates stress on the TBC layer in a controlled manner, allowing evaluation of TBC quality at critical locations without requiring perfect uniformity across the entire component.
Solution Approach 2:
The test piece is prepared with pre-defined geometry parameters and TBC application specifications before testing, establishing controlled conditions that compensate for manufacturing variations and enable accurate damage evaluation despite non-uniform TBC application.
3Measurement precision
If round holes with pins are used for attachment, then bending moment influence is reduced, but device complexity increases due to additional attachment components
Solution Approach 1:
Round holes with pins serve as an intermediary attachment mechanism between the compression testing device and the test piece. This simple yet effective design reduces bending moment influence by providing stable, centered attachment points without requiring complex fixation systems.
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 approach allows for precise evaluation of TBC damage on bending parts under compression stress, improving the assessment of TBC quality and durability on gas turbine blades and combustor components.
Implementation Method 1
applying compression stress to the test piece in a direction for bringing the pair of arm parts close together
Data Source
AI summary
A testing method of thermal barrier coating (TBC) is for evaluating the presence or absence of damage to TBC formed on a bending part on which compression stress acts. The method includes a test piece that includes a pair of arm parts, a bending part arranged between the pair of arm parts, and a TBC layer on a bending surface of the bending part; attaching the test piece to a compression testing device after preparing the test piece; and applying compression stress to the test piece in a direction for bringing the pair of arm parts close together after attaching the test piece with the compression testing device. The pair of arm parts are arranged so as to separate from each other from base end portions toward front end portions of the arm parts. The bending part is arranged between the base end portions.