基于离散元法的滩涂埋栖贝类仿生挖掘铲设计与试验

Design and Experiment of Bionic Digging Shovel for Tidal Flat Buried Shellfish Based on Discrete Element Method

摘要:

针对传统滩涂埋栖贝类挖掘时存在的挖掘阻力大、作业效率低以及土壤扰动大等问题,提出一种基于螃蟹步足特征的仿生挖掘铲设计方法,旨在提升贝类采收的作业效能。首先,通过三维扫描技术,对螃蟹步足的形态结构、运动特性观测与分析,提取出步足末端尖锐弧度、节段式表面肌理特征等仿生要素。其次,以提取的仿生特征为核心设计依据,结合滩涂土壤物理力学特性完成仿生挖掘铲的三维建模,并通过离散元法(DEM)进行挖掘过程数值仿真,分析仿生挖掘铲与滩涂底质土壤的作用规律及减阻特性。最后,搭建室内试验台架,开展挖掘速度、挖掘阻力和土壤扰动对比试验,探究仿生挖掘铲的实际作业性能。仿真试验结果表明,仿生挖掘铲的平均阻力为151.42N,减阻率达17.45%;其平均土壤疏松度为33.43%,比平面挖掘铲减少6.91%。开展土槽试验,对比仿生挖掘铲与平面挖掘铲的滩涂挖掘作业性能,测得二者挖掘阻力平均值分别为162.41、189.27N;结果表明仿生挖掘 铲相较平面挖掘铲在作业过程中的挖掘阻力与土壤疏松度分别降低14.19%和4.98%,实际减阻率与仿真试验结果相吻合,满足滩涂埋栖贝类采收作业的减阻要求。

Abstract:

In view of the problems of high digging resistance, low operational efficiency and severe soil disturbance in the traditional harvesting of buried shellfish in tidal flats, a bionic digging shovel design method was proposed based on the bionic characteristics of crab pereiopods, aiming to improve the operational performance of digging operations. Firstly, the morphological structures and motion characteristics of crab pereiopods were observed and analyzed by means of 3D scanning technology, and key bionic elements such as the sharp curvature of the pereiopod extremities and the segmented surface texture features were extracted. Secondly, the 3D structural modeling of bionic digging shovel was completed through integration of extracted bionic features and physicomechanical properties of tidal flat soil. Furthermore, numerical simulation of digging process was conducted via discrete element method (DEM) to analyze the interaction mechanism and drag reduction performance between bionic digging shovel and tidal flat sediment soil. Finally, a bench test device was established to carry out comparative tests on digging speed, digging resistance and soil disturbance, to investigate the actual operational performance of the bionic digging shovel. Simulation results showed that the bionic digging shovel had an average resistance of 151.42N, with a drag reduction rate of 17.45%. Its average soil looseness was 33.43%, which was 6.91% lower than that of the flat digging shovel. Then, soil trench tests were performed to compare the digging performance of the two shovels, with the average digging resistance measured as 162.41N and 189.27N, respectively. Test results indicated that the bionic digging shovel decreased digging resistance and soil looseness by 14. 19% and 4. 98% compared with that of the flat digging shovel, and its actual drag reduction rate was consistent with the simulation results, meeting the drag reduction requirements for tidal flat shellfish harvesting.