Support vector machine based automatic focusing method of ultrasonic phased arrays of ring welds

Abstract

The invention discloses a support vector machine based automatic focusing method of ultrasonic phased arrays of ring welds. The method includes: establishing a rectangular coordinate system, taking a least squares support vector regression (LSSVR) machine as the regression model and Gaussian radial basis function as the kernel function, performing training with input and output which are subjected to standardized processing, and establishing a prediction model of LSSVR initial function; taking a generalization error calculated with a k-fold cross validation method as the target function, optimizing the LSSVR initial function by adopting an optimization method combining a coupling-simulated annealing algorithm with a grid searching method to acquire an optimal hype-parameter and an LSSVR optimization model, predicting tested data to acquire the output, performing inverse normalization processing to obtain the optimal acoustic beam path plan of a corresponding partition, performing reverse solution according to the Fermat theorem to obtain time delay, and applying ultrasonic signals to perform focusing detection on ring weld defects. By the arrangement, the method has the advantages that intelligent ring weld defect detection is realized, and detection precision and efficiency are effectively improved.

Description

technical field [0001] The invention belongs to the technical field of industrial ultrasonic nondestructive testing, and relates to an automatic focusing method of an ultrasonic phased array for circumferential welds based on a support vector machine. Background technique [0002] Welding connection is the most important and widely used connection method in pipeline engineering, especially the circular welding method. In various large-scale pipeline engineering projects at home and abroad, most of the pipeline laying work is completed by the circular welding process. However, in the pipelines that are connected and laid by welding, various defects will inevitably occur during the welding process. During service or extended service, the pipeline operates in high temperature, high pressure and corrosive environments, and is subjected to harsh conditions such as fatigue and impact. Under these conditions, the development of weld defects will be greatly accelerated, which will ...

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Problems solved by technology

However, in the actual inspection, the most suitable focusing method needs to be selected for different groove angles, defect areas, and wedge equipment positions in order to accurately and efficiently detect girth weld

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