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Optimization methodology of a product of white line by computational analysis using statistical approach and finite elements

Sousa C. J., Marcondes P. V. P., Lajarin S. F.

Archives of Materials Science and Engineering

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2016

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Vol. 81, nr 1

30--36

EN

Purpose: The industry constantly seek reduction of production costs combined with improved product quality. The major challenge faced is to maintain the product quality. In this work, it is proposed an optimization methodology for a product of the white line. The objective is to study the behavior of some components after a reduction in sheet thickness and maintain the same original structural loads. Design/methodology/approach: A two-dimensional mathematical model, obtained in CAD software, for numerical simulation of the effects of the reduction in thickness, is examined. Finally, it was developed an optimized methodology, based on mathematical and statistical analysis, in order to calculate the possible sheet thickness reduction from its original structure. Findings: It was observed that it is possible by means of computer simulation and appropriate statistical analysis to decrease the thickness of assembled components in order to optimize costs and processes. Research limitations/implications: Since this is an experimental research with numerical data, it would be fundamental for this technique of optimization a future research with physical products for comparison with the computational data. Originality/value: The objective of experiment is maintain the product quality and because it is a job for optimization of processes and consequently costs, the great beneficiary will be the industry.

2

Approach to the prediction of thermal fatigue of aluminium high pressure die casting (AlSI H13) using the Basquin equation and finite elements

Concer D., Woellner N., Marcondes P. V. P.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 55, nr 2

439--445

EN

Purpose: The main aim of the present study was to analyze the influence of the thermal fatigue on the AISI H13 die surface during the aluminium high pressure die casting process. Design/methodology/approach: Two different gradients of temperature were considered (ΔT = 200 and 250°C). The thermal stresses were obtained through computer numerical analysis - Finite Element Method. Then an analytical study, through the equation of Basquin, was conducted to determine the number of cycles until the die failure. Findings: Taking in account the divergences found in the solutions for determining the number of life cycles to die failure and guided by technical data and commercial experience of life cycles for the AISI H13 steel it was possible to propose coefficients of correction for the equation of Basquin. Research limitations/implications: It should be highlighted that the use of the proposed corrected coefficients for the Basquin equation can show a satisfactory results related to the practice - valid only for similar conditions of this work. Practical implications: The behavior of the steel used for the dies are dependent of the temperature and density, elastic modulus, Poisson’s ratio, coefficient of thermal expansion, hardness, thermal conductivity and yield strength and an incorrect steel selection can lead to thermal stresses amplitude favorable for the onset of the cracks. Originality/value: The dies play an important role in the aluminium high pressure die casting process. During the die manufacturing process the die design and the steels behavior are a major concern on efficient manufacturing, i.e. related to maximize the life cycle. During the injection process the thermal fatigue is one of the responsible factor of onset of cracks - estimated to be approximately 80%.

3

Numerical and experimental true strain assessment on sheet forming using mapped versus free meshing

Lajarin S. F., Magalhães J. S. F., Marcondes P. V. P.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 49, nr 2

323--330

EN

Purpose: The main aim of the present study was to analyze the influence of the algorithmic theories of generation and control of triangular, quadrilateral, hexahedral and tetrahedral meshing, i.e. which are the most common types of meshes used in the software of finite elements for large plastic deformation. The importance of these methods is due to the fact that they are the spine of Finite Element Methods (FEM). Design/methodology/approach: It was numerically evaluated the parameters influencing mapped (structured) and free meshing on sheet forming simulation (stretching). For the tests a stretching tool with geometry proposed by Nakazima was used. The study presents the results in terms of the major true strains (ε1, ε2, ε3) and a comparison with experimental data was carried out (validation). Findings: The analysis showed that Shell-type elements are dependent of the element format choice and the way of application in the geometry. Objects built with Shell type elements, i.e. components that will suffer large plastic deformation are extremely sensitive to the mesh format, refinement and way that it was applied. A relationship was also shown among equivalent meshes for elements in the format Tri and Quad. Research limitations/implications: To describe the complete influence of the type of meshing are beyond the scope of this study as it was used only one commercial software and one method of forming. Practical implications: The correct choice of the meshing parameters can provide more accurate results during the simulations of sheet stretching process. Originality/value: The paper shows the differences and implications of the correct choice of meshing during finite element analysis.