Dynamic analysis of Baja-type vehicle subjected to excitation by irregular road profile

Resumo

Automotive vehicles are complex dynamic systems that travel over uneven roads of different qualities.
This interaction induces vibrations whose characteristics depend on the suspension system, speed, and pavement

type, among other factors. Extended exposure to vibrations can be annoying and harmful to human health, de-
pending on the acceleration levels. At Baja SAE competitions, small off-road vehicles are designed and built to

withstand rough terrains. Therefore, knowing the vehicle’s response to irregularities is relevant to ensuring compli-
ance with safety requirements. In this paper, a computational routine is designed to evaluate the dynamic response

of a BAJA-type vehicle to excitations induced by an irregular surface. A three-dimensional full-car model with
eight degrees of freedom simulates the vehicle’s vertical dynamics. The road surface roughness is modeled in
the frequency domain using Power Spectral Density functions, which are converted to time-domain signals. The
numerical integration of the equations of motion is made through Newmark’s method. The code is validated using

commercial software and data from the literature. The outputs are the displacement, velocity, and acceleration sig-
nals for each vehicle’s degree of freedom. Results evidenced the suspension system’s effect on damping vibration

levels experienced by the driver in relation to the base motion of the wheels.