基于有限元方法的蜘蛛网阻拦猎物过程模拟

Simulation of prey stopping process by spider webs based on finite element method

为揭示蜘蛛网阻拦猎物过程的内在力学规律,基于理论和有限元方法对这一过程进行了研究。首先,根据已有实验结果建立了蜘蛛网径线和周线的应力-应变关系。然后,给出了单根丝线受横向冲击问题的理论解,并利用LS-DYNA有限元软件对该问题进行了数值模拟,有限元数值解与理论解一致。最后,利用LS-DYNA有限元软件模拟了蜘蛛网阻拦猎物的过程,得到的网内最大应变值和能量曲线与已有实验结果一致。计算结果表明,在蜘蛛网对猎物动能的耗散中,径线占主导地位;与冲击位置相邻的径线应力水平很低,有利于蜘蛛网的修复,径线中点附近的区域最有利于较大初始动能猎物的阻拦。

In order to discover the mechanical characteristics of spider webs to capture a flying prey,the actual stopping process is investigated based on the theoretical and finite element methods（ FEM）. First,the stress-strain relationships were built for radial silks and capture spirals in the orb web from the existing experiments. Then,the dynamic response of a single silk thread under transverse impact was solved theoretically.The problem was also simulated using the LS-DYNA software and the numerical results were in good agreement with the theoretical solution. Finally,the actual process for the real web stopping a flying prey was simulated by the LS-DYNA software. The predicted maximal strain of silks in the web and the energy curves agree with the existing experiment results. The numerical simulation shows that the radial silk plays an important role in absorbing the kinetic energy of the flying prey. The stress of radial silks near the impact point is rather low,which is helpful in localizing the damage of radial threads in contact with the prey and repairing the web.When the prey impacts the web with large kinetic energy,the best intercept area is near the middle region of radial threads.