scholarly journals Stress Transfer from Axially Loaded Fiber to Matrix in a Microcomposite

1994 ◽  
Vol 365 ◽  
Author(s):  
Chun-Hway Hsueh

ABSTRACTThe shear lag model has been used extensively to analyze the stress transfer in a singe fiberreinforced composite (i.e., a microcomposite). To achieve analytical solutions, various simplifications have been adopted in the stress analysis. Questions regarding the adequacy of those simplifications are discussed in the present study for the following two cases: bonded interfaces and frictional interfaces. Specifically, simplifications regarding (1) Poisson's effect, and (2) the radial dependences of axial stresses in the fiber and the matrix are addressed. For bonded interfaces, the former can be ignored, and the latter can generally be ignored. However, when the volume fraction of the fiber is high, the radial dependence of the axial stress in the fiber should be considered. For frictional interfaces, the latter can be ignored, but the former should be considered; however, it can be considered in an average sense to simplify the analysis. Comparisons among results obtained from analyses with various simplifications are made.

2004 ◽  
Vol 19 (12) ◽  
pp. 3633-3640 ◽  
Author(s):  
Ho J. Ryu ◽  
Kyung H. Chung ◽  
Seung I. Cha ◽  
Soon H. Hong

The creep behaviors of 20 vol% SiCw/2124Al, extruded with different ratios, and SiCp/2124Al, reinforced with 10–30 vol% SiC particles, were investigated to clarify the effects of aspect ratio, alignment, and volume fraction of reinforcement on creep deformation. The effective stresses on the matrix of SiC/Al composites are calculated based on the generalized shear-lag model. The minimum creep rates of SiCw/2124Al extruded with different ratios and SiCp/2124Al reinforced with different volume fractions of SiC particles are found to be similar under a same effective stress on matrix, which is calculated by the generalized shear-lag model. The subgrain sizes in matrices of crept SiC/Al composites are dependent on the effective stress on matrix but not on the applied stress on the composite. It is suggested that the role of SiC reinforcements is to increase the creep resistance of SiC/Al composite by reducing the effective stress on matrix.


2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Quan Yuan ◽  
Mengjun Wu

An improved shear-lag model is proposed to investigate the mechanism through which the surface effect influences the stress transfer of multilayered structures. The surface effect of the interlayer is characterized in terms of interfacial stress and surface elasticity by using Gurtin–Murdoch elasticity theory. Our calculation result shows that the surface effect influences the efficiency of stress transfer. The surface effect is enhanced with decreasing interlayer thickness and elastic modulus. Nonuniform and large residual surface stress distribution amplifies the influence of the surface effect on stress concentration.


AIAA Journal ◽  
2019 ◽  
Vol 57 (5) ◽  
pp. 2123-2133 ◽  
Author(s):  
Santosh Kapuria ◽  
Bhabagrahi Natha Sharma ◽  
A. Arockiarajan

1996 ◽  
Vol 5 (5) ◽  
pp. 096369359600500 ◽  
Author(s):  
John A. Nairn ◽  
H. Daniel Wagner

A shear-lag analysis based on energy is used to predict the amount of debonding that occurs when a fiber fragment breaks into two fragments. The shear-lag analysis reproduces all features of more sophisticated analyses. A drawback of the shear-lag analysis, however, is that it depends on an unknown parameter which can be expressed in terms of an effective fiber volume fraction. If the effective fiber volume fraction can be determined (by experiments or by advanced stress analyses), the shear-lag model can be used to interpret debonding experiments.


2014 ◽  
Vol 81 (9) ◽  
Author(s):  
S. I. Kundalwal ◽  
M. C. Ray ◽  
S. A. Meguid

In this article, we investigate the stress transfer characteristics of a novel hybrid hierarchical nanocomposite in which the regularly staggered short fuzzy fibers are interlaced in the polymer matrix. The advanced fiber augmented with carbon nanotubes (CNTs) on its circumferential surface is known as “fuzzy fiber.” A three-phase shear lag model is developed to analyze the stress transfer characteristics of the short fuzzy fiber reinforced composite (SFFRC) incorporating the staggering effect of the adjacent representative volume elements (RVEs). The effect of the variation of the axial and lateral spacing between the adjacent staggered RVEs in the polymer matrix on the load transfer characteristics of the SFFRC is investigated. The present shear lag model also accounts for the application of the radial loads on the RVE and the radial as well as the axial deformations of the different orthotropic constituent phases of the SFFRC. Our study reveals that the existence of the non-negligible shear tractions along the length of the RVE of the SFFRC plays a significant role in the stress transfer characteristics and cannot be neglected. Reductions in the maximum values of the axial stress in the carbon fiber and the interfacial shear stress along its length become more pronounced in the presence of the externally applied radial loads on the RVE. The results from the newly developed analytical shear lag model are validated with the finite element (FE) shear lag simulations and found to be in good agreement.


2004 ◽  
Vol 261-263 ◽  
pp. 1421-1426
Author(s):  
Hong Gun Kim ◽  
Sung Mo Yang ◽  
Hong Gil Noh ◽  
Dong Joo Lee

An investigation of composite mechanics to investigate stress transfer mechanism accurately, a modification of the conventional shear lag model was attempted by taking fiber end effects into account in discontinuous composite materials. It was found that the major shortcoming of conventional shear lag theory is not being able to provide sufficiently accurate strengthening predictions in elastic regime when the fiber aspect ratio is very small. The reason is due to its neglect of stress transfer across the fiber ends and the stress concentrations that exist in the matrix regions near the fiber ends. To overcome this shortcoming, a more simplified shear lag model introducing the stress concentration factor which is a function of several variables, such as the modulus ratio, the fiber volume fraction, the fiber aspect ratio, is proposed. It is found that the modulus ratio is the most essential parameter among them. Thus, the stress concentration factor is expressed as a function of modulus ratio in the derivation. It is also found that the proposed model gives a good agreement with finite element results and has the capability to correctly predict the variations of the internal quanitities.


2007 ◽  
Vol 334-335 ◽  
pp. 333-336
Author(s):  
Souta Kimura ◽  
Jun Koyanagi ◽  
Takayuki Hama ◽  
Hiroyuki Kawada

A shear-lag model is developed to predict the stress distributions in and around an isolated fiber in a single-fiber polymer matrix composite (PMC) subjected to uniaxial tensile loading and unloading along the fiber direction. The matrix is assumed to be an elasto-plastic material that deforms according to J2 flow theory. The stress distributions are obtained numerically and compared with a different shear-lag model that employs total strain theory as a constitutive equation of the matrix material. An effect of the difference between the models on the derived stress state is discussed.


2017 ◽  
Vol 26 (3-4) ◽  
pp. 95-103 ◽  
Author(s):  
Vijay Choyal ◽  
Shailesh I. Kundalwal

AbstractIn this work, an improved shear lag model was developed to investigate the interfacial characteristics of three-phase hybrid nanocomposite which is reinforced with microscale fibers augmented with carbon nanotubes on their circumferential surfaces. The shear lag model accounts for (i) radial and axial deformations of different transversely isotropic constituents, (ii) thermomechanical loads on the representative volume element (RVE), and (iii) staggering effect of adjacent RVEs. The results from the current newly developed shear lag model are validated with the finite element simulations and found to be in good agreement. This study reveals that the reduction in the maximum value of the axial stress in the fiber and the interfacial shear stress along its length become more pronounced in the presence of applied thermomechanical loads on the staggered RVEs. The existence of shear tractions along the RVE length plays a significant role in the interfacial characteristics and cannot be ignored.


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