Dynamic Analysis And Durability Research Of Hydraulic Mount Of Engine

Powertrain Mount System (PMS) serves as the most important set of vibration-isolation and noise-reduction for powertrain and the vehicle body. Undesirable vibrations for powertrain mounts are generally from two possible excitation sources. The first one, from engine oscillation, typically contains high frequencies small amplitudes. The second one originates from road inputs and engine torque during harsh accelerations, with low frequencies and large amplitudes. Accordingly, PMS serves two main functions:power train support and bi-directional vibrations isplationin all complex operation modes. The ideal PMS can effectively reduce the vibration generated by the road random spectrum and engine periodic operation. Hydraulic Mount (HM) is widely used in automotive industry in view of good dynamic response and low cost.Based on the structure and the working principle of a detailed analysis of hydraulic mount, using the theory of fluid mechanics, mechanical model and mathematical model of hydraulic mount nonlinear were established. Then, numerical simulation model was established by using the simulation tool of Matlab/Simulink, and conducted dynamic simulation calculation, analyzed the stiffness of rubber main spring, the equivalent piston area of rubber main spring, the inertia-tract equivalent cross-sectional area and the length of inertia-track to influence of dynamic characteristics of hydraulic mounts.Taking the rubber spring of a hydraulic engine mount for car powertrain as an example, the method for Finite Element Analysis (FEA) of rubber isolators is studied in this paper. The fundamental theory for the FEA of rubber components is reviewed, and the experimental method for obtaining the constants of the hyperelastic material constitutive model is presented. The characteristics of the main rubber spring of a hydraulic enginemount with non-linear finite element software ABAQUS are analyzed here. According to the stress contour to identify the location of fatigue failure of the two kinds of mounting, and consistent with the actual fracture surface of mounting through pre-judgment of fracture surfaces. Also the structural parameters of rubber main spring to the affect law of static and dynamic characteristics was calculated and analyzed, which by modifying the sensitive parameters and improving system performance, designed product and matched to provide guidance for hydraulic mount.Based on fracture theory, stress intensity factor at crack tip can be calculated directly with the stress results of stress finite element analysis, the direction angle of crack propagation and the intensity factor range of equivalent stress can be obtained with the apply of the principle of maximum axial stress, by specifying the crack growth of a small increment, the new crack front is came into being, then the step by step for tracking is on the crack propagation. To simmulate the initiation and propagation of crack with the COHESIVE that belong to the finite element of ABAQUS.