Discrete element method for adhesion properties evaluation of deep-sea sediment from macro and micro perspectives

基于离散单元法的深海沉积物宏细观粘附特性研究

The adhesion between the mining machine and the deep-sea sediments will significantly affect the driving performance of the mining machine in the deep-sea environment.When the mining machine and the deep-sea sediment interaction simulation was carried out,the accuracy of the particle interaction parameters will directly affect the simulation results.This study proposed a method to systematically calibrate the interaction parameters between deep-sea sediment and grouser through the combination of experiment and simulation.The uniaxial compression test and macro adhesion test and corresponding discrete element numerical simulation were carried out,modifying the contact parameters until the simulation results are close to the experimental results.Then the micro-parameters of the JKR adhesion contact model were back calibrated with the test results,and the contact parameters between soil particle-soil particle and soil particle-metal are calibrated.Besides,the adhesion test shows that the adhesion forces were ranked in the order of 5052<STi80<TA2<TC4 under the same surface roughness,which indicates the aluminum alloy 5052 has the best anti-adhesion performance.The relationship between surface adhesion force and microscopic contact parameters was studied by discrete element numerical simulation,and the result shows that the coefficient of static friction and the coefficient of rolling friction has little effect on adhesion force.While it is mainly affected by the coefficient of restitution and surface energy,the surface adhesion force tends to decrease with the increase of the coefficient of restitution and increase with the growth of surface energy.The obtained parameters of soil particle to soil particle and soil particle to metal affecting the adhesion can contribute to the design optimization for the grouser of mining machines to decrease surface adhesion and enhance its movability and mining efficiency.

集矿机与深海沉积物之间的粘附会显著影响集矿机在深海环境中的行走性能,当在进行集矿机与深海沉积物相互作用仿真时,颗粒相互作用参数选用的准确度将会直接影响仿真结果。本文提出一种通过实验与模拟相结合的方法来系统地标定深海沉积物与集矿机之间相互作用参数的方法,进行了单轴压缩试验和宏观粘附试验以及相应的离散元数值模拟,通过修改接触参数直到模拟的结果接近试验结果,然后根据试验结果对JKR粘附接触模型的微观接触参数进行回校,实现了土颗粒-土颗粒、土颗粒-金属之间的接触参数的标定。另外粘附试验表明,在相同表面粗糙度下,测得的附着力顺序5052<316L<STi80<TA2<TC4,这表明铝合金5052的抗粘附性能最好。通过DEM模拟,研究了表面粘附力与微观接触参数之间的关系。结果表明:粘附力与静摩擦系数、滚动摩擦系数关系不大,其主要受恢复系数和表面能的影响,且随着恢复系数的增大而减小,随着表面能的增大而增大。所获得的土壤颗粒对土壤颗粒和土壤颗粒对金属的粘附影响参数,有助于集矿机履齿的设计优化,以降低表面粘附,提高其可移动性和采矿效率。