Mathematical model of the modified tissue deformation under stretching

One of the effective methods for modifying natural and synthetic materials is a use of the flocking process. To analyze a quality of the modified fabrics, it is useful to have mathematical models describing a stress-strain state of the fabrics when exposed to various loads. A method has been developed for determining the stiffness characteristics of a flocked fabric based on the results of testing samples cut at different angles to the base at different tensile forces. This technique makes it possible to analyze the effect of flocking on the mechanical characteristics of the fabric. It was revealed that the theory of mixtures, when averaging the properties of the fabrics and glue with respect to thickness, does not allow determining the stiffness characteristics with acceptable accuracy. The limits of applicability of the theory of mixtures were determined when carrying out averaging of the mechanical characteristics with respect to the area of the flocked fabrics

NON-LINEAR BEHAVIOUR MODELLING OF ANISOTROPIC AND COMPOSITE MATERIALS AND DESIGN OF CONSTRUCTIONS OF THEM

The work covers the very anisotropic bodies of fibre composite material (FCM) type and constructions of them. The aim is to perform the asymptotical analysis of determining correlations for the very anisotropic materials, to obtain the simplified models of non-linear straining and to develop the new design methods of the constructions of them. The new simplified models for non-linear straining of the fibrous materials have been obtained, the methods for experimental determination of the mechanical characteristics have been created, the new method for design of the constructions within the limits of the maximum equilibrium theory has been developed. The algorithms and programs for design of the non-linear-elastic and plastic characteristics in FCM on base of the test data analysis of the coiling cylindrical shells and also the methods and programs for design of the multilayer shells of non-linear-elastic, viscous-elastic and plastic material have been developedAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio

Mathematical model of the modified tissue deformation under stretching

One of the effective methods for modifying natural and synthetic materials is a use of the flocking process. To analyze a quality of the modified fabrics, it is useful to have mathematical models describing a stress-strain state of the fabrics when exposed to various loads. A method has been developed for determining the stiffness characteristics of a flocked fabric based on the results of testing samples cut at different angles to the base at different tensile forces. This technique makes it possible to analyze the effect of flocking on the mechanical characteristics of the fabric. It was revealed that the theory of mixtures, when averaging the properties of the fabrics and glue with respect to thickness, does not allow determining the stiffness characteristics with acceptable accuracy. The limits of applicability of the theory of mixtures were determined when carrying out averaging of the mechanical characteristics with respect to the area of the flocked fabrics

The Influence of the Aggressive Medium upon the Degradation of Concrete Structures: Numerical Model of Research

This article discusses the impact of the aggressive environment on the pattern of pore distribution, strength, and mass absorption of investigated samples. For this purpose, a physical and numerical research model has been developed based on Fick’s second law and Zhurcov’s theory. Consequently, computer tomography research revealed that pore redistribution was revealed in test samples due to exposure. The degradation model is proposed assuming that in the first stage of interaction between concrete constructions and aggressive medium, the product of interaction is accumulated in the surface of structures and pores. Interaction products in the form of needle-shaped crystals grow in time and create additional stress in the body of the structure, resulting in partial distribution of the surface of the structure due to the growth. In this state, the excretion of dissolved substances (in the form of citrate and calcium acetate), leaching of Ca(OH)2, and decalcination of CSH lead to a decrease in the strength of cement stone. Based on the developed numerical models, the dependences of aggressive environment impact on the on the parameters of the structure of cement composites at different exposure times were obtained. For the samples obtained during the activation of Portland cement in the electromagnetic mill, energy parameters of the destruction process are 1.85–2.2 times heavier than the control compositions. The samples obtained by activating Portland cement in the electromagnetic mill have a higher susceptibility to an aggressive environment (they absorb 1.8 times more energy per unit of time for structure transformation). However, the higher U-energy barrier (1.85 times greater than the control composition) provides both a longer term of exploitation and a lower kinetics of the change in the strength of the material