Longitudinal Waves in Fiber-Reinforced Composite at Low and High Frequency Ranges

1977 ◽  
Vol 44 (3) ◽  
pp. 492-494
Author(s):  
C. H. Yew ◽  
P. N. Jogi

A method for studying the behavior of transient longitudinal waves in fiber-reinforced composites, both in high and low frequency ranges, is presented. The results agree well with the solutions obtained by means of the transform method. The dispersive effect of waves to the interpretation of experimental results is also demonstrated by comparing the results obtained from the ultrasonic pulse technique.

1999 ◽  
Vol 66 (3) ◽  
pp. 709-713 ◽  
Author(s):  
R. S. Feltman ◽  
M. H. Santare

A model is presented to analyze the effect of fiber fracture on the anisotropic elastic properties of short-fiber reinforced composite materials. The effective moduli of the material are modeled using a self-consistent scheme which includes the calculated energy dissipated through the opening of a crack in an arbitrarily oriented elliptical inclusion. The model is an extension of previous works which have modeled isotropic properties of short-fiber reinforced composites with fiber breakage and anisotropic properties of monolithic materials with microcracks. Two-dimensional planar composite systems are considered. The model allows for the calculation of moduli under varying degrees of fiber alignment and damage orientation. In the results, both aligned fiber systems and randomly oriented fiber systems with damage-induced anisotropy are examined.


2012 ◽  
Vol 461 ◽  
pp. 338-342 ◽  
Author(s):  
Da Zhao Deng ◽  
Ji Xiang Luo

Based on the Voronoi cell finite element can also reflect fiber reinforced composites interface to take off the layer and matrix crack propagation of the new cell (X-VCFEM cell)[1]. Combined with the re-mesh strategy and grid dynamic technology, Simulated analysis in different inclusion distribution, interface crack propagation for fiber reinforced composites, the results show that for the model with multiple Voronoi cell, The horizontal tension was the largest; For only a Voronoi cell, The size of the horizontal tension was little change.The result was very important reference value for manufacturing process and engineering application of fiber reinforced composite materials.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2559 ◽  
Author(s):  
Yiou Shen ◽  
Jiayi Tan ◽  
Luis Fernandes ◽  
Zehua Qu ◽  
Yan Li

It is well-known that the presence of the delamination in a plant fiber-reinforced composite is difficult to detect. However, the delamination introduces a local flexibility, which changes the dynamic characteristics of the composite structure. This paper presents a new methodology for composite laminate delamination detection, which is based on dynamic mechanical analysis. A noticeable delamination-induced storage modulus reduction and loss factor enhancement have been observed when the delaminated laminate was subjected to a forced oscillation compared to the intact composite laminate. For delamination area of 12.8% of the whole area of the composite laminate, loss factor of approximately 12% increase was observed. For near-to-surface delamination position, loss factor of approximately an 18% increment was observed. The results indicate that the delamination can be reliably detected with this method, and delamination position shows greater influence on the loss factor than that of the delamination size. Further investigations on different frequencies and amplitudes configurations show that the variation of loss factor is more apparently with low frequency as well as the low amplitude.


2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Przemyslaw Lopato ◽  
Grzegorz Psuj ◽  
Barbara Szymanik

The inspection of thin basalt fiber reinforced composite materials was carried out using two nondestructive methods: terahertz time domain imaging and infrared thermography. In order to combine the information about the defects arising in examined materials the inspection results were parametrized. In order to acquire more information content, new approximation based features are proposed. Then, a knowledge extraction based multivariate analysis of preselected features’ vector was carried out. Finally, in order to integrate features distributions of representing different dynamic level of information, a multiresolution wavelet based data fusion algorithm was applied. The results are presented and discussed.


2014 ◽  
Vol 687-691 ◽  
pp. 4244-4247 ◽  
Author(s):  
Lun Li ◽  
Huang Jing

Composite materials help to improve the needs of all types of sports equipment performance and lightweight. In recent years, composite materials used in the race bike, a variety of bats, climbing wall materials and other aspects have made new progress. In this paper introduces the composites and the characteristic of fiber-reinforced composite materials and indicate several examples about fiber reinforced composites in sports equipment applications.


1992 ◽  
Vol 1 (3) ◽  
pp. 096369359200100 ◽  
Author(s):  
K Jayaraman ◽  
K L Reifsnider

Attention has been focused recently on the interphase in continuous, unidirectional fiber-reinforced composites. In this study, the interphase region is modeled as a non-homogeneous, orthotropic material with continuously varying properties. A previously proposed solution method is used to determine the local stress fields in the constituents - the fiber, interphase and matrix - and the results are presented.


Nowadays, Natural Fiber Reinforced composites (NFCs) are emerging to be a good substitute for synthetic fiber reinforced composites as NFCs have many advantages such as low density, high specific strength, recyclability, low cost and good sound abatement quality etc. Among all types of NFCs, a vast study has been done on banana fiber and kenaf fiber reinforced composite. However, only limited work has been done on the banana fabric, kenaf fiber reinforced composite and the effect of their hybridization on mechanical properties. In this paper, an attempt has been made to study the mechanical properties of the banana fabric, kenaf fiber and hybrid banana fabric/kenaf fiber reinforced composites. Effect of alkali treatment on kenaf fiber reinforced composite is discussed in the paper. For the present work, plain-woven banana fabric and randomly oriented kenaf fiber are used as reinforcement while the epoxy resin is used as a matrix. samples are fabricated using hand lay-up and vacuum bagging method. Curing is done at ambient temperature (250C-300C) for 48h. Tensile, impact and hardness test has been performed on a specimen according to ASTM standards. Improvement in mechanical properties is observed after alkali (6% NaOH) treatment on kenaf fiber reinforced composite. Tensile testing behavior of randomly oriented kenaf fiber composite has been studied using Finite element method and results are compared with experimental investigations. This topic present big potential because it seeks to find solution for sustainable development with environmental concerns.


The objective of this study is to investigate the fatigue behavior of sisal fiber reinforced with carbon nanotubes. The hand lay-up technique is used to prepare the composite material samples. The fatigue response of pure polymer matrix, composite material which is prepared by reinforcing a sisal fiber reinforced with a polymer matrix was studied. The effectiveness of nano reinforcement of fatigue response is identified from experiments. Later, the fatigue response of sisal and nano particle reinforced sisal fiber composites (hybrid composite) is identified with irregularities by using finite element based software ANSYS. The elastic properties of sisal fiber reinforced composite and carbon nanotube reinforced composite is estimated by using the principles of Micromechanics and Macro-mechanics. The failure mechanism of polymer, conventional sisal fiber composites and nano filled sisal fiber reinforced composites are identified. The effect of the shape of the irregularities on the fatigue response is also identified from ANSYS software. From the present work, it is observed that, the reinforcement of nano reinforcement has considerable influence on the fatigue response of the resulting composite.


Author(s):  
Md. Koushic Uddin ◽  
Muksit Ahmed Chowdhury ◽  
Sonia Hossain ◽  
Md Zahidul Islam ◽  
Mohammad Shamim Sardar ◽  
...  

Fiber reinforced composite materials are attractive because of their properties such as high toughness, water resistance and can be adapted to meet the specific needs of a variety of applications. Incorporation of natural fibers can reduce the dependency over synthetic fibers. In this work, Jute glass fiber reinforced composites are fabricated by simple hand lay-up technique using epoxy resin as a matrix and various mechanical properties like tensile strength, flexural strength, impact strength and also the water absorption properties of the composite specimens are evaluated and analysed thoroughly. It is observed that incorporation of optimum amount of jute fibre with glass fibre improved mechanical properties can be achieved. Finally cost of composites are analysed and compared.


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