Search results for "Multilayer structure"
showing 4 items of 4 documents
Size-filtering effects by stacking InAs/InP (001) self-assembled quantum wires into multilayers
2002
Multilayer structure containing vertically stacked InAs/InP self-assembled quantum wires have been successfully grown by molecular-beam epitaxy. The influence of the InP spacer layer thickness on the structural and optical properties of the wire superlattice has been studied by means of transmission electron microscopy and photoluminescence. The coherent propagation of the strain field in the sample with a 5-nm-thick spacer determines by a size filtering effect a good homogeneity and uniformity of the wire stacks, and hence a good optical quality. The exciton recombination dynamics in the wire superlattice cannot be related to thermal escape of carriers out to the barriers, as occurs in sin…
A beam finite element for magneto-electro-elastic multilayered composite structures
2012
Abstract A new finite element based upon an elastic equivalent single-layer model for shear deformable and straight magneto-electro-elastic generally laminated beam is presented. The element has six degrees of freedom represented by the displacement components and the cross-section rotation of its two nodes. The magneto-electric boundary conditions enter the discrete problem as work-equivalent forces and moments while the electro-magnetic state characterization constitutes a post-processing step. The element possesses the superconvergence property for the static problem of beams with uniform cross-section and homogenous material properties along the beam axis direction. Moreover, it is free…
Heterogeneous structures studied by an interphase elasto-plastic damaging model
2013
Heterogeneous materials present a mechanical response strongly dependent on the static and kinematic phenomena occurring in the constituents and at their joints. At the mesoscopic level the interaction between the units is simulated by mean of apposite mechanical devices such as the zero thickness interface model where contact tractions and displacement discontinuities are the primary static and kinematic variables respectively. In heterogeneous materials the response also depends on joint internal stresses. The introduction of internal stresses brings to the interphase model or an enhancement of the classical zero-thickness interface. With the term 'interphase' we shall mean a layer separa…
Characterization of impervious layers using scale models and an inverse method
2009
We describe a novel procedure that uses an inverse method to determine unknown parameters for impervious layers used in multilayer structures. The proposed model of the multilayer structure is limited to an ideal double plate separated by an unbonded, fibrous, sound-absorbing material. Experimental data were obtained by nearfield acoustic holography for the calculation of the transmission loss of various multilayer structures mounted in a window in a wooden box designed specifically for this purpose. We used the Trochidis and Kalaroutis forecast model of acoustic insulation for multilayer structures, which is based on a spatial Fourier transform. The experimental pressure and velocity data …