Plane stress measurement of orthotropic materials using critically refracted longitudinal waves

Wang, Wei; Zhou, Yufeng; Meng, Sheng; Chen, Dongkangkang

doi:10.1016/j.ultras.2018.03.015

Cited by 24 publications

(12 citation statements)

References 20 publications

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“…For SLM forming parts manufactured with 316 L stainless steel, the acoustic-elastic coefficient varies with the scanning strategy used in the forming process. For the same SLM forming parts, the acoustic-elastic coefficient parallel to the LCR wave propagation direction is about three times that of perpendicular to the LCR wave propagation direction, which is consistent with existing research [10]. Figures 10-12 show the ultrasonic testing results of the three kinds of specimens manufactured using meander, stripe, and chess board scanning strategies respectively.…”

Section: Discussionsupporting

confidence: 84%

“…In the actual testing process, when the temperature, surface roughness and coupling mode remain unchanged, the acoustic time difference is ∆t i = t i − t i 0 = ∆t M + ∆t S , so as shown in Equations (8)-(10), the acoustic time difference varied linearly with the stress. The constant terms in Equations (8)- (10) indicate the acoustic time difference is caused by the microstructure of material. As shown in Figure 18, 316 L stainless steel specimens manufactured by SLM technology have obvious anisotropic characteristics, and the microstructures vary with the change of the fixed positions of the transducers in the specimen manufactured using the same scanning strategy.…”

Section: Acoustic-elastic Equations For Testing Stress In 316 L Stainmentioning

confidence: 99%

“…Residual stress seriously affects the mechanical properties of SLM forming parts [8]. The critical refraction longitudinal (LCR) wave test for stress has been extensively studied [9][10][11], it has the advantages of safety, nondestructiveness, and on-line detections. The method utilizing ultrasonic velocity [12][13][14] to measure stress is the focus of current research.…”

Section: Introductionmentioning

confidence: 99%

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Study on the Measurement of Stress in the Surface of Selective Laser Melting Forming Parts Based on the Critical Refraction Longitudinal Wave

Yan

Pan

2019

Coatings

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Measurement and control of stress in the metal forming layer is the basic problem of selective laser melting (SLM) forming parts. The critical refraction longitudinal (LCR) wave method to test stress in metallic materials has been extensively studied. However, when testing of stress in selective laser melting (SLM) forming parts using this method, some deep-seated regularities of this technology are still not clear. In order to reveal the mechanism of the LCR wave method to measure stress in SLM forming parts, specimens made of 316 L stainless steel were manufactured using meander, stripe, and chessboard scanning strategies. Static load tensile test were applied to SLM forming specimens, with the purpose to demonstrate the scanning strategy has important effect on the LCR wave method to test stress in SLM forming parts. The regularity of the LCR wave velocity on stress is obtained in this study. The anisotropic microstructure of SLM forming parts has an unneglectable effect on the LCR wave stress test. The essential principle of anisotropic microstructure effecting the LCR wave velocity in SLM forming parts were revealed in the experiments. The results of the experiment provide a basis for non-destructive and reliable test of stress in SLM forming parts and other inhomogeneous materials.

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Section: Discussionsupporting

confidence: 84%

Section: Acoustic-elastic Equations For Testing Stress In 316 L Stainmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Study on the Measurement of Stress in the Surface of Selective Laser Melting Forming Parts Based on the Critical Refraction Longitudinal Wave

Yan

Pan

2019

Coatings

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“…In this method, the ultrasonic wave velocity was measured based on the propagation time obtained through a phase correlation algorithm, and the strain was obtained using a scanning acoustic microscope. Wang et al [19] proposed an equation that determined the relationship between the stress, in the area beneath the surface, and propagation time of critically refracted longitudinal waves in a carbon-fiber-reinforced plastic composite, and concluded that the propagation time was linearly dependent on the stress. They calculated that the acoustoelastic coefficient was consistent with the experimental results.…”

Section: Introductionmentioning

confidence: 99%

An Ultrasonic Longitudinal Through-Transmission Method to Measure the Compressive Internal Stress in Epoxy Composite Specimens of Gas-Insulated Metal-Enclosed Switchgear

et al. 2020

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Situations of internal stress in basin insulators inside gas-insulated metal-enclosed switchgear (GIS) can lead to cracks, which can influence the safety and stability of apparatus. However, there is currently no research on internal stress measurements for composites of GIS basin insulators, and only measurements for surface stress. In this paper, an internal stress measurement method for GIS epoxy composite is proposed using an ultrasonic longitudinal through-transmission technique based on the acoustoelastic effect. An internal stress measurement system is developed to investigate the relationship between the uniaxial compressive internal stress and the velocity of the ultrasonic wave vertical to the stress in epoxy composite within a range of 0-70 MPa, and to calculate the acoustoelastic coefficient of epoxy composite. The effects of system delay are eliminated in measuring the propagation time. Some epoxy composite cuboid specimens with similar materials and using a manufacturing process similar to those of 252 kV GIS basin insulators are synthesized, and the uniformity of the internal stress in cuboid specimens is verified by finite element simulation. The results reveal a linear increase of the ultrasonic longitudinal wave velocity with increasing stress. It has been shown that the average acoustoelastic coefficient of GIS epoxy composites, using the longitudinal waves vertical to the stress, is 4.556 × 10 −5 /MPa. Additionally, the absolute errors of the internal stress measurements are less than 12.397 MPa. This research shows that the ultrasonic method based on the acoustoelastic effect for measuring the internal stress in GIS epoxy composites is feasible.

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“…Ramasamy et al [24] proved the effectiveness of L CR waves by comparing the finite element simulation method with the L CR experimental method. Wang et al [25] presented the velocity variations of L CR waves induced by orthotropic anisotropy and internal stresses.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Uncertain Factors on Measuring Residual Stress with Critically Refracted Longitudinal Waves

2019

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Critically refracted longitudinal (LCR) waves are commonly used to evaluate the residual stress of a material. The utilization of LCR waves is advantageous in that these waves are not sensitive to the texture of the material. Thus, LCR can be considered as a bulk longitudinal mode and can penetrate into the material well below its surface. However, while measuring the residual stress, the precision of the LCR wave travel-time is influenced by several uncertain factors. In order to further improve the accuracy of test results, we developed a measurement approach based on three aspects. First, the distances between the transmitter and the receivers were determined by transducer signal analysis. Second, for the residual stress detection to be consistent, transducers with different frequencies presented similar beam divergence angles. Finally, three different frequencies were used to evaluate the residual stress throughout the plate thickness. Based on the results of the above analysis, we used LCR waves to test 304 stainless steel plates. The detection error of residual stress measurement was ca. ±23 MPa. When compared with the X-ray diffraction approach, our method showed similar trends for the same regions of the specimens.

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Plane stress measurement of orthotropic materials using critically refracted longitudinal waves

Cited by 24 publications

References 20 publications

Study on the Measurement of Stress in the Surface of Selective Laser Melting Forming Parts Based on the Critical Refraction Longitudinal Wave

Study on the Measurement of Stress in the Surface of Selective Laser Melting Forming Parts Based on the Critical Refraction Longitudinal Wave

An Ultrasonic Longitudinal Through-Transmission Method to Measure the Compressive Internal Stress in Epoxy Composite Specimens of Gas-Insulated Metal-Enclosed Switchgear

Investigation of Uncertain Factors on Measuring Residual Stress with Critically Refracted Longitudinal Waves

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