Mechanical Postbuckling Behavior of Circular Plates Through Concept of Equivalent Radial Tensile Load

Aerospace and automobile structural systems are assemblages of simple structural members like, columns, circular and rectangular plates etc., designed with lesser margins of safety and also have minimum mass, are subjected to severe mechanical or thermal loads during the service conditions. As such, these structural members are relatively more flexible, compared to the same used in the other fields of engineering. Due to these requirements, the study of the thermal or mechanical postbuckling behavior of these structural members gained importance. To predict the mechanical or thermal postbuckling behavior of these structural members, a more rigorous geometric nonlinear (large deflections) analysis is required. The present study deals with the concept of the effective tensile load developed, due to large deflections, to derive a simple heuristic formula, called simply as the formula, to predict the mechanical postbuckling behavior of circular plates, called simply as plates, without going for complex mathematical treatment1,2. The circular plate problem,formulated in the polar coordinate system, is relatively more involved, as the radial and circumferential strains are coupled by the radial displacement, compared to the other structural members, which are formulated in the Cartesian coordinate system. Such formulas are handy and useful to the designers/analysts to quickly evaluate the mechanical postbuckling behavior of the plates, in the iterative design/analysis cycle

Combined effects of geometric and material non-linearities on one dimensional structural members

Combined effects of geometric and material nonlinearities on a uniform column subjected to an axial compressive load are presented in the present note. A simple, direct iterative numerical method has been proposed to study the geometric and material non-linear behavior of columns subjected to varying boundary conditions. Introduction of material non-linearity in the large deflection analysis of columns subjected to an axilll compressive load reveals a reduction in Euler stress obtained when compared to the effect of geometric non-linear analysis and increase in the same when compared to the effect of material non-linear analysis. A convergence study has been carried out for the results obtained from the proposed iterative method to prove the efficacy

Instrumentation to Measure the Heat Transfer Coefficients in an Automobile Radiator

The present investigation aims in development of an instrumentation to measure the heat transfer coefficients in an automobile radiator

Enhancement of Heat Transfer Coefficient in an Automobile Radiator Using Multi Walled Carbon Nano Tubes (MWCNTS)

Enhancement of heat transfer coefficient continues to be an important research area in various fields of engineering ranging from microelectronics to high powered automobiles. The initial effort in the present research study is to enhance the heat transfer coefficient in a vehicle radiator using nanofluids with high thermal conductivity. The world’s most abundant element ‘Carbon’ astoundingly exists in various structures and one such form is tube commonly known as Carbon Nanotubes (CNTs). Heat transfer enhancement in water and coolant based systems with different concentrations of nano particles (carbon nanotubes) have been investigated from an engineering system perspective. One such system considered is a “SUZUKI (800CC) - CAR RADIATOR”, cooling circuit using different nanofluids to replace the conventional engine coolant. In the present study, the effect of nano-fluid heat transfer to enhance in water and coolant based systems with multi walled carbon nanotubes has been investigated. The improvement of heat transfer when compared to water, coolant (water + ethylene glycol 60:40) and water with MWCNTS and coolant with MWCNTS has been studied. It has been observed that there is an enhancement of heat transfer up to 30% when coolant and CNTS are used as a cooling medium

Structural Properties Of Similar And Dissimilar Aluminum Alloy Joints By FSW

The present study aims to predict the mechanical properties of similar and dissimilar aluminium alloy friction stir Welded joints. The present research also addresses the challenges in joining aluminium alloys Al5083 and Al6061 of 5mm thickness at varying process parameters. A total number of 24 joints have been fabricated with a set of eight joints each for Al6061(similar), Al5083(similar) and a combination of Al5083 x Al6061(dissimilar alloy) as per the experimental plan by Taguchi technique using L8 orthogonal array. The dimensions of the plates are chosen in such a way that the weld length is fixed to 150 mm. The tensile strength and the micro hardness of the welded joints as well as micro structures have been examined. Taguchi technique has been utilized to study the optimized value of the process parameters. The process parameters for joining these have been identified as rotational speeds at 1000 and 1600 rpm, traverse speed 40 and 160mm/min and axial force of 2.5 and 3.5kn

Experimental Investigation Of Relative Performance Of Water Based Tio2 And Zno Nanofluids In A Double Pipe Heat Exchanger

This paper deals with experimental determination of convective heat transfer coefficient in a counter flow double pipe heat exchanger using water based TiO2, ZnO nanofluids with 0.002% & 0.004% volume concentrations. Experiments are conducted at various Reynolds numbers ranging from 1600 to 6100. From the experimental results it is found that heat transfer coefficient increases with increase of volume concentration of nanoparticles as well as Reynolds number. Enhancement of heat transfer coefficient between nanofluids with 0.002% volume concentration of TiO2, ZnO and the inner walls of copper tube in a double pipe heat exchanger increased up to 30.37% and 57.31% respectively. The enhancements are as high as 66.12% and 78.30% when the volume concentration is 0.004% of TiO2 and ZnO respectively for same set of operating conditions when compared to pure water at Reynolds number 6100. The experimental results are presented in graphical form. The variation of heat transfer coefficient in both dimensional and non-dimensional form are presented as a function of Reynolds number for different volume concentrations of nanofluids. The effectiveness of heat exchanger is also presented as a function of volume concentration of nanofluids

Mechanical Properties Of The Friction Stir Welded Dissimilar Aluminium Alloy Joints

The present investigation aims in assessment of the mechanical properties of friction stir welded dissimilar metal alloy joints. The optimized process parameters have been predicted for obtaining the strength of the joints in comparable to the base metal. Aluminum 5083 and aluminum 6061 sheets of 5mm thick have been considered for fabricating the dissimilar joints due to their range of usage in most of the engineering applications. Dissimilar FS welded joints were fabricated by varying the process parameters like rotational speed, traverse speed and axial force fixing the Al 5083 on the advancing side and Al 6061 on the retreating side. Two levels of these parameters have been chosen at 1000 rpm and 1600 rpm, 40mm/min and 160 mm/min and 2.5kN and 3.5kN for rotational speed, traverse speed and axial force respectively. Taguchi technique was used to optimize the process parameters by selecting an L-8 orthogonal array consisting of 8 experimental runs. The mechanical properties like the yield strength, elongation, tensile strength and micro hardness of these joints fabricated has been evaluated at all these process parameters

A hybrid Simulation model for Green Logistics Assessment in Automotive Industry

The aim of this paper is to assess green logistics practices in automotive industry by using simulation method. In automotive industry logistics involves the integration of manufacturing, assembly, and distribution activities. The proposed model will assist decision makers acquire an in-depth understanding of environmental impacts and costs associated. The main issues that should be considered include: Carbon Dioxide (CO)emission, re-use and recycling of material, waste disposal and energy utilization. A combined model of system dynamics (SD) and discrete event simulation (DES) will be used. The trade-offs between costs and environmental protection will be analyzed. The results indicate that there exist positive tradeoffs between green practices (CO2reduction, promoting recycling, and water and energy conservation) and operational costs

Evaluating the Strength of the Friction Stir Welded Joints at Various Rotational Speeds

The present research paper aims in evaluating the strength of the welded AA6351 alloy plates of 6 mm thick by using friction stir welding technique at different rotational speeds The applied welding technique is capable of achieving the mechanical properties of the alloy close to that of the original alloy. In the present investigation, the speeds of the spindle were varied from 1100 rpm to 1500 rpm with a constant transverse speed of 20 mm/min. The tensile strength of the joints is determined by an universal testing machine. The results from the present investigation show that the values of the yield strength were very much closer to the values of the AA6351Alloy prior to welding. It has been found from the experiments that the strength of the joints increases with the increase in the rotational speed; however, the same is decreasing after achieving certain speed

Effect of Welding Speed on Microstructure and Mechanical Properties due to The Deposition of Reinforcements on Friction Stir Welded Dissimilar Aluminium Alloys

The strength of the welded joint obtained by solid state stir welding process was found to be improved as compared to fusion welding process. The deposition of reinforcements during friction stir welding process can further enhance the strength of the welded joint by locking the movement of grain boundaries. In the present study, the aluminium alloys AA2024 and AA7075 were welded effectively by depositing the multi-walled carbon nanotubes in to the stir zone. The mechanical properties and microstructures were studied by varying the traverse speed at constant rotational speed. The results show that rotating tool pin stirring action and heat input play an important role in controlling the grain size. The carbon nanotubes were found to be distributed uniformly at a welding speed (traverse speed) of 80mm/min. This enhanced the mechanical properties of the welded joint. The microstructure and Electron dispersive X-ray analysis(EDX) studies indicate that the deposition of carbon nanotubes in the stir zone was influenced by the traverse speed