No description available.

No description available.

A non-linear finite element computer program capable of predicting the complete response of two-dimensional reinforced concrete members was developed. This tool which accounts for the stress strain characteristics of cracked concrete was used to predict the responses of a number of members containing discontinuities. These members included corbels, dapped end beams, beams with web holes, and deep beams. The results of tests performed by the author as well as tests performed by other researchers were compared with the non-linear predictions. In addition, simple strut and tie models suitable for designing regions near discontinuities were developed. The predictions obtained by these models were compared with the non-linear finite element predictions and with the test results.

SUMMARY Bakšytė E. Investigation of strength and rigidity of asymmetric multilayered elements: Master thesis of mechanical engineer / research advisor prof. J. Bareišis; Šiauliai University, Technological Faculty, Mechanical Engineering Department. – Šiauliai, 2004. – 69 p. This theme of master’s work in mechanical engineering is urgent: along with appearing new composition substances and growing demands towards strength, rigidity, stability, mass and piece of the constructions, more and more often the multilayered construction elements are used, enabling obtaining of the necessary constructional features in the desirable direction, evaluating total load, working environment and other important requirements. Though the projecting questions of multilayered construction elements were analysed, no asymmetric constructions, made of three substances, were analysed. In this work I analyse strength and rigidity of asymmetric multilayered elements, made of the following composition substances: carbon plastic, hot setting glass plastic and apoxy resin. In order to perform analytic calculations, I selected the construction element with height h = 120 mm, width b = 50 mm, length l = 1000 mm, affected with 10 kN force. In the work I present dependence or neutral axle position factor, rigidity and tension upon the relative layer thickness rates, material allocation in the construction element cross - section as well as number of the layers. Change regularities and their... [to full text]

No description available.

No description available.

No description available.

No description available.

No description available.

The primary aim of this study is to assess the applicability and performance of the finite element method (FEM) in solving structural optimization problems with stability constraints. In order to reach this goal, several optimization problems are solved using FEM which are briefly described as follows: The strongest column problem is one of the oldest optimization problems for which analytical solutions exist only for some special cases. Here, both unimodal and bimodal optimization of columns under concentrated and/or distributed compressive loads with several different boundary conditions and constraints are performed using an iterative method based on finite elements. The analytical solutions available in the literature for columns under concentrated loads and an analytical solution derived for simply supported columns under distributed loads are used for verification purposes. Optimization results are presented for fibre-reinforced composite rectangular plates under inplane loads. The non-uniformity of the in-plane stresses due to stress diffusion and/or in-plane boundary conditions is taken into account, and its influence on optimal buckling load is investigated. It is shown that the exclusion of the in-plane restraints may lead to errors in stability calculations and consequently in optimal design. The influences of the panel aspect ratio, stacking sequence, panel thickness, and the rotational edge restraints on the optimal axially compressed cylindrical and non-cylindrical curved panels are investigated, where the optimal panel is the one with the highest failure load. The prebuckling and the first-ply failure loads of the panels are calculated and minimum of these two is selected as the failure load. The results show that there are distinct differences between the behaviour of cylindrical and non-cylindrical panels. The formulations of the finite elements which are used throughout the study are given and several verification problems are solved to verify the accuracy of the methodology. The computer codes written in Matlab are also given in the appendix sections accompanied with the selected codes used for optimization purposes. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2006.