Abstract

In many practical engineering applications there is the interaction of distinct domains, where coupling effects are important in assessing the structural response. A particular case is given by the interaction between a vibrating structure and a reservoir, with the latter conveniently simplified to an acoustic model. This paper presents a closed form analytical solution to the dynamic interaction problem of a framed structure and a two dimensional acoustic cavity system. Initially, eigenvalues and eigenmodes are obtained accurately and then individual contributions of each mode are combined to build the structural dynamic response. A fourth order Runge‐Kutta numerical integration routine is applied on the evaluation of relative displacements. Finally, practical applications are given, where the proposed method is employed effectively in the solution of sine and seismic excitations. These results are compared to finite element models, with an excellent agreement achieved by the proposed procedure. It is also verified that the fundamental mode shape governs the dynamic response, enabling the use of simplified expressions for the generalized parameters. Immediate results include validation of numerical solutions as well as parametric studies of the involved variables. The proposed procedure can be extended for different sets of boundary conditions.

Abstract

In order to solve problems arising in ordinary heat pump system for pure electric vehicles at ultra-low temperature, a low pressure gas-injection scroll compressor is designed, and a mathematical model is established. Comparison with the experimental results shows good accuracy of the theoretical prediction. Document type: Article

Abstract

The present study addresses the retrofitting of running-bond masonry walls through the application of oriented strand board (OSB) timber panels aiming to increase the masonry flexural strength and deformation capacity under out-of-plane actions. This paper presents the numerical analysis of masonry prisms to complement the information provided by the experimental campaign developed on flexural performances of timber retrofitted masonries. The numerical model represents the masonry components (brick and mortar) as a three-dimensional volume via volumetric finite elements, i.e. hexahedral 8-node linear brick elements with reduced integration and hourglass control. The nonlinear properties of the mortar joints and the brick units have been calibrated through information that resorts from experimental characterization tests. The numerical damage pattern and load-displacement capacity curve are compared with the experimental observations. A good agreement has been found and, therefore, the calibrated model can be employed in parametric studies, to further analyse the efficiency of the proposed timber masonry retrofit technique, and to more complex structural study cases.