变色龙舌头弹射过程的有限元模拟与仿真

Finite element simulation of chameleon tongue ejection process

变色龙捕食过程中舌头作为典型的生物软组织,能够以很快的速度弹射至一倍体长,因此探究变色龙舌头弹射过程并对其力学性能进行研究,对于以变色龙为仿效对象的仿生机械设计和开发领域中生物信息的提取尤为重要。根据高速摄像机下的变色龙捕食过程中舌头的比例建立了舌头的有限元模型,对舌头弹射过程进行了有限元仿真,初步确定了材料的本构模型以及材料的本构参数。考虑到变色龙舌头的弹出过程主要是由舌尖(加速肌)表面受到的压力驱动而产生,建立了变色龙舌头的“压力驱动模型”,通过在加速肌表面施加压力曲线,对变色龙舌头的弹射过程进行了有限元模拟与仿真,得到了整个弹射过程的速度曲线和位移曲线。然后引入神经网络,并将有限元分析和神经网络相结合对每一阶段的加载力数值进行优化,得到变色龙舌头弹射过程的最佳加载力,基于所得到的加载力对变色龙舌头的弹射过程进行有限元仿真,得到整个加载过程的速度曲线和位移曲线,与文献中实验所得到的速度曲线和位移曲线进行对比,验证了预测结果的正确性。

Typical of biological soft tissues,the chameleon's tongue is able to eject at twice its length at great speed dur⁃ing preying.Therefore,it is particularly important to explore the process of chameleon tongue ejection and study its me⁃chanical properties for the extraction of biological information in the field of bionic mechanical design and development with chameleon as the object of imitation.The finite element model of the tongue is established according to the propor⁃tion of the tongue in the process of the chameleon preying on the camera.The constitutive model and the constitutive pa⁃rameters of the material are determined preliminarily.Considering that the eject process of the chameleon tongue is main⁃ly driven by the pressure on the surface of the tongue tip(accelerator muscle),the"pressure driven model"of the chame⁃leon tongue is established.Finite element simulation and simulation of the chameleon tongue ejection process were car⁃ried out by applying pressure curve on the acceleration muscle surface.The velocity and displacement curves of the whole ejection process are obtained.Then the neural network was introduced,and the finite element analysis and neural network were combined to optimize the loading force at each stage,so as to obtain the optimal loading force during the chameleon tongue ejection process.Based on the obtained loading force,the finite element simulation of the chameleon tongue ejection process was carried out,and the velocity curve and displacement curve of the entire loading process were obtained.Compared with the velocity curve and displacement curve obtained by the experiments in the literature,the cor⁃rectness of the predicted results is verified.