Papers by Keyword: Mesh Density

Abstract: The effect of new adhesion promoters on the bond strength of rubber compounds with rubber cord based on synthetic isoprene rubber SKI-3, as well as on the structure of their vulcanizates, is investigated. The synthesized additives were taken as adhesion promoters: 2,4-diphenylcarbamidotoluene (DPKT); 2-isocyanatophenylcarbamidotoluene (IPCT) and the industrial promoter is Manobond 680C. Tests were conducted to determine the adhesion strength to the metal cord and the density of the cross-linking of the obtained rubber compounds by the dosage of additives. It is determined that the maximum value of adhesion had mixture containing 1.2 parts by weight of 2-isocyanato-phenylcarbamidotoluene and Manobond 680C. It was found that the introduction of additives DPCT and IPCT leads to the formation of additional cross-links in the vulcanizates. Rubbers containing additives in an amount of 0.4-1.2 parts by weight have the highest density of crosslinking. The studies made it possible to hypothesize the relationship between the particle size and the electrokinetic potential of blocked urea-based isocyanates with the strength of brass-metal cord-rubber bonding. The results obtained indicate that the greater the electrokinetic potential of the synthesized additives and the lower the average particle size, the better the additive is distributed in the rubber compound and affects the formation of the adhesive layer at the brass-metal cord-rubber interface.

Abstract: During the last decades the application of composite materials in various structures has become increasingly popular. Advanced hybrid composites are useful in marine and aerospace engineering. In this contribution, impact response and damage process by a drop-weight instrument on glass reinforced (GLARE) 5 fibre-metal laminates (FMLs) with different impacted energy were presented. After comparing and analyzing the histories of contact force, central displacement, absorbed energy and force-deflection for GLARE 5 (2/1) with impacted energy of 8J, 10J and 15J, respectively. The fact that aluminium layers play an important role in absorbing energy was proved. Moreover, A numerical methodology including user material subroutine VUMAT, Johnson–Cook flow stress model is employed to simulate the response of the contact force, deflection, absorbed energy and corresponding failure modes in low-velocity impact of FML. After comparing the five simulation results with different mesh density, the influence of mesh density on simulation results was investigated and presented. The optimalizing mesh size which considered both computational efficiency and accuracy was found.

Abstract: Using finite element method, models of different element mesh density for the center hole in flat plate were established according to one actual steel plate with central circular hole. The stress concentration coefficients of these models were calculated by means of numerical method. Then the calculated results were compared with the theoretical solution results of Elastic Mechanics. And it was analyzed subsequently that the influences which were caused by different element mesh density on the stress concentration coefficients around the hole in flat plate. The relationship between the element mesh density and the stress concentration coefficients around the hole in flat plate was proposed finally. Results show that the element mesh density for calculation affects the stress concentration coefficients around the hole in flat plate significantly, but the influence is few when the mesh density increases to a certain extent.

Abstract: Metallic sandwich panels based on lattice cell structures have been developed for a wide range of potential applications with their lightweight and multi-functionality. Structural performance of sandwich panels can be predicted from the studies on the mechanical properties of a unit cell. Numerical investigations on the unit cell can provide efficient guidelines for the design of overall core structures for a specific application. When any types of external forces are applied on the sandwich panel, each truss member of the unit cell undergoes severe plastic deformation without any restrictions so that the deformation behavior is strongly dependent on mesh density and element type. Therefore, in order to improve simulation accuracy and minimize calculation time, it is necessary to investigate the influence of element type and mesh density on that. In this work, as the preparatory stage to predict the mechanical behavior of a pyramidal unit cell, a series of finite element simulations for various element sizes and types were carried out. The influence of mesh density and element type on the simulation accuracy was investigated in diverse aspects; calculation time, resultant load, deformed geometry, effective modulus and peak stress.

Abstract: The Hybrid Cellular Automata (HCA) algorithm has been used by several researchers to optimise structures during the last decade. Close observation of their work shows that the proposed optimisation algorithms are sensitive to the controller (local rule), the design variable and the field variable used. The aim of this work is to identify and understand the important parameters when using the HCA algorithm to optimise structures. For static loading, it is shown that the most important parameters are the design variable, the constraints on the design variable, the local rule, and the mesh density of the structure. The choice of the design variable affects the selection of the target value and the homogeneity of the resulting optimum structure. With constraints on the design variable, it is shown that the algorithm cannot always drive the structure to an optimum solution, as stresses in the resulting structure can be significantly higher than expected. Besides, the choice of the local rule and the mesh density of the structure can affect the convergence rate and may cause the algorithm to arrive at a local optimum rather than the global optimum solution.