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Strength and durability of commercial vehicle structure is of prime importance to users while quicker time to market and least material cost are demands of competitive world. This requires assessment not just with simplistic loadcases but robust and accurate predictions closely co-relating real proving ground conditions. This paper demonstrates systematic approach of first road load predictions using MBD model, then stress analysis using FE model and finally life prediction using fatigue solver. MBD model was built using flex body, air suspensions with rigid links and tires with FTire characteristics. Same model ran on various virtual proving grounds and load history at various joints were extracted. Then inertia relief stress analysis with unit loads were carried out in Nastran and output stresses were mapped against load history in fatigue solver.

During design and development of a cabin for any commercial vehicle, meeting the strength requirements of front impact as per Indian regulation (AIS-029) is a very critical milestone. AIS-029 regulation consists of three destructive tests, i.e. Front Impact Test (Test A), Roof Strength (Test B) and Rear Wall Strength (Test C). Study of energy absorbing front cabin mount, its stiffness balance with chassis and CAE correlation with physical test is demonstrated in this study. [1]

Door slam test is one of the important durability tests in door design and development. Door requires to meet certain performance requirements like it should close properly (no metal to metal contact), there should not be any leakage, and closing operation should be smooth & with minimal effort and it should survive the life of the vehicle. Virtual simulation of door slam test, correlation with physical test results and effect of various parameters like seals stiffness are demonstrated in this study. Slam Analysis was carried out in LS-Dyna solver before physical test. This not only helped in avoiding initial structural design flaws, but also helped us in deciding door latch position, effect of mass distribution in the door and study of force distribution between primary seal, secondary seal and door latch. Primary and secondary seals played a critical role in the analysis. An intended length of both the seals was tested first to get its stiffness curve.

Lot of CAE (Computer Aided Engineering) based evaluation methods and DVPs (Design Verification Process) are available which are derived from acceleration data, strain data acquired on vehicle over proving ground. Using peak load summary from acceleration inputs generic gravity loads get derived. Use of these loads for CAE analysis are having certain advantages like faster concept level evaluation, broader perspective and confidence on concept design. But there are few limitations of using these methods like it gives only broader perspective of concept design and not able to capture many failure modes and locations as per RWUP (Real World Usage Pattern). This paper explains the advantages of using WFT (Wheel Force Transducer) data for getting more reliable, realistic and co-relating more failure modes on the vehicle. WFT data acquired on all four wheel-ends at wheel center. Each wheel end transducer records 3 translational and 3 rotational forces.