Abstract

This paper addresses the need to minimize of vibration levels of unsprung weight of elements of vehicles suspension are considered. In the study design, some methods of parametric optimization with dynamic vibration absorbers (DVA) in elements of a nonlinear suspension with dynamic mechanical properties have been applied. To determine the low frequency components of vibration of laminated composite plates with the DVA system numerical estimates of the vibration of the equivalent plate of Timoshenko used. One structural version for ensuring the preservation of the residual space of the passenger cabin of the bus during the rollover according to norms 66 is considered. The energy-absorbing structure of the roof of the bus is made in the form of tubular space-frame made of composite materials.

Abstract

This paper describes a question of evaluation necessity of bridge cranes using the method of limit deformation state and oscillation damping. The solution was performed by means of theoretical analysis and an experimental verification at the selected bridge crane. The final result sounds that in the case of a correct strength computing of given bridge crane, it is not necessary to also check deformation and damping of oscillation as well. Web of Science 108 158 141 Document type: Article

Abstract

At the state of art, current simulative methods modelling joint properties as fixed interaction between components or concentrate on the characterization of the joint stiffness and damping of coupled metallic structures. In the current work, the developed thin layer interaction (TLI) method was applied to study the influence of the joint stiffness and damping of plastic components coupled with metallic structures. The joint stiffness and damping of different coupled metallic-plastic joint structures was characterized experimentally and was used to fill the reduced transverse shear stiffness and damping tensors of the numerical TLI model. The TLI model was used to determine the structural dynamics behavior of a short glass fiber reinforced plastic engine bracket mounted to a steel block. The comparison of experimental and simulative results shows a better correlation under the usage of the TLI model compared to a fixed modeled joint behavior. As result, the TLI model allows a better prediction of the structural dynamics of coupled plastic components. Further researches focus on the accurate experimental estimation of the boundary conditions regarding excitation and mounting of the plastic components. Thus, a more realistic modelling of the numerical joint boundary conditions is possible for an improved simulation of the structural dynamics of plastic components.

Abstract

Rezumat"/jats:title" "jats:p" Lucrarea prezintă rezultatul încercărilor efectuate la cicluri cinematice cu deplasări instantanee armonice pentru elemente elastomerice cu rol de izolare dinamică în conformitate cu SR EN 1337-3 şi SR EN 15129. Valorile amortizării interne determinate pe standuri de încercare în condiţiile din documentele de referinţă trebuie corelate cu valorile sistemului de dispozitive antiseismice elastomerice ce echipează un sistem dinamic supus acţiunilor seismice exterioare."/jats:p" "jats:p"În acest caz, pentru fiecare situaţie reală, proiectantul trebuie să realizeze corelaţia dintre cele două valori ale amortizării obţinute în laborator cu amortizarea specifică sistemului structural care este supus acţiunilor dinamice exterioare. Din lucrare rezultă echivalenţa necesară astfel încât, valorile experimentale să poată fi corectate în mod riguros şi să poată reprezenta parametrii reali ce trebuie luaţi în calcul. Document type: Article