Abstract: When carrying out structural health monitoring on complex structures using Lamb wave, the finite element simulation of Lamb wave propagation process is usually performed. However, because of the size of the model, composite anisotropy and other reasons, much boundary reflected wave will produce and cover the damage waveform. Therefore, it is very important to establish the absorbing boundary to inhibit the influence of the reflected wave. This paper applies an absorbing boundary that incorporates Combin14 spring damper elements. The influence of several parameters to the absorption are studied. The parameters include the length of the absorbing boundary, the frequency, the direction of Combin14 element. And the results are compared with the traditional damping increasing absorbing boundary. The study indicates that both of the frequency and the length of the absorbing boundary have no effect on the absorbing effect of the absorbing boundary, but the wave-absorbing boundary length must be larger than that of wavelength to achieve the best absorbing effect. When the Combin14 elements are set in the direction of wave propagation, the absorbing effect will be best. Compared with the increasing damp absorbing boundary, the simulation time-consuming of the spring damper absorbing boundary obviously cut back and the absorbing effect is better in the low frequency band.

Key words: spring damper Combin14 element, absorbing boundary, Lamb wave, composite, finite element simulation