An intelligent algorithm based on evolutionary strategy and clustering algorithm for Lamb wave defect location

2020 ◽  
pp. 147592172095959
Author(s):  
Honglei Chen ◽  
Zenghua Liu ◽  
Bin Wu ◽  
Cunfu He

Imaging algorithms for visualization of defects play a significant role in Lamb wave–based research of nondestructive testing and structural health monitoring. In classical algorithms, the position or distribution of defects is located by mapping the amplitude or phase information of signals from the time domain to every discrete spatial grid of the structure. It is time-consuming. In this study, the diversity, statistical, and fuzzy characteristics of the elliptic imaging algorithm are analyzed first; then, an intelligent defect location algorithm is proposed based on the evolutionary strategy and the K-means algorithm. The position of defects can be identified by observing the distribution of individuals. There are six parts in the proposed algorithm, including the data structure design, adaptive population screening, adaptive population reproduction, diversity maintenance mechanism, and cutoff criterion. Considering the statistical and fuzzy characteristics in the detection, several specific input parameters are defined in our algorithm, such as the distance-dependent screening threshold, path-dependent residual vector, and path-independent residual. To maintain the diversity of individuals in the analysis, we have made two adjustments to the evolutionary strategy: one is to optimize the population screening and reproduction steps with the K-means algorithm, and the other is to add a diversity maintenance method into the evolutionary strategy. The effectiveness of the proposed intelligent defect location algorithm is verified by numerical simulations and experiments. Numerical studies indicate that the proposed algorithm has a reliable performance in the detection of defects with different shapes and sizes. In the experimental research, we demonstrate that the efficiency of the proposed algorithm is about 200 times faster than the elliptic imaging algorithm. And the optimum parameter setting of the algorithm is investigated by analyzing the influence of parameter setting on the detection.

2021 ◽  
Vol 120 ◽  
pp. 102435
Author(s):  
Lei Yang ◽  
Huaixin Wang ◽  
Benyan Huo ◽  
Fangyuan Li ◽  
Yanhong Liu

2021 ◽  
Vol 25 (6) ◽  
pp. 1453-1471
Author(s):  
Chunhua Tang ◽  
Han Wang ◽  
Zhiwen Wang ◽  
Xiangkun Zeng ◽  
Huaran Yan ◽  
...  

Most density-based clustering algorithms have the problems of difficult parameter setting, high time complexity, poor noise recognition, and weak clustering for datasets with uneven density. To solve these problems, this paper proposes FOP-OPTICS algorithm (Finding of the Ordering Peaks Based on OPTICS), which is a substantial improvement of OPTICS (Ordering Points To Identify the Clustering Structure). The proposed algorithm finds the demarcation point (DP) from the Augmented Cluster-Ordering generated by OPTICS and uses the reachability-distance of DP as the radius of neighborhood eps of its corresponding cluster. It overcomes the weakness of most algorithms in clustering datasets with uneven densities. By computing the distance of the k-nearest neighbor of each point, it reduces the time complexity of OPTICS; by calculating density-mutation points within the clusters, it can efficiently recognize noise. The experimental results show that FOP-OPTICS has the lowest time complexity, and outperforms other algorithms in parameter setting and noise recognition.


2013 ◽  
Vol 588 ◽  
pp. 140-148 ◽  
Author(s):  
Rafal Radecki ◽  
Wieslaw Jerzy Staszewski ◽  
Tadeusz Uhl

Lamb waves are the most widely used guided ultrasonic waves for structural damage detection. One of the major problems associate with Lamb wave propagation is the effect of temperature on wave propagation parameters. It is important that these parameters are more sensitive to damage than to varying temperature. The paper demonstrates how amplitude and arrival time of Lamb waves are affected by temperature. The analysis is performed for the experimental data gathered from Lamb wave propagation in a damaged aluminium plate. A simple clustering algorithm is used to distinguish between "undamaged" and "damaged" conditions in the presence of changing temperature.


2013 ◽  
Vol 333-335 ◽  
pp. 2130-2135
Author(s):  
Kui Hua Geng ◽  
Jing Guo ◽  
Wen Gui Su ◽  
Shi Guang Du

Based on finite element analysis technology, a static simulation model of the swing-rod constraint reciprocating piston-type oil-free air compressor was established for stress analysis of the compressor. Simulation results show that the stress in the main parts of the new compressor is within the permitted range, so structure design and parameter setting of the compressor are reasonable. Moreover, the force condition of seal rings is improved by adding swinging-rod constraint mechanism, which will prolong the service life of seal rings. With this study, these simulation results will guide further modification and performance improvement of the compressor.


2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881408 ◽  
Author(s):  
Zhong-hang Bai ◽  
Shan Zhang ◽  
Man Ding ◽  
Jian-guang Sun

Modular design can shorten the product development cycle and enhance the product research and development capability of enterprises. To better solve the problem of module interface coupling after module partition, the present modular product design method has been improved based on the theory of inventive problem solving and axiomatic design theory. This article summarizes the engineering parameters commonly used in modular design based on the requirement analysis and conflict problems of modular structure design. And in the process of dividing the functional modules by fuzzy clustering algorithm, we propose defining and classifying the principle (technical) correlation between parts by these parameters. Then the coupling relation of each module interface is analyzed by the design matrix of axiomatic design and the conflict solving tool of the theory of inventive problem solving is utilized for decoupling. Finally, the high chair is taken as the design object and the design process is used to verify the feasibility of this method.


2019 ◽  
Vol 23 ◽  
pp. 165-165
Author(s):  
Shiwei Ma ◽  
Shuhao Cao ◽  
Yu Lu ◽  
Hanfei Zhang ◽  
Qingwei Xia ◽  
...  

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