基于多体动力学与颗粒动力学耦合的挖掘载荷计算与研究

Excavator Load Analysis Based on Multi-Body Dynamics and Particle Dynamics

为获得较为精确的挖掘阻力,进一步求出挖掘机所受的动态载荷,建立了多体动力学-颗粒动力学耦合的动态仿真方法。首先,建立挖掘机工作装置三维模型,以实测的动臂、斗杆和铲斗油缸位移变化曲线作为驱动,完成挖掘机工作装置的多体运动学分析,获得铲斗质心处的运动速度、铲斗相对斗杆和连杆在铰点上的角速度。然后,通过离散单元法建立挖掘介质的颗粒模型,利用已求得的铲斗运动参数对其运动进行定义,模拟铲斗在挖掘时的真实工况,求得铲斗在挖掘不同介质时所受的挖掘阻力和阻力矩,最后再通过多体动力学分析求解各铰点处的动态载荷。分析表明,挖掘介质为矿石与干砂时,挖掘阻力和阻力矩波动更为明显且铰点载荷也更大。

In order to obtain more accurate excavation resistance and find the dynamic load of the hinges,a coupling simulation method of multi-body dynamics and particle dynamics was established.First,the three-dimensional model of the working device of excavator is established.Based on the measured displacement curves of the boom,bucket and bucket cylinder,the multi-body kinematics analysis of the working device for the excavator is implemented.And movement speed at the center of the bucket,rotating angular velocity on the hinges of bucket and arm,bucket and connecting rod are obtained.According to the discrete element method,the particle model of excavating medium is reasonably established,and the movement of the bucket is defined according to the experiment motion parameters.Then,the mining resistance and moment are acquired when the excavator is working in different mediums.Finally,the dynamic loads at hinges are obtained through the multi-body dynamics analysis.The results show that the fluctuation of excavation resistance and resistance moment is more obvious and the load of hinge is larger when the mediums are stone and dry sand.