Search results for " Transient analysis"
showing 9 items of 9 documents
On the dynamic behavior of piezoelectric active repair by the boundary element method
2011
The dynamic behavior of piezoelectric active repair bonded on cracked structures is analyzed in this article. The boundary element code used to perform the simulations is implemented in the framework of piezoelectricity in order to model the coupling between the elastic and the electric fields, which represents the most important feature of piezoelectric media. The fracture mechanics problem, i.e. the crack, as well as the bonding layer between the host structure and the active patch is modeled by means of the multidomain technique provided with an interface spring model. More particularly, the spring interface model allows considering the bonding layer as a zero-thickness elastic ply char…
Piezoelectric energy harvesting from raised crosswalk devices
2015
This paper presents the main characteristics of an experimental energy harvesting device that can be used to recover energy from the vehicular and pedestrian traffic. The use of a piezoelectric bender devices leads to a innovative approach to Henergy Harvesting. The study focuses on the definition and specification of a mechanical configuration able to transfer the vibration from the main box to the piezoelectric transducer. The piezoelectric devices tested is the commonly used monolithic piezoceramic material lead-zirconate-titanate (PZT). The experimental results estimate the efficiency of this device tested and identify the feasibility of their use in real world applications. The results…
On the transient response of actively repaired damaged structures by the boundary element method
2010
The transient fracture mechanics behavior of damaged structures repaired through active piezoelectric patches is presented in this paper. The analyses have been performed through a boundary element code implemented in the framework of piezoelectricity to take account of the coupling between the elastic and the electric fields, which represents the peculiar feature of piezoelectric media. The multi-domain technique has been also involved to assemble the host structures and the active patches and to model the cracks. Moreover, the patches have been considered elastically bonded to the damaged structure by means of a zero thickness adhesive layer. This has been achieved through the implementat…
Decay Heat Removal and Transient Analysis in Accidental Conditions in the EFIT Reactor
2008
The development of a conceptual design of an industrial-scale transmutation facility (EFIT) of several 100 MW thermal power based on accelerator-driven system (ADS) is addressed in the frame of the European EUROTRANS Integral Project. In normal operation, the core power of EFIT reactor is removed through steam generators by four secondary loops fed by water. A safety-related decay heat removal (DHR) system provided with four independent inherently safe loops is installed in the primary vessel to remove the decay heat by natural convection circulation under accidental conditions which are caused by a loss-of-heat sink (LOHS). In order to confirm the adequacy of the adopted solution for decay…
A boundary element model for piezoelectric dynamic strain sensing of cracked structures
2011
A piezoelectric sensor model is here presented for the Structural Health Monitoring (SHM) of damaged structures. A boundary element approach based on the Dual Reciprocity BEM is then used to model and analyze the transient response of a piezoelectric patch bonded on a cracked beam. The BE model is written for the piezoelectric problem employing generalized displacements. The multidomain boundary element technique is implemented to model non-homogeneous and cracked configuration, taking contact conditions into account. Analyses have been carried out for an isotropic beam with a piezoelectric strip attached on it and dynamical results for the undamaged structure have been compared with FE res…
A marching-on in time meshless kernel based solver for full-wave electromagnetic simulation
2012
A meshless particle method based on an unconditionally stable time domain numerical scheme, oriented to electromagnetic transient simulations, is presented. The proposed scheme improves the smoothed particle electromagnetics method, already developed by the authors. The time stepping is approached by using the alternating directions implicit finite difference scheme, in a leapfrog way. The proposed formulation is used in order to efficiently overcome the stability relation constraint of explicit schemes. In fact, due to this constraint, large time steps cannot be used with small space steps and vice-versa. The same stability relation holds when the meshless formulation is applied together w…
Evaluation of radiated EMI in 42 V vehicle electrical systems by FDTD simulation
2007
In this paper a full 3D numerical scheme, based on the finite difference time domain method, is used to predict the electromagnetic radiated interference generated by 42 V vehicle power electronic driven electrical loads. An experimental set-up has been arranged on purpose in order to validate the proposed simulation tool. To this aim, the features of a semi-anechoic electromagnetic chamber have been exploited in order to operate in a shielded test site for the measurement of near field radiated emissions. Two different three-dimensional geometrical configurations of realistic vehicle installations of the loads, are studied. A comparative analysis among measured and computed results is perf…
TRANSIENT AND FREE-VIBRATION ANALYSIS OF LAMINATED SHELLS THROUGH THE DISCONTINUOUS GALERKIN METHOD
2022
This paper presents a novel formulation for linear transient and free-vibration analysis of laminated shell structures based on Interior Penalty discontinuous Galerkin (DG) methods and variable-order through-the-thickness kinematics, whose combined use allows solving the shell problem with high-order accuracy throughout both the shell thickness and the shell modelling domain. The shell geometry is described via a generic system of curvilinear coordinates using either an analytical or a NURBS-based parametrization of the shell mid surface; the formulation also allows for the presence of cut-outs, which are implicitly represented by means of a level set function. After deriving the governing …