CAJ | 학술논문

轴对称载荷是管道中轴对称模态导波激励的有效方法。然而，受换能器安装误差等因素的影响，激励载荷多会变为非轴对称载荷，进而使激励出的导波模态变得复杂。对非轴对称多元载荷条件下纵向模态导波的激励问题进行了深入研究。考虑两种典型的非轴对称载荷，采用简正模态展开技术，建立了导波激励声场与边界载荷的量化关系，进而分析了各模态导波的产生机理及载荷阵列对纵向导波激励的影响。采用有限元数值模拟验证了理论预测结果。考虑实际管道检测中出现的非轴对称载荷，提出了一种载荷补偿策略并进行了实验验证。结果表明，该方法能够有效抑制弯曲模态导波的产生，同时也有助于改善导波信号的噪声水平。
축대칭재하시관도중축대칭모태도파격려적유효방법。연이，수환능기안장오차등인소적영향，격려재하다회변위비축대칭재하，진이사격려출적도파모태변득복잡。대비축대칭다원재하조건하종향모태도파적격려문제진행료심입연구。고필량충전형적비축대칭재하，채용간정모태전개기술，건립료도파격려성장여변계재하적양화관계，진이분석료각모태도파적산생궤리급재하진렬대종향도파격려적영향。채용유한원수치모의험증료이론예측결과。고필실제관도검측중출현적비축대칭재하，제출료일충재하보상책략병진행료실험험증。결과표명，해방법능구유효억제만곡모태도파적산생，동시야유조우개선도파신호적조성수평。
Axisymmetric surface loading is an effective method to excite axisymmetric guided waves in pipes. However,non-axisymmetric surface loading appears due to various influence factors,such as,transducer installation error and it leads to the complex excited guided wave modes.Here,longitudinal guided waves excited by non-axisymmetric multielement surface loading were investigated deeply.Two typical non-axisymmetric loadings were considered and analyzed.Based on the normal modal expansion technology,the quantitative relationship between applied boundary loadings and guided wave excitation acoustic field was built,and then the generation mechanism of individual guided wave was analyzed and the effects of non-axisymmetric loading array on the generation of longitudinal guided wave were studied. Theoretical predictions were verified with the finite element simulations.For the non-axisymmetric surface loading occurring in the actual pipe inspection,a new loading compensation strategy was proposed and verified with tests.The results showed that the compensation strategy can suppress the flexural modes effectively,and is helpful to improving the noise level of guided wave signals.