Design of optimum vibration absorbers for a bus vehicle to suppress unwanted vibrations against harmonic and random road excitations

Unwanted vibrations of vehicles are regarded as harmful threats to human health in biomechanical and psychophysical terms. Road roughness is considered as the main cause of unwanted vibrations of bus vehicles. Vertical seat vibrations were found via simulating a 10-Degree-Of-Freedom (10-DOF) model of an intercity bus vehicle under harmonic and random excitations caused by road roughness. To suppress undesirable vibrations, mass-spring-damper passive absorbers were proposed in a 13-Degree-Of-Freedom (13-DOF) model of the bus. Following the optimization of the characteristics of embedded passive absorbers under each seat and implementation of the designed absorbers, the vertical displacement amplitudes in the frequency responses of the seats were reduced, especially near the resonant frequencies of the bus. In addition, vertical displacement and acceleration amplitudes decreased in the random excitation of road roughness. According to the results, optimized mass-spring-damper absorbers were proposed as a practical solution to suppress the effects of unwanted vibration on bus vehicles. (C) 2021 Sharif University of Technology. All rights reserved.