Papers by Keyword: Mechanical Stresses

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.

Abstract: In this article we intend to make an overview on the forces and deformations arising on the mandible and to study how the soft parts of the face are deformed, using an analysis of the influence of mechanical stresses using a finite element computer program. Thus, from the engineering point of view we propose a validation of medical results with an overview about the directions of deformation of the bones and soft parts due to normal growth of individuals. For this purpose we have used a 2D finite element static analysis of the mandible and soft tissue.

Abstract: Within the framework of the two-phase grain model (by the example of γ-Fe203 cobalt coated particles) a theoretical analysis of the effect of uniaxial mechanical stresses on the magnetization of the system of hetero-phase interacting nanoparticle was held. It is shown that stretching leads to reduction when compression increases the coercive force Hc and doesnt change the residual saturation magnetization Irs of the system of interacting particles. "Smoothing" the hysteresis loop and "lowering" the magnetization curve, the magnetostatic interaction between particles decreases both Hc, and Irs, giving the fact that hysteresis characteristics of an ensemble of interacting nanoparticles change much more in stretching than in compression.

Abstract: Significant scientific work has been dedicated for exploration of the infrared applications within wood science and technology, not much has been done linking it to the mechanical testing. It is expected that due to mechanical stresses (and related deformations) the interaction between constitutive elements of wood changes, proportionally to the stresses applied. The response of the material to mechanical stresses (such as tensile loading) on the molecular level should be therefore detectable by means of infrared spectroscopy. Dedicated tests have been devoted for proving this hypothesis. Self-developed testing machine has been integrated with infrared spectrometer in order to conduct a series fully controlled mechanical tests. It was possible to predict stress level of wood during tension by applying proper chemometric analysis (partial least square (PLS) models). Implementation of infrared spectroscopy in to timber engineering and mechanical testing of wood provides very essential supplement to the typical information collected during standard tests. More additional tests and reference data is necessary in order to create more reliable and universal model suitable for routine assessments. Nevertheless, it was demonstrated that prediction of the stress on the basis of the infrared spectra is possible.

Abstract: In the dual-phase model of interacting nanoparticles stretching leads to a decrease in both coercive force H_c and saturation remanence I_rs , and compression — to their growth. Magnetostatic interaction between particles also decreases both H_c and I_rs . Theoretical analysis was carried out in the framework of the dual-phase system of interacting particles on the example of nanoparticles γ-Fe₂ O₃, epitaxially coated with cobalt.

Abstract: In this paper we investigate the dependence of the magnetic states of heterophase particles on mechanical multiaxial stresses. It is shown that for such particles, there are four possible states, and the conditions of stability of these states are determined.

Abstract: The SiC_xN_yH_z Films Were Prepared by PECVD Method Using Organosilicon Volatile Compound Hexamethyldisilazane as a Precursor. Some Important Physical and Chemical Properties Were Studied by the Complex of Modern Physical Methods. It Was Shown that at Low Deposition Temperatures the Films Contain the Chemical Bonds of Organic Nature and Have Low Values of Young’s Modulus, Refractive Index and Density. They Possess High Elasticity which Indicates to their Polymeric-Like Structure. At Higher Deposition Temperatures the Films Are Inorganic Composite Materials Consisting of Amorphous Part and Nanocrystals of Graphite and Silicon Nitride. Decrease in Optical Band Gap and Coefficient of Thermal Expansion Is Observed with Deposition Temperature Increase.

Abstract: In order to study the influence of mechanical stress fields on the kinetics and texture evolution of grain growth, experiments were performed on high purity aluminium. Samples were annealed under the influence of different mechanical stresses. The temporal evolutions of grain sizes and of macrotexture were analysed in ependence on the applied stress. The results show that mechanical stresses can change the kinetics of grain growth and slow down the increase in the grain size. Also effects on the texture evolution were observed and shall be discussed.