Simulation Study On Impact Of Cylinder Piston Rod And Bush

As an important pneumatic actuator element, the cylinder plays an important role in industrial production, and it has great practical significance to improve the life and efficiency of the cylinder. In the impact of the cylinder, when the cylinder piston impact to the front end cover with a high speed and suddenly stop, the piston rod and the bush will have a greater stress, repeated collision will lead to inevitable wear and tear of the piston rod and bush, produce gas leakage, vibration and other phenomena, then impact the cylinder’s performance and service life, so accurate understanding of the impact characteristic of the cylinder is the key to improve the performance and service life. In this paper, the method of modeling and simulation is used to analyze the centralized and distributed parameters of the cylinder in the process of impact.In order to solve the velocity, displacement, radial shock, the dynamic stress distribution and the deformation of the piston rod and the bush during the cylinder impact, a combined simulation method of Matlab and ANSYS/Ls-dyna is presented in this paper.Firstly, Using Matlab to establish the cylinder model and simulate, in order to get the simulation results of inner pressure, displacement and velocity of the cylinder, secondly the results of Matlab are used as the simulation conditions, adding them on the cylinder simulation model, and more accurate displacement and velocity, radial shock, the dynamic stress distribution and the deformation between the piston rod and the bush can be obtained by solving the solution. There are many factors that affect the impact of the cylinder, the impact speed of the piston rod, the load, the bush width, the gap between the piston rod and bush are the most important four factors. Therefore, In this paper control variable method is also used to distinguishing analysis the influence of the four factors on the stress distribution and deformation of the cylinder, and combine the analysis result with the bush mechanical properties, a further study is carried out.The simulation results show the dynamic stress distribution and deformation of the cylinder at each moment, it also show the radial shock and rebound situation of the cylinder,and the change of the displacement and velocity of the cylinder during the whole impact.Simulation results indicate that during the impact of the cylinder, affected by the load draginfluence, piston and piston rod appear obvious tilt, resulting in bush and the cylinder tube present some obvious stress points. Under the influence of different impact velocity and different load, the maximum stress and deformation of the cylinder are changed regularly,and it approximately present proportional relationship with the velocity and load, The increase of the gap and decrease of bush width can cause the stress and deformation of the cylinder increase. According to the simulation results, it can be conjectured that the value range of the speed and load, to avoid the irreversible deformation of the maximum extent.