Didier Trichet

A statistical approach of temperature calculation in electrical machines

The thermal behavior of electrical machines is studied. The finite element method is used to calculate the magnetic field and temperature distribution inside the machine. The conductors are randomly distributed inside the slots using the Monte-Carlo method. The random distribution of the maximum temperature of the windings is calculated and its limits of confidence are evaluated.

Microscopic and macroscopic electromagnetic and thermal modeling of Carbon Fiber Reinforced Polymer Composites

An electromagnetic and thermal model of carbon fiber reinforced polymer composite material is introduced. This model takes into account the influence of different fiber orientations on the electromagnetic parameters. These parameters are defined in microscopic scale and introduced in finite-element-method model in macroscopic scale.

3-D Simulation of induction heating of anisotropic composite materials

This paper presents a three-dimensional modeling of induction heating of conductive composite materials using the shell elements. These elements are generalized by taking into account the anisotropic behavior of the load. Magnetic fields and temperatures on the composite load are then calculated and compared with experimental measurements.

A magneto-thermal study of a high-speed synchronous reluctance machine

The paper presents a magneto-thermal model of a high-speed synchronous reluctance machine (SRM). Both magnetic and thermal aspects are described using two-dimensional and three-dimensional finite-element method for machine modeling. Additional current harmonics losses, friction losses, and convective exchange coefficients at high speed are estimated. Finally, test results on a 20kW, 20 000rpm SRM are reported and compared with the simulation results

Interaction Between Electromagnetic Field and CFRP Materials: A New Multiscale Homogenization Approach

In this paper, a new multiscale homogenization method is introduced to calculate the field and current distribution inside carbon fiber reinforced polymer composites submitted to an external electromagnetic field. In the microscopic scale, the real structure of the material is taken into account and electromagnetic and electrical equivalent properties are calculated using finite-element method (FEM). In the macroscopic scale, these properties are introduced in an impedance network or in an anisotropic-finite elements method according to the working frequency. The simulating results are in accordance with experimental ones and will allow a better modeling of composites.

Determination of the Electrical Conductivity Tensor of a CFRP Composite Using a 3-D Percolation Model

In this paper a percolation model is used to determinate the electrical conductivity tensor of one layer of carbon fiber composite. For this kind of material, fibers are randomly distributed in the resin. To take into account this distribution a virtual 3-D material model is developed and coupled with a homogenization method to overcome the scale factor problem. The electrical conductivity tensor is then used to simulate the induction heating of a multilayer composite.

Electromagnetic and thermal behaviors of multilayer anisotropic composite materials

A methodology based on shell elements, to study the electromagnetic and thermal behavior of multilayered anisotropic conductive composite materials, is presented. The anisotropic behavior and orientation of each layer of the composite material has been taken into account. The model is validated with experimental results. It is then applied to study the induction heating of composite materials, and also to detect the delamination in these materials

3-D Numerical Modeling of the Thermo-Inductive Technique Using Shell Elements

Thermo-inductive testing is a new technique used for health investigations on different components of automotive and aeronautic industries. In this technique, eddy current deviation around the default creates local heating which can be detected by an infrared camera. The purpose of this work is to develop a 3-D finite-element model as a support tool to study the reliability of the technique. To reduce the number of unknowns, shell elements are introduced to model defects or thin conductive regions. Inspected materials are classified into metallic and composites. Investigations on various parameters of the technique and crack dimensions are performed in order to optimize the method. Experimental and simulation results show that the method is well suited.

Asymptotic calculation of equivalent electromagnetic and thermal properties for composite materials

In this paper, the asymptotic development method is used to study the electromagnetic and thermal behavior of nonhomogeneous materials. The method, widely used in high frequency applications, is adapted to an induction heating system of partially conducting composites. The asymptotic method, based on the spatial filtering of the electromagnetic field, is applied to study the composite materials with periodic structure. The model is valid when the size of the elementary cell is small compared with the dimensions of the system. For large cells, the model gives an average value of field. A local solution is then used to improve the homogenized field. The conditions of using the model for nonperiodic structures are also discussed.

3-D Modeling of Thermo Inductive Non Destructive Testing Method Applied to Multilayer Composite

In this paper, a 3-D modeling of a thermo inductive nondestructing testing (NDT) technique applied to carbon fiber reinforced polymer (CFRP) composite is presented. A multiscale approach is used to calculate the electromagnetic and thermal field distribution. The relevance of the technique is then discussed for different positions of flaws and the optimal frequency is estimated.