CAE Methodology of Leaf Spring Suspension and Its Experimental Verification for Commercial Vehicle 2017-26-0246
The job of a suspension system is to maximize the friction between the tires and the road surface, to provide steering stability with good handling and to act as a cushioning device to ensure the comfort of the driver and passengers. The suspension system also protects the vehicle and any cargo or luggage from damage and wear.
Commonly the strength of these suspension systems is evaluated by endurance trials on field or Rig testing which are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation provide useful information early in the design cycle and save significant time and cost. However, the virtual method also needs validation, which can be achieved by physical co-relations (via rig tests).
A study has been done to predict the behavior of Leaf Spring Suspensions entirely through the FEA (Finite Element Analysis) route and correlating those results with physical test. Initially the acceleration data is abstracted via RLDA (Road Load Data Acquisition) pasting the accelerometers at axle points. Strain Gauges are used to acquire strain values with respect to accelerations. This acceleration data is then used as input in rig setup at axle points and relatively strain is measured at same strain gauge locations as done while RLDA. This is done primarily to validate the test rig.
After Rig validation, a virtual validation is required. Leaf Spring assemblies modeled in FEA are similar to rig test bed setup. Tests are performed on the rig and gauges are used to extract the data for virtual co-relation. At the time of simulation, various parameters have been modified to achieve realistic behavior. Correlations between Stiffness and Stress have been achieved at these strain gauge locations between the Rig test and CAE (Computer Aided Engineering) results.
Correlation (around 90%) has been achieved between Rig test data and FEA results at measured locations. Correlation has helped in reducing product design time and cost of running the rig until crack. This process has also reduced the cost by using soft validation for multiple Leaf Spring Suspensions like Semi-elliptical, Parabolic, Weveller, Bogie and Bell Crank. Hence, this FEA based methodology has facilitated our organization in designing an excellent suspension system which will prove beneficial to our customers.