Papers by Keyword: Bending Stiffness

Abstract: The article suggests the use of glued reinforced wooden beams with increased load-bearing capacity. The beam is provided with reinforcing elements in the grooves, namely, in the lower zone – prestressed flexible bundles made of composite, and in the upper zone – steel rods. The analysis of structural behaviour of the beam and the location of the reinforcing elements, the calculation of the bearing capacity of beams and evaluation of the effectiveness decision on material and Flexural rigidity. Composite rods can be prestressed to increase the efficiency of the reinforcement and increase the beam stiffness and load-bearing capacity. Installation of reinforcing elements along the line of action of the main tensile stresses in a wooden beam creates tension in them, which allows the use of flexible bundles and leads to a decrease in the complexity of their installation in the lower grooves, and, therefore, reduces the complexity of manufacturing a wooden beam as a whole.

Abstract: Reinforced bubble deck slab is a structural slab that contains high-density polyethene (HDPE) hollow spherical plastic bubble balls forming a slab with less concrete volume compared to the normal reinforced concrete slab. Reducing certain volumes of concrete from 30 to 50% will affect the performance of the slab structure in particular the flexural and shear capacity. Thus, in this research the effect of area loading on the flexural performance of bubble deck slabs is investigated by considering the slabs to be one-way supported slabs. The square deck slabs used were 1200mm by 1200mm for the width and length with a thickness of 230mm. A total of 36 HDPE hollow spherical plastic bubble balls with a 180mm diameter were placed in the bubble deck slab specimens which reduce significantly the structural self-weight. In this paper, the experimental results of the flexural performance of the reinforced bubble deck slab, (BD slab) compared with a conventional reinforced concrete slab, simply supported, subjected to static area loadings, are presented. The effect of the load applied in the experiments on the flexural strength, bending stiffness and load-deflection behaviour of both types of slabs have been discussed including the crack propagation and crack pattern. In general, the conventionally reinforced solid slab, simply supported (SS) has a 60.6% higher resistance against bending deformation than the reinforced bubble deck slab.

Abstract: In this paper, the mechanical behavior of steel-concrete composite slim beams was investigated by experiments, and the influence of sectional dimension of steel beams on the bending stiffness and flexural capacity of composite slim beams was evaluated. Test results show that good cooperative performance can be achieved in steel-concrete composite slim beams and the relative slip between steel and concrete is very small. The steel-concrete slim beam presents considerable deformation ability beyond the service stage, which indicates that the composite slim beam has good ductility. In addition, sectional dimension of steel beams is proved to have significant influence on both the bending stiffness and flexural capacity of composite slim beams.

Abstract: The application of Glass Fibre Reinforced Thermoplastics (GFRTP) is expected to reduce the weight of automobiles. In order to use GFRTP for automotive parts, it is essential to apply Computer Aided Engineering (CAE) technology. Until now, prepreg sheets with thermosetting resin matrix are assumed to be used for materials in simulation software. When FRTP is applied for materials in simulation software, it is required to grasp the characteristics of FRTP under moulding temperature. In our previous study, a system capable of evaluating the tensile properties of FRTP laminates at moulding temperatures had been developed and their tensile properties had been evaluated. Bending stiffness under moulding temperature is also required for simulation software. While bending stiffness can be determined using Young's modulus for isotropic materials, thermoplastic prepregs have large anisotropy, especially at moulding temperature. In this study, a system that enables self-weight deflection test of thermoplastic resin laminate under moulding temperature was developed and self-weight deflection characteristics of plain weave GFRTP were evaluated. The analysed results in which the bending stiffness under the moulding temperature of GFRTP was taken into account, gave the most suitable results to the experimental results.

Abstract: Biological effects of essential oils are investigated for many years. This work is focused on exploring the influence of saturated vapours components of essential oils on the mechanical, optical and chemical properties of cellulose and lignocellulose materials. Diluted vapours of active ingredients of essential oils could be used in future to protect archives made of cellulose materials. For testing were chosen ingredients of essential oils, that showed the highest bactericidal activity. Saturated vapours of these components act on selected cellulose and lignocellulose materials for a predetermined time. From the mechanical properties were measured tensile strength, bending stiffness and compressive strength. Optical properties are represented by the colour difference ∆E and chemical properties by pH change.

Abstract: This article focuses on creating an algorithm for the calculation of bending stiffness of an arbitrary polygonal cross section, including the first derivatives of this stiffness with respect to all the input variables. The coordinates of vertices of the cross section are also among these input variables. The algorithm is in principle based on dividing the cross section into trapezoids, calculating zero, first and second moment of area of these trapezoids, including partial derivatives with respect to all the input variables, and then compiling all these partial results into a final output. A DLL library based on this algorithm is then used in an optimization solver based on a reduced‑gradient method. This solver is put into practice to optimize the given cross section characteristics according to prescribed criteria.

Abstract: In this work the mechanical performance of various sandwich constructions with respect to core material were experimentally evaluated. Sandwich structures were made of glass prepreg and three types of plastic core using vacuum bagging, technology traditionally used for production of parts for transport industry. The aim of this study is to analyze the impact of the core material type and its thickness on bending behavior at different environmental temperatures. Moreover, the effect of core layers compared to one layer core of same thickness was determined. Conducted research provided useful information of bending behavior and showed specific failure modes of individual sandwich constructions.

Abstract: In order to solve the problem of bending stiffness parameters identification of practical stay-cable, and provide bending stiffness correction for tension measurement. A method to identify cable bending stiffness parameters is proposed, and its basis theory established in paper. The method was applied to Xiazhang Sea-Crossing Bridge, the results showed that: Identification bending stiffness ratio is between 0.33 to 0.54 for relatively short cables of South Branch Bridge, and it tends to decrease with increase of cable length and force. However, the identification bending stiffness is close or equal to 0 EI_max for relatively long cable of North Branch Bridge. It testified that the effect of bending stiffness for long cable tension is small in engineering.

Abstract: Von Misses truss is one of the best examples to explain nature of non-linear solution and define the snap-through. Linear buckling analysis and nonlinear finite element approaches are compared in presented paper. At the present time theoretical models for the evaluation of the ultimate load assume a structure with imperfections. The peculiarities of the effect of the magnitude and mode of initial imperfections are investigated. Effect of member stiffness on the load level in critical point of nonlinear solution, as well as the relative position with respect to the critical load from buckling analysis are analyzed. To obtain the nonlinear equilibrium paths, Newton-Raphson iteration algorithm has been used. Obtained results are compared with those gained using ANSYS system.

Abstract: The paper applies composite technology into the field of hydraulic metal structures and hydropower construction mechanical equipment design, and presents the method of optimum design of hydraulic steel gate metal sandwich construction and simulation analysis. According to characteristics of the structure of the flat hydraulic steel gate and selecting the appropriate metal sandwich construction, this paper optimize the design of a hydraulic steel gate of metal sandwich construction from the perspective of light-weight purpose of structure. Considering the overall mechanical behavior of steel gate structures and using technology of three-dimensional modeling and numerical simulation, this paper has a numerical simulation analysis on the optimum hydraulic steel gate. Numerical simulation analysis and theoretical calculation results show the optimum structure of hydraulic steel gate is reasonably practicable.