Papers by Keyword: Contact

Abstract: The coming of network era makes home office style become quiet popular.This paper, through analysing architecture space of SOHO ,probes its form and sills in two aspects of interior space and communication space ,summarizes SOHO's feature and prospects its future development.

Abstract: Extreme temperature measurements of Ni/Ti/Al contacts to p-type SiC (N_a = 1∙10¹⁸cm^-3), with a specific contact resistivity ρ_c = 6.75∙10^-4 Ωcm² at 25 °C, showed a five time increase of the specific contact resistivity at -40 °C (ρ_c = 3.16∙10^-3 Ωcm²), and a reduction by almost a factor 10 at 500 °C (ρ_c = 7.49∙10^-5 Ωcm²). The same response of ρ_c to temperature was seen for contacts on lower doped epitaxial layer. Also N-type nickel contacts improved with higher operational temperature but with a considerably smaller variation over the same temperature interval. No degradation of the performance was seen to either the Ni/Ti/Al or the Ni contacts due to the high temperature measurements.

Abstract: FRP (Fiber Reinforced Plastic) materials are corrosion resistant not requiring any specific treatment. The utilization of these materials is expanding. New research works have started to focus on using these materials on self-contained formwork in composite systems. It allows decreasing the concrete cover on minimum value just to assure sufficient bonding between reinforcement and concrete (the influence of aggressive environment is minimal). Moreover, the stay-in-place formwork is self-contained. It means using this system as formwork during casting of concrete and another supporting structure is not needed. The paper is focused on experimental analysis of stay-in-place GFRP (Fiberglass Reinforced Plastic) formwork in composite system (three-functional GFRP formwork and reinforced concrete slab – RC slab) and its use on floors in building structures. The load-carrying capacity of the composite system is highly influenced by quality of cohesion between GFRP formwork and concrete. This cohesion was investigated by using “push tests”. The results from experimental push tests were compared with the numerical model and also will serve for numerical modelling of real bonding of the girders.

Abstract: Finite element simulation technology was applied to the steady heat transfer and thermo-mechanical coupling analysis in order to investigate the influence of thermal load on stress intensity and sealing performance. An finite element heat transfer model of cylinder head joint assembly was set up, based on which the steady heat transfer analysis was performed subsequently by applying reasonable boundary conditions and loads. The influence on cylinder head sealing performance due to thermal field under the thermal stress conditions was evaluated by using the finite element method. The results showed that the thermal load increases the bolt tensile force and the gasket pressure, which help to improve the sealing performance. Compared to the mechanical load case, the thermo-mechanical stress of the liner and the cylinder head is obviously increased, so the thermal load is not neglectable when calculating the stress intensity of the cylinder head and the cylinder liner.

Abstract: The technogenic fluorineanhydrite is a waste product from the production of fluoric acid. It can have binding properties after its activation by some known chemical compounds, and so it may be used as a binder for the production of construction materials, in particular, the polystyrene concrete. The article considers the fluorineanhydrite composition as well as the polystyrene concrete produced on its basis with a surface-active additive and staple basalt fibre. The results of micro-structural and chemical analyses of developed composite are given. The polystyrene concrete (D 700 density class) has been developed with the ultimate compression strength value of 1.8 MPa and the water-resistance coefficient value of 0.68.

Abstract: The slips on packer play an important role on supporting packer and locking rubber tube after they have been anchored, and their performance directly affects the oil yield and production safety. In this paper, the contact between a type of packer slips and casing is analyzed using the finite element software Abaqus, the stress and displacement fringe graphs of the casing under working conditions are obtained, and it offers the guidance on optimal design for packer slips.

Abstract: Finite element simulation technology was applied to the steady heat transfer and thermo-mechanical coupling analysis in order to investigate the influence of thermal load on stress intensity and sealing performance. An finite element heat transfer model of cylinder head joint assembly was set up, based on which the steady heat transfer analysis was performed subsequently by applying reasonable boundary conditions and loads. The influence on cylinder head sealing performance due to thermal field under the thermal stress conditions was evaluated by using the finite element method. The results showed that the thermal load increases the bolt tensile force and the gasket pressure, which help to improve the sealing performance. Compared to the mechanical load case, the thermo-mechanical stress of the liner and the cylinder head is obviously increased, so the thermal load is not neglect able when calculating the stress intensity of the cylinder head and the cylinder liner.

Abstract: Surface cracks arising during rolling sliding contact of a wheel and a rail are investigated. A two-dimensional crack model is proposed which calculates the crack driving force using the configurational force concept. The numerical applicability of the configurational force concept for surface shear cracks under cyclic contact loading is discussed and compared to the J-integral concept. A single inclined crack in a rail loaded by an accelerated wheel is investigated. The material of the rail is described by a cyclic plastic kinematic hardening model. The evolution of the crack driving force during several cycles is investigated.

Abstract: This article presents a non-linear model of deep groove ball bearing and results of simulation. Vibrations of this bearing are studied for a wide range of clearance. An evolution from periodic to chaotic vibrations is visible due to increase of clearance. A number of phenomena associated with non-linear dynamics are observed, for instance: bistability, chaotic vibrations, windows of periodical vibrations, jump of amplitude, period-doubling cascade leading to chaos, bifurcation directly leading to chaos, and self-similarity of a Poincaré section. Moreover, amplitudes of vibrations are presented as functions of clearance. This provides an opportunity to select failure modes. Unfortunately, relations clearance amplitude and amplitude - clearance are ambiguous.

Abstract: In mixed-mode crack propagation the crack faces frequently touch each other. The ensuing friction is expected to decrease the crack propagation speed. This effect is usually not taken into account, however, a realistic prediction of this effect may increase the calculated life and consequently increase the length of the inspection intervals. In this paper, penalty contact conditions are introduced in between the crack faces of the automatically generated mesh in a cyclic crack propagation. Special attention is given to the contact formulation and the area in which contact is defined. It is shown that the resulting crack propagation rate is significantly reduced by the introduction of friction provided that positive Mode-I is not significantly involved.