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In this paper, we report results of stress analysis and fatigue life assessment of a number of spot weld joints. Models are presented for corrugated plates, jointed to an L-shape plate using 7 and 14 spot welds, which are subject to four different types of alternating loading conditions. The analyses are based on the solutions obtained from the ANSYS7 finite element package, using solid elements. In this study, strains and stresses in the weld nugget are evaluated. However, the primary focus is on strain-based fatigue life assessment which considers the 3D state of stress around the weld nugget and the nonlinear effects of the materical and the geometry.

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In this paper, we report results of stress analysis and fatigue life assessment of a number of spot weld joints. Models are presented for corrugated plates, jointed to an L-shape plate using 7 and 14 spot welds, which are subject to four different types of alternating loading conditions. The analyses are based on the solutions obtained from the ANSYS7 finite element package, using solid elements. In this study, strains and stresses in the weld nugget are evaluated. However, the primary focus is on strain-based fatigue life assessment which considers the 3D state of stress around the weld nugget and the nonlinear effects of the materical and the geometry.

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In the present study the phenomenon of drying a clay brick ceramic is analyzed. Strain–Stress equations coupled to heat and mass transfers during drying of deformable two-phase media has been modeled and both 2D and 3D arrangements have been studied. In order to compare the results, two samples with identical compositions are used for both configurations. The material is considered as a two-phase, homogeneous, isotropic, and highly shrinkable medium. The principal equations of the model, because of the shrinkage behavior are written in a Lagrangian formulation. The model is solved numerically by a finite difference method and Validation of results is achieved by comparing the numerical results with experimental data. The model being developed allows the derivation of the time and space moisture contents, strains, and stresses incurred as a result of drying. A significant difference was observed between the results obtained for the two different configurations particularly in intensity of the stress causing cracking

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Drying of porous materials is a critical step in the production of many products such as ceramics, brick and tile. Quality of dried product is severity influenced by drying processes. The aim of the present work is modeling of convection drying of a ceramic by using diffusion model. Material properties changes such as Young's modulus and shrinkage factor to moisture content are considered in simulation. Both two and three dimensional configurations have been investigated. The model is solved numerically by a finite element method. A significant difference was observed between the results obtained for the two different configurations particularly in the intensity of the drying-induced stresses. Validation of results is achieved by comparing the numerical and experimental results. The effect of Young's modulus variation has been investigated. It was observed that drying-induced stresses are highly affected by Young's modulus variations. According to the results, none of the simulation methods, cannot be regarded as a safer method in crack prediction. The changes in Young's modulus, Has no effect on the location of maximum stress However, delays in the timing of it.

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The main scope of this paper is the analysis of the specifications of deflagration-induced and detonation-induced deformation and fracture behaviors of cylindrical tubes. The main characteristics of deformation and fracture behaviors were studied through experimentations on steel pipes and failure analysis of a compressed natural gas (CNG) cylinder. The paper also reports the results of transient-dynamic elasto-plastic finite element (FE) analyses of the combustion-induced deformation and fracture behaviors of the pipe and the CNG cylinder. The FE models were composed of 3D brick elements equipped with interface cohesive elements for crack growth analysis. Very good agreements were found between the simulation results and the observed deformation and fracture patterns. It was shown that, because of different loading conditions, specific deformation and fracture features can develop during the explosion process.

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The 5052 aluminum alloy was lap joined to Al-1050 clad steel sheet (with Al-1050 thickness of 1mm) using gas tungsten arc welding (GTAW) process with 4047 Al-Si filler metal at the welding currents of 80, 100 and 120 A. Effect of welding current was studied on the weld microstructure, intermetallic compounds layer and tensile strength of the joints. Microstructural studies were done using optical and scanning electron microscopes (SEM) equipped with energy dispersive spectroscopy (EDS) and tensile strength of the joints was determined by shear-tensile test. Results shows that the reaction layer included two Al3Fe and Al5Fe2 intermetallic phases formed at the interface of the St-12 base sheet and Al-1050 clad layer. Maximum average thickness of the reaction layer was ~3.5 µm .It seems that presence of Al-1050 layer prevents excessive growth of Al-Fe intermetallic layer. The joint tensile strength decreased almost linearly by enhancement of the welding current and the primary α-Al dendrite arm spacing increased and Al-Si eutectics were distributed more uniformly. As a result, the crack easily grows and fracture force reduces. The maximum tensile strength of the joints reached to ~190 MPa, i.e. ~80% of 5052-H34 aluminum base metal strength. During the shear-tensile test, fracture in all the joints was started from the root of the weld and then propagated inside the weld metal with an angle of ~70 with respect to the Al-1050 base sheet. Stress analysis in weld showed that fracture in the joint was controlled predominantly by the maximum normal stress.

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The satellites on the ground during construction and transportation, in launching stage and operation in space are under various types of dynamic loads, including high and low frequency vibrational loads, acoustics, shock, impact, etc., each of which can be an important source in the creation of stress on the satellite. The satellite components should be designed in such a way that can continue to operate while facing these situations. Electronic boards, in particular their solder joints, are critical components of satellites. Therefore, investigation of damage in design process of boards have great importance. Loading pattern on the satellite during its operation is usually random which considered as quasi-static load. Improvement of the design of the satellite against the weaknesses shown while facing different loads is essential, and given the fact that it is time consuming and costly to carry out laboratory tests, the use of analytical methods for checking the strength and lifetime of the structure can be very useful. In this research, random vibrations environment is equivalent to pseudo-static loads, and using the multilayer plate theory, the stresses in solder joints and failure of joints under this loading will be investigated. Also, the effect of parameters such as electronic board width and the boundary condition of the printed circuit board on the solder joints' stress will be considered in analytical solution.

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Aerodynamic and optimal design of a blade of a horizontal axis wind turbine (HAWT) has been performed in order to extract maximum power output with considering the strength of the blade structure resulted from different loads and moments. A design procedure is developed based on the Blade Element Momentum (BEM) theory and suitable correction factors are implemented to include three-dimensionality effects on the turbine performance. The design process has been modified to achieve the maximum power by searching an optimal chord distribution along the blade. Based on the aerodynamic design, the blade loads have been extracted and the blade mechanical strength has been investigated by analyzing the thickness of the blade surface and the blade material. The developed numerical model can be considered as a suitable tool for aerodynamically and mechanically design of a turbine blade. The results for a 500 W turbine show that the turbine performance improves by 5% approximately, by modifying chord radial distribution. Yield stress analysis shows the effect of introduced chord distribution on the blade strength, in different blade thicknesses and different blade materials. In addition, optimum tip speed ratio for having favorable mechanical safety factor is derived. Three different airfoil are examined for this investigation and comparing their mechanical safety factor.

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The mechanical flow meter is a widely used tool in various industries such as the oil industry. A pair of oval gears is used in the mechanical flow meter. The most important issue in the oval gear is the lack of uniformity in the shape of its teeth. This lack of uniformity prevents the gears from interfering with each other, for this reason, similar to the circular gear, it is not possible to machine.  For the oval gear machining, tool design, or the use of the wire-cut method is required. As a result, it is necessary to know the profile of oval gear teeth. Therefore, in this article, the relations governing oval gears have been investigated. In these relationships, the number of teeth, geometric dimensions, and equations of motion have been investigated. Then, it was modeled using the Gear-Otix software and with the help of the results of the relationships of the gears, the interference conditions of the two gears were checked in this software, and finally, the stress analysis of the gear was done by using Comsol software for the appropriate state. With the help of the created model, it is possible to produce this gear using the wire-cut method.