scholarly journals Geometric Non-Linear Analysis of Auxetic Hybrid Laminated Beams Containing CNT Reinforced Composite Materials

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3718
Author(s):  
Xu-hao Huang ◽  
Jian Yang ◽  
Iftikhar Azim ◽  
Xing-er Wang ◽  
Xin Ren
Keyword(s):  
Poisson’S Ratio ◽  
Shear Deformation Theory ◽  
Linear Analysis ◽  
Poisson's Ratio ◽  
Perturbation Approach ◽  
Maximum Magnitude ◽  
Reinforced Composite ◽  
Non Linear ◽  
Out Of Plane ◽  
Deflection Theory

In the current work, a novel hybrid laminate with negative Poisson’s ratio (NPR) is developed by considering auxetic laminate which is composed of carbon nanotube-reinforced composite (CNTRC) and fiber-reinforced composite (FRC) materials. The maximum magnitude of out-of-plane NPR is identified in the case of (20 F/20 C/−20 C/20 C) S laminate as well. Meanwhile, a method for the geometric non-linear analysis of hybrid laminated beam with NPR including the non-linear bending, free, and forced vibrations is proposed. The beam deformation is modeled by combining higher-order shear-deformation theory (HSDT) and large deflection theory. Based on a two-step perturbation approach, the asymptotic solutions of the governing equations are obtained to capture the linear and non-linear frequencies and load-deflection curves. Moreover, a two-step perturbation methodology in conjunction with fourth-order Runge–Kutta method is employed to solve the forced-vibration problem. Several key factors, such as CNT distribution, variations in the elastic foundation, and thermal stress, are considered in the exhaustive analysis. Theoretical results for some particular cases are given to examine the geometric non-linearity behavior of hybrid beam with NPR as well as positive Poisson’s ratio (PPR).

scholarly journals Prediction of Pore Size Characteristics of Needle-Punched Nonwoven Geotextiles Subjected to Uniaxial Tensile Strains

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Lin Tang ◽  
Qiang Tang ◽  
Aolai Zhong ◽  
Hanjie Li
Keyword(s):  
Pore Size ◽  
Poisson’S Ratio ◽  
Poisson's Ratio ◽  
Uniaxial Tensile ◽  
Modified Model ◽  
Pore Sizes ◽  
Pore Size Distributions ◽  
Out Of Plane ◽  
Tensile Strains ◽  
The Difference

A modified theoretical model has been proposed to predict the pore size characteristics of nonwoven geotextiles under certain uniaxial tensile strains, considering the difference between the out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles. The pore size distributions (PSDs) and O95 subjected to different levels of uniaxial tensile strains in two needle-punched nonwoven geotextiles have been investigated by the dry sieving test. The variation of the fibre orientation with tensile strains and the corresponding effect on pore sizes has been evaluated by image analysis. The out-of-plane Poisson’s ratio and the in-plane Poisson’s ratio of geotextiles have been examined. A comparison has been made between the predictions of the original and the modified models. It is shown that the modified model can more accurately predict the decreasing rate of the PSDs, O95, and O98 than the original one. The corrected theoretical O95 and O98 under certain strains can provide a reference for the filtration design under engineering strains. The fibres reorientating to the loading direction result in the increase of the directional parameter with increasing tensile strains, which leads to the decrease of pore sizes. The theoretical PSDs are sensitive to the variation of directional parameter.

Second-order statistics of large-amplitude free vibration of a random composite plate

2009 ◽  
Vol 223 (8) ◽  
pp. 1099-1113 ◽  
Author(s):  
P Dash ◽  
B N Singh
Keyword(s):  
Free Vibration ◽  
Composite Plate ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Element Model ◽  
Perturbation Approach ◽  
Deterministic System ◽  
Laminated Composite Plate ◽  
System Equation ◽  
Non Linear

This article addresses the non-linear free vibration stochastic characteristic of a laminated composite plate having random material properties. The transverse shear effects have been included in the system equation in the frame work of higher-order shear deformation theory. The analysis uses Green—Lagrange non-linear strain—displacement relationship to model geometric non-linearity. Direct iteration approach is used to handle deterministic system non-linearity and perturbation approach is presented to handle the randomness in the system properties. Mean and variance of the random natural frequencies have been obtained by employing a C0 isoparametric non-linear finite-element model. Comparisons with the published results show the accuracy of the proposed procedure. A few results covering various features have been presented for a laminated composite plate with different boundary conditions.

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