Search Results

This paper presents the CAE technique to estimate the dynamic stress in a vehicle structure at an early stage in the vehicle design process, using modal stress superposition. Dynamic joint reaction forces are obtained by flexible multibody dynamics simulation using DADS. Stress influence coefficients are computed through the inertia relief analysis using MSC/NASTRAN. A test vehicle was run over a zigzag bump course with a constant speed of 40km/hr, and the results of the numerical analysis were compared to those of the test.

The air distribution duct with multiple outlets is an essential part of the automotive air-conditioning system in a bus. The estimation of airflow rate in an automotive air-conditioning duct is typically very complicated due to large variations in cross-sectional area and abrupt changes in flow direction, as well as unbalanced distribution of the flow. This paper describes numerical simulations performed for two simplified air conditioning ducts used in a medium bus. The three dimensional Navier-Stokes code was used to evaluate the overall pressure, velocity field, and distribution rate at each diffuser according to the change of cross-sectional duct area and diffuser area. In addition, a one-dimensional program based on the Bernoulli equation was developed to obtain the optimum diffuser area required to equalize discharge flow rate at each outlet. The results of this analysis were compared to the results obtained from experimental measurement and CFD simulation.