JOURNAL OF SIMULATION AND ANALYSIS OF NOVEL TECHNOLOGIES IN MECHANICAL ENGINEERING (JOURNAL OF SOLID MECHANICS IN ENGINEERING)
Year:2013 | Volume:6 | Issue:SPECIAL ISSUE 2 (19)|Papers Count:8

An analysis is conducted to examine the market visibility of small aircrafts as a transportation mode in competition with automobiles and scheduled commercial air travels. This is due to by estimating the pool of users that would potentially switch on-demand air travel due to cost/time saving. These new aircrafts greatly increase the practicality of regional aircrafts as a transportation mode that can avoid the congestion associated with other modes. In this research, after introducing small aircrafts as a new mode of transportation, we use some modeling method such as ‘’DSM’’ (Decision Supporting Model) and ‘’TSAM’’ (Transportation System Analysis Model) to investigate and need assessment of small aircraft transportation (SAT).

By increasing the power of computer systems and enhanced power of the components and their temperature, including the central processing unit (CPU), air cooling just is not effective. Therefore there is need for more powerful systems to cool down and increase the power of the cooling system. In this article simulation of the heat exchanger material of the fluid cooling system has been studied using the ANSYS-Fluent software. In this kind of heat exchanger, the water based aluminum oxide nanofluid is used instead of water to increase the total heat transfer coefficient and decrease the output temperature and enhancement of fluid cooling system performance. Results with different speeds of 1000 rpm, 1500 rpm and 2000 rpm and for various volume fractions (1-3%) have been obtained. By increasing rotational speed from 1000 rpm to 2000 rpm the flowing capacity has increased from 0.0138 kg/s to 0.026 kg/s. At speed of 1000 rpm, the amount of heat transfer has increased about 13% for the 3% volume fraction. By increasing the volume fraction of aluminum oxide nanofluid, the total heat transfer coefficient increases too. This increase in the heat transfer coefficient is approximately similar at different speeds and decreases the output temperature of the radiator fluid.

Glue joints are more useful agents in Aerospace industry. So in this article we presented a new method for used of glue joint. In this method the maximum stresses that occurs at the edges of the bottom of glue joint and cause ultimate failure in this type of connection is decreased and therefore increases the glue joint strength. In this method the glue in the overlapping area is considered discrete and separate columns. Also, the connection is assumed to be uniform for the proposed method. As a result of this case is used of less glue in the connection. First the proposed method is studied and distribution of tension in the glue is analyzed. Then glue joints for common conditions are modeled with finite element softwares.

The following article investigates buckling of moderately thick circular Nano plates with an orthotropic property under uniform radial compressive in-plane mechanical load. Taking into account nonlocal elasticity theory (Eringen), principle of virtual work, first order shear deformation plate theory (FSDT) and nonlinear Von-Karman strains, the governing equations are obtained based on the displacements. The stability equations are derived from the neighbor equilibrium state. The differential quadrature method (DQM) as a numerical procedure is applied to discretize the derivatives of equations with a non-uniform mesh point distribution (Chebyshev-Gauss-Lobatto). The accuracy of the present results is validated by comparing the solutions with those reported in the available literatures. The effect of nonlocal parameter, thickness and radius are investigated on non-dimension of buckling loads. From results, it is possible to see that the non-dimension of buckling load of Graphene sheets increases by decreasing flexibility of boundary condition and increasing the rate of nonlocal parameter. It is possible to observe that by increasing the non-dimensional thickness of the plate, the non-dimension of buckling load reduces.

Hydroxyapatite (HA) is one of the most important bioactive ceramics because of its biocompatibility and structural similarity to the mineral part of bones and teeth. It has a broad clinical application in the field of dentistry, orthopedic and coatings of Biomaterials. The aim of this study is to construct nano-hydroxyapatite micro particles using calcite, silica and zinc oxide. Using ball milling, the powder of these three compounds, crushed and then are molded in a cylindrical shape. Then the whole thing is compressed and heated in an oven.by considering the differential of X ray it is possible to obtain the most suitable milling time, temperature and baking time. The graph of the analysis of the samples was compared with the HS results. According to the results, the sample A with 10 hours of milling, heating temperature of 1100oC for 2 hours produced the most amount of Hardestunate product among the others samples.

In industrial production systems, one of the most important factors in the economic field machining operations is to reduce the tool wear. Abrasive nature of the phenomenon is dependent on many factors, including temperature, machining conditions (cutting speed, forward speed cutting depth) and shortage of coolant. All of these parameters lead to tool wear. If we do not study the tool wear precisely, it will impose extra cost in manufacturing processes. These extra costs are due to the reproduction of goods which is due to the replacement of tools and the sharpening operation of tools. In this study, an in vitro study done on tool wear SNMM120404 and the effect of parameters such as rotation speed of the spindle chuck, feed rate and depth of tool wear is investigated.

Studying Fracture Mechanics in order to estimates lifetime of Mechanical parts in designing process and manufacturing have tremendous role in this realm. Stress intensity factor comes into design which is not only dependent on geometry but also extremely to load condition; for instance, it is important in failure processes (brittle and ductile Materials) or to predict the remaining life time of a mechanical part under fluctuating stress. Stress intensity factor should not be mixed up with stress concentration factors. This dimensionless factor, is used to quantify how "concentrated" the stress is. Stress concentration factors are due to geometrical changes of cross sections and are independent of the load condition. In this article, the modeling and growth of a crack during the tension operation is considered using Ansys Software. Stress intensity factor obtained from Ansys software are compared with to Westgard function calculation results.

Porous materials are lightweight, flexible and resistant to hairline cracks. So today with the development of technology porous structures are produced for use in various industries. These structures are widely used in beams, plates and shells. The purpose of this paper is to analytically investigate the effect of porosity on axial symmetry plane of sheet metals with bending and buckling loads. For this purpose, a circular plate with simply supported edges under uniform radial pressure and vertical pressure distribution is investigated. Mechanical properties of porous sheets are isotropic in sheet plane and variable in thickness direction. Field displacement is extended in accordance with the first order shear deformation theory. Then, using the principle of virtual work and applying the calculus of variations, differential equations, and equations for bending sheet stability are achieved. Continuing the used of these equations and Galerkin method, bending and buckling of the sheet is calculated. Buckling load is calculated for all types of porosity can be observed with increasing porosity, critical buckling load decreases. The distribution of bending stress and deflection in sheet analysis was obtained. To verify the results of bending and buckling of the sheet, the results were compared with the homogeneous sheet with classical theory.