Numerical study of the plasticity effect on the behavior of short steel columns filled with concrete loaded axially

For more than two decades, the construction technique using concrete filled steel tube (CFST) has been widespread throughout the world. Indeed, it has been demonstrated that the use of normal or high strength concrete, confined in a steel tube of circular shape can considerably improve its ductility as well as its load capacity, owing to the combination of the qualities of the two constituent materials; these tubes have an effortless execution, indeed, the concrete used in the CFST does not require formwork nor reinforcement, a durability of the two materials as well as a good behavior to fire, which was the effect desired at the origin of their elaboration. In this paper, we study the axial compression behavior of short circular steel tubes filled with concrete; their modelling will be performed using the ABAQUS/Standard calculation program. In order to accurately determine their behavior, we have created different models. Indeed, these tubes will be modeled in order to simulate different plastic state behaviours, namely a perfect elasto-plastic state, an elasto-plastic state with multilinear strain hardening and a third elasto-plastic behavior with strain hardening proposed by Tao et al. The tested columns consist of circular hollow sections which are designated in the literature as Concrete Filled Steel Tube (CFST), for which we vary the diameters, heights as well as the wall thicknesses, and which we fill with concrete of different qualities. The compressive behavior, including ultimate loads, confinement, load-deflection relationship and failure modes, was obtained from numerical models and compared with experimental and theoretical results based on Eurocode 4. All these results showed a good agreement and a satisfactory correlation, allowing us to assume that a correct modelling can be sufficient to simulate the behavior of CFST

Synergetic and sliding mode controls of a PMSM: A comparative study

International audiencePermanent magnet Synchronous machines (PMSM) provide high efficiency, compact size, robustness, lightweight, and low noise; these features qualify them as the best suitable machine for medical applications. Without forgetting its simple structure, high thrust, ease of maintenance, and controller feedback, make it possible to take the place of steam catapults in the future. This paper presents the synergetic control approach for PMSM. Synergetic control theory is purely analytical and is based on nonlinear models, provide asymptotic stability. This approach allows to reduce the chattering phenomenon. To verify the performance characteristics of this approach, we compare it with sliding mode. Simulation results are presented to show the effectiveness of the proposed control method

Design and simulation analysis of outer stator inner rotor DFIG by 2D and 3D finite element methods

In this paper, a time stepping 2D and 3D FEM is performed for modeling and analysis interior rotor DFIG .The finite element method currently represents the state-of-the-art in the numerical magnetic field computation relating to electrical machines. FEM is a numerical method to solve the partial differential equations (PDE) that expresses the physical quantities of interest, in this case Maxwell’s equations. This will result in a more accurate result compared to analytical modeling, which can be regarded as a simplification of the PDE. FEM analysis is used for transient mode, magnetic field calculation, the magnetic flux density and vector potential of machine is obtained. In this model we including, non linear material characteristics, eddy current effect, torque-speed characteristics, ambient temperature effect and magnetic analysis are investigate

Dynamic Design and Simulation Analysis of Permanent Magnet Motor in Different Scenario of fed Alimentation

This paper deals with investigation on non purely sinusoidal input supply analysis of line-start PMM using finite element analysis (FEA), in the present times a greater awareness is generated by the problems of harmonic voltages and currents produced by non-linear loads like the power electronic converters. These combine with non-linear nature of PMM core and produce severe distortions in voltages and currents and increase the power loss, additional copper losses due to harmonic currents, increased core losses, electromagnetic interference with communication circuits, efficiency reduction, increased in motors temperature and torque oscillations. In addition to the operation of PMM on the sinusoidal supplies, the harmonic behavior becomes important as the size and rating of the PMM increases. Thus the study of harmonics is of great practical significance in the operation of PMM

Stochastic Estimation Methods for Induction Motor Transient Thermal Monitoring Under Non Linear Condition

<b>The induction machine, because of its robustness and low-cost, is commonly used in the industry. Nevertheless, as every type of electrical machine, this machine suffers of some limitations. The most important one is the working temperature which is the dimensioning parameter for the definition of the nominal working point and the machine lifetime. Due to a strong demand concerning thermal monitoring methods appeared in the industry sector. In this context, the adding of temperature sensors is not acceptable and the studied methods tend to use sensorless approaches such as observators or parameters estimators like the extended Kalman Filter (EKF). Then the important criteria are reliability, computational cost ad real time implementation.</b