JOURNAL OF SIMULATION AND ANALYSIS OF NOVEL TECHNOLOGIES IN MECHANICAL ENGINEERING (JOURNAL OF SOLID MECHANICS IN ENGINEERING)
Year:2013 | Volume:6 | Issue:SPECIAL ISSUE 1 (18)|Papers Count:7

Collapse by buckling a quite common phenomenon in sheets under pressure. When these structures caused by defects such as corrosion and cracks the time of the occurrence of this phenomenon is sensitive and critical load to be significantly reduced. Therefore, in this article sheet of aluminum Al 1200 by cracks in a part of the sheet will be considered. Left angle on the critical buckling load effect both experimentally and theoretically calculated. STM-250 experiments using theoretical analysis using Abaqus software is done and the results are compared with theoretical and experimental.

In this paper, the vibration of composite cylindrical shell with piezoelectric layers in the interior and exterior surfaces is investigated. The composite shell without piezoelectric layers can be studied and compared the results with the results of other researchers, the cylindrical shell laminated with layers of piezoelectric vibration checked. The result is a three-dimensional elasticity equations relationships because they do not apply any approximate gain are quite analytical. Shells intended, is closed and has restricted the mainstays in the end it was simple, and the results for the ratio of the radius and the radius of the different thickness are obtained.

This work focuses on the dynamical behavior of carbon nanotubes, including vibration, wave propagation and fluid-structure interaction. In the present research, transverse vibration of nano fluid conveying carbon nanotubes is investigated. To this end, based on the nonlocal and strain-inertia gradient continuum elasticity theories and by using rod and Euler-Bernoulli beam models, the system’s dynamical behavior is modeled and then, the governing equation of motion is solved and discretized by applying the weighted-residual Galerkin approximate method. Moreover, effect of considering nano-scale fluid flowing through the nanotube, the boundary conditions, the different elastic mediums and the van der Walls interaction between the layers of multi-walled carbon nanotubes on the natural frequencies, critical velocities and stability of the system are considered. The results show that the passing fluid flow and the axially moving of nanotube decrease the system’s natural frequencies especially for nanotubes with large internal radius and in high fluid flow and axially moving speeds of nanotube. In addition, it is observed that the natural frequencies and stability of the system strongly depend on the small-scale parameter (nano-scale), mainly in the longitudinal vibration.

Thin-walled structures like crash boxes may be used as energy absorption members in automotive chassis. There have been many studies addressing the behaviors of energy absorption members on frontal crash. These researches have attempted to predict the energy absorption and maximum impact load in shell structures. The energy absorption and maximum impact load depend on many parameters including boundary condition, strain rate, history of plastic deformation during metalworking, geometry; and material and impact energy (i.e. mass and velocity of the striker). This study examined the crash behavior of tube made of the extruded aluminum alloy EN AW-7108 T6 using an elastic boundary condition instead of rigid boundary condition- on the bottom of a crash box. Analytical, Numerical analytical methods is used in this study to simulated crash box behavior, Results showed that using elastic boundary could change the deformation mode and decrease the maximum impact load.

In this paper the studies of the two-phase super Plasticity stainless steels is studied. The aim of this study obtained the suitable criteria to thermo-mechanical treatment condition for decrease the microstructure (grain size) and super plasticity property in two-phase stainless steels. Also here we want to show the appropriate ranges of temperature and strain rate used in the process super plasticity to obtain maximum elongation for this kind of steel. The results showed that by using thermo-mechanical treatment that consists of dissolving, rolling and annealing, the grain size can be achieved to 0.5-4 mm.The maximum elongation is achieved 1000% in the temperature range 800-1000oC and strain rate is achieved 0.01-0.1 s-1. Under these conditions, the sensitivity coefficient of strain rate is around 0.6.

Given the substitution process of generators using renewable energy sources instead of conventional generators in modern power systems, this paper proposes a Monte Carlo based method to determine an optimal level of this change. At first, LOLE index of the system was calculated without wind power to obtain the reference index. Then, the wind turbine units are replaced with the conventional generators. This purpose has been achieved in stages with the gradually reduced portion of conventional generators and increased portion of the of wind turbine generators in order to pave the way for the calculation of the required amount of wind power using Monte Carlo simulation method. The LOLE index at each step was compared with the base LOLE index. In the end, the 5% annual load increment rate in the development strategy with the focus on sole wind power generation was investigated and the power needed for each load increment was calculated. The proposed method was implemented on IEEE-RTS system.

In this paper, the vibration characteristics of multi-layer shell that internal and external surfaces with a layer of piezoelectric sensor and actuator is investigated. The backrest shell laminated with simple analytical method to evaluate and the results were compared with results obtained by other researchers. The numerical solution methods (GDQ) for shells with piezoelectric layers and plain bearings, compared with analytical solution and then a variety of boundary conditions is studied. Using the equations of motion, the fundamental equations and relations Krnsh- displacement, State-space equations derived the equations using approximate separate layer, State-space equations with constant coefficients will become. These equations can be solved using natural frequencies in the backrest shell simple to obtain. If the abutments are not simple, solving equations differentials State-space analysis is not possible and should be used numerical methods. A fourth difference method numerical method common with the small number of sample points can be exact to achieve. By dq, State-space differential equations are solved and the non-traction conditions by applying high and low levels, can be found at the natural frequency. The direct and inverse piezoelectric effect, piezoelectric layer and composite layer thickness ratio of the radius of the middle of a thick crust on the vibrational behavior is studied.