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1.
Shape optimization of truss-stiffened shell structures with variable thickness
Marko Kegl, Boštjan Brank, 2006, original scientific article

Abstract: This paper presents an effective approach to shape optimal design of statically loaded elastic shell-like structures. The shape parametrization is based on a design element technique. The chosen design element is a rational Bézier body, enhanced with a smoothly varying scalar field. A body-like designelement makes possible to unify the shape optimization of both pure shells and truss-stiffened shell structures. The scalar field of the design element is obtained by attaching to each control point a scalar quantity, which is an add-on to the position and weight of the control point. This scalar field is linked to the shell thickness distribution, which can be optimized simultaneously with the shape of the shell. For linear and non-linear analysis of shell structures, a reliable 4-node shell finite element formulation is utilized. The presented optimization approach assumes the employment of a gradient-based optimization algorithm and the use of the discrete method of direct differentiation to perform the sensitivity analysis.Four numerical examples of shell and truss-stiffened shell optimization are presented in detail to illustrate the performance of the proposed approach.
Keywords: mechanics of structures, shape optimization, shells, trusses, Bézier body, numerical methods, optimum design
Published: 30.05.2012; Views: 1097; Downloads: 64
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Basic solutions on shape complexity evaluation of STL data
Bogdan Valentan, Tomaž Brajlih, Igor Drstvenšek, Jože Balič, 2008, original scientific article

Abstract: Purpose of this paper is to present basic solutions on shape complexity, based on basic information of the STL data. Design/methodology/approach: Paper presents a few methods of mathematically evaluating the complexity of the shape. Methods vary from very simple based on the number of triangles in STL file, STL file size and the parts volume, to the more complex mathematical evaluation based on the basic relations of the STL data. Findings: We discovered that evaluation of shape complexity based only on basic data of STL data gives us some basic results on part complexity and can be used for further researches. Research limitations/implications: For parts with large block volume/part volume ratio and thinner parts with free form surfaces only the first method is suitable and gives suitable results. Practical implications: In a rapidly developing field of manufacturing technologies choosing the optimal manufacturing procedure is a difficult and crucial decision. Usually the decision is based on experience evaluation that is fast and can be optimal. Usually, this method produces goods results, but in some cases this method can lead to cost increases and reduced economic efficiency without us even knowing that. Therefore, it is crucial, that a fast and simple solution is developed, by which the optimal way of manufacturing can be determined. Originality/value: Choosing maximum efficient manufacturing processes on base of part complexity is a new perspective in manufacturing, which, properly evolved and complied can cause revolution in manufacturing optimization, especially in hybrid manufacturing processes.
Keywords: manufacturing systems, shape complexity, complex shapes, manufacturing optimization, engineering design, STL files, STL file parameters
Published: 01.06.2012; Views: 1172; Downloads: 35
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4.
Parameter optimization of tube hydroforming
Edina Karabegović, Miran Brezočnik, 2012, original scientific article

Abstract: Tube hydroforming is mostly applied in automotive industry. In this respect, necessity for the procedure improvement of fluid forming is constant. One of the reasons of its improvement is the procedure performance in optimal conditions. The process parameters have the direct influence on quality and optimal of forming procedure. This paper provides an example of the fluid pressure optimization in T-shape tube hydroforming. Three types of material have been analysed, with three wall thickness and three course levels of axial printers. For the optimization, the evolutional method with applied genetic algorithm (GA) was utilized. The application of GA is significant in solving of many problems in engineering practice. The simplicity and adaptability of the genetic algorithm to the engineering problem results with the increasing volume of applications in a research work. In this paper we investigated interactions of the internal parameters of the T tube hydroforming process, towards achieving the GA model for the optimal internal pressure, necessary for hydroforming.
Keywords: hydroforming, tube, modelling, optimization, parameter, genetic algorithm, T-shape
Published: 10.07.2015; Views: 979; Downloads: 22
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5.
Optimiranje oblike konstrukcij: tristranični projektni element
Marko Kegl, 2002, original scientific article

Abstract: Prispevek obravnava izpeljavo tristraničnega projektnega elementa za uporabo pri optimalnem projektiranju oblike konstrukcij. Osnova za izpeljavo novega elementa je tristranična Bézierjeva ploskev, ki je običajno parameterizirana z uporabo težiščnih koordinat. V prispevku je uporabljena drugačna parameterizacija, ki je bolj prilagojena postopkom optimizacije oblike. Na podlagi te ploskve je definiran projektni element-Bézierjevo telo, katerega mreža nadzornih točk ima v tipološkem pomenu obliko tristranične prizme. Uporaba izpeljanega elementa je ponazorjena na dveh številčnih zgledih.
Keywords: structural design, shape optimization, element design
Published: 10.07.2015; Views: 553; Downloads: 13
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