A Finite Element Simulation Study on Reducers Based on Ultrasonic Guided Waves

2020 ◽  
Author(s):  
Zhang Pu-Gen ◽  
Ding Ju ◽  
Yang Yu-Qing ◽  
Xu Jin-Sha ◽  
Lin Jin-Feng
Keyword(s):  
Guided Waves ◽  
Simulation Experiment ◽  
Mode Conversion ◽  
Ultrasonic Guided Waves ◽  
Propagation Characteristics ◽  
Circumferential Crack ◽  
Axial Crack ◽  
The Difference ◽  
Pass Through ◽  
The Time Domain

Abstract Due to its special structural form, the reducers have common corrosion defects such as corrosion thinning, cracks and so on after being strongly impacted by the medium inside the pipes. However, there are few studies on the detection of reducers with the help of ultrasonic guided waves at present. In order to explore the effect of reducers to ultrasonic guided waves detection, the propagation characteristics of ultrasonic guided waves in reducer were simulated by using ABQUES. In the simulation, L (0, 2) mode was used to detect the reducer by two set of experiments. The first set of simulation experiment, L (0, 2) mode was excited from the large end of the pipe to detect the pipe with axial crack, circumferential crack and no crack respectively. The second set of simulation experiment, L (0, 2) mode was excited from the small end of the pipe to detect the pipe with axial crack, circumferential crack and no crack. The ability to detect defect was assessed by the time domain waveform of reflected echo, and the dynamic stress distribution cloud map is used to visually explain the propagation characteristics of the guided waves passing through the reducer, and the difference of detection capability between the two ends of excitation is judged by comparing the detection results. The conclusion shows that it is more sensitive to detect defect when ultrasonic guided waves are excited at the larger end, the ability to detect defects is weak when ultrasonic guided waves are excited at the small end. The mode conversion occurs and generate F (1, 1) mode, when the guided waves pass through the reducer from both ends. This paper provides effective technical guidance when ultrasonic guided waves detect defect on reducers.

Fatigue crack detection under the vibration condition based on ultrasonic guided waves

2019 ◽  
pp. 147592171986077 ◽  
Author(s):  
Yanping Zhu ◽  
Fucai Li ◽  
Wenjie Bao
Keyword(s):  
Fatigue Crack ◽  
Crack Detection ◽  
Guided Waves ◽  
Fatigue Testing ◽  
Ultrasonic Guided Waves ◽  
Testing Platform ◽  
Vibration Condition ◽  
Fatigue Crack Detection ◽  
The Difference ◽  
Index Value

Ultrasonic guided wave is an encouraging tool in structural health monitoring for civil, mechanical, ship, and aerospace devices. Most of heavy devices required a long-time running during the service, and the structure of these devices is under the vibration condition due to their inherent properties and working condition. This article mainly researches fatigue crack detection in vibration condition caused by operation using ultrasonic guided waves, aiming to study the application of ultrasonic guided waves in the field of structure dynamics. The detection method based on the difference index and the sequence curve of difference index between different states of crack is proposed to detect fatigue crack in vibration condition. The experiments are carried out on the fatigue testing platform and the vibration test-bed to investigate the relationship between opening states of fatigue crack and the difference index value of ultrasonic guided waves. In order to reduce the influence of loads applied by the fatigue testing platform on ultrasonic guided waves propagation, the initial experiment is first carried out to select the range of applied loads which have minimal influence on wave propagation. The results show that loads from 0 to 24 MPa have minimal effect on ultrasonic guided waves, and the difference index values of intact beam and cracked beam are in different orders of magnitude. Therefore, the method based on difference index value and sequence of difference index is credible to detect fatigue crack for structure in vibration condition.

Propagation characteristics of ultrasonic guided waves in continuously welded rail

2017 ◽  
Vol 31 (19-21) ◽  
pp. 1740075 ◽  
Author(s):  
Wenqing Yao ◽  
Fuwei Sheng ◽  
Xiaoyuan Wei ◽  
Lei Zhang ◽  
Yuan Yang
Keyword(s):  
High Speed ◽  
Guided Waves ◽  
Wave Structure ◽  
Dispersion Analysis ◽  
Ultrasonic Guided Waves ◽  
Bulk Wave ◽  
Propagation Characteristics ◽  
Destructive Testing ◽  
Continuously Welded Rail ◽  
Vibration Modal

Rail defects cause numerous railway accidents. Trains are derailed and serious consequences often occur. Compared to traditional bulk wave testing, ultrasonic guided waves (UGWs) can provide larger monitoring ranges and complete coverage of the waveguide cross-section. These advantages are of significant importance for the non-destructive testing (NDT) of the continuously welded rail, and the technique is therefore widely used in high-speed railways. UGWs in continuous welded rail (CWR) and their propagation characteristics have been discussed in this paper. Finite element methods (FEMs) were used to accomplish a vibration modal analysis, which is extended by a subsequent dispersion analysis. Wave structure features were illustrated by displacement profiles. It was concluded that guided waves have the ability to detect defects in the rail via choice of proper mode and frequency. Additionally, thermal conduction that is caused by temperature variation in the rail is added into modeling and simulation. The results indicated that unbalanced thermal distribution may lead to the attenuation of UGWs in the rail.

Propagation characteristics of ultrasonic guided waves in bolts embedded in soil

2006 ◽  
Author(s):  
Yaxin Sun ◽  
Cunfu He ◽  
Bin Wu ◽  
Xiuyan Wang ◽  
Zenghua Liu
Keyword(s):  
Guided Waves ◽  
Ultrasonic Guided Waves ◽  
Propagation Characteristics

Efficient Modeling of Nonlinear Scattering of Ultrasonic Guided Waves From Fatigue Cracks Using Local Interaction Simulation Approach

2016 ◽  
Author(s):  
Yanfeng Shen ◽  
Carlos E. S. Cesnik
Keyword(s):  
Fatigue Crack ◽  
Guided Waves ◽  
Mode Conversion ◽  
Fatigue Cracks ◽  
Guided Wave ◽  
Ultrasonic Guided Waves ◽  
Nonlinear Scattering ◽  
Absorbing Boundary ◽  
Interaction Simulation ◽  
Interior Damage

This paper presents an efficient modeling technique to study the nonlinear scattering of ultrasonic guided waves from fatigue damage. A Local Interaction Simulation Approach (LISA) is adopted, which possesses the versatility to capture arbitrary fatigue crack shapes. The stick-slip contact dynamics is implemented in the LISA model via the penalty method, which captures the nonlinear interactions between guided waves and fatigue cracks. The LISA framework achieves remarkable computation efficiency with its parallel implementation using Compute Unified Device Architecture (CUDA) executed on GPUs. A small-size LISA model is tailored for the purpose of extracting the guided wave scattering features. The model consists of an interior damage region and an exterior absorbing boundary. The interior damage region captures various types of fatigue crack scenarios, while the exterior absorbing boundary surrounds the damage model to eliminate boundary reflections. Thus, the simulation of guided wave scattering in an infinite media can be achieved utilizing a small-size local LISA model. Due to the parallel CUDA implementation and the small-size nature, this local LISA model is highly efficient. Selective mode generation is achieved by coupling/decoupling excitation profiles with certain wave mode shapes, which allows the study of sensitivity of different wave modes to a certain fatigue damage situation. At the sensing locations, mode decomposition is performed on the scattering waves, which enables the study of mode conversion at the damage. Fourier analysis allows the extraction of scattering features at both fundamental and higher harmonic frequencies. A numerical case study on nonlinear scattering of guided waves from a fatigue crack is given. The higher harmonic generation and mode conversion phenomena are presented using the wave damage interaction coefficients (WDIC), from which the sensitive detection directions can be inferred to place sensors. This study can provide guidelines for the effective design of sensitive SHM systems using nonlinear ultrasonic guided waves for fatigue crack detection.

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