ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

The earthworm’s surface was selected as the object to study the mechanism of resistance reduction of wavy surface, and discrete element method (DEM) was used to simulate the dynamic response of the contact soil particle with wavy surface. The results of simulation showed that the contact time was shorter when the particle contacted with wavy surface, and the particle separated at 1.0s. Macroscopic showed that the porosity was formed between the wavy sample and soil particle. X direction displacement of the contact particle was increased linearly and in the same direction, the average displacement was 60.33mm.Y direction velocity was changed with the concave-convex of the wavy surface like sinusoidal variation, and generated microseism, the amplitude of the wavy surface was bigger than the smooth surface. Contact position directly determined the size and direction of the contact force. Analysis showed that the amplitude and frequency of the contact particle with wavy surface was greater than smooth surface. The results can supply the reference to design the bionic wavy surface.