Composite materials are popular in aerospace engineering because of their light weight, high strength to weight ratio, stiffness to weight ratio and tailoring properties. However, the modeling of composites is still a challenging task because of its highly uncertain material properties which arise from the manufacturing process.The effect of material uncertainties in failure strength and reliab...

The nonlinear free vibration for viscoelastic cross-ply moderately thick laminated composite plates under considering transverse shear deformation and damage effect is investigated. Based on the Timoshenko-Mindlin theory, strain-equivalence hypothesis, and Boltzmann superposition principle, the nonlinear free vibration governing equations for viscoelastic moderately thick laminated plates with ...

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...

An analytical and numerical solution for the free vibration of laminated polymeric composite plates with different layups is studied in this paper. The governing equations of the laminated composite plates are derived from the classical laminated plate theory (CLPT) and the first-order shear deformation plate theory (FSDT). General layups are evaluated by the assumption of cross-ply and angle-p...

Carbon-fiber-reinforced epoxy-matrix composite (CFRP) laminates with thin plies have strong damage-resistance properties compared standard prepregs. The static and fatigue tensile fracture behavior of cross-ply CFRP should be further studied to establish the applicability thin-ply prepregs for industrial structures. In this study, cross-ply, high-strength polyacrylonitrile (PAN)-based carbon-fi...

The time course of changes in plasma bone turnover markers following an acute bout of resistance training (RT) or plyometrics (PLY) has not been well characterized. This study is the first to compare the acute response of bone formation and resorption markers to a single bout of RT or PLY. Using a partially randomized, cross-over study design, 12 recreationally active men, aged 43 ± 5 yr, each ...

A comprehensive approach for the analysis and design of pultruded FRP beams in bending is presented. It is shown that the material architecture of pultruded FRP shapes can be efficiently modeled as a layered system. Based on the information provided by the material producers, a detailed procedure is preserited for the computation of fiber volume fraction (V r) of the constituents, including fib...

This paper developed three-dimensional (3D) Finite Element Analysis (FEA) to investigate the effect of fibre lay-up on the initiation of failure of laminated composites in bending. TsaiHill failure criterion was applied to identify the critical areas of failure in composite laminates. In accordance with the 3D FEA, unidirectional ([0]16), cross-ply ([0/90]4s) and angle-ply ([±45]4s) laminates m...

Studying the fiber positioning in yarn structure is essential point to understand different characteristics of yarns that counted as alternatives each other. This study explores packing densities single-ply, two-ply and Siro-spun spun have been stated alternative types considering production method or structure. In study, Modal, Tencel, polyethylene teraphtalete, cotton fibers represent micro, ...