Vincenzo Minutolo

Distributed Strain Measurement along a Concrete Beam via Stimulated Brillouin Scattering in Optical Fibers

The structural strain measurement of tension and compression in a 4 m long concrete beam was demonstrated with a distributed fiber-optic sensor portable system based on Brillouin scattering. Strain measurements provided by the fiber-optic sensor permitted to detect the formation of a crack in the beam resulting from the external applied load. The sensor system is valuable for structural monitoring applications, enabling the long-term performance and health of structures to be efficiently monitored.

On initial postbuckling of composite plate assemblies by semianalytical procedure

This article deals with the buckling and postbuckling analysis of thin-walled composite structures made of assemblies of plates by means of a semianalytical approach. Both open and closed sections are analyzed. An orthotropic constitutive model is introduced in order to evaluate composite material behavior. The proposed method is shown to be quite efficient from a computational point of view and to offer significative advantages in optimization design procedures over the finite-element method. Some examples are discussed in detail.

BUCKLING OF COMPOSITE PLATES WITH ARBITRARY BOUNDARY CONDITIONS BY A SEMI-ANALYTICAL APPROACH

A semi-analytical approach for the buckling analysis of symmetrically laminated rectangular plates under arbitrary constrains is presented. In the proposed method, the out-of-plane displacement field is assumed to be of a multiplicative form containing two vectors of functions, one being prescribed and the other to be determined, depend on separate variables. As a consequence, one may solve the equilibrium equation analytically, and obtain exact buckling loads for the biaxial compression and different boundary constrains. Several cases of plate buckling under different load combinations are studied, in order to demonstrate the applicability of the proposed approach. The results obtained are compared with the existing ones, where available in analytical form, and approximate results obtained by other numerical methods.

Buckling Analysis of Mindlin Plates Under the Green–Lagrange Strain Hypothesis

In the present paper, the influence of Green–Lagrange nonlinear strain-displacement terms, usually considered negligible under the von Karman hypothesis, on the buckling of isotropic, moderately thick plates and shells, is investigated. The first order shear deformation plate theory is applied and the governing equations, containing nonlinear terms related to both in-plane displacement and out-of-plane rotations usually ignored in the literature, are derived using the principle of minimum of the strain energy. The general Levy type solution method is employed, and exact buckling loads and mode shapes are derived. To verify the accuracy of the solution obtained, comparisons with existing data are first made. Then, through graphics and tables, the effect of the nonlinear strain-displacement terms for a range of boundary and load conditions, variations of aspect ratio, thickness ratio and changes in geometry is presented. The results obtained show that the von Karmans model can sensibly overestimate the critical load for structures characterized by the modes involving comparable in-plane and out-of-plane displacements.

A numerical model based on closed form solution for elastic stability of thin plates

An analytical approach for studying the elastic stability of thin rectangular plates under arbitrary boundary conditions is presented. Because the solution is given in closed-form, the approach can be regarded as exact under the Kirchhoff-Love assumption. The proposed procedure allows us to obtain the buckling load and modal displacements that do not depend on the number of elements adopted in the numerical discretization using, say, the finite element method.