In this paper, free vibration analysis of a polymer-based nano-composite beam reinforced by boron-nitride nanotubes and subjected on elastic foundation, is studied. Smooth and defect-free nanotubes with uniform and directly- orientated in matrix are intended. Also, nanotubes’ distribution in the thickness direction of beam is regarded as a uniform distribution of the three different targeted on...

This study introduces the free vibration analysis of multilayered symmetric sandwich Timoshenko beams, made of functionally graded materials with two edge cracked, using the finite element method and linear elastic fracture mechanic theory. The FG beam consists of 50 layers, located symmetrically to the neutral plane, whose material properties distribution change along the beam thickness, accor...

During the past few decades, a significant amount of research has been conducted in the area of non-destructive damage evaluation (NDE) based on changes in dynamic properties of a structure. System Identification and damage detection plays a crucial role in structural dynamics and vibro-acoustic system optimization. The later approach is based on the ‘Modal Analysis” The dynamic behaviors of th...

A nonlocal anisotropic elastic shell model of a microtubule (MT) has been established in this paper. The proposed model exactly expresses the persistence length, the growth rate for buckling and the buckling load which include the small scale effects in a closed form. The predicted results of our model indicate that the length-dependence of the persistence length is sensitive to the small scale...

A Timoshenko beam theory for layered orthotropic beams is presented. The theory consists of a novel combination of three key components: average displacement and rotation variables that provide the kinematic description of the beam, stress and strain moments used to represent the average stress and strain state in the beam, and the use of exact axially-invariant plane stress solutions to calibr...

A finite element model based on the layerwise theory is developed for the analysis of transverse cracking in cross-ply laminated beams. The numerical model is developed using the layerwise theory of Reddy, and the von Kármán type nonlinear strain field is adopted to accommodate the moderately large rotations of the beam. The finite element beam model is verified by comparing the present numeric...

This study presents an analytical solution for free vibration analysis of two-dimensional functionally graded (2D-FG) porous sandwich beams. The equations motion the beam were derived using Hamilton's principle, and then Galerkin method was employed to solve equations. material properties beams vary with thickness length each layer according power-law function. mechanical gradually changed from...