Structural optimization with CADO method for a three-dimensional sheet-metal vehicle body

The aim of this study is to increase power/weight ratio of a steel-alloyed vehicle body without any structural weakness and to use an integrated engineering solution of "computer-aided design, engineering and optimization (CADO)". In this optimization study, primarily the body's "computer-aided design (CAD)" parametric model has been prepared for some static analyses are essential for the design study. In the following step, some critical dimensions of the structure's parts have been defined as design parameters. The goal of the optimization study is a minimization of critical equivalent stress value is under the yield limit. In addition, a sensitivity study has been made on the body model with stress measures for an in-depth analysis. In various steps, Pro/Engineer CAD and Pro/MECHANICA computer-aided engineering (CAE) software has been used. Finally, the obtained results have been presented as both visually and in diagrams or tables. In other words, this study can be defined as a computer-aided design and optimization application of a sophisticated three-dimensional (3D) sheet-metal structural model. Consequently, for the solution of a sophisticated structural design problem, it has been seen that integrated CAD/CAE programs supported optimization techniques are vital much more proper to provide the time, error and cost reduction compared to classical design processes, can be given as contributes of this study to previous literature. (C) 2010 Elsevier B.V. All rights reserved

Tribological properties of MgZrO3 coatings deposited by plasma spraying

Because of thermal barrier properties, ceramic-based coatings are widely used for the design of components at high temperature applications. Therefore, 304 L stainless steel substrates were coated with MgZrO3 coatings using atmospheric plasma spray technique. These coatings consist of a transition from the metallic bond layer to cermet and from cermet to the ceramic layer. Produced samples were characterized by optical microscope, scanning electron microscope and X-ray diffraction techniques. Wear tests were carried out in ball-on-disc system at ambient and dry friction conditions under 2 N load for 0.1, 0.15 and 0.2 m s(-1) sliding speeds. The results showed that the friction coefficient values changed between 0.250 and 0.259 depending on sliding speed. The specific wear rate values rise also from 3.4470 to 5.5535 x 10(-3) mm(3) N-1 m(-1) with increasing sliding speed. Detailed examination of formed wear tracks on sample surfaces showed plastic deformation, materials transfer and microcracks

Tribological properties of MgZrO3 coatings deposited by plasma spraying

Because of thermal barrier properties, ceramic-based coatings are widely used for the design of components at high temperature applications. Therefore, 304 L stainless steel substrates were coated with MgZrO3 coatings using atmospheric plasma spray technique. These coatings consist of a transition from the metallic bond layer to cermet and from cermet to the ceramic layer. Produced samples were characterized by optical microscope, scanning electron microscope and X-ray diffraction techniques. Wear tests were carried out in ball-on-disc system at ambient and dry friction conditions under 2 N load for 0.1, 0.15 and 0.2 m s(-1) sliding speeds. The results showed that the friction coefficient values changed between 0.250 and 0.259 depending on sliding speed. The specific wear rate values rise also from 3.4470 to 5.5535 x 10(-3) mm(3) N-1 m(-1) with increasing sliding speed. Detailed examination of formed wear tracks on sample surfaces showed plastic deformation, materials transfer and microcracks

Finite Element and Experimental Analyses of an Armoured Vehicle Subjected to Landmine Blast

Landmines severely threaten the armoured vehicles. The principal objective is to present a methodology for blast simulations of vehicles subjected to landmine explosions. First, free field blast experiment of 2 kg TNT charge in a steel pot is carried out to validate the blast parameters used in the numerical simulation. Overpressure-time history collected in the free field blast experiment is compared to the numerical simulation results. Numerical simulations are performed in LS-DYNA hydrocode that employs Arbitrary Lagrangian Eulerian formulation enabling a fully coupled interaction between the blast wave, the detonation gases, and the vehicle. Second, the full-scale field test of an armoured vehicle exposed to 6 kg of TNT charge in a steel pot underneath the rear end of the vehicle is conducted. Maximum dynamic deformations measured inside the vehicle are compared to the results calculated in the numerical simulation. Results show that the numerical simulation is in good agreement with the full-scale field test

Comparison of the thermal stresses developed in diamond and advanced ceramic coating systems under thermal loading

Surface preparation techniques such as plasma spraying, physical vapour deposition and chemical vapour deposition have been used to make convenient material combinations for the use in high-technology requirements. High-temperature coating are used for two main functions. Either to protect a base metal against corrosion or erosion, or to minimise wear. A third function is to reduce the temperature of the base metal in the case of thermal barrier coatings. In this investigation, thermal and structural finite element analysis has been employed to analyse the level of stresses developed in coatings subjected to thermal loading. Diamond, Si3N4, Al2O3 and TiC coating systems were modelled. Coatings with NiAl interlayer material were also modelled. Nominal and shear stresses at the critical interface regions (film/interlayer/substrate)were obtained and compared. The results showed that the level of the thermal stresses is influenced by coating material, coating thickness, interlayer material thickness and the mismatch of the thermal and mechanical properties between coating and substrate materials. It is also concluded that the finite element technique can be used to optimise the design and processing of diamond and ceramic coatings. (C) 2000 Elsevier Science Ltd. All rights reserved

Structural Strength and Fatigue Life Calculation of Y32 Bogie Frame by Finite Element Method

In this study structural strength and fatigue life estimation of Y32 bogie frame were examined by finite element method. A static structural and fatigue life simulation were performed according to TS EN 13749 standard. The results of the static structural and fatigue life simulations depicted that Y32 bogie manufactured by Tuvasas achieved the regulations

Comparison of thermal stresses developed in Al2O3-SG, ZrO2-(12% Si+Al) and ZrO2-SG thermal barrier coating systems with NiAl, NiCrAlY and NiCoCrAlY interlayer materials subjected to thermal loading

In this investigation, thermal and structural finite element analysis has been employed to analyse the level of stresses developed in Al2O3-spherical cast iron (SG), ZrO2-(12% Si + Al) and ZrO2-SG coatings subjected to thermal loading. Coatings with a coating-to-substrate thickness ratio of 1/10 were modelled. ZrO2-SG coatings with an NiAl, NiCrAlY or NiCoCrAlY interlayer, and with different combinations of these interlayer materials, were also modelled. Nominal and shear stresses at the critical interface regions (film/interlayer/substrate) were obtained and compared. The results showed that the ZrO2-SG coatings have a higher thermal shock resistance than the Al2O3-SG and ZrO2-(12% Si + Al) coating systems. Furthermore, the interlayer thickness and material combinations have a significant influence on the level of thermal stresses developed. It is also concluded that the finite element technique can be used to optimise the design and processing of ceramic coatings. (C) 1999 Elsevier Science S.A. All rights reserved

Influence of SiO2 and MnO2 additives on the dry friction and wear performance of Al2O3 ceramic

Alumina is widely selected in the design of components for high engineering applications mainly because of its high wear resistance, high compressive strength, low specific density and high temperature capability. Processing and manufacturing of pure alumina products is a difficult and expensive task. Therefore, additional compounds are added to alumina to reach more complex component design, to minimise the product processing and manufacturing costs. In this investigation we studied and explored the influence of additional compounds, speed and load values on the friction and wear behaviour of alumina ceramic. Wear tests for alumina and alumina samples contained w3% SiO2 and w1.5%MnO2, addition compounds was carried out with a pin-on-disc machine. Tribological tests were under 2.5, 5 and 10 N loads and at speeds of 0.5 and 1 m/s. The specific wear rates were deduced from mass loss. The wear rate for alumina without additional compounds was in the order of 10(-8) to 10(-7) mm(2)/N. while the wear rate values for alumina with additional compounds were in the order of 10(-6). Moreover, the wear rate showed more sensitivity to the applied load, particularly at low sliding speeds. (C) 2000 Elsevier Science Ltd. All rights reserved