No abstract

Progress and demands of all types of constructions imposed the need for the development of modernstructures that are lightweight, but at the same time have high damping capacity and stiffness. Theconsequences of these requirements are increased dynamic problems related to vibrations anddissipative processes in structure connection joints. Structural joints are the main reason for thesignificant reduction of the level of energy dissipation and source of structural damping so thereforethey have become a subject of interest to many researchers. The aim of this paper is to present someproblems regarding research of structural damping and the importance of study Contact Mechanicsto better understand the problem of structural damping.

This paper presents the finite element modeling of bolted joints for structural dynamic analysis to achieve a reasonable accuracy in simulation results. Non-linear effects in splice connected joints involve normal compressive loads holding components together combined with dynamic lateral loads inducing some amount of shear slip in contact interaction between elements of splice connection joint. The complexities of the slip process are responsible for the nonlinear nature of the interfaces, both in terms of stiffness and dissipation. Exploring the physics of joints directly is not readily done because key interactions takes place at the interface of surfaces, where instrumentation cannot be placed without changing the problem. Consequences of the specific conditions of joint connections are increased dynamic problems related to vibrations and dissipative processes in structure connection joints. Structural joints are the main reason for the significant level of energy dissipation and source of structural damping. The aim of this paper is to present some problems regarding research of structural damping and the importance of study Contact Mechanics to better understand the problem of structural damping.

The challenge that will be posed to researchers for an even longer period is the development of a predictable model for describing mechanical connections, their variable stiffness and dissipative contact interaction processes. The main challenge to this goal lies in the lack of understanding of how friction behaves on a small scale. Coulomb friction, a large heuristic model is not predictable and has actually been proven to be untrue in many modes. Expecting a universal law of friction for all types of materials and therefore contact interactions is not very realistic. Instead, the goal of the international research community is to develop a predictable model for a limited range of cases. So far, the metal-metal contact is most often tested, respectively the contact interaction behaviour of aluminium and steel elements of different quality. We also know that in the application those two metals are most often found in making mechanical connections. The aim of this paper is to make a brief overview of some of the previous tests and approaches to the study of contact interaction in mechanical connections and the role of friction in energy dissipation.

Problems involving contact are of great importance in industry related to mechanical and civil engineering, but also in biomechanics and other applications. The contact interaction between surfaces in a bolted splice connection joint or area through which tire interacts with the road is not known a priori, leading to a nonlinear boundary value problem. Due to the rapid improvement of modern computer technology, today one can apply the tools of computational mechanics to analyze contact problems with limited accuracy, depending on design requirements. However, even now most of the standard finite element software is not fully capable of solving contact problems, including friction, using robust algorithms. The aim of this paper is to present some basic concepts of Contact Mechanics. To illustrate the difficulties arising in computational contact mechanics, Newton-Raphson scheme was used to solve simple 1D contact problem using penalty method.