A novel signal processing method for TSA applications

A novel development of the thermoelastic stress analysis (TSA) technique for testing mechanical components under the random load condition is presented. The method proposed does not need a reference signal to reduce the amount of noise in the thermoelastic images, allowing an easier application of the TSA to the real working condition of mechanical components. Noise is filtered out by means of a numerical algorithm based on the hypothesis that a random thermoelastic signal can be approximated with a harmonic signal. Some notched specimens under the pseudo-random load condition have been tested using either the proposed method or a commercial one (DeltaTherm data processing procedure). Results obtained with both methods are in good agreement.

[1]  J. M. Dulieu-Smith.  Alternative calibration techniques for quantitative thermoelastic stress analysis , 1995 .

[2]  P. Stanley,et al.  Quantitative stress analysis by means of the thermoelastic effect , 1985 .

[3]  Md. Kamrul Hasan,et al.  Wavelet-domain iterative center weighted median filter for image denoising , 2003, Signal Process..

[4]  Alexander K. Mackenzie.  Effects Of Surface Coatings On Infra-Red Measurements Of Thermoelastic Responses , 1989, Other Conferences.

[5]  Xavier Maldague,et al.  Theory and Practice of Infrared Technology for Nondestructive Testing , 2001 .

[6]  W. M. Cummings,et al.  Thermoelastic stress analysis , 1991 .

[7]  T. G. Ryall,et al.  Design of a focal-plane array thermographic system for stress analysis , 1995 .

[8]  Lawrence P. Huelsman.  Active and Passive Analog Filter Design : An Introduction , 1993 .

[9]  M. Biot.  Thermoelasticity and Irreversible Thermodynamics , 1956 .

[10]  Richard E. Blahut,et al.  Fast Algorithms for Digital Signal Processing , 1985 .

[11]  Thermoelastic stress analysis with standard thermographic equipment by means of statistical noise rejection , 1996 .

[12]  Levent Onural,et al.  A class of adaptive directional image smoothing filters , 1996, Pattern Recognit..

[13]  T. G. Ryall,et al.  Performance of the FAST system for stress analysis , 1995 .

[14]  Maamar Bettayeb,et al.  A new robust scheme for harmonic elimination , 1997 .

[15]  Claude S. Lindquist,et al.  Optimizing Elliptic Filter Selectivity , 2001 .