No abstract

No abstract

No abstract

Rubber bump stops are used in automotive suspension systems to absorb energy, limit the motion of wheels, and reduce vibrations. They are made from elastomeric materials that are non-linear and exhibit large deformation under loading. In the present paper, the bump stop used in a double-wishbone suspension system was analysed numerically to obtain the load-displacement curve and compared with experimental test data. The numerical analysis was done with a non-linear finite element (FE) model using ABAQUS software. The results showed good agreement between numerical and experimental data, with a difference of less than 2 per cent between them. Then dynamic analysis of the suspension system with the bump stop was done to recognize the stress and acceleration effects arising from use of this part in the system. For different vehicle velocities, the comparison between von Mises stress curves in two cases, with and without a bump stop on the lower control arm, showed higher stresses in the lower control arm in the presence of the bump stop and the comparison between acceleration curves showed lower acceleration in the lower control arm with the bump stop. Thus automotive engineers must pay attention to these effects to design suspension components correctly.

The dynamic loadings can be more harmful than static ones for the human lumbar spine health. Consequently, the prediction of the spine behavior under dynamic and vibration loads is vital and can be achieved by creating a precise finite element model in which the dynamic mechanical properties of the components need to be estimated. For this purpose, noninvasive experimental modal analysis can be applied to evaluate the dynamic mechanical properties of the spine in the numerical simulation by supplying the structural dynamic characteristics (natural frequencies, mode shapes, and damping ratio) of the system. Since the most adequate model for the human lumbar segment is a sheep model, in this paper, a 3D finite element model of a fresh spinal lumber segment of a sheep is generated based on the poroelasticity theory via Abaqus and is updated utilizing particle swarm optimization (PSO) algorithm and experimental modal analysis. In this regard, the frequency response function (FRF) of the specimen is obtained by performing the experimental modal test and the modal parameters are derived by using the rational fraction polynomial method. Afterward, the sensitivity analysis is carried out to determine the appropriate design variables. Finally, the PSO algorithm using experimental data is employed to update the design variables, including the elastic material properties and the structural damping factors of the specimen components, and the stiffness and damping coefficient of the suspension system. According to the results, the error percentage between the numerical FRF and the experimental one decreases remarkably after model updating indicating the high efficiency of the methods used.