Nonlinear ultrasonic beam aliasing calculation method and system

Abstract

The invention provides a nonlinear ultrasonic beam aliasing calculation method and system, and the method comprises the steps: a nonlinear response obtaining step: setting the form of an input signalfunction, and obtaining the nonlinear response of a certain observation point in the structure of an ultrasonic propagation medium; a phase changing step: changing the phase of the input signal function, and obtaining the nonlinear response at the observation point again; an arithmetic mean acquisition step: superposing the nonlinear responses obtained in the previous two times and taking half ofthe nonlinear responses to obtain an arithmetic mean; and a signal processing step: carrying out signal processing on a new result obtained after superposition, and analyzing frequency components suchas higher harmonics and resonance waves in the new result. According to the method, in nonlinear ultrasonic beam aliasing response analysis, even-order higher harmonics and resonance wave componentscan be effectively extracted by using a positive and negative phase response superposition method, the influence of fundamental frequency wave components is remarkably and greatly weakened, and the method is simple, convenient, visual and efficient.

Description

technical field [0001] The present invention relates to the field of ultrasonic technology, in particular to a nonlinear ultrasonic beam aliasing calculation method and system. In particular, it relates to a nonlinear ultrasonic beam aliasing calculation method based on the positive and negative phase response superposition method. Background technique [0002] Ultrasonic technology based on linear theory has many deficiencies in the sensitivity of micro-damage and early damage detection. The nonlinear ultrasonic detection method developed in recent years can take advantage of the nonlinear response generated by ultrasonic waves propagating in the structure, that is, the output signal is in the Evaluating the change in frequency can identify the performance degradation of the material at the microscopic level, and has a high detection sensitivity for the change of the microstructure in the early stage of damage. Because materials often show some nonlinear mechanical charact...

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Problems solved by technology

Compared with the fundamental frequency component, the amplitude and energy of the resonant wave and high-order harmonic component are more than an order of magnitude lower. Due to the dominance of the fundamental frequency component in the results obtained by the current calculation method, it is often difficult to Intuitively distinguish the existence of Xie Zhenbo and high-order harmonic components, so it is necessary to adopt a new nonlinear ultrasonic beam aliasing calculation method based on positive and negative phase response superposition method

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