Comparison of motor stator teeth built of soft magnetic composite and laminated silicon steel sheets in an axial flux permanent magnet synchronous machine

This paper compares the iron losses generated by the concentrated excitation windings for the axial flux permanent magnet synchronous machine stator core elements constructed with laminated silicon steel sheets and soft magnetic composites. The two types of eddy current losses for laminated silicon steel sheets are taken into account. A 3D nonlinear finite element method in the time domain is used to calculate all flux density distributions for various frequencies and different magnitudes. Experimental measurements are also performed to validate the 3D model

The analysis of embankment dams by nonlinear finite element method

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Three-Dimensional Thermo-Elastic-Plastic Finite Element Method Modeling for Predicting Weld-Induced Residual Stresses and Distortions in Steel Stiffened-Plate Structures

The objective of the present paper is to develop nonlinear finite element method models for predicting the weld-induced initial deflection and residual stress of plating in steel stiffened-plate structures. For this purpose, three-dimensional thermo-elastic-plastic finite element method computations are performed with varying plate thickness and weld bead length (leg length) in welded plate panels, the latter being associated with weld heat input. The finite element models are verified by a comparison with experimental database which was obtained by the authors in separate studies with full scale measurements. It is concluded that the nonlinear finite element method models developed in the present paper are very accurate in terms of predicting the weld-induced initial imperfections of steel stiffened plate structures. Details of the numerical computations together with test database are documented

A phase-field model of relaxor ferroelectrics based on random field theory

A mechanically coupled phase-field model is proposed for the first time to simulate the peculiar behavior of relaxor ferroelectrics. Based on the random field theory for relaxors, local random fields are introduced to characterize the effect of chemical disorder. This generic model is developed from a thermodynamic framework and the microforce theory and is implemented by a nonlinear finite element method. Simulation results show that the model can reproduce relaxor features, such as domain miniaturization, small remnant polarization and large piezoelectric response. In particular, the influence of random field strength on these features are revealed. Simulation results on domain structure and hysteresis behavior are discussed and compared with related experimental results.Comment: 8 figure

Nonlinear structural behaviour of membrane-type LNG carrier cargo containment systems under impact pressure loads at −163 °C

This paper is a sequel to the paper dealing with quasi-static responses previously studied by the authors. The structural failure of membrane-type liquefied natural gas carrier (LNGC) cargo tank is an important issue in the construction of ultra-large an LNG carrier. However, quasi-static analysis to investigate the structural failure is difficult and tends to give conservative results. To compensate the weak points of the quasi-static analysis, a procedure for the dynamic analysis was developed to assess the structural failure using nonlinear finite element method. A nonlinear finite element method is employed to model metal membrane, insulation and surface contacts. Various element formulations are tested at different points along a corrugated surface to optimise the accuracy of the model with respect to computation time. Material properties used in the model are calibrated based on experimentally measured values at cryogenic conditions (−163 °C). The model is used to predict the structural failure under different impact pressure loads and loading patterns. It is concluded that the structural damage is less likely to occur under 30 bar

Fast Stiffness Matrix Calculation for Nonlinear Finite Element Method

We propose a fast stiffness matrix calculation technique for nonlinear finite element method (FEM). Nonlinear stiffness matrices are constructed using Green-Lagrange strains, which are derived from infinitesimal strains by adding the nonlinear terms discarded from small deformations. We implemented a linear and a nonlinear finite element method with the same material properties to examine the differences between them. We verified our nonlinear formulation with different applications and achieved considerable speedups in solving the system of equations using our nonlinear FEM compared to a state-of-the-art nonlinear FEM. © 2014 Emir Gülümser et al

A Lagrange Multiplier-based Technique within the Nonlinear Finite Element Method in Cracked Columns

In this research, two energy-based techniques, called Lagrange multiplier and conversion matrix, are applied to involve crack parameters into the non-linear finite element relations of Euler-Bernoulli beams made of functionally graded materials. The two techniques, which divide a cracked element into three parts, are implemented to enrich the secant and tangent stiffness matrices. The Lagrange multiplier technique is originally proposed according to the establishment of a modified total potential energy equation by adding continuity conditions equations of the crack point. The limitation of the conversion matrix in involving the relevant non-linear equations is the main motivation in representing the Lagrange multiplier. The presented Lagrange multiplier is a problem-solving technique in the cracked structures, where both geometrical nonlinearity and material inhomogeneity areas are considered in the analysis like the post-buckling problem of cracked functionally graded material columns. Accordingly, some case-studies regarding the post-buckling analysis of cracked functionally graded material columns under mechanical and thermal loads are used to evaluate the results

SHEAR BUCKLING ANALYSIS OF CORRUGATED WEB I-GIRDER WITH 3D NONLINEAR FINITE ELEMENT METHOD

This paper presents a shear buckling analysis of corrugated web I-girder beam using nonlinear finite element analysis. An in-house finite element package called 3D-NLFEA is used in the simulation. The steel material is modelled as solid elements with one-eight aspect ratio between the element size and its thickness. The double sine waves equation is used to generate the initial imperfection in the corrugated web. The nonlinear geometry deformation, which is essential in capturing the buckling behavior, is considered using the 2nd order analysis in 3D-NLFEA. A comparison with the carried out experimental test in the laboratory showed that the peak prediction from the analytical model was in good agreement. Furthermore, using the double sine waves equation as the initial imperfection can closely predict the buckling mode and shapes of the corrugated web I-girder as obtained from the experimental test

CALCULATION OF PAVEMENT PERMANENT DEFORMATION USING PERZYNA’S ELASTO-VISCOPLASTIC MODEL

In this work, a method for calculation of pavement permanent deformation due to traffic loading is presented. The mechanics behavior of asphalt concrete layer is considered as Perzyna’s elasto-viscoplastic material. The pavement permanent deformation is incrementally calculated using nonlinear finite element method. Model parameters are determined using Hamburg Wheel Tracking Test result.In this work, a method for calculation of pavement permanent deformation due to traffic loading is presented. The mechanics behavior of asphalt concrete layer is considered as Perzyna’s elasto-viscoplastic material. The pavement permanent deformation is incrementally calculated using nonlinear finite element method. Model parameters are determined using Hamburg Wheel Tracking Test result

Buckling and postbuckling of an imperfect plate subjected to the shear load

The stability analysis of an imperfect plate subjected to the shear load is presented. To solve this problem, a specialized computer program based on FEM has been created. The nonlinear finite element method equations are derived from the variational principle of minimum of total potential energy. To obtain the nonlinear equilibrium paths, the Newton-Raphson iteration algorithm is used. Corresponding levels of the total potential energy are defined. Special attention is paid to the influence of imperfections on the post-critical buckling mode. Obtained results are compared with those gained using ANSYS system