Purpose of this study is to obtain failure modes and failure loads of two Parallel pin loaded holes in unidirectional glass fibre/epoxy by adding nanoclay in the absence of nanoclay composite laminates using finite element analysis; the results are validated through experiment. The geometrical parameters studies in this survey include the distance between the diameter of the hole (e/d) and the free edge of specimen, the distance between two holes-to-hole diameter (M/d). The samples were exposed to constant speed tensile loading. The results showed that by adding nanoclay, failure load increases and failure modes varies from shear out to bearing failure. Furthermore, increasing distance from the free edge of the pin centre’s increases load bearing capacity of two type of composite materials and changes the failure mode from shear to the bear, it increases and decreases the distance from canter’s of pin in layers with and without nanoclay particles, respectively and changes failure mode from shear to bear mode. In order to find morphology of specimens and dispersion quality, Scanning Electron Microscope (SEM) was used. For predicting failure load and differentiating failure modes, Tsai-hill failure criteria associated with material property degradation is used. Experimental and FEM results indicate importance of considering the impact of e/d and M/d ratios in the design of two Parallel pin joints. ANSYS was used to carry out numerical simulation and the results denote a good agreement between numerical and experimental results. In this study, by designing an experimental and numerical procedure to estimate the effect of nanoclay, on failure mode and failure load of typical composite material, glass-epoxy, we could illustrate that adding nanoclay brought with it improvement of shear and tensional strength of glass-epoxy about 10 %. پرونده مقاله

In this paper, crushing length, deformations and energy absorption of thin walled square and rectangular composite tubes which are reinforced with Aluminium and SMA wires and without wire have been investigated under a quasi-static lateral load, both experimentally and numerically. To experimental study, square and rectangular composite tubes have been fabricated with SMA wire, Aluminium wire and without wire. To validate the results, a finite element model is constructed and analysed under the same conditions by using FEM27 and LS-DYNA software packages for composite tubes with Aluminium wire and without wire. The numerical results are in a good agreement with the experimental data. The results show that section geometry and the types of reinforcement wires have a considerable effect on the energy absorption. Rectangular cross-section samples with SMA wires have the most energy absorption capacity. پرونده مقاله

In this paper, deformations and energy absorption capacities of thin-walled tubes with different section geometries (circle, square, rectangle, hexagon and triangle) under quasi-static in-plane loading are investigated. The tubes have the same material properties, mass, volume, lengths and average section area and the loading conditions are similar for all of the specimens. In order to investigate the behaviour of the tubes, more than 100 tests are carried out and numerical simulations are performed. The numerical results are in good agreement with experimental data and show that the section geometry has an important effect on energy absorption capacity so that the circular and square sections have the least and the most capability of energy absorption, respectively. Furthermore, for a specific tube, the absorbed energy increases with the wall thickness. The first peak load in load-displacement curves has the greatest and the smallest values for rectangular and circular sections, respectively. پرونده مقاله

In this paper, the vibration behavior of the sandwich beams with functionally graded face-sheets is investigated based on the high order sandwich beam theory.The properties of the FGM are varied gradually across the thickness of the structures in accordant with the power-law rule. First-order shear deformation theory and polynomial patterns are used to model the displacements of the face-sheets and the core, respectively. The governing equations of the motion are obtained based on Hamilton’s energy principle and solved by a Galerkin method. An algebraic method is used to reduce the number of equations. Boundary conditions are considered as simply supported and clamped.The effect of the power-law index and geometrical variations are surveyed on the fundamental frequency parameter for different sandwich beams in some numerical examples. In order to verify the results of the present study, they are compared with special cases of the literature. پرونده مقاله