Test Analysis And Optimization Of Dump Truck Cab Suspension System

Isolation performance of cab suspensions has important influence oncommercial vehicle NVH performance. To study the isolation extent of cabsuspensions and get the degree of suspension optimization parametersadaptation from different driving conditions to the vehicle in different speeds,taking bad cab vibration from a dump truck drove in the medium and highspeeds as an example, dump truck cab suspension tests, analysis andoptimizations have been conducted by road and modal test, analyzing thevibration signals and modal parameters, building the finite element model anddynamics model, and optimizing parameters.To found vibration source and solve the problem, road tests in differentspeed levels were conducted and vibration signals were collected. Through thecontrast of power spectrum density curves in different speeds, the resultsshowed that main excitation source of the vehicle or components resonancewere radial beats of wheels. Through the contrast of power spectrum and crosspower spectral density curves, the results showed that front suspensions and cabsuspensions played an opposite role in vibration transfer path, and the right cabsuspension played the most reverse role. To get vibration characteristics of the cab, cab modal tests were conducted.Acceleration sensors in the cab body were arranged, the cab was struck by a testhammer in different directions, and cab modal parameters were collected andanalyzed. The results showed that the first frequency of the cab modal exceededthe design requirements, and reached the desired level.On this basis, a finite element model of the dump truck cab was built, andthe numerical modal was calculated. Through comparing the shapes andfrequencies of the cab modal, the finite element model was verified. Then arigid body dynamics model and a rigid-elastic coupling dynamics model werebuilt for the cab suspension system in ADAMS and verified by the road test.After comparing two models deviation, stability of rigid body model in variousconditions was better than rigid-elastic coupling model.To meet the minimization goals of cab floor vertical vibration amplitudeusing the rigid body model and taking stiffness and damp of the cab suspensionas test factors, parameters of the cab suspension were optimized in four differentspeeds conditions and two kinds of suspension parameters scheme. Theoptimization results showed that the optimized parameters in four conditionshad different degrees of improvement in cab floor vertical vibration amplitude;especially the asymmetric damping parameter program in medium and highspeeds on flat road can be applied well to various speed conditions. In this casethe parameter value obtained is recommended as the best optimized value.