Testing and Characterization of Engine Mount Designs

Abstract:

Automotive bushings, layered bearings and mounts are used in suspensions of light and heavy commercial vehicles and passenger car applications. The design of these components consists of single rubber pieces or a number of rubber-metal layers. The designs and sizes are made of varying materials, and dimensions so that a wide range of operating conditions are acceptable to the designs. The rubber materials are generally from the 45 durometer to 65 durometer range. The steel layers mounted on a layered bearing are from 3 to 7 numbers. All the components are assembled together on the chassis by means of fasteners and associated fittings. These rubber springs when mounted on the axle of the vehicle take up the entire vehicle load, and are also expected to isolate vibrations under all operating conditions.

Methodology:

The physics involved in these simulations are complex and can be summarized as follows:

  1. Non-linear material property of the rubber and steel material has to be included.
  2. To realistically model the service behavior of the  assembly non-linearity relating to the presence of different layers have to be taken into account.
Figure 1: FEA Models and Deformed Shapes of the Components

Results and Discussion:

The FEA model and the deformation plots are shown in the Figure 1. The rubber-metal bonded layers and rubber materials were modeled in Abaqus using 3-dimensional continuum elements. High stresses were noted at the different locations in the design. Frequency analysis was carried out to find the natureal frequency of the spring. The large deformation elastic analysis allowed the non-linear material materials to be adequately defined.

References:

  1. Dassault Systemes, Abaqus theory and reference manuals.
  2. Sai Anuraag K. A. and V. Sivaram, Comparison of static , dynamic and shock analysis for two and five layeredcomposite leaf spring”, Journal of Engineering Research and Applications 2012.
  3. Yunhe Yu, Nagi G. Naganathan, Rao V. Dukkipatit, Review of Automotive Vehicle Engine Mounting Systems, International Journal of Vehicle Design, 2000 Vol. 24.