Search results for "Finite element method"
showing 10 items of 746 documents
Essential Measurements for Finite Element Simulations of Magnetostrictive Materials
2018
We discuss which magnetoelastic material properties are essential to measure in order to model magnetostrictive materials in finite element simulations. We show knowing the magnetic constitutive relation is sufficient, if the elastic behavior without magnetic field is known a priori. We neglect hysteresis, and our starting point is to express the effect of mechanical deformation on the magnetic constitutive relation with a small strain tensor and magnetic flux density. It follows that the (energetic) state of a magnetostrictive material is independent of its history. Then, a certain choice of history allows us to keep magnetism and elasticity distinct. We demonstrate with open source softwa…
A Magnetohydrodynamic Generator for Marine Energy Harvesting
2018
In this article we present an approach to the description of Magneto-hydrodynamic Marine Energy Harvesting (MHMEH) system. Preliminarly, a general discussion on the principle of operation is presented. Successively, in order to move beyond the analytical model, a 3-D MHD modeling tool and a Runge Kutta method based solver are presented and they are used to investigate an alternative MHD solutions. Some numerical analyses are given.
Numerical study for a new methodology of flaws detection in train axles
2013
Train loads and travel speeds have increased over time, requiring more efficient non-destructive inspection methods. Railway axles are critical elements; despite being designed to last more than 20 years several cases of premature failure have been recorded. Train axles are inspected regularly, but the limits associated to the traditional inspection technologies create a growing interest towards new solutions. Here a novel non-destructive inspection method of in-service axles based on non-contact data collection is presented. The propagation of surface waves, generated by a thermo-elastic laser source, is investigated using a finite element method based on dynamic explicit integration. Coup…
Deformation and failure of MXene nanosheets
2020
This work is aimed at the development of finite element models and prediction of the mechanical behavior of MXene nanosheets. Using LS-Dyna Explicit software, a finite element model was designed to simulate the nanoindentation process of a two-dimensional MXene Ti3C2Tz monolayer flake and to validate the material model. For the evaluation of the adhesive strength of the free-standing Ti3C2Tz-based film, the model comprised single-layered MXene nanosheets with a specific number of individual flakes, and the reverse engineering method with a curve fitting approach was used. The interlaminar shear strength, in-plane stiffness, and shear energy release rate of MXene film were predicted using th…
Micromechanisms of load transfer in a unidirectional carbon fibre–reinforced epoxy composite due to fibre failures. Part 1: Micromechanisms and 3D an…
2006
This study gives a detailed analysis of load distributions around fibre breaks in a composite and the mechanisms involved in load transfer. In contrast to other studies reported in the literature the analysis considers different configurations of composite damage from the failure of a few fibres to the failure of many. The model considers the elastic case with and without debonding at the broken fibre/matrix interface. In this way, the usual limitations of the finite element approach are overcome so as to take into account the numbers and interactions of broken fibres whilst maintaining an evaluation of the various fields involved, in particular the stress fields associated with fibre failu…
Improving the Efficiency of NFC Systems Through Optimizing the Sintered Ferrite Sheet Thickness Selection
2020
The reduction of embedded portable devices involves a magnetic field interference problem when it integrates near field communication (NFC) due to the presence of conductive surfaces, such as ground planes, batteries, or metallic enclosures. Flexible sintered ferrite sheets (FSFS) represent an interesting shielding solution to prevent electromagnetic interferences problems related to NFC, thanks to their ability to control the magnetic flux. The characterization of FSFS effectiveness is analyzed as a function of the sheet thickness in this contribution. This is performed with the aim of determining which is the optimum thickness value to retune an NFC antenna to its original operation frequ…
Electromechanical Impedance Method to Assess the Stability of Dental Implants
2017
In this paper we illustrate the application of the electromechanical impedance (EMI) technique, popular in structural health monitoring, to assess the stability of dental implants. The technique consists of bonding a piezoelectric transducer to the element to be monitored. When subjected to an electric field, the transducer induces low to high frequency structural excitations which, in turn, affect the transducer's electrical admittance. As the structural vibrations depend on the mechanical impedance of the host structure (in this case the implant secured to the jaw), the measurement of the PZT's admittance can infer the progress of the osseointegration process. In the study presented in th…
The modeling of dissimilar welding of immiscible materials by using a phase field method
2013
A multiphysical model of high power beam welding of immiscible materials is developed to explain the influence of operational parameters and materials properties on resulting morphology by simultaneous solving of heat transfer, fluid flow and mass transfer problems. The introduction of phase field description of the interface motion between two immiscible liquids allows obtaining the cartography of melted zone in function of two key-parameters: the position of heat source relatively to joint line and the welding speed. Due to the short thermal cycle limiting mass transfer, high power beam welding techniques may result in very inhomogeneous melted zones. In this study, the interest is paid t…
Using a neural network for predicting the average grain size in friction stir welding processes
2009
In the paper the microstructural phenomena in terms of average grain size occurring in friction stir welding (FSW) processes are focused. A neural network was linked to a finite element model (FEM) of the process to predict the average grain size values. The utilized net was trained starting from experimental data and numerical results of butt joints and then tested on further butt, lap and T-joints. The obtained results show the capability of the AI technique in conjunction with the FE tool to predict the final microstructure in the FSW joints.
Continuous dynamic recrystallization phenomena modelling in friction stir welding of aluminium alloys: A neural-network-based approach
2007
The current paper focuses on the continuous dynamic recrystallization phenomena (CDRX) occurring in friction stir welding processes of AA6082 T6 aluminium alloys. In particular, in order to predict the average grain size, a properly trained neural network is linked to the finite element method (FEM) model of the process. The utilized net, which takes as inputs the local values of strain, strain rate, and temperature, was trained starting from experimental data and numerical results. The obtained results show the capability of the artificial intelligence (AI) technique in conjunction with the FE tool to predict the final microstructure in the joint section.