Papers by Keyword: Numerical Model

Abstract: Glass has got important role in modern architecture not only because of its transparency, interior lighting and for aesthetical function but nowadays also more often for its load bearing function. Design of structural glass elements is limited by the lack of knowledge and standards, especially in case of stability problems of beams or columns. Slender glass beams with rectangular cross-section tend to fail because of instability.

Abstract: Fundamental knowledge of the mechanical properties of used materials are the basic preconditions for a successful construction of a final product. For seam as well as the reliability of its strength in some cases we need to know certainty when there will be the malfunction. In this study a spun of polyester thread were sewn on a material used for car seat cover. A single or multiaxial loading either static or dynamic has been used in the field of automotive textiles as well as for conventional materials. There is no standard method of measurement for the determination of dynamic strength of sewn seams and therefore it was necessary to construct a device that may measure the strength of seams under dynamic stress. It was carried out an experimental determination of the tensile strength under a static and shock loading for the textile part itself, then for the thread and also for them all together. A lot of very sophisticated numerical models of the individual materials structures in the world generally exist but considerably less is in this field taken into account the behavior of the whole.The aim of this work is with using the commercial software ANSYS create a contact numerical model that will be able to predict behavior of stitched seams and can be used instead of the classical experiments.

Abstract: Composite structures are now increasingly used for their properties in all areas of industrial production where high specific strength is demanded. They gradually replace metal parts and components not only because they are lighter, but above all for their comparable and in many ways even better mechanical properties. Knowledge of behavior of simple synergies between the fibres and the matrix allows the prediction of behavior of complex components and their application in practice. The subject of this article is a description of an experiment and numerical model, that compares the mechanical properties of carbon fiber composite with the values obtained using analytical models. Carbon composite samples were studied in laboratory conditions through Barrier test (ie. Crash test).

Abstract: In the article the combined influence of surface effect, proximity effect, ring effect and slot effect on active and self-inductive resistances of the inductor, placed inside the hollow cylindrical workpiece, are investigated. It had been shown that the combined influence of these effects forms a distribution of current over cross-section of the inductor tube. That current determines the values of active and self-inductive resistances of the inductor. There had been presented dependencies of relative coefficients of active and self-inductive resistances of the inductor and relative geometrical parameters of the system "inductor – hollow finite-sized workpiece", the gap between the inductor and the workpiece, and specific resistance of heated nonmagnetic workpiece in presence and absence of internal magnetic core.

Abstract: Composite slabs with prepressed embossments present an effective solution for horizontal structures. Prepressed embossments ensure composite action after hardening of concrete. Longitudinal shear failure mode typically governs if the shear resistance of embossments is not sufficient for full composite action. Mutual separation of thin-walled sheeting from concrete and its deformation inside the rib is characteristic for this failure mode. Design methods for composite slabs use full scale bending tests in several series to determine their bearing capacity. A less expensive alternative is to use small-scale shear tests to determine shear characteristics of the sheeting. This paper presents detailed numerical models of slab in shear and models of slab in bending with and without embossments. These models are compared with previously performed experiments. Key WordsComposite slab; steel sheeting; concrete; prepressed embossment; longitudinal shear; experiment; numerical model

Abstract: Pretensioned concrete beams are used as a main load bearing member for composite bridges with a span to 30 m. The advantage of longitudinal prefabrication technology of beams for small span bridges is quick installation, savings of straight supporting scaffolding of centers and formwork. The amount of labour with formwork, reinforcement and concrete including work with scaffolding of centers on site is reduced at a minimum. During searching applications of steel fiber reinforced concrete (SFRC) suitable for this kind of structure a pretensioned concrete beam suitable for a bridge bay with a span from 12 to 15 m has been chosen for an investigation. Three types of beam were manufactured for experimental tests. The beams were supposed to be a part of a bridge bay with a composite slab. These pretensioned beams were made of SFRC. In case of the experimental tests, a cast-in place concrete cover from plain concrete was casted on the top of the beams. The cast-in place concrete cover simulated a top composite slab. The bearing capacity of the beams with the cast-in place concrete cover was tested until their destruction. The tested beams showed higher bearing capacity than it was determined by a theoretical calculation. The beams also demonstrated high safety against collapse during structure overloading. The process of the experimental testing was also simulated on a numerical nonlinear model and then the results were compared. The result comparison of the both types of tests did not show any significant irregularities.

Abstract: This paper established a three-dimensional model of asphalt pavement by finite element analysis method, studied the effects of vehicle braking on the asphalt pavement, and analyzed the mechanical law of asphalt pavement through comparing the stress of pavement asphalt when the vehicle is in uniform motion or braking condition. The results show that the vertical stress, vertical displacement and horizontal shear stress of the asphalt pavement increase significantly while the vehicle is under the braking condition. In every asphalt pavement structure layer, the maximum horizontal shear stress under vehicle braking condition are all about four times to that of under vehicle uniform motion, so it’s necessary to significantly improve the shear strength of the asphalt pavement in these sections which often bear automobile braking force.

Abstract: The coastal circulation is one of the focuses in environmental protection. A self-adaptive numerical model of the circulation in the East China Sea (the Bohai Sea, Huanghai Sea (Yellow Sea) and East China Sea) (ECS) is established for the first time. By using a self-adaptive grid system, the grids are denser at the continental slope of the ECS. Thus, the difficult problem of applying a 3-dimensional (3D) baroclinic model with coordinate transformation at continental slope is solved. This model can be used to simulate 3D baroclinic current fields and to obtain wind-driven, thermohaline and tide-induced Lagrangian circulation.

Abstract: Presentation of the numerical model describing a design and functionality of the prototype of surface condition detector is the paper subject. The detector, by monitoring the frictional coupling between so-called “tracking wheel” of the dedicated measuring transducer and a rail can analyse the condition of rail surface (presence of any factor that can deteriorate friction coefficient) [1]. Signal generated at the detector outlet, carrying information about local condition of rail surface, can be used to adjust braking torque of vehicles or machines moving on a track. Authors expect that implementation of the method will eliminated dangerous elongation of braking distance of rail vehicles in the result of loss of adhesion. Structure of detector of rail surface condition is described and its principle of operation is presented in a form of numerical model. Results of numerical simulations are given and they are compared with the measurements taken on the testing facility in real conditions.

Abstract: EHD micro-jet can deposit rule and functional patterns in a direct, continuous and controllable manner, and has the advantages of good compatibility, high resolution and simple structure, thus becoming a cost-effective and high-efficiency technology. Through numerical method, obtain the three dimensional model of cone-jet and emphasize the correlation of sediment diameter and PEO concentration. The theoretical graphics agree well with the experimental data, which can explain and provide some theoretical basis for the experiments.