Papers by Keyword: Coupling

Abstract: This paper focuses on the theoretical and experimental verification of a behaviour composite reinforced concrete bed for installation in high-precision machine tools. The design solution consists of coupling the steel shell and HPC concrete filling, which ensures the high rigidity of the bed. Studies in this article were aimed at describing, in detail, the behaviour of the bed, from production to setting into its final position. An integral part of the solution was implementing the measurement of the response of the real bed segment using the installed monitoring system as well as the numerical simulations performed on the assembled FEM model. Thanks to the modular design of the bed, it was possible to verify the behaviour of the simulated load during the operation of the machine tool on a smaller sample. The aim is to verify the functionality of the coupling and, based on the comparison of measured and theoretical data, to define the critical points of the composite and, thus, provide a basis for design optimisation in order to maximise the monitored parameters.

Abstract: At present, when connecting polyethylene pipes for gas pipelines, two basic methods of welding are used: hot tool butt welding and welding with couplings and embedded heater. Hot tool flare welding is mainly used in polymer water supply systems. This paper presents results of research on implementation of this welding method when connecting polyethylene pipes in gas supply systems. It is proposed to use pieces of polyethylene pipes of larger diameter as couplings. Preliminary prolonged tensile tests of obtained welded joints showed effectiveness of this technology when joining polyethylene pipes.

Abstract: The purpose of this study is to explore the forms and characteristics of reflection crack in asphalt overlay of old cement pavement, so as to provide reference for effective prevention and treatment of reflection crack.By means of ANSYS finite element software, considering the coupling effect of temperature and vehicle in different working conditions, the influence of cooling on asphalt overlay was analyzed, and the location and form of crack were discussed.The analysis results show that tensile crack and shear crack are more likely to occur near the joint of old cement pavement, and shear crack is more likely to occur in areas outside the joint, about 1/2 wheel length from the joint of cement pavement.The prevention and treatment of crack at different locations should be carried out according to different working conditions.

Abstract: The results of the research on development of technology for welding polymer pipes at low climatic temperatures in open air without the use of temporary heated structures are presented. The most common welding methods are considered: butt welding with a heated tool, electrofusion welding with embedded heating element and socket welding. Tests on welded joints show that the developed technology for welding in open air without the construction of shelters provides the same level of quality as when welding at admissible temperatures.

Abstract: Based on nonlinear dynamics theory and knowledge of complex network, this paper expanded the range of two-layer network synchronization to projective outers synchronization. A mathematical model was constructed and feasibility of synchronization was demonstrated. Then we improved the model in order to study the function of different couplings [1]. Numerical examples are examined to compare the synchronizability of projective outer synchronization with different couplings. A rule called "outer small-world effect" was found due to simulation experiment. Finally, some instances were used to explain experimental results.

Abstract: The prestressed concrete confinement vessel is the third and last barrier in Nuclear Power Plants (NPP). In case of a severe accident (loss of cooling agent of the reactor for instance), pressure and temperature will increase in the nuclear vessel (0,5 MPa and 180°C during 2 weeks). Due to elevated temperatures, the evolution of basic creep will be accelerated. In this case, due to internal pressure, some tensile stresses could appear in specific parts of the structure and induce cracking. The modelling of basic creep and its couplings with temperature is very important for the safety of the structure (tightness of the concrete vessel). Here we present a model considering the following elements: a coupling between creep and damage is introduced, kinetics of basic creep is affected by temperature by the means of an Arrhenius thermo-activation, damage due to the increase of temperature is taken into account. The model is compared with the available experimental results. This work is a part of the MACENA project.

Abstract: Still more and more applications using synthetic polymers find new material alternative in materials based on synthetic polymer filled with nature fibers mainly plant fibers. Not only in common applications but also in technical applications is possible to use nature fiber composites. But some additional modifications are necessary to perform to gain properties possible to use in technical applications. Mainly increasing adhesion between matrix and fibers is the most common intent of these additional operations. This paper deals with maleic anhydride based coupling agent and silane coupling agent effect in the polypropylene matrix and jute fiber composite and its mechanical properties. By using of silane coupling agents was achieved mechanical properties which are possible to compare with composites with glass fibers mechanical properties mainly in case of the flexural and tensile modulus and mainly was gained significant increasing of composite production system stability.

Abstract: The purpose of this study aims at the kinematic study of generalized Oldham couplings by conducting kinematic analysis, kinematic simulation, and prototype experiment. First, the characteristics of generalized Oldham couplings are presented. Then, kinematic analysis and kinematic are performed. Finally, a prototype and its associated experimental setup are established. An experiment is conducted to evaluate the performance of the coupling. The simulated result shows that the output of the coupling is non-uniform, and close to a sinusoid. The experimental result indicates that the experimental output approximately agrees with the theoretical, but with fluctuations and a phase lag.

Abstract: The aim of this paper is to study the simulation of cogging process using a thermo-mechanical partitioned algorithm. The thermal and mechanical problems are solved separately. The mechanical problem is based on the balance equation whereas the thermal problem is based on the heat equation. The two physics are coupled trough the mechanical parameters that depends on the thermal problem and vice versa. The results obtained using the software Forge3 show that the mechanical deformation is high inside the zone of deformation and negligible outside whereas the temperature is high overall the mesh with a gradient at the zone of contact between the dies and the work piece.

Abstract: The experimental results are presented for the research on stress in the connecting elements of the rods at a rotational-impact loading. The oscillograms are made demonstrating the power pulses and tangential stresses in the threaded joint.