Applied Mechanics and Materials Vol. 756

Abstract: A new efficient modeling technique is proposed to study delamination propagation in thin-walled composite structures. This technique is based on interaction of layers-shells and utilizes ANSYS^® software package. The methodology has been tested on DCB, ENF and MMB configurations.

Abstract: The model of transfer of polluting substance is considered. inverse extremum problem of identification of the coefficients in an elliptic diffusion-reaction equation is formulated. The solvability of this problem is proved, the application of Lagrange principle is justified and the optimality system is constructed for specific cost functional. The numerical algorithm based on Newton-method of nonlinear optimization of linear elliptic problems is developed and programmed on computer. The results of numerical experiments are discussed

Abstract: Results are presented of numerical simulation of a laser system performance with account of limitations induced by a flexible mirror. The method of finite elements was used to calculate deformations of a mirror reflecting surface. Solution to the parabolic equation describing propagation of a laser beam in the turbulent atmosphere and effects of its backscattering was obtained on the base of the splitting algorithm. It was shown that effectiveness of the adaptive system is not influenced considerably by restrictions characteristic to the mirror.

Abstract: The effect of high-enthalpy gas flow on transpiration cooling systems is considered. The influence of thermo-physical properties and porosity of some metals on heat transfer of the models is studied.

Abstract: In this work, thermal expansion coefficient of composite is calculated on the base of the model transient zone formation between spherical inclusion and matrix. Effective properties of particle surrounded by transient zone are used when composite properties are calculated. Different models leads to qualitative results similar to each other. Quantitative results depend on sintering temperature and time, on inclusion sizes and volume part of inclusions.

Abstract: This article introduces research results by members of the Chair for Applied Mathematics, Tomsk Polytechnic University, who are also members of the scientific school of Development of Physical Foundations of Software for Energetic and Information Representation of Functional Characteristics of an Organism for Medical and Preventive Tasks. In this article development of a universal mathematical apparatus to solve the tasks of monitoring, adaptation and regulation is described. To evaluate severity of change in a state vector, which describes mutual dynamic interactions among state variables of a system, geometric means of the vector and its deviation rate are used. Basic principles of assessment of dynamic susceptibility in systems are given. Coefficients that represent deviation of state variables from equilibrium values are described. Ability of regulatory mechanisms of a system to assure its stable functioning is explained.

Abstract: Avoiding disasters due to resonance is a major concern in construction projects such as buildings, bridges and pipelines. This paper uses the Concept Design Analysis (CODA) method that is capable of supporting the described Value-Driven Design (VDD) methodology. While VDD promotes the use of a system wide ‘value’ function during conceptual design, the CODA method allows mapping customer needs into engineering characteristics in order to calculate a single normalized design metric. The CODA method employs three different merit functions: maximizing (more is better), minimizing (less is better), and optimizing (target is better). This paper proposes a new merit function called avoidance function that allows excluding a range of engineering characteristics, e.g. avoiding a range of resonant frequencies. An example of a simple CODA model for a bicycle wheel design selection with the proposed the avoidance function is presented.

Abstract: The present paper focuses on calculation of the effective diffusion coefficient of a matrix composite with spherical inclusions. We address the problem of the effective diffusion coefficient dependence on the size of the inhomogeneities. In this work, the basic idea of replacing an inhomogeneous inclusion by an equivalent homogeneous one is formulated. The diffusivity contribution tensor, that characterizes the inclusion’s contribution to the overall process of diffusion, is derived in the course of analysis. It is shown that the effect of the interphase reduces the “apparent” volume fraction of inclusions. The thickness of the interphase zone is identified as the parameter of dominant importance among all the characteristics of the interphase.

Abstract: Impact devices are used in various areas of mechanical engineering and deal with a variety of materials. At the moment, it is determined that an increase in the duration of the impact impulse ensures the constant contact of a headgear (tool) with the work environment. This increases the efficiency of impact devices. We have proposed a shaper that allows to control the shape and duration of the impact impulse. In this paper, results of mathematical modeling of the pneumohydraulic impact device with elastic and viscoelastic shaper is considered. Several designs of impact devices are presented. Parameters which affect the impact impulse are determined. These results can be used in constructing pneumohydraulic impact devices for a specific area of implication.

Abstract: Numerical investigation of stressed-strain state composite plate is carried out for the conditions of one-axial loading and nonstationary heating. The state of plane stress was assumed. Various methods had been used for the calculation of effective properties: elastic constants and thermal expansion coefficient. The influence of the coupling between thermal and mechanical processes on temperature, stress and strains fields was investigated.