The Finite Element Analysis And Simulation Of Excavator Working Device

Excavator has been widely used in the construction of various infrastructure projects. Its work environment is generally very severe, and the working device is the component that directly affected by external load, the level and quality of its design is an important indicator of advanced machine. The excavator working device is taken as the research object in the thesis to study its dynamic simulation and finite element stress analysis, to identify the area of dangerous stress. Taking it as a theoretical basis to make the structural design of working device in order to get a more reliable and comprehensive program of structural improvements. The specific works were as follows:(1) Using Pro/ENGINEER to establish the 3D model of excavator working device parts, then getting the assemble model by assembling the parts.(2) Importing the 3D model to ADAMS to create its virtual prototype. To study the force of the hinge points, loading the calculated resistance to the bucket. Taking the simulation of the bucket excavation to obtain the force changing curves of the hinge points on the working device, the force provide the base to the components design and analysis.(3) Importing the model to the ANSYS to make the finite element static analysis. As the connection between the arm and other components is splice, to avoid the increase of the local stiffness and stress by full constraints, using couple DOF of the two components that hinged together to simulate the rotation motion. Then calculating the problem use the computer, AYSYS will give the cloud chart of stress and deformation of the arm when the calculation is done. The results shows great stress concentration appears at the weld zone between the rear-end of the support of the rod hydrocylinder and the uppercoverplate of the arm, and the stress is 398.968MPa ,which has beyond the yield limit of the material, the structural needs optimization and improvements.(4)The improvement scheme is: extending the length of the steel plate of the support of the rod hydrocylinder, which will increase the contact area between the support and the uppercoverplate of the arm. Making the FEM analysis again, the result shows the stress in the region is significantly reduced to 277.238MPa , and the strength of the structural meets the requirements. (5)Taking modal analysis of the arm to get the preceding six-order natural frequencies and shapes. The result shows that the frequency that the engine makes is not equal to the natural frequency of the arm, there is no resonance; and the frequencies that produce by the external load is far lower than the first natural frequency of the arm, there is no resonance as well.Using virtual prototyping and finite element method can discover the deficiencies of the product in the design process. Compared with the traditional method, modern design method can effectively shorten the development cycle, reduce costs, and improve the level and quality of development.