CAJ | 학술논문

在对管型结构的导波检测过程中，需要预先选定导波模态，并确定激励频率，这个选择的过程存在一定的盲目性，而在多次反复试验中确定最佳激励模态和频率也会带来精力、时间、硬件资源的耗费问题。介绍一种信号处理方法，在宽频信号作为激励产生响应的基础上，采用该算法可获得其频带范围内任意单频激励信号对应的响应，有效解决了预先选定模态及频率的问题。同时，引入时频分析技术，根据缺陷反射回波能量的分布情况快速确定具有低模态转换响应的导波频率区间。通过对比各频率计算结果的模态和缺陷反射信号幅值，发现缺陷管中理想的激励导波频率在140～180 kHz，且缺陷反射回波幅值随激励信号周期增加而增加，但这种特点在低频表现得不明显。这为根据管中缺陷大小及类型，选择不同激励频率和周期提供了理论依据。
재대관형결구적도파검측과정중，수요예선선정도파모태，병학정격려빈솔，저개선택적과정존재일정적맹목성，이재다차반복시험중학정최가격려모태화빈솔야회대래정력、시간、경건자원적모비문제。개소일충신호처리방법，재관빈신호작위격려산생향응적기출상，채용해산법가획득기빈대범위내임의단빈격려신호대응적향응，유효해결료예선선정모태급빈솔적문제。동시，인입시빈분석기술，근거결함반사회파능량적분포정황쾌속학정구유저모태전환향응적도파빈솔구간。통과대비각빈솔계산결과적모태화결함반사신호폭치，발현결함관중이상적격려도파빈솔재140～180 kHz，차결함반사회파폭치수격려신호주기증가이증가，단저충특점재저빈표현득불명현。저위근거관중결함대소급류형，선택불동격려빈솔화주기제공료이론의거。
Pre-selecting mode and frequency of excitation signal is very important in guided wave inspection for pipe structures. The method by repeating trials to determine the optimum mode and frequency will enhance the consumption of energy, time and hardware resources. It shows a signal processing method to analysis the propagation property of various guided waves in pipes. Any response of single-frequency component contained in the broadband of the chirp signal could be obtained by this method. Simultaneously, the time-frequency analysis method is used to select the desired tone burst excitation through comparing the energy distribution of defect reflection signals. Verified by the finite element simulation, it is effective solution to find the guided wave that with lower mode conversion in propagation in pipe structures. After comparing the mode purity and the reflection amplitude, the results show that the frequency band between 140 kHz and 180 kHz is more suitable for using as excitation. In contrast to low frequency band, the reflection amplitude of signals obtained in this band increases along with the increase of excitation cycles. This provids a theoretical basis for the defects in accordance with the size and types chooses a suitable excitation frequency and period in nondestructive testing.