石鳖抗冲蚀磨损三维数值模拟

Three Dimensional Numerical Simulation of Anti-erosion Characteristics of Chiton Acanthochiton rubrolineatus

利用ANSYS/LS-DYNA显式动力分析软件,对仿石鳖壳板的构形单元仿生模型和构形-凹槽形态及构形-凸包形态二元耦合仿生模型的动态冲蚀磨损过程进行了三维数值模拟,对比分析了不同耦元对靶材抗冲蚀性能的影响规律。3种模型在整体水平上抗冲蚀性顺序依次为凸包弧形板、凹槽弧形板和光滑弧形板。在弧形板峰部,凹槽的应力分散效应即抗冲蚀性能明显优于凸包;而在翼区,凸包的抗冲蚀性能显著优于凹槽,说明石鳖壳板在进化过程中优化出了最佳的形态组合,即壳板峰部分布有粗大的纵肋(肋间相对形成凹槽),而翼区则分布有大量的凸包,从而可以有效抵抗强烈的海砂冲蚀。

Molluscan shells lived in harmony with nature upon the combination of multiple factors,e. g.,surface morphologies, multilevel structures and component materials, and achieved an optimum adaptation to the surroundings based on such biological coupling functions. The Polyplacophora usually has complex surface topography and specific living behaviors which showed exceptional anti-erosion property. Thus,the chiton Acanthochiton rubrolineatus was selected to study its bionic anti-erosion mechanism. According to biological coupling and bionic anti-erosion property of chiton,the explicit dynamic software ANSYS / LS-DYNA was used to simulate the erosive process of uni-bionic model of configuration and configuration-groove / convex morphology dual-bionic coupled model imitating the shell surface of chiton. The mechanism of erosion of each model was comparatively analyzed. The overall erosion resistance of the three models was sorted as convex-curved plate,groove-curved plate and smoothcurved plate. However,in the peak of the curved plate,the stress dispersion effect of groove was much better than that of convex,whereas the stress dispersion effect of convex was better than that of groove at the pterion region. The simulation results indicated that the shell plate of chiton evolved an optimum combination of morphologies with thick riblets distributed in the peak( grooves were formed between the riblets) and convexes scattered around the pterion region,and thus the chition was endowed with exceptional anti-erosion property. The current research result could be further used in the series of agricultural irrigation machinery,such as water pump,turbine pump,spray irrigation equipment and drip irrigation system.