Ultrasonic Measurement Of Residual Stress Research Articles

Denoising of LCR Wave Signal of Residual Stress for Rail Surface Based on Lifting Scheme Wavelet Packet Transform

According to the acousto elastic effect, the residual stress on the surface of the rail can be evaluated by measuring the change in the propagation velocity of ultrasonic waves, such as longitudinal critically refracted (LCR) waves on the surface of the rail. The LCR wave signal is often polluted by a variety of noise sources, coupled with the influence of the poor surface condition of the inspected component, which greatly reduces the detectability and online measurement ability of the LCR wave signal. This paper proposes the application of the lifting scheme wavelet packet transform (LSWPT) denoising method to solve the noise suppression problem of LCR wave signal. The traditional wavelet transform (WT), wavelet packet transform (WPT), as well as the lifting scheme wavelet transform (LSWT) and lifting scheme wavelet packet transform are compared and analyzed in the soft thresholding and hard thresholding processing of denoising ability and efficiency of the noisy LCR wave signal. The experimental results show that the LSWPT method has the characteristics of fast calculation speed and a good denoising effect, and it is an efficient method of denoising signals for on-line ultrasonic measurement of residual stress on the rail surface.

Robotic Ultrasonic Measurement of Residual Stress in Complex Curved Surface Components.

The automatic measurement, especially for products with complex shapes, has always been one of the most important application areas of robots. Aiming at the challenge of measuring residual stress under curved surface, in this paper, the residual stress ultrasonic measuring robot system with two manipulators is constructed, which is based on combining industrial robot technology with residual stress ultrasonic nondestructive measuring technology. The system is mainly composed of a motion control system, an ultrasonic detection system, and a data processing system. The robotic arm controls the movement of the two ultrasonic transducers along the set scanning path which is based on the geometric model of components and adjusts the transducer's posture in time according to the shape of the workpiece being measured. The configuration information based on workpiece coordinate system is transformed into a position data that takes into consideration the first critical angle and can be recognized by the robot. Considering the effect of curvature, the principle model of residual stress measuring by the critical refraction longitudinal wave is established. The measured signal including the stress state of the measured region, as well as the actual position and posture information of the transducers, is processed by the computer in real time, which realizes automatic nondestructive measurement of residual stress under curved surface.

Experiment and numerical simulation for laser ultrasonic measurement of residual stress

Laser ultrasonic is a most promising method for non-destructive evaluation of residual stress. The residual stress of thin steel plate is measured by laser ultrasonic technique. The pre-stress loading device is designed which can easily realize the condition of the specimen being laser ultrasonic tested at the same time in the known stress state. By the method of pre-stress loading, the acoustoelastic constants are obtained and the effect of different test directions on the results of surface wave velocity measurement is discussed. On the basis of known acoustoelastic constants, the longitudinal and transverse welding residual stresses are measured by the laser ultrasonic technique. The finite element method is used to simulate the process of surface wave detection of welding residual stress. The pulsed laser is equivalent to the surface load and the relationship between the physical parameters of the laser and the load is established by the correction coefficient. The welding residual stress of the specimen is realized by the ABAQUS function module of predefined field. The results of finite element analysis are in good agreement with the experimental method. The simple and effective numerical and experimental methods for laser ultrasonic measurement of residual stress are demonstrated.

Research on Making Constant Valve Block of Residual Compressive Stress Based on Ultrasonic Testing

We proposed a new method of measuring the residual stress for the component based on the acoustoelastic theory and focused on a new technology of making constant value block of residual stress by shot peening in order to solve problems of residual stress testing by ultrasound. Monitored the residual stress value of block by self-developed ultrasonic residual stress measurement system. The results indicate that the value of the test block changes not much, so it can provides a new way to improve the ultrasonic testing of residual stress.

Ultrasonic Measurement of Hoop Residual Stress in Stainless Steel Pipes

The ultrasonic measurement of residual stress is based on the acoustoelastic law which is defined as the relation between the ultrasonic wave velocity and the material stress. The longitudinal critically refracted ( L CR ) waves are popular ultrasonic waves in the ultrasonic stress measuring application which are considered in this study to measure hoop residual stresses of welded pipes made from austenitic stainless steel. The stress measuring is applied on the inner and outer surface of pipes separately to evaluate variation of hoop residual stresses through the thickness of pipe. Furthermore, regarding to this theory that different ultrasonic wave frequencies could penetrate in different depths of material which leads to measuring the through thickness stress, four different testing frequencies of transducers are employed (1 Mhz, 2 Mhz, 4 Mhz and 5 Mhz transducers). It has been concluded that the difference in hoop residual stresses between inner and outer surfaces (which means that the variation of hoop stresses through the thickness) of pipes can be evaluated by L CR waves. These waves also showed good potential in measuring residual stresses in the welded zone and base metal of welded pipes.

Potentialities of Ultrasonics for Evaluating Residual Stresses: Influence of Microstructure

The good control of residual stress level in mechanical components is an important factor, particularly for a good fatigue strength of these components. This paper presents advances obtained at the technical center for mechanical engineering industries (CETIM) in the field of development of an ultrasonic method for stress measurements. This method is potentially advantageous because it is nondestructive, has good portability, and is easy to use. In the paper are discussed the results obtained with ultrasonics on steel welded plate, and a comparison is made with stress measurement obtained by incremental hole-drilling method, and X-ray diffraction. These results are also validated by thermal relaxation of the plates. The paper discusses also the microstructure influence on ultrasonic measurements and methods for adjusting the ultrasonic measurements to improve the agreement with results obtained from other techniques. In conclusion is emphasized the interest for studying the ability of the ultrasonic residual stress measurement method in different industrial cases.

Ultrasonic measurement of residual stress : Fukuoka, H. Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United States), 18–20 Sep. 1985. pp. 275–300. Martinus Nijhoff Publishers (1987)

Ultrasonic measurement of residual stress : Fukuoka, H. Solid Mechanics Research for Quantitative Nondestructive Evaluation, Proceedings of the ONR Symposium on Solid Mechanics Research for QNDE, Northwestern University, Evanston, Illinois (United States), 18–20 Sep. 1985. pp. 275–300. Martinus Nijhoff Publishers (1987)

Ultrasonic measurement of residual stress in steels using critically refracted longitudinal waves (L) : Leon-Salamanca, T.; Bray, D.E. Proceedings of the 1990 SEM Spring Conference on Experimental Mechanics, Albuquerque, New Mexico (United States), 4–6 Jun. 1990. pp. 271–278. Society for Experimental Mechanics (A990)

Ultrasonic measurement of residual stress in steels using critically refracted longitudinal waves (L) : Leon-Salamanca, T.; Bray, D.E. Proceedings of the 1990 SEM Spring Conference on Experimental Mechanics, Albuquerque, New Mexico (United States), 4–6 Jun. 1990. pp. 271–278. Society for Experimental Mechanics (A990)

Ultrasonic measurement of residual stress in steels using critically refracted longitudinal waves (L) : Teodoro, L.-S. Dissertation Abstracts International, Vol. 50, No. 1, 110 pp. (Jul. 1989)

Ultrasonic measurement of residual stress in steels using critically refracted longitudinal waves (L) : Teodoro, L.-S. Dissertation Abstracts International, Vol. 50, No. 1, 110 pp. (Jul. 1989)

Ultrasonic residual stress measurement in welded plates : Hiramatsu, Y.; Iwashimizu, Y. Residual Stresses — III, Science and Technology. Vol. 1. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. 304–309. Elsevier Applied Science (1992) ISBN 1-85166-858-6 (Vol. 1)

Ultrasonic residual stress measurement in welded plates : Hiramatsu, Y.; Iwashimizu, Y. Residual Stresses — III, Science and Technology. Vol. 1. Edited by H. Fujiwara, T. Abe and K. Tanaka. pp. 304–309. Elsevier Applied Science (1992) ISBN 1-85166-858-6 (Vol. 1)

Ultrasonic measurement of residual stress : Fukuoka, H. Solid mechanics research for quantitative nondestructive evaluation, Proceedings of the ONR symposium on solid mechanics research for QNDE, Northwestern University, Evanston, Illinois (United States), 18–20 Sep. 1985. pp. 275–300. Martinus Nijhoff Publishers (1987)

Ultrasonic measurement of residual stress : Fukuoka, H. Solid mechanics research for quantitative nondestructive evaluation, Proceedings of the ONR symposium on solid mechanics research for QNDE, Northwestern University, Evanston, Illinois (United States), 18–20 Sep. 1985. pp. 275–300. Martinus Nijhoff Publishers (1987)

Ultrasonic Measurement of Residual Stress in Textured Materials

Abstract A method is developed that determines the state of stress in a test piece in the presence of texture, that is, preferred grain orientation. This method uses frequency domain analysis of the acoustic birefringence by which an ultrasonic shear wave propagating in a material travels at slightly different velocities in the polarizations parallel and perpendicular to the axes of texture or stress. Results obtained from a Ti-6%Al-4%V block confirm that the velocity shift is linearly dependent on the amount of stress, but is independent of frequency in the case of stress as opposed to the texture. Experimental considerations involving transducer characteristics, bond (transducer to specimen) characteristics, specimen size, and signal processing are discussed in relation to the reliability and repeatability of the data.

An Analytical Approach to Reference Samples for Ultrasonic Residual Stress Measurement

Abstract While residual stress measurements using ultrasonic techniques have been under development for some time, practical applications are still limited. One of the difficulties is the lack of suitable reference samples for instrument calibration. This paper specifically addresses the question of how to produce a known stress-state reference sample, and ultrasonically determine its zero stress state. The approach was to design and construct a sample possessing residual stresses that can be deduced from established theory. A shrink-fit ring-plug assembly was fabricated from carefully screened aluminum bar stock, forming a disk suitable for both longitudinal and shear wave calibration. Here we report results using longitudinal waves.