OVERVIEW OF STRUCTURAL TOPOLOGY OPTIMIZATION METHODS FOR PLANE AND SOLID STRUCTURES

Topology optimization for structural design is a special type of problem in the optimization field. Although there are efforts to apply classic optimization techniques, the particularities of topology structural optimization have given birth to dedicated, more efficient and reliable methods. This paper is intended as an overview of both the currently accepted and the promising new methods for topology optimization as found in the scientific literature of the last 20 years. Five types of methods are described and compared, highlighting the differences, advantages and pitfalls of each one: evolutionarybased algorithms, Solid Isotropic Microstructure with Penalization (SIMP) methods, Evolutionary Structural Optimization (ESO) methods, Soft-Kill Option (SKO) and level-set methods

COMPARATIVE STUDY FOR THE SIZE OPTIMIZATION OF A TAPERED PIPE CANTILEVER BEAM USING GENETIC ALGORITHMS

This paper is intended as an investigation of the possibilities offered by coupling the scientific programming language MATLAB with the finite element package Abaqus in order to perform parametric structural optimization with genetic algorithms. To illustrate the methodology, a tapered pipe cantilever beam with a force applied at the free end was chosen and analyzed in 3 different modeling approaches: as a straight bar using 1D finite elements, as a shell using 2D finite elements and as a solid structure using 3D finite elements. The bar is modeled in the FEA software Abaqus and the scripts to modify it from code were written in the programming language Python. These scripts are called interactively and iteratively by the optimization algorithm written in MATLAB, in order to evaluate the fitness of the solutions. Besides proposing a methodology for shape optimization, this study also compares the differences in efficiency and results obtained by modeling a part with different types of finite elements

Effect of phosphate/fluoride electrolytes on mass and dimensional stability of anodization bath manufactured by FDM

Present paper is an experimental study on mass and dimensional stability of components manufactured by additive technology of Fused Deposition Modeling (FDM) from PLA and ABS filaments, components to be subjected to the action of aqueous phosphate/fluoride solutions during the process of surface modification and TiO2 nanotubes development on the surface of titanium based materials by electrochemical anodization. Several specimens were printed with 30% and 100% fill density; we used control samples of PP, PLA and ABS in order to compare the results. The specimens and control samples were in contact with 1M H3PO4 + 0.5 wt% HF electrolyte, for 2 hours and 48 hours. Regarding mass stability we found that the specimens’ mass is increasing after exposure to electrolyte, showing absorption on to the material, the mass gain being up to 0.2% from initial mass. Dimensional stability is also questionable; there are modifications of up to 0.05 mm after 48 hours exposure to electrolyte. All of our results lead to the conclusion that, even if FDM has certain advantages in terms of flexibility of design and short design to product time, drawbacks appear in terms of mass and dimensional stability when the printed components work in aqueous acid solutions, raising questions regarding their safe utilization over time

Optimized anodization setup for the growth of TiO2 nanotubes on flat surfaces of titanium based materials

An extensive research work on development of nanostructured TiO2 layers on the surface of titanium based materials for biomedical implants led the authors to the optimization of process parameters of electrochemical anodization in phosphate/fluoride based electrolytes. Based on those parameters, a dedicated optimized electrochemical anodization setup was originally designed and realized. The anodization bath was designed in order to provide a proper circulation of electrolyte and the possibility of distance anode-cathode modification, the DC power supply was designed accordingly to the electrical parameters requested by the nanotubes development, and a dedicated software (Nanosource) was developed for process control and ease and flexibility of process parameters acquisition, storage and processing

Effect of phosphate/fluoride electrolytes on mass and dimensional stability of anodization bath manufactured by FDM

Present paper is an experimental study on mass and dimensional stability of components manufactured by additive technology of Fused Deposition Modeling (FDM) from PLA and ABS filaments, components to be subjected to the action of aqueous phosphate/fluoride solutions during the process of surface modification and TiO2 nanotubes development on the surface of titanium based materials by electrochemical anodization. Several specimens were printed with 30% and 100% fill density; we used control samples of PP, PLA and ABS in order to compare the results. The specimens and control samples were in contact with 1M H3PO4 + 0.5 wt% HF electrolyte, for 2 hours and 48 hours. Regarding mass stability we found that the specimens’ mass is increasing after exposure to electrolyte, showing absorption on to the material, the mass gain being up to 0.2% from initial mass. Dimensional stability is also questionable; there are modifications of up to 0.05 mm after 48 hours exposure to electrolyte. All of our results lead to the conclusion that, even if FDM has certain advantages in terms of flexibility of design and short design to product time, drawbacks appear in terms of mass and dimensional stability when the printed components work in aqueous acid solutions, raising questions regarding their safe utilization over time

Optimized anodization setup for the growth of TiO

An extensive research work on development of nanostructured TiO2 layers on the surface of titanium based materials for biomedical implants led the authors to the optimization of process parameters of electrochemical anodization in phosphate/fluoride based electrolytes. Based on those parameters, a dedicated optimized electrochemical anodization setup was originally designed and realized. The anodization bath was designed in order to provide a proper circulation of electrolyte and the possibility of distance anode-cathode modification, the DC power supply was designed accordingly to the electrical parameters requested by the nanotubes development, and a dedicated software (Nanosource) was developed for process control and ease and flexibility of process parameters acquisition, storage and processing