Multiscale modeling is a recent approach to simulating molecular systems, such as membranes and liposomes, in which different levels of detail are combined. By using distinct models it is often possible to speed up or enrich the sampling of a given system. Examples are: the use in Molecular Dynamics simulations of both coarse-grained and fine-grained representations, either simultaneously or alternating in time or space domains. Another possible

The purpose of this paper is to show the possibility of finding the location and to describe internal discontinuities in plates made of plastic materials using non-destructive evaluation methods. Their effect on the mechanical behaviour is also evaluated by means of numerical calculus. The technique of computer tomography („CT”) is used as a non-destructive evaluation method whereas the numerical calculus is realized by the finite element method.

This work brings to the forefront local nonlinear problems that appear in junctions of beam structures made of plastics, subjected to heavy loads. We also revealed the notions of local problems and heavy loads. These theoretical aspects are explained with the help of two beam structures of various complexity, made of plastic, with local problem. The results are presented as stress maps, maps of mechanical strains, charts with the evolution of the

This paper presents the influence of the position of an applied static load on a honeycomb sandwich with core made of resin impregnated honeycomb and caps made of epoxy resin. The nonlinear analyses were concentrated underneath the area of applied force and on the side of one wall of the honeycomb. The results obtained can be used to determine the effect of a small area impact on a honeycomb sandwich or to establish the stress distribution pattern

Fracture toughness occurring in a material that has micro-cracks may be improved by particle addition, these particles having different properties than the basic material. This paper includes the outcome of a research on the influence of softer or harder particles added to the basic material, on the stresses occurring in the immediate vicinity of micro-cracks. Our research is designed to determine to what extent this process may result into preventing

Fiber-reinforced polymeric composite materials present an orthotropic distribution of their mechanical and elastic characteristics. This behaviour is mainly due to the fact that the fabric used behaves differently under the same type of stress, on different directions. The procedure described by our paper enables researchers to determine the elastic modulus of such materials, on three different directions, using a specially designed specimen. The

Most of the problems of modern engineering are solved using numerical methods. In order to use a numerical method the first step that must be performed is to generate a numerical model that contains all the input data in terms of geometry, material data, boundary conditions (loads and support). Ideally a structure must be defined only using hexahedral elements that are capable to provide the best results. This paper presents a method for generation

This paper presents some modelling techniques useful for the optimisation of numerical models of vehicle interior parts in terms of improving the structural response in impact applications. A procedure regarding the random distribution of thickness of the elements for a selected area within a user-specified tolerance is presented. Procedures implemented in a custom-written code and the algorithms used for the random distribution are also presented.

For the modeling and usual analysis of mechanical structures it is considered that the whole structure and its components accomplish one of the fundamental conditions of strength of materials – the condition of continuity and homogeneity. This paper presents some modeling techniques useful for the optimization of the numerical models in order to improve the structural response for impact applications. As some parts have to be damaged a material

The paper presents the results of a combined numerical and experimental study for validation of a new three-dimensional specialized finite element, used for modelling the behaviour of laminated composite materials, reinforced with fibers. First, the stress and strain state in a circular plate loaded with an uniformly distributed force and fixed on the contour is evaluated using the proposed finite element. Two types of laminated composites are considered,