Defects Inspection in Wires by Nonlinear Ultrasonic-Guided Wave Generated by Electromagnetic Sensors

Abstract

<jats:p>Steel wires are widely used as raw materials for spring valves in engines. Considering the quality and safety issues of their structure, there is a demand to develop nondestructive inspection approaches to detect initial damages in steel. In this study, nonlinear ultrasonic-guided waves generated by an electromagnetic acoustic transducer (EMAT) were used to inspect the defects in steel wires. As one of the noncontact testing methods, the use of EMAT has significant advantages to decrease the nonlinearity induced by instruments and transducer contact condition. The principles of design and manufacturing of EMAT are first introduced. The fundamental theory of nonlinear guided waves is also briefly discussed in this investigation. Phase-matched guided wave modes were generated and measured by using EMAT. Variations of acoustic nonlinearity corresponding to existing defects in specimens were obtained. A scanning electron microscope (SEM) was used to check the existence of microdefects in specimen. The results indicate that the use of EMAT can be an effective means to generate and measure nonlinear ultrasonic-guided waves for inspection of microdefects.</jats:p>

Analysis of the Principle, Facility and State-of-art Applications of Different Types Inductive Sensor

“…Thirdly, exploring applications in other fields. Traditional electromagnetic sensors suffer from nonlinearity errors and zero residual voltage [17]. To reduce the impact of these factors, differential design and low-frequency design are commonly used, along with minimizing interference from temperature and other noise sources to improve data accuracy.…”

Numerical and Experimental Analysis of DVA on the Flexible-Rigid Rail Vehicle Carbody Resonant Vibration

“…Modal analysis is employed to solve the linear system's motion equations without damping and to find the system's natural frequency [48][49][50]. Analytical approaches could not precisely determine the natural frequency due to the complicated construction of the CB [37,[51][52][53][54][55][56][57][58][59][60][61][62]. However, finite element methods might be used to solve it [3].…”

Ultrasonic Nonlinearity Experiment due to Plastic Deformation of Aluminum Plate Due to Bending Damage

“…Li Weibin conducted experiments to characterize the thermal fatigue damage of composite laminates using second harmonic Lamb waves [ 15 ] and investigated the effect of material microstructure evolution on the acoustic nonlinear response of ultrasound in rolled copper and brass [ 16 ]. In addition, Li W. and Park J. conducted a study to detect micro-cracks in materials using non-contact electromagnetic ultrasonic transducers [ 17 , 18 ]. Lissenden presented a method for detecting local fatigue damage on an aluminum plate by utilizing a PVDF (polyvinylidene difluorine) sensor to simultaneously receive shear-horizontal waves and the secondary Lamb waves they generate.…”