Dynamic Analysis on Excavator Considering Flexibility
The hydraulic excavator has an extensive application in such engineering fields as construction, civil, transportation, mining and military.According to on-site failure analysis on the SY215 excavator, it was observed that the part near the joint connecting the boom and the arm is more likely to suffer damage among all of the joints, which decreases the usage year of the excavator.In order to determine the stress of the key points on the boom during the digging process, the excavator is modeled as a rigid-flexible coupling multibody system, and the analysis of planar flexible multibody dynamics is carried out considering flexible deformation.The most easily-damaged part, boom, is assumed as a flexible body, with remaining 10 parts as rigid bodies.Finite element method is used to discretize the boom.Based on the principle of virtual work, the variational equations of motion are derived taking both the large-scale motion of the system and the deformation of the boom into consideration.By leading into kinematic constraint equations, the equations of motion of the flexible multibody system are established.In addition, the digging forces are modeled as STEP functions, and the general mass matrix of the system is changeable while the soil surface is dug by excavators bucket.When solving the non-linear differential-algebraic equations numerically by means of Runge-Kutta method and Gaussian Elimination, the value of velocity and displacement are corrected since there are errors resulting from integration.As a result, the forces applied on the joints of the boom and the Von-Mises yield stress of key points during the whole digging period are calculated.It is found that the amplitude of the vibration of the joint forces is large, resulting huge energy loss of the boom.The largest force applied on the boom is the driving force of the hydraulic bar of the boom, however, according to the stress data, the key points near the joint of boom and arm experience the largest stress.It is shown that the maxim stress of the point reaches 100Mpa, which coincides with the on-site observation that the joint of the boom and the arm is firstly damaged.Finally it is proposed that the points near the joint connecting the boom and the arm are easy to suffer damage.
Luning Fang Jinyang Liu
Department of Engineering MechanicsShanghai Jiao Tong UniversityDongchuan Road 800Shanghai,200240,Ch Department of Engineering Mechanics Shanghai Jiao Tong University Dongchuan Road 800 Shanghai,200240
国际会议
上海
英文
1-5
2012-08-26（万方平台首次上网日期，不代表论文的发表时间）