Papers by Keyword: Fe

Abstract: In wafer-based silicon solar cell technology cleaning of silicon surfaces has so far been treated without much interest – the cheapest, simple solution, which means mostly rinsing with or dipping into diluted acids (HCl, HF), was the best. Whatever worked was rarely further investigated. Hence, not much work has been published in the field of contamination control and cleaning process optimization and development. With solar cell efficiencies increasing and processes becoming more and more sensitive, the interest in quality control and optimization of cleaning processes is rising.

Abstract: The stress concentration of SWATH’s cross-deck structure is serious and the problem of its structure strength appears particularly important. In this paper, A 3-D global element model of SWATH was built, the design Loads, load cases and boundary conditions were studied. on the base of that, the structure response analysis was completed. The result show that the global ship’s stress is small in all load cases of head seas and oblique seas, and the bulkheads have serious stress concentration phenomenon in beam seas.The result can offer the reference for SWATH’s design and development.

Abstract: Multi-material and hybrid constructions are increasingly used in the automotive industry with the aim of achieving significant weight reductions of conventional car bodies, and thereby lead to effective reductions of fuel consumption. In this respect, the use of aluminum and short fiber reinforced plastics represents an interesting material combination. A full exploitation of such a material combination requires a suitable joining technique. Among different joining techniques, clinching represents one of the most appealing alternatives for automotive applications. This contribution deals with the experimental tests for determination of material behaviour of two representative materials PA6GF30 and EN AW 5754, which are used for parameterization of material models needed for numerical analysis of the clinching process using the FE software LS-DYNA. With regard to the material modeling of the aluminum sheet, an isotropic material model based on the von Mises plasticity implemented in LS-DYNA was chosen. For the description of the strain hardening behaviour of the aluminum sheet at high equivalent plastic strains, the hydraulic bulge test was carried out in addition to the uniaxial tensile test. For modeling of the short fiber reinforced thermoplastic a semi-analytical model for polymers (SAMP-1) available in LS-DYNA was taken. This material model uses an isotropic pressure dependent yield surface for the description of homogeneous materials. Finally, the FE model of clinching process is presented and an outlook of planned activities is given in terms on determination of the yield surface and hardening behaviour of PA6GF30 at high plastic strains.

Abstract: The L1₀-FePt/Fe based exchange coupled composite (ECC) bilayer media is one candidate to extend the areal density of magnetic recording system and solve writability issue in trilemma. L1₀-FePt is the great high magnetic anisotropy material. Therefore, the magnetic parameters of this material such as magnetocrystalline anisotropy constant, K_u, saturation magnetization, M_s, and exchange coupling between a soft/hard interface, are important on magnetic material properties. In this work, the effects of magnetic parameters on magnetic properties of L1₀-FePt/Fe based ECC bilayer media are simulated by the object oriented micromagnetic framework based on Landau-Lifshitz-Gilbert equation. The ECC bilayer media can reduce switching field, H_sw, of media lower than available writing head field. Hence, writability issues of high K_u media can be achieved. Reducing H_sw of ECC bilayer media obtains from lower K_u and higher M_s values. This work can achieve writing capability of a future magnetic recording system.

Abstract: The three-dimensional finite element (FE) numerical simulation of extrusion forming of AZ31 matrix magnesium alloy was analyzed in four extrusion velocities. The flow pattern and the influence of extrusion velocity for the temperature, the distribution of effective stress and strain of composites were analyzed. The results showed that, when the extrusion velocity increased from 1.5 mm/s to 4.5 mm/s, the heat flux under steady extrusion state would change from-2.77e+004 (Wm²) to 1.14e+005 (Wm²), meanwhile the effective stress and strain increased at first and then decreased, and the average effective strain and stress value were smallest when v = 4.5 mm/s. It showed that along with the increase of the extrusion velocity, the rise degree of the temperature increased and the distribution of the effective stress and strain tended to be more evenly. Finally, the best extrusion technical parameters of AZ31 magnesium alloy were determined, that was the extrusion velocity was equal to 4.5 mm/s when extrusion ratio was 25 and extrusion temperature was 350 °C.

Abstract: By considering the four secondary moment functions ,which are developed according to virtual plastic stress distribution at the perforated section of continuous composite beam. reinforced opening proved to be necessary and reliable .Several reinforcing methods are reserched. mechanical properties are compared with FE results in different reinforced continuous composite beam.The result indicates that the bending and vertical shear capacity of continuous composite beam with web opening can be effectively enhanced to a certain extent. In addition,stiffness and local stability at web opening area are also increase. Effective reinforcing method is presented and can be used in engineering practice.

Abstract: The influence of Fe on microstructure and the expansion coefficient and thermal conductivity of Al-30 wt.% Si alloy was studied. Results show that the primary silicon morphology and size changed significantly after joining the Fe, by angular blocky primary silicon sheet or plate into small pieces and then into a polygonal large lump, edge and angle are passivated. As the content of Fe is 0.3 wt.%, material expansion coefficient and high thermal conductivity. Later, with the increase of the content of Fe, alloy point defect and line defect, surface defect and large area defect increase, the thermal conductivity of materials and inflation performance declined. When the content of Fe is 0.1 wt.%, materials with high thermal conductivity and low thermal expansion coefficient, the heat storage performance impact is minimal.

Abstract: A 6061 aluminium rectangular tube extrusion using porthole dies was simulated by finite element software DEFORM-3D. The speed, stress, strain and temperature in the extrusion was given and analyzed. Using the original porthole die, the speed at the bearing entrance is not uniform. Bearing length at the rectangular corners should be increased. The stress, strain and temperature near the bearing are the largest, so the region of the die should be treated and enhanced.

Abstract: The effect of Fe on the performance of rare earth aluminum conductor was investigated in this paper. The tensile strength, elongation and conductivity of the alloys were tested. The study results showed that Fe can significantly increase the tensile strength and elongation of the aluminum rod. However, with the increasing content of Fe, the conductivity of the aluminum rod reduced more obviously. In comprehensively considering the tensile strength, elongation and conductivity, the alloy gained better mechanical properties and conductivity when ω (Fe) was 0.3%.

Abstract: Paradela Bridge is a metallic bridge located along the bank of the Tua River in northern Portugal. While the bridge is not currently in service, its structure is representative of many metallic truss structures built across the continent between the XIX and the XX century. Tua Line belongs to the Douro area that UNESCO recently declared as world heritage. This study acquires its importance since it might serve as an insight for the study of many other similar structures all over the country. This paper comprises a historic investigation of archived documents, an on-site survey to evaluate its present conditions, a dynamic testing and the construction and calibration of numerical models in finite element analysis (FEA) software, structural assessment and capacity rating estimation. The purpose of constructing numerical models was to evaluate the suitability of the bridge under the original loading and in accordance to modern design standards. The historical research revealed that the truss bridge was designed as a simply supported element and that a series of hand calculations were carried out on individual structural elements (e.g. main trusses, stringers and floor beams). Furthermore, a dynamic test was conducted in order to identify the global dynamic properties of the structure and to calibrate numerical models that ensure reliability and representativeness. FE models served through the structural assessment of the bridge in accordance with modern design codes and to estimate the safety of the bridge. Likewise, a nonlinear failure analysis was also conducted in order to estimate the capacity rate of the bridge and the likely failure modes.