Evaluation of some parameters influencing vibrothermographic crack heating

Lesthaeghe, Tyler

doi:10.31274/etd-180810-3949

Cited by 2 publications

(2 citation statements)

References 8 publications

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“…e effect of ultrasonic infrared detection of cracks mainly depends on the three aspects of ultrasonic excitation energy and heat generation mechanism of crack action, parameters in the detection process, and signal processing of infrared heat maps. ere is no scientific conclusion about the heat generation mechanism in the current research, and the mainstream friction heat generation mechanism still cannot perfectly explain all heat generated in the crack area [20][21][22]. e detection parameters include the parameters of the workpiece and the detection conditions of the ultrasonic infrared system.…”

Section: Introductionmentioning

confidence: 99%

A Defect Detection Method for the Surface of Metal Materials Based on an Adaptive Ultrasound Pulse Excitation Device and Infrared Thermal Imaging Technology

Zhang

Cao

et al. 2021

Complexity

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Ultrasonic excitation has been widely used in the detection of microcracks on metal surfaces, but there are problems such as poor excitation effect of ultrasonic pulse, long time to reach the best excitation, and difficult to find microcracks. In this paper, an adaptive ultrasonic pulse excitation device and infrared thermal imaging technology have been combined, as well as their control method, to solve the problem. The adaptive ultrasonic pulse excitation device adds intelligent modules to realize automatic adjustment of detection parameters, which can quickly obtain reliable excitation; the multidegree-of-freedom base realizes the three-dimensional direction change of the ultrasonic gun to adapt to different excitation occasions. When the appropriate ultrasonic excitation makes microcracks in the resonance state, the microcracks can be frictionated, which produce heat rise with the temperature. Then, the microcrack defect can be detected by the infrared thermal instrument through the different surface temperatures with imaging recognition method. Our detection experiments of the titanium alloy plates and the aluminum alloy profiles of marine engineering show that the method can get reliable detection parameters in a short time and measure the crack length effectively. It can be used in many aspects such as crack detection in mechanical structures or complex equipment operating conditions and industrial production processes.

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Section: Introductionmentioning

confidence: 99%

A Defect Detection Method for the Surface of Metal Materials Based on an Adaptive Ultrasound Pulse Excitation Device and Infrared Thermal Imaging Technology

Zhang

Cao

et al. 2021

Complexity

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show abstract

“…In this model, the heat intensity generated at the crack is assumed as directly proportional to the product of contributions from the extrinsic parameters (vibration and frequency) and the intrinsic parameters (crack closure stress and mobility). Mathematically, this model is represented as G ∝ V × C × M, where G is the total heat intensity generated at the crack, V represents the contribution from vibrational strain and excitation frequency, C represents the closure state of the crack, and M is the crack mobility (the relative motion between crack faces) [15]. This empirical model can be interpreted as follows: The heat intensity is zero if the dynamic strain or the frequency is zero.…”

Section: Introductionmentioning

confidence: 99%

Determining heat intensity of a fatigue crack from measured surface temperature for vibrothermography

Vaddi

Lesthaeghe

Holland

2020

Meas. Sci. Technol.

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We propose a simulation -assisted linear-inversion method to estimate heat intensity generated at a fatigue crack during vibrothermographic nondestructive evaluation. In vibrothermography, mechanical excitation is applied to a test specimen, and the contacting crack faces generate heat which flows to the surface and can be detected by an infrared camera. The heat intensity generated at the crack is not a directly measurable quantity, and instead has to be estimated by inverting the measured crack surface temperature. This inversion is an ill-posed problem because of the inherently diffusive nature of heat flow. The proposed method in this paper attempts to estimate the crack heat intensity by minimizing the squared error between numerically modeled crack heating and the experimentally measured surface temperature of the crack. We demonstrate that with reasonable assumptions, the effect of diffusion on the heat intensity can be overcome, and it is possible to estimate the crack heat intensity. Furthermore, we reconstruct the surface temperature on two different material systems and quantify the reconstruction accuracy of the least-squares inversion algorithm.

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Evaluation of some parameters influencing vibrothermographic crack heating

Cited by 2 publications

References 8 publications

A Defect Detection Method for the Surface of Metal Materials Based on an Adaptive Ultrasound Pulse Excitation Device and Infrared Thermal Imaging Technology

A Defect Detection Method for the Surface of Metal Materials Based on an Adaptive Ultrasound Pulse Excitation Device and Infrared Thermal Imaging Technology

Determining heat intensity of a fatigue crack from measured surface temperature for vibrothermography

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