This paper discusses some aspects of FEA-based design procedures driven by topology optimization methods. Within this scope the problem of ensuring the robustness and reliability of optimized load-carrying lightweight parts is addressed. To achieve this goal the engagement of the so called design configuration with subsequent topology optimization is proposed. Adequate configuration tools can be used to define a shell/lattice structure and subsequent topology optimization makes sure to remove the stress concentrations and lower the stress levels to a minimum. The numerical and experimental results of the presented example illustrate the importance of proper cell type and orientation selection, as well the importance of optimization, especially, if the underlying part is planned to be produced by 3D printing.
COBISS.SI-ID: 20622614
This article presents a new approach aiming to reduce gear vibration and weight by modifying its body structure. The primary objective was to reduce vibration and noise emission of spur gears. For this purpose, a solid gear body was replaced by a lattice structure, which was expected to raise the torsional compliance of the body. The lattice structure was configured and optimized by a FE-based topology optimization software. For experimental purposes, the optimized gear was produced from Titanium alloy Ti-6Al-4V ELI by using Selective Laser Melting technique. In the tests, the sound pressure of various running gear pairs was measured in order to estimate and compare the properties of a solid gear, of a lattice gear, and of a lattice gear, filled with polymer to increase the structural damping. It was experimentally confirmed that the cellular lattice structure of a gear body and addition of a polymer matrix may significantly reduce the vibration.
COBISS.SI-ID: 21357846
Paper presents the research on possibilities of assuring accuracy of selective laser sintered parts. Research has proven the hypothesis that geometrical properties of part significantly influence the shrinkage and laser heat affected zone size at selective laser sintering. Results analysis has enabled the development of shrinkage and laser heat affected zone size prediction model and consequently improved the accuracy of parts with different geometrical properties. The main goal of the research was to achieve constant accuracy for patient-specific medical accessories manufacturing.
COBISS.SI-ID: 22122262
Important goal of Structural Health Monitoring is detection of disintegration process in material in early stage of operation. One possibility is by monitoring the influence of surface degradation process on change of residual stresses during fatigue loading. Results of this investigation are important in analysis of condition and possibility for a Fiber Bragg Grating sensor installation for continuous strain measurements on the surface. The initial condition of the material surface is a consequence of sheet Al7075-T6 plate manufacturing procedure, but during the high cycling fatigue loading, the surface degradation with micro-grain separation occurred. Quantitative measurement of this process consist SEM surface analysis and residual stress measurement in some stage of fatigue loading. It was found the material surface is affected by fatigue loading level and loading ratio. Electro polished and no-electro polished surface have been observed and analyses. Results show that the range of residual stress change is the similar after same number of fatigue cycles.
COBISS.SI-ID: 21771798
The effect of local deformation on the fracture behaviour of TiAl alloys was investigated. Roller indentations impressed parallel to the crack plane significantly improve the fracture toughness. The residual strains present in the indentation zone were characterized by X-ray diffraction and modelled using finite element (FE) calculations. The experimentally observed macrostrains exhibit remarkable crystallographic anisotropies and are unequally shared between the major alloy constituents. The mechanisms behind the observed toughening have been discussed in terms of the residual strains and factors improving the crack tip plasticity. With regard to intended high-temperature applications, the temperature retention of the toughening effect was studied.
COBISS.SI-ID: 20949014