Fatigue Design Optmization of Torque Arm Bush Mount for Heavy Truck Applications

Design Development and Finite Element Analysis (FEA) of Torque Arm Bush Mount for Heavy Truck Applications


A Torque Arm Bush is a metal-elastomer bonded component that forms an integral part of a heavy truck bogie or suspension system. Many different designs exist in the market today and each one with its own unique geometry, material and load application conditions. This analysis demonstrates the hyperelastic material characterization testing, material constant generation and FEA on the component to predict the service performance.


The physics involved in the simulation are complex and can be summarized as follows:

  1. Elastomer performance is markedly non-linear.
  2. Loading conditions like axial, radial, conical, torsional must be defined in multiple steps as per the service conditions and loading cycles.
  3. Large strain deformation with contacts

Figure 1: Hyperelastic Material Characterization Testing               Figure 2: FEA Model of the Torque Arm Bush Mount Assembly


  • Material Study and Characterization to understand static and dynamic material properties.
  • Develop material constants and design concepts based on load-deflection and performance characteristics.
  • Use Finite Element Analysis (FEA) to optimize the design and understand FMEA.
  • Provide assembly modeling & drawings for prototype manufacturing.

Figure 3: Shows the Comparison between FEA and Experimental Testing Results

Figure 4: Deformed Shape and Stress-Strain Distribution in the Torque Arm Bush Mount

Results and Discussion:

The principal deformation modes of a heavy duty suspension component were modeled in Abaqus using hyperelastic analysis. High stresses were noted along the curvature locations in the design under conical deformations and confirmed by fatigue testing. This  locations were identified as ‘hot-spots’ and are fatigue-critical locations. The geometrical and material parameters were optimized to better mitigating the stresses and reduce the fatigue failures.


  1. Dassault Systemes, Abaqus theory and reference manuals
  2. Yunhi, Yu, Nagi G Naganathan, Rao V Dukkipati, A literature review of automotive vehicle engine mounting systems, Mechanism and Machine Theory Volume 36, Issue 1, January 2001.
  3. Srinivas, K., Material Characterization And CAE For Non-Metallic Materials & Manufacturing Processes, SAE Symposium on CAE Applications for Automotive Structures, Detroit, November 2005.


  • Advanced Softwares like Abaqus, Static testing machines are available in-house and design iterations can be carried out on the fly.
  • Full material characterization capabilities of polymeric materials for FEA
  • Capabilities for fatigue durability testing In-house.
  • Advanced material testing facilities like DMA, DSC, TGA and TMA also available.