Papers by Keyword: Deflection

Abstract: In this article the use possibility of icosahedron type spatial dot lattices as constructive networks of many-sided domes is considered. The dome triangular panels design with the plywood coverings supported the board edges is accepted. Comparison of results of calculation with the valid work of a triangular Orto-tropic plate at a bend is made. The description of preparation and carrying out static tests of a plywood covering on a cross bend is provided.

Abstract: It is presented the study of the beam samples reinforced with metal armature, BFRP armature and beams with hybrid reinforcement using metal and BFRP armature. Half of the tested samples of beams were manufactured on concrete with river sand, as a fine aggregate. The others were made on concrete with fractionated fine wastes of Mining and Beneficiary complex (MBC) instead of the river sand. The tests were carried out by static loading of the scheme of a single-run free beam loaded in the thirds of gear. It was established that the beams reinforced with BFRP armature and the beams with hybrid reinforcement showed an increase of strength, about 40%, compared with the beams reinforced with metal reinforcement. The deflections of the beams reinforced with BFRP armature were 315% -331% higher than the deflections of the beams reinforced with metal reinforcement and 165% -205% higher than it is allowed by standards. The use of hybrid reinforcement allowed reducing their deflections in two times compared to the beams reinforced with BFRP armature. At a load level of 60% of the destructive, the deflections of beams with hybrid reinforcement BFRP and metal armature did not exceed the maximum permissible norm. When concrete samples manufactured, the substitution of the river sand with fine fractionated wastes from the Mining and Beneficiary complex (MBC) did not affect their durability and deformability (the difference between the values according to these indicators is within the statistical error).

Abstract: The main task of construction is providing buildings with the property to remain operable throughout the entire life cycle. The level of bearing capacity, both of individual structures and buildings as a whole, depends on many factors.

Abstract: The article deals with the change in the deflection of partially prestressed elements under repeated loading. Depending on the classes and the ratio of stressed and non-tensioned reinforcement, the effect of different levels of the repeated load application on the deformability index of the bent ferro-concrete elements is analyzed. Analysis of the experimental and calculated values ​​of deflections of rectangular profile beams after application of static repeated loads showed that regulatory documents underestimate the effect of the operational level repeated loads on the change in deflections at both average and high loading levels by more than 30%. Comparison of deflection values ​​was made immediately after application of repeated loads at the level of 60% from the destructive ones and after lifting the load to the level of 80%. To correct the values ​​of deflections within the limits of the calculated dependences of the norms, when subjected to the operational level repeated loads, it is proposed to take the value of the coefficient characterizing the elastoplastic properties of concrete equal to 0.3 for practical calculations. The results of the study increase the convergence of the experimental and theoretical values ​​of deflections in the range considered.

Abstract: Nowadays a concept of a beam with a corrugated wall in construction mechanics does not exist. Such designs do and they are used in construction. Definition of the intense deformed condition of a beam with a corrugated wall is a relevant task. In this article the task of tension distribution nature assessment in the cross section of a beam in a corrugation height variation was discussed. The task was solved in the course of the numerical experiments with application of the finite element method (FEM). The problem was solved for beams with different shapes of the lines forming a corrugation. It was established that the geometrical form of a corrugation practically didn't influence the nature of tension distribution on a beam section and tension distribution on the cross section of beams with a corrugated wall depends generally on the corrugation height relation to its width.

Abstract: Increasing pressure in separate areas when reconstructing and improving industrial buildings, may necessarily mean strengthening structural surfaces of buildings. In experimental and analytical assessment hollow cores slabs are represented as T-beams and I-beams. The width of the beam edge decreases according to the dimensions of the voids inside the slab. In this paper the authors test bearing strength and deformability of hollow core slabs in different conditions of strengthening. Furthermore, the scholars perform their calculations in a non-linear system, with a progressive loading, until the samples are destroyed, with a plastic hinge formed in the area extended in a slab cross section. Simulation and figure analyses were designed in ANSYS program. The researchers’ resulting of the stress-strain state of hollow core slabs is observed experimentally at various stages of loading. The researchers compared calculations of slabs with the full-scale cross section shape and calculations of the same I-beam slabs. Though, the investigators dwell on the impact of the cross-section on the results of the maximum slab deflections. The paper is also dedicated to a variety of strengthening modes and it explains that the cracking point for full-scale slabs comes after.

Abstract: Textile concrete (TRC) is a modern material that has been the subject of many scientific studies over the past two decades. It is a material based on a fine-grained cement-based matrix, fiber reinforced, fabric of acrylic-resistant glass, basalt or carbon reinforcement. The products from this material are thin-walled elements, which can be used, for example, for facade claddings elements, lost formwork, shell structures, garden architecture or for strengthening or repair of existing structural elements. This paper presents some examples of the behavior of glass reinforced textile concrete during exposure to road salts, under load of bending moment, at long-term loading at elevated temperatures, and assessment of glass fiber resistance during exposure simulating concrete pore solution.

Abstract: The silicon carbide cubic polytype (3C-SiC) is perfectly appropriate to fabricate microelectromechanical systems. However, for such applications, the stress can largely influence both the fabrication of 3C‑SiC‑based microsystems and their related mechanical properties. Accordingly, in this study, we investigated the influence of strong aluminum incorporation towards the mechanical properties of 3C-SiC epilayers grown on silicon substrates.

Abstract: The most frequent research methods applied in various areas of scientific research are computer modelling and numerical simulation. The trend of using finite element method (FEM) gradually replaces classical methods of exploring phenomena. The method is suitable for investigating technical phenomena in the field of construction, mechanics and strength, as well as in other disciplines. Its suitability for the area of ​​strength will be demonstrated in the current paper which presents solutions to various embeddings of a beam under bend. The beam was loaded with an external uniformly distributed load q(x) along its entire length. The research aim was to determine the maximum load and maximum deflection of the beam depending on the beam position and the material used. The beam under bend was selected as the most commonly used structural element. Analytical solution to bending moment and displacement forces is suitable for simple beam loads. Modelling and numerical simulations provide solution to complex problems and different load variations, while identifying changes in material properties of the structural element under consideration. The results are then evaluated and judged on the basis of the maximum strength of the structural material, while meeting the safety condition of the maximum load or maximum deflection. Modelling via FEM is a flexible research method applicable in all research areas.

Abstract: Beam-like members such as shafts, levers, frame components, beam structures, etc. are regularly designed and constructed in the field of mechanical and civil engineering. It is pertinent to know the structural integrity of the design before construction or fabrication. Beam deflection and stress calculations can be cumbersome and results from commercial simulation packages are not devoid of truncation and/or round-off errors because they are based on numerical schemes. To reduce or eliminate these issues, a computational tool, CABDA, has been designed and developed on matlab. The algorithm is based on analytic equations of beam deflection and bending stress theories; a design flow chart and graphic user interface were done to implement the algorithm. Experiments and simulations have been carried out for steel and brass rectangular beams which were compared with results obtained from CABDA for the same beam model. Average deflection errors recorded for steel beam are-0.4 and-0.015; for brass beam are-0.69 and-0.1 for experiment and simulation respectively. Average bending stress error recorded is-0.19 for simulation. It is observable that simulation results compare closely but CABDA gives exact results and therefore is very appropriate for simple beam problems.