时域有限差分法研究长骨中的超声导波

目的基于时域有限差分(finite-difference time-domain,FDTD)法研究长骨弹性模量对超声导波传播特性的影响,为早期骨质疲劳的超声导波检测方法提供理论依据。方法对长骨进行理论建模,并对不同弹性模量下的长骨模型进行FDTD仿真;通过对仿真数据的分析,计算出不同模式导波的相速度、群速度、中心频率及能量等特性参数。结果长骨的弹性模量与超声导波的传播特性参数密切相关,各个导波模式的相速度、群速度、中心频率和能量均随弹性模量的减小而减小,其中L(0,5)模式的变化趋势最为显著。结论超声导波的传播特性参量能够反映出长骨弹性模量的变化,进而为长骨早期疲劳诊断提供了一种可能的方法。

Ultrasonic guided waves in long bones based on finite-difference time-domain method

Objective To discuss the effects of elastic modulus on propagation characteristics of ultrasonic guided waves in long bones based on finite-difference time-domain (FDTD) method, so as to provide the theoretical references for evaluating bone fatigue damage at the early stage. Methods A cylinder was used to model the long bone, and FDTD method was used to simulate the long bone with different elastic modulus. Then, the propagation characteristics of different guided wave modes were calculated, including the phase velocity, the group velocity, the central frequency and the energy. Results The elastic modulus of long bones was closely related with the propagation characteristics of ultrasonic guided waves. The phase velocity, the group velocity, the central frequency and the energy were all reduced with the decrease in elastic modulus, and the variation tendency of L(0,5) mode was the most obvious. Conclusions The propagation of ultrasound guided waves can reflect the variation of elastic modulus of long bones, which provides a possible way to evaluate the fatigue damage at the early stage in long bones.