Use of Thermal Stress Analysis for Defect Detection

Author: Dhananjaya Kithsiri Imiya Kankanamalage

Imiya Kankanamalage, Dhananjaya Kithsiri, 2023 Use of Thermal Stress Analysis for Defect Detection, Flinders University, College of Science and Engineering

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This research evaluates the viability of Thermoelastic Stress Analysis (TSA) for detecting near surface internal defects in metal structural elements. The study explores the influence of varying loading conditions and defect locations on the detectability of damages using TSA. Experimental procedures were conducted under cyclical flexural and uniaxial loading, assessing the effects of load amplitude and frequency on damage detectability. A Finite Element model was also developed to evaluate its accuracy under different load conditions. The results demonstrate that TSA is highly effective in precisely detecting and locating internal defects, particularly at higher loading amplitudes and desired frequencies. Higher load amplitudes improve detectability, allowing for the identification of defects at greater depths from the surface. In-plane amplitude measurements excel at detecting surface-level damages, while quadrature amplitude measurements are more effective in identifying deeper internal damages. Higher frequency levels enhance TSA's capability to detect internal damages, although the relationship between frequency and TSA amplitude levels is nonlinear and requires further investigation. The flexural loading test encountered limitations, but statistical analysis suggests the effectiveness of TSA at higher flexural loading amplitudes. The Finite Element model accurately represents varying uniaxial loading cases but necessitates further study on the effects of load signal frequency. Overall, this research provides conclusive evidence supporting TSA as a highly capable full-field nondestructive testing method for detecting internal defects in metals. Future work should explore the nonlinear relationship between frequency and TSA amplitude levels and further investigate capabilities of TSA with flexural loading conditions.

Keywords: Non-destructive testing, NDT, Thermoelastic Stress Analysis, TSA, Full field stress analysis, Damage detection of metals, Internal damage detection, near surface damage detection

Subject: Engineering thesis

Thesis type: Masters
Completed: 2023
School: College of Science and Engineering
Supervisor: Stuart Wildy