one of the simplest numerical integration method which provides a large saving in computational efforts, is the well known one-point Gauss quadrature which is widely used for 4 nodes quadrilateral elements. On the other hand, the biggest disadvantage to one-point integration is the need to control the zero energy modes, called hourglassing modes, which arise. The efficiency of four different anti-hourglassing approaches, Flanagan (elastic approach), Dyna3d, Hansbo and Liu have been investigated. The first two approaches have been used in 2 and 3-D explicit codes and the latter have been employed in 2-D implicit codes. For 2-D explicit codes, the computational time was reduced by 55% and 60% for elastic and Dyna3d, respectively. However, for 3-D codes the reduction was dependent on the number of elements and was obtained between 50% and 70%. Also, the error due to the application of elastic methods was less than that for Dyna3d when the results were compared with those obtained from 2-points Gauss quadrature. Nevertheless, the convergence occurred more rapidly and the oscillations were damped out more quickly for Dyna3d approach. For implicit codes, the anti-hourglassing methods had no effect on the computations and therefore a 2-points Gauss quadrature is recommended for implicit codes as it provide the results more accurately

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.

Wavelet Analysis has called the attentions in numerical solutions of PDEs in recent years. Because of orthogonality and compact support of Daubechies scaling functions, these functions have excellent ability of providing good accuracy and convergence for the approximation of the solution in singularities. In this article the method of using these functions for numerical solving of PDE for Euler–Bernoulli beams is formulated. This procedure needs to calculate derivatives and integrals of scaling functions as the shape functions of wavelet-based Finite element method. Because of non-explicit formulation and high oscillation of these functions, conventional methods -like Gauss method for integration- are not suitable and accurate. Thus some special methods are formulated for these requirements. The ability and high accuracy of wavelet-based beam element for different boundary conditions and loads is shown in some examples.

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.

This paper presents a technique to evaluate the fracture parameters by combining the edge based smoothed Finite element method (ESFEM) and the scaled boundary Finite element method (SBFEM). A semianalytical solution is sought in the region close to the vicinity of the crack tip using the SBFEM, whilst, the ESFEM is used for the rest of the domain. As both methods satisfy the partition of unity and the compatibility condition, the stiffness matrices obtained from both methods can be assembled as in the conventional Finite element method. The stress intensity factors (SIFs) are computed directly from their definition. Numerical examples of linear elastic bodies with cracks are solved without requiring additional post-processing techniques. The SIFs computed using the proposed technique are in a good agreement with the reference solutions. A crack propagation study is also carried out with minimal local remeshing to show the robustness of the proposed technique. The maximum circumferential stress criterion is used to predict the direction of propagation.

Background: Since three decade ago, the application of the concept of Finite element analysis (EEA) have received a keen interest among dental investigators. In practice the FEA provides detailed stress information regarding to a non-homogenious body such as craniofocal skeletal growth, tooth post ceramo-metal crowns and etc. The aim of this study was the determination of the influence of stress distribution at the cement interface of metal ceramic restoration-dentin. Materials and methods: An idealized metal-ceramic crown model was developed. The model was divided into very small segments. Various loading conditions was applied to the model. A super sap software was used for analyzing the stress distribution. Results & Conclusion: The results of this study suggest that the higher shear stress was developed in the cervical region by two dimensional methods.

The main objective of this paper is to provide an applied algorithm for analyzing propeller-shaft vibrations in marine vessels. Firstly an underwater marine vehicle has been analyzed at different speed in unsteady condition using the Finite volume method. Based on the results of this analysis, flow field of marine vehicle (wake of stern) and velocity inlet to the marine propeller is extracted at different times. Propeller inlet flow field is applied in the boundary element code and using this code, marine propeller has been analyzed in unsteady state. In continue, main / lateral forces and moments over the propeller are extracted. Then the data obtained from the boundary element code alongwith exact geometry of the propeller and shaft have been studied, using Finite element code. Natural and forced frequency of the propeller have been determined in various modes of vibration. According to obtained data from Finite element method (FEM) numerical analysis, maximum displacement of propeller is for displacement of the propeller tip in forced vibration state.

In this paper, we propose a mathematical model for the human arterial tree. The Finite element method is used to solve the set of one-dimensional governing equations for blood flow. This model is able to predict the characteristics of blood flow such as the pressure wave propagation and the flow rate with reasonable accuracy. Comparison between three different models of blood; Newtonian, Power Law and Casson shows that the Casson model has almost similar results as the Newtonian, and the results from the Power Law model are close to the inviscid model. Comparison between the steady-state and the unsteady model demonstrates that the steady-state model can be used to predict the mean value of the unsteady variations within an acceptable accuracy range. The proposed model is also capable to predict the effects of different parameters on the blood pressure and the flow rate in arterial tree such as resistance and compliance of distal capillary beds.

Background and Aim: Considering the importance of the design of framework in the stress distribution and probability of creating initial cracks in connectors region, proper design of framework is considered as a requirement. For this purpose, in order to examine the stress distribution in two designs of straight and curved framework, comparison was made using FEM method.Materials and methods: Research using a descriptive method of FEM was performed. A laboratory prototype was produced and was scanned in a digital form, using CMM equipment by the laboratory and a super spot from the geometry of the part was created. The super spot was transformed to a 3D solid model by utilizing Catia software. The above model was divided into a high number small elements, using Meshing method, by Abaqus software to analyze the Finite elements. Afterwards, by Boundary Condition definition, the part was ready to be analyzed. The mechanical properties of Zirconia was entered into the software in the form of a table. Reviewing stress distribution in the bridge specially with the stress on connectors region was performed. Three vertical loading models for each part were applied in central and distal Fosa and analyzed separately.Results: In this study, the findings were described in the form of Von mises stress in Mpa scale. The stress in the Curved model was more than the Straight model. As a result, the stress distribution is more desirable.Conclusion: According to the results of this study, the straight model showed a more desirable stress distribution compared with the curved model. However, it should be noted that these results were obtained in F.E. environment.