复合材料基体裂纹光纤光栅非线性超声Lamb波检测试验研究

Evaluation of Composite Matrix Crack Using Nonlinear Ultrasonic Lamb Wave Detected by Fiber Bragg Grating

针对复合材料基体裂纹引起的超声非线性问题,研究了一种具有比例–积分–微分反馈控制的高灵敏度、大带宽相移光纤光栅超声检测系统。利用相移光栅系统检测在复合材料中传播的超声Lamb波信号,对Lamb波进行数据处理,分离出了频率为2.0MHz的二次谐波成分。结果表明,随着裂纹个数的增加,相对非线性参数线性增长,且相比压电传感器检测结果,相移光栅检测的相对非线性参数具有更高的增长速率。提出的相移光纤光栅传感系统可应用于复合材料的基体裂纹损伤评估,且具有很高的可靠性。

A high-sensitive and broad-bandwidth phase-shifted fiber Bragg grating based ultrasonic detection system with proportional-integral-derivative feedback controller was proposed to evaluate the ultrasonic nonlinearity induced by the matrix crack in carbon fiber reinforced plastic.After the optical fiber sensing system detected the ultrasonic Lamb wave propagating in a composite laminate,the second harmonic components with a frequency of 2.0MHz was extracted from Lamb wave signals by data processing.The result show that the relative nonlinear parameter grew linearly with the increase of crack numbers.In comparison with conventional lead zirconate titanate sensor,the relative nonlinear parameter detected by the phase-shifted fiber Bragg grating sensor shows a higher growth rate.Thus,the proposed fiber optic-ultrasonic detection system with high reliability can be applied to the evaluation of matrix cracks damage of composite materials.