Papers by Keyword: Thickness

Abstract: Optimized design of Silicon Carbide (SiC) power devices depends, besides power device physics, also on consideration of basic properties and technological readiness of the material. This paper presents a novel analysis of the dependence of variation of epitaxial doping and thickness on the determination of the optimum design point of SiC devices. We introduce electric field at epitaxy-substrate interface as a useful parameter in controlling the dependence of device parameters on epitaxy. Using this method as criterion for design can improve the robustness of SiC devices to epitaxial variation and hence the process yield.

Abstract: The aim of this study is to evaluate the mechanical properties and study the failure of laminated glass reinforced composite coated with gelcoat of different thickness. Firstly, the gelcoat was applied to the mould using brush and subsequently, glass fiber reinforced composite laminates were fabricated on it using vacuum bagging technique. The mechanical properties of the composites various were tested by using tensile and three-point flexural tests. The fracture behaviour of different gelcoat thickness was observed using scanning electron microscope (SEM) to determine the failure behaviour that occurred. The flexural test was performed in two ways, i.e., gelcoat layer facing top and facing down. For both flexural tests, composite coated with 0.30 mm thick of gelcoat shows the highest mechanical strength. Tensile test is useful to investigate the interfacial bonding in between gelcoat and laminate composite. The composite coated with 0.40 mm of gelcoat showed the highest tensile strength, an increase of 38 % compared to the uncoated composite. It was observed that an increase in gelcoat thickness increased the brittleness of the laminated composite. From the failure analysis, failures were caused by the delamination of matrix between the plies, while the gelcoat was still strongly bonded with composite laminate.

Abstract: Zirconia is an extremely successful material for prosthetic restorations, offering attractive mechanical and optical properties. It offers several advantages for posterior restorations because it can withstand physiological posterior forces. The aim of the study was to achieve the influence of zirconia framework thickness on the mechanical behavior of all-ceramic crowns using numerical simulation. For the study a premolar was chosen in order to simulate the mechanical behavior in the components of all-ceramic crowns and teeth structures regarding to the zirconia framework thickness. Maximal Von Mises equivalent stress values were recorded in teeth and restorations. Due to the registered maximal stress values it can be concluded that it is indicated to achieve frameworks of at least 0.5 mm thickness in the premolar area. Regarding stress distribution concentration were observed in the veneer around the contact areas with the antagonists, in the framework under the functional cusp and in the oral part overall and in dentin around and under the marginal line, also oral. The biomechanical behavior of all ceramic crowns under static loads can be investigated by the finite element method.

Abstract: In this article the flanging method of thin-walled ring blanks using the elastic punch and rigid die scheme is investigated. Presence of a cylindrical portion near the larger edge and a flat area at the side of the blank hole is mandatory. Such conditions allow producing conical parts with minimal thickness variation by altering height of the cylindrical portion. Conducted experimental studies showed that the minimal thickness variation values are not exceeding 16% for different materials and relative thicknesses less than 0,01.

Abstract: The article discusses theoretic foundations and parameters of a latch die cutting process modelled in the software system Deform - 2D. The analysis concerns standard methods of latch cutting which causes the excessive edge deformation (over 10% of a sheet thickness) that does not meet the customers' requirements.

Abstract: This paper briefly describes the principle of the ultrasonic single point incremental forming of the sheet metal. In which we established the finite element model and finished the finite simulation with ABAQUS. According to the simulation result, we analyzed the influence law of vibration frequency of the axis on the distribution of the stress and strain of the sheet metal, the thickness, and the axial force in the process of ultrasonic single point incremental forming of the sheet metal. The result shows that the influence on the stress and thickness of the sheet metal is minimal, and the influence on the strain follows the law of cosines in which the strain is minimum when the vibration frequency is equal to 15kHZ.The influence on the axial force is that when the frequency is f=0kHz～40kHz the axial force decreases with the increase of the frequency. However, the axial force increased dramatically with the increase of the frequency when the frequency is above 40kHz.

Abstract: A calculation scheme to gain the relationship between the thickness of shrink-fit holder and thermodynamic properties. Based on the theoretical analysis of fitting molder between shrink-fit holder and tool, then the thermodynamic properties of the shrink-fit holder and cutting tool such as contact pressure, equivalent stress and deformation are analyzed at different thickness of shrink-fit holder in static, under cutting force and inducting heating by using the finite element software ANSYS. The results show that the total contact pressure and maximum equivalent stress increased and the minimum thermal displacement difference decreased with the increase of holder thickness. Under the action of cutting force, the contact stress on the tool holder no longer uniformed and the maximum contact stress significantly increased, cutting tool also deformed. Finally a method to determine the reasonable holder thickness is given and it has a practical guiding significance for the design and selection of the shrink-fit tool holder.

Abstract: This paper investigated the effect of density and thickness on flexural strength and dimensional stability of laminated floor panel. The focus of this research is to acknowledge the suitability of Kenaf fibres as raw material for floor panel. The evaluated floor panel samples consist of high density fibreboard as a core of floor panel and resin impregnated paper as lamination. The core was made up from Kenaf (Hibiscus cannabinus) bast fibres that were used to fabricate dry-formed fibreboard at three different board densities (850, 960 and 1000 kg/mʒ) with the thickness of 8mm and 12mm for each board. Bending modulus of elasticity (MOE), modulus of rupture (MOR), water absorption (WA) and thickness swelling (TS) were measured for each panel in accordance to BS EN standard. The overall result showed increasing density and thickness increased were MOE, MOR, TS and WA. Density and thickness were significantly affecting all the panels’ properties except for MOR, TS and WA.

Abstract: This study provides a better understanding of the effect of density and thickness on impact strength of laminated floor panel from Kenaf high density fibreboard (KHDF). The objective of this study was therefore to determine the role of density and thickness on the impact strength of laminated floor panel. Laminated floor panels consisted of high density fibreboard (HDF) as core and decorative paper as surface layer and backing. Kenaf bast fibres were used for HDF with three different densities (850, 960 and 1000 kg/m³) with thickness of 8mm and 12mm for each panel. Energy (J) value was evaluated to determine the impact strength of all various floor panels. It was found that thickness has affected statistically on impact strength while there was no significantly difference existed on density of laminated floor panel on impact strength.

Abstract: A larger diameter of femoral head of artificial hip joint (AHJ) is commonly recommended for increasing range of motion (RoM) and for avoiding dislocation. Unfortunately, increasing that diameter will reduce the material liner thickness of the acetabular component. The behaviour of the AHJ contact system with thickness variation of the Ultra High Molecular Weight Polyethylene (UHMWPE) acetabular liner was studied numerically and experimentally. Finite element analysis was employed for calculating contact stresses and the wear volume was measured experimentally. Numerical results show higher contact stresses with decreasing liner wall thickness. Yet, the experimental results suggest that wear decreases as well with decreasing wall thickness. These findings are important in designing an optimised acetabular liner for larger RoM.