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In recent years graphical dynamic system simulation has become very important in the design and development stage, as new strategies can be examined without expensive measurements. This paper describes the development of a real time simulation model for a turbocharged diesel engine and an automatic transmission of a tracked vehicle using graphical programming environment in Matlab/Simulink. This work is part of a vehicle simulation model which is under development. A Mean Value Engine Model (MVEM) is used for simulation of engine dynamics. A Torque Converter (TC) is used as a fluid coupling between the engine and the transmission gearbox. This model is used to predict the dynamic response, both in steady and transient operation. Various illustrative studies have been conducted to demonstrate the capability of the model to predict the transient system response.

A 3-degrees of freedom rigid body model has been developed to predict the directional response of a light passenger vehicle. An attempt has also been made to modify and use the finite element model developed for determining the vibration response of the vehicle to predict the directional response of the vehicle. The Newmark time integration scheme has been used as solver. The tyre properties such as lateral stiffness, cornering stiffness, self-aligning torque stiffness have been measured using the facilities of (CIRT) Central Institute of Road Transport, Pune. The simulation results of directional response of the vehicle in terms of roll angle, yaw rate and lateral acceleration for the sinusoidal and ramp steering inputs (applicable in tests such as the Slalom test and J-turn manoeuvre respectively) to the vehicle at constant speed have been presented.

In commercial vehicles, exhaust system is normally mounted on frame side members (FSM) using hanger brackets. These exhaust system hanger brackets are tested either as part of full vehicle durability testing or as a subsystem in a rig testing. During initial phases of product development cycle, the hanger brackets are validated for their durability in rig level testing using time domain signals acquired from mule vehicle. These signals are then used in uni-axial, bi-axial or tri-axial rig facilities based on their severity and the availability of test rigs. This paper depicts the simulation method employed to replicate the bi-directional rig testing through modal transient analysis. Finite Element Method (FEM) is applied for numerical analysis of exhaust system assembly using MSC/Nastran software with the inclusion of rubber isolator modeling, meshing guidelines etc. Finite Element Analysis (FEA) results are in good agreement with rig level test results.