Applied Mechanics and Materials Vol. 617

Abstract: In this article impact loading of concrete slabs has been presented. Different methods for calculate impact force have been considered. Numerical models of two slabs with different boundary condition have been solved while using finite element method in ANSYS software. In the final part of the paper, z-direction displacements and bending moments of models have been compared.

Abstract: In the recent years a big focus is subjected to the response of structures subjected to out-of-plane loading such as blasts, impact, etc. not only to homogenous materials, but also to heterogeneous materials, such as composites. Such form of loading can cause considerable damage to the structure. In the case of layered composite materials the damage can have several forms, starting from damage in layers up to delamination and full damage of the construction. This paper describes the investigation of shockwave propagation in composite structures caused by impact loading. The composite consists of carbon fibers in a polymer matrix, in which the fibers are much stiffer then the matrix. Finite element simulations were carried out for a “bird” strike impact on a composite wing leading edge. Results show a good impact resistance and good damping abilities of shockwaves.

Abstract: Environmental (community) noise, particularly road traffic noise, has attracted widespread attention in recent decades as a major environmental health concern. The aim of the study was to determine the impact of environmental noise on psychosocial well-being of young healthy individuals and to follow the time trends of exposure in the period of 10, 15, 20, 25 years. The validated methodology was used to assess noise annoyance, interference with activities and sleep disturbance; the objectification of noise levels was done by direct measurement using sound level analyzer with a module for frequency analysis. The results revealed the sharp increase during the years 1989 and 1999 (the period of political and socio-economic transformation and the changes in traffic management) and the decrease in the year 2013. The findings of our study indicate the need for preventive measures to reduce environmental noise exposure in residential areas and to emphasize the importance of the elaboration of methods for environmental noise exposure risk assessment.

Abstract: The main task of this contribution was to explain the ways of the spread of noise pollution from the traffic. Descriptive simulation explains justification of each road construction by a simple way. It is confirmed that the projects which had contained a noise study simulation were easier to enforce for public than those without it. Also vegetation growth simulation in different time horizons is already slowly becoming an important part of the urban transport projects, due to the increasing of environmental pressure. Practice shows that the design value of these simulations is increasing because of the rising of the global traffic load.

Abstract: An excessive noise exposure not only decreases work quality and productivity, it also negatively affects human health. The most accurate data on noise levels can be obtained by measurements; however this approach is really time-consuming and its application is sometimes rather complicated. More frequently, calculation methods are used. The design methodology suggested by Liberko has been used for the calculations in Slovakia since 1991 [1]. As has been proved by experience, there is a need to re-evaluate some parts of the Slovak calculation methods and extend the number of initial parameters, so that much higher accuracy could be achieved. The layout (or the location) of the railway line is one of the parameters that at all events influence the level of noise caused by tramway transport. Providing that the ride of the tramway car is ideally straight in line, the forces that develop in a curve influence the acoustic situation in the vicinity of a moving tramway car. As this parameter has not yet been taken into account in calculations, the paper presented analyses the grounds for its use in noise prognoses.

Abstract: This paper is focused on the static analysis of cable-membrane structures using the dynamic relaxation method. Several different processes of dynamic relaxation method are compared in this paper. The techniques with viscous damping and the techniques with kinetic damping are used. The efficiency and stability of each process are compared to selected 3D examples of cable-membrane structures. The effect of mass distribution along the structure is also of interest and it is studied in the paper.

Abstract: The aim of this contribution is a form-finding process. It is the problem of initial pre-stressed shape generation of membrane constructions. The contribution deals with specific aspects of this process and the necessity of introducing stabilization with regard to its practical application. Individual examples will show the results of methods described in this paper.

Abstract: The knowledge of the dynamic state and structure of the system allows to describe its behavior, and allows creating prognosis models of the system behavior in the function of dynamic evolution time, based on the model of the technical state symptoms growth. Most often, however, there are no known equations describing behaviors of the system in the function of dynamic evolution time, which accounts for the need to apply new tools to examine the dynamic state. There is, therefore, the requirement to experimentally verify analytical technical models as the proper one is a model which is verified in practice. An experiment is, therefore, often only an inspiration for further researches leading to the optimization of the construction. In this work presented are chosen problems of machines’ technical state diagnosis with the use of identification and technical diagnostics methods. Relations between methods of dynamic state evaluation and methods of technical state evaluation were indicated. Example modal analysis results illustrate the complexity of projecting dynamic state researches into diagnostic researches of machine state evaluation.

Abstract: The chosen problems of identification the state destruction of wall elements in work were introduced. It was showed on possible relationships between methods of opinion of dynamic state and methods of opinion of destruction the wall elements. Near they utilizations experimental modal analysis they illustrate the complexity the problems and need of optimization of number component measuring the examples - results of investigations.

Abstract: This paper deals with a problem of eigenfrequencies of cylindrical tank (steel water tank). For an ANSYS analysis of eigenfrequencies some numerical models of cylindrical tank are used and finally results got by these models are compared with experimental results in laboratory. In final part of the paper some crucial results are presented both in a graphical and numerical way.