Numerical FEM Analysis Research Articles

Evaluation of Reinforced Concrete Design for an Underground Outlet Manifold in Shanxi Yellow River Diversion Project

In order to verify the design feasibility of the reinforced concrete lining of the outlet manifold in Shanxi Yellow River Diversion Project (YRDP), field investigations on rock mass deformability, in situ stress and hydraulic jacking measurements have been carried out. Based on the results obtained, 3-D FEM numerical analyses have been performed to calculate the stress distribution in a reinforced concrete lining under internal and external water pressure. Furthermore, the initial designed shape and steel ratio of concrete have been modified to satisfy the requirements for the limit crack width design criteria in China and decrease the tensile stress level in concrete. The new steel ratio of reinforced concrete has been calculated on the basis of the numerical results considering the modified shape of the outlet manifold. Both the owner and designer of YRDP have adopted the steel ratio of concrete in the working design and construction of the outlet manifold.

A modeling methodology for finite element mesh generation of multi-region models with parametric surfaces

This paper presents a description of the reorganization of a geometric modeler, MG, designed to support new capabilities of a topological module (CGC) that allows the detection of closed-off solid regions described by surface patches in non-manifold geometric models defined by NURBS. These patches are interactively created by the user by means of the modeler's graphics interface, and may result from parametric–surface intersection in which existing surface meshes are used as a support for a discrete definition of intersection curves. The geometry of realistic engineering objects is intrinsically complex, usually composed by several materials and regions. Therefore, automatic and adaptive meshing algorithms have become quite useful to increase the reliability of the procedures of a FEM numerical analysis. The present approach is concerned with two aspects of 3D FEM simulation: geometric modeling, with automatic multi-region detection, and support to automatic finite-element mesh generation.

Dynamics of multi-body rotors: numerical and experimental FEM analysis of the Scientific Earth Experiment Galileo Galilei Ground

Some small scientific satellites can be regarded as free, multi-body, supercritical and statorless rotors. Classical rotordynamics does not cover the dynamic behaviour and the stability analysis of such rotating systems, being focused on fixed rotors. Attitude dynamics usually deals with single rigid spacecrafts, sometimes equipped with flexible appendices like solar arrays or antennas. The case of the Galileo Galilei Ground (GGG) test facility is herewith analyzed through a numerical and experimental investigation on the dynamic behaviour of a fixed multi-body fast-spinning rotor in order to validate the design approach proposed for Galileo Galilei (GG) spacecraft.

Optimization of the magnetic configuration in EMS-MAGLEV systems

The paper describes a fully automated procedure to optimize the configuration of the magnetic circuit in EMS- MAGLEV systems. The procedure elaborates the results obtained through FEM numerical analyses and automatically re-defines the parameters of the configuration to minimize a suitable objective function, which takes into account both significant electromagnetic quantities and design constraints.

Computation of 3D electromagnetic field and torques in spherical motors

A spherical motor is a novel electromechanical device that has obtained worldwide attention for its attractive advantages. A general analysis of electromagnetic torque in double excited spherical motor has been completed on the calculation of its 3D electromagnetic field distributions. The analysis accounts for the effect of open‐end region in the stator. Double scalar magnetic potentials method has been used in the FEM numerical analysis. On the computation results, the other electromagnetic parameters can be calculated, which will be very significant in the design and performance prediction of the spherical motor. The calculation results indicate that the device is capable of continuous speed control and efficient torque production.

FEM calculation of the LSM propulsion force in EMS-MAGLEV trains

The paper describes a procedure to determine the propulsion force produced by the linear synchronous motors used in magnetically levitated vehicles of electromagnetic type. The formulation enables to compute the instantaneous value of the force starting from the winding inductances calculated via FEM numerical analysis. The results are compared to the ones obtainable by means of two other procedures implemented in a commercial FEM code and show that, under the same accuracy, the proposed procedure requires less calculation time.

先端複合材料パネルの面内せん断試験法での試験片形状と繊維配置方向の検討

The mechanical in-plane shear testing method for unidirectional CFRP panels has not yet been authorized internationally because of its difficulty in obtaining the uniform shear stress field. A revised picture-frame fixture was proposed to obtain the essential in-plane shear properties along fibers in the previous paper, but the specimen configuration included curved corners which exhibit stress concentration. In the present paper, an attempt was offered to simplify the specimen configuration in order to obtain more uniform shear stress distribution than as seen in the previous specimens which were used in the picture frame fixture. Furthermore, another proposal was offered where the fiber direction was changed perpendicularly in rail shear methods. The experiments on unidirectional CFRP specimens together with the numerical FEM analyses were carried out in order to verify the advantages of such revisions by which the higher true shear strengths were obtained without stress concentration.