Surrogate Model for Aerodynamic and Handling Stability Optimization of a Tractor-Trailer in Crosswinds

Abstract

AbstractA surrogate model based aerodynamic shape optimization method applied to the wind deflector of a tractor-trailer in crosswind is presented in this paper. The aerodynamic drag coefficient and handling stability of the tractor-trailer subjected to crosswinds is analyzed. The numerical results show that the wind deflector can influence drag coefficient and the lateral displacement of the tractor-trailer in crosswinds in great degree. Four parameters are used to describe the wind deflector geometry: Width, Length, Height and Angle. A 30-level design of experiments (DOE) study using the optimal Latin hypercube method is conducted to analyze the sensitivity of the design variables and build a database to set up the surrogate model. The surrogate model is constructed based on the Kriging interpolation technique. The fitting precision of the surrogate model is examined using a computational fluid dynamics (CFD) and multi-body dynamics and certified using a surrogate model simulation. Finally, multi-island genetic algorithm is used to optimize the shape of the wind deflector based on the surrogate model. The maximum tolerance between the results of the CFD and multi-body dynamics simulation and the surrogate model is only 2.02 %. When using the optimal design variables, the aerodynamics drag coefficient decreases maximum by 6.23 % and the lateral displacement decreases maximum by 4.67 %.KeywordsMultidisciplinary optimizationVehicle aerodynamicsMulti-body dynamicsCrosswind