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Vibrations affect vehicle occupants and should be prevented early in design process. Powertrain (PT) wiggle is one of the well-known issues. It is the 3rd order lateral vibration, forced by half shaft inner LH/RH plunging tripod joints [1,2]. Lateral PT resonance (7-15Hz) occurs at certain vehicle speed during acceleration and may excite lateral, pitch and roll PT modes. Typically, PT wiggle occurs in speed range of 5-25kph. Vibration is noticeable on driver and passenger seats mostly in lateral direction. The inner half shaft joints are the major source of vibration. Unfortunately, existing MBD tools like Adams [3] are missing detailed tripod joint representation because of complex mechanical interactions inside the joint. At least three sliding contacts between tripod rollers and joint housing, lubricant inside the can and combination of rotation and plunging make the modeling too complicated.

Driveline launch shudder is a second-order vibration phenomenon excited by the driveline system in vehicles. It is experienced as low-frequency tactile vibrations at the vehicle seat track and is further deteriorated by a high torque demand from the engine. These vibrations are unwanted and affect the vehicle ride quality. A virtual method has been developed in ADAMS/Car to simulate the driveline launch shudder event for solid axle suspension architecture vehicles. Detailed modeling of the full vehicle system with appropriate boundary conditions has been presented. The simulated driveline launch shudder event has been quantified in the form of axle windup and accelerations at the driveline pinion, center bearing and seat track locations. A physical test correlation case study has been performed to validate the developed virtual method. This virtual method is also successfully applied to provide a driveline launch shudder mitigation enabler to improve vehicle ride performance.

This paper describes a new capability for fully coupled cosimulation of an explicit computational fluid dynamics code (MSC.Dytran) with an implicit mechanical systems simulation code (MSC.ADAMS). Particular interest is paid to baffled fluid tanks mounted on heavy trucks, although the system can be used to simulate the interaction between many fluid and mechanical systems. The interprocess communication approach used for the cosimulation is based on standard TCP/IP protocols and socket connections, so that it can be used on a wide range of computer platform combinations. A stand-alone interface code communicates with and controls the flow of both ADAMS and the multiple Dytran processes, which can be running on different hardware and different operating systems. The method has been quantitatively verified in laboratory tests of a small (15 liter) tank.

The crushing of a partially filled fuel tank is an important aspect of rear impact safety. A simulation will be presented of this event, where the fuel tank contains both fuel and air, and is crushed beyond failure. The simulation process starts with proper initialization of the fuel and air inside the tank under gravity loading, after which the fuel tank will be crushed between a wall and a moving rigid barrier. Once the fuel tank material fails, fuel leakage will be predicted. Multiple, adaptive Euler domains are used to model the baffles inside the tank and the surrounding air. Since the model includes fuel and air, a multi-material Euler solver is required. The simulation is performed with MSC.Dytran.

The Adaptive Multiple Euler Domains technology in MSC.Dytran has been extended for the Multi-material Euler Solver. This paper demonstrates the application of this new method to the dynamics of fuel tank filling. The interest in applicability of MSC.Dytran to fuel tank filling originated from a major car manufacturer. The model includes both the fuel and the air inside the tank. The simulation process starts with properly initializing the fuel and air inside the tank under gravity loading. The fuel filling process will then be demonstrated, including the venting of air through a venting tube. The simulation is performed with MSC.Dytran.

Brake groan noise and vibration occurs in a stopped vehicle by the simultaneous application of torque to the wheel and the gradual release of brake pressure. Eventually the torque load breaks the friction between pad and rotor causing slippage and energy release. If the torque load is not large enough to maintain slippage, a sustained stick-slip vibration, called groan, can occur which transmits a low frequency noise to the vehicle interior. In some cases the noise levels caused by groan can be objectionable, thus procedures for developing remedial designs are needed. To this end, a project was performed to analytically simulate groan vibration in a vehicle with a McPherson strut type suspension. The goal was to demonstrate that analytical models could be used to simulate groan behavior and to identify suspension components that affect the groan behavior. The ADAMS software was used to model a brake/suspension system.

To predict structure-borne interior noise using CAE simulation, it is important to establish a model for both the noise and vibration transfer path, as well as the excitation source. In the passenger vehicle, powertrain and road induced loads are major input sources for NVH. This paper describes a process to simulate the structure-borne road noise to 150Hz. A measured road surface is used for input for the simulation. Road surface data, in the form of height vs. distance, is converted to enforced motions at the tire patch in the frequency domain for input to the vehicle system model. The input loads are validated by the comparison of wheel hub excursions. The ability of the CAE simulation model to predict interior acoustic responses is shown by the comparison of the simulation results with measured vehicle interior responses.