One of the defects resulted from working under high temperature and pressure in the rotor of rotary machines is local run out (bending). To remove this bending, flame straightening processcan be used. In this method, by heating the rotor at the maximum bent point, bending is fixed to some extent due to thermal gradient created and local plastic deformation. One of the serious limitations inresearch in this field is expensive and scarce hardware which has limited empirical and theoretical scope of the research. In this study, Finite Element Simulations of the process on sample rotors are examined. In these Simulations, heat flux on the heating point of the rotor is assumed as normal Gaussian distribution, while in previous studies, flame’ sheat flux was considered as constant. To verify the results of this study, experimental tests have also been arranged. Simulation results with the assumption of Gaussian flux show more consistency with the experimental results.

Changes of up to 80°C has been reported for oral cavity temperature. This could well effecti on the nature of restorations for example failure of bonding of adhesive restorations. It is advocated that using opaque layer in porcelane to restorations could reduce this problem. This experimental study was designed to evaluate the effect mentioned using Finitelement analysis method.Results showed that cooling has a more destructive effect than warming process restorations with the presence of opaque having a Finitelement analysis effect on restorations.

This research investigates the motion of microorganisms in an incompressible Newtonian fluid using the Finite Element method in 2D and 3D. The undulating motion generated inside a microswimmer's tail creates hydrodynamic forces within the fluid, which its reaction force propels the microswimmer forward. The Navier-Stokes equation is coupled to Newton's law and solved in the computational domain to simulate the microswimmer's motion. In the first part of this study, the effect of geometric parameters (channel width) and wave parameters (wave amplitude and wavelength) on the swimmer's velocity was investigated. The obtained results indicated that the trend of velocity changes in 2D is not predictable, and the channel height affects this relationship significantly. In the second part of this study, the synchronized swimming phenomenon in 2D and 3D was investigated using the developed model. The results showed that the average swimming velocity in 2D side-by-side, 3D side-by-side, and 3D top-bottom configurations increases by 12%, decreases by 10%, and increases by 7%, respectively. Finally, by examining the pressure distribution in the computational domain, it can be concluded that the force dipoles created by the microswimmers' undulating tails, and their position, are the reason behind the increase or decrease of the average swimming velocity.

Electroslag welding is widely used in column joints. However, the process of electroslag welding has a higher heat input than other welding processes, which results in dramatic changes in microstructure and mechanical properties, especially grain size and toughness. These connections are very vulnerable when subjected to dynamic loads and earthquakes. Therefore, the study of heat transfers and its effect on the mechanical properties of these joints is important. Considering the importance of this, in the present study, a Finite Element model is proposed to study the thermal behavior of this process, then the accuracy of the model is measured according to the practical experiments of the microcontroller. For verification, several practical examples of welding were performed and then, to evaluate the size of the pit pool, welded sections of the macrovar were prepared to confirm the assumptions of the model. In the next step, the validated model is used to study the thermal behavior of the system and the distribution of temperature according to the variables of current, voltage and speed. In this regard, due to the complexity of the process, it is not possible to carry out all Simulations with software menus, so much of the Simulation was written with the language of the ANSYS software.

Background and Aim: The movement of molars has been evaluated in many studies to correct Cl II malocclusion by non-compliance appliances but the results are controversial. The aim of this study was to compare the upper first and second molars' movement in cervical headgear (HG) and pendulum appliance (PEND) by Finite Element method.Materials & Methods: For modeling process, one of the best dry skulls was CT scanned (l mm slices). Modeling was done according to the mechanical properties of cortical and trabecular bone of maxilla and PDM and teeth and transferred to computer by scanner. Elementing, meshing and loading was done. The magnitude of force for both appliances was 250 gr and line of force for HG was 20 degree above the occlusal plane action and for PEND was along the midlingual surface of upper first molar crown. Tooth movement analysis was performed by the software named Ansys 5.71.Results: The amount of dislocation of the 1st molar cusps tip (mesiobuccal, mesiopalatal, distobuccal, distopalatal) at presence of second molar in bucco-lingual dimension showed distal-in rotation in HG and mesial-in rotation for pendulum. In mesio-distal dimension, the four cusps of 1st molar moved distally in HG and palatal cusps moved more in PEND. In vertical dimension, 1st molar showed extrusion in HG and intrusion in PEND for distal cusps.Conclusion: The presence of second molar had impact on the quality of upper first molar in both appliances and it moved in a distal direction, extruded and buccal drifted in both of them. Therefore, with regard to the cooperation of the patients, pendulum appliance is recommended to correct Cl II malocclusion instead of cervical headgear.

In the current research, Finite Element Simulation and experimental tests have been used to design, manufacture, and evaluate the performance of a high-power ultrasonic circular radiator called ultrasonic airborne. The two main goals in the design are to achieve a nominal resonance frequency of 20 kHz in the longitudinal mode shape of the transducer and booster assembly and the flexural mode shape of the circular radiator plate and to remove the disturbing modes from the frequency range of the main mode shape. After designing and manufacturing the sample based on the Simulation results, experimental tests consisting of a modal impact test, impedance analysis, and amplitude measurement were performed. Simulation results, including the resonance frequency and position of the node and anti-node, were compared with the experimental results. The experimental test results of the resonance frequency compared with the Simulation results, indicate the accuracy of the prediction of the results of the resonance frequency with the designed nominal value (error less than 0.5%). Also, the disturbing mode shapes were at an acceptable distance from the main flexural mode shape of the radiator. Reasonable agreement is achieved between experimental vibration amplitude measurement and Finite Element Simulation predictions (position of the node and anti-node).

Throughout the present study, a Simulation of tire–soil interaction model was considered with special view at the two-Dimensional (2-D) Finite Element Method (FEM) model of carcass. In contrast with the existing 2-D tire models, in the new model it was not tried to find a mathematical description for the global reaction of tires, but was based on a mechanical structure of the basic components of a tire. Here, the reproduction of the carcass as the most challenging part for a 2-D model was described in details. Also, the reproductions of tire wall model as a hyperelastic material and soil model as an elastopelastic one were investigated. Coefficients of mechanical behavior of silty-loam soil were accurately assessed to obtain an effective Simulation. The results of Simulation implemented in MATLAB7 Software, showed that the radial-ply tire benefitted from a greater tractive efficiency than the bias one within the same conditions on silty-loam soil. Bias-ply tires suffered from a greater motion reduction (slip) and while their gross traction was slightly greater than that of radial-ply tire. The net traction force was estimated as the same for both tires. Also, the results of Simulation and tests revealed that the radial-ply tire bore lower rolling resistance than bias-ply tire on silty-loam soil in similar conditions. Based upon the Simulation results, the effects of slip, inflation pressure and mechanical stiffness of soil on tractive efficiency were satisfactorily predicted.

Reshaping process is a widely used method for producing tubes with non-circular cross sections. Owing to the friction between pipe and rolls, initial round pipe moves forward and consequently, it gradually formed into square or rectangular one. In practice, geometric profile of the rolls will be changed after a while. These changes would be detrimental the production of faultless products. Therefore, in this paper the reshaping process is studied considering wear phenomena on the rolls. This study is a co-operation with a related industry at which square tubes are produced using reshaping process. In order to investigate the production line, considering industrial datasheets, the process is modeled by means of a commercial FEM package, ABAQUS\Explicit. The reshaping process is simulated as a 3D model and subsequently the sustainable regions to wear are investigated. The influences of significant parameters such as material and thickness of strip, as well as friction coefficient on the worn area, are studied. At the end, the FEM reults are comprised with the experiments reults and a good consistency between them is seen.