Interfacial characteristics of hybrid nanocomposite under thermomechanical loading

2017 ◽  
Vol 26 (3-4) ◽  
pp. 95-103 ◽  
Author(s):  
Vijay Choyal ◽  
Shailesh I. Kundalwal
Keyword(s):  
Axial Stress ◽  
Interfacial Shear Stress ◽  
Transversely Isotropic ◽  
Hybrid Nanocomposite ◽  
Shear Lag ◽  
Shear Lag Model ◽  
Three Phase ◽  
Lag Model ◽  
Interfacial Characteristics ◽  
Good Agreement

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.

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

1994 ◽  
Vol 365 ◽  
Author(s):  
Chun-Hway Hsueh
Keyword(s):  
Analytical Solutions ◽  
Volume Fraction ◽  
Axial Stress ◽  
Stress Transfer ◽  
Radial Dependence ◽  
Shear Lag ◽  
Shear Lag Model ◽  
The Matrix ◽  
Lag Model ◽  
Loaded Fiber

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.

Shear Lag Model for Regularly Staggered Short Fuzzy Fiber Reinforced Composite

2014 ◽  
Vol 81 (9) ◽  
Author(s):  
S. I. Kundalwal ◽  
M. C. Ray ◽  
S. A. Meguid
Keyword(s):  
Polymer Matrix ◽  
Interfacial Shear Stress ◽  
Stress Transfer ◽  
Fiber Reinforced ◽  
Shear Lag ◽  
Fiber Reinforced Composite ◽  
Shear Lag Model ◽  
Transfer Characteristics ◽  
Reinforced Composite ◽  
Lag Model

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.

Analysis of Stresses for Cross-Ply Laminates with Multiple Matrix Cracks under Bending

2011 ◽  
Vol 311-313 ◽  
pp. 256-259
Author(s):  
Qing Dun Zeng ◽  
Mao Hua Ouyang
Keyword(s):  
Finite Element ◽  
Approximate Solutions ◽  
Stress Distributions ◽  
Shear Lag ◽  
Transverse Cracks ◽  
Shear Lag Model ◽  
Matrix Cracks ◽  
Variational Solutions ◽  
Lag Model ◽  
Good Agreement

On the basis of the shear-lag theory, a layered shear-lag model was established to study the stress redistributions of cross-ply laminates with multiple transverse matrix cracks in the 90º ply under bending. The present results are in a good agreement with variational solutions and finite element results and show that approximate solutions of stress distributions for cross-ply laminates with transverse cracks under bending can be obtained by using a shear-lag method. The present paper therefore affords a new way or method for studying the stress redistributions and failure mechanism for cross-ply laminates with flaws under bending.

scholarly journals Analytical Study of a Pin-Loaded Hole in Unidirectional Laminated Composites With Triangular and Circular Fibers

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Hossein Robati ◽  
Mohammad Mahdi Attar
Keyword(s):  
Composite Structures ◽  
Analytical Study ◽  
Glass Fibers ◽  
Stress Fields ◽  
Shear Lag ◽  
Stress Concentrations ◽  
Equilibrium Equations ◽  
Shear Lag Model ◽  
Lag Model ◽  
Good Agreement

The problem of stress concentrations in the vicinity of pin-loaded holes is of particular importance in the design of multilayered composite structures made of triangular or circular glass fibers. It is assumed that all of the fibers in the laminate lie in one direction while loaded by a force p0 at infinity, parallel to the direction of the fibers. According to the shear lag model, equilibrium equations are derived for both types of fibers. A rectangular arrangement is postulated in either case. Upon the proper use of boundary and bondness conditions, stress fields are derived within the laminate, along with the surrounding pinhole. The analytical results are compared to those of the finite element values. A very good agreement is observed between the two methods. According to the results, composite structures made of triangular glass fibers result in lower values of stress concentrations around the pin, as opposed to those of circular glass fibers.

Cohesive-Shear-Lag Modeling of Interfacial Stress Transfer Between a Monolayer Graphene and a Polymer Substrate

2015 ◽  
Vol 82 (3) ◽  
Author(s):  
Guodong Guo ◽  
Yong Zhu
Keyword(s):  
Fracture Toughness ◽  
Shear Stress ◽  
Interfacial Shear Stress ◽  
Stress Transfer ◽  
Interfacial Shear ◽  
Interfacial Stress ◽  
Monolayer Graphene ◽  
Shear Lag ◽  
Shear Lag Model ◽  
Lag Model

Interfacial shear stress transfer of a monolayer graphene on top of a polymer substrate subjected to uniaxial tension was investigated by a cohesive zone model integrated with a shear-lag model. Strain distribution in the graphene flake was found to behave in three stages in general, bonded, damaged, and debonded, as a result of the interfacial stress transfer. By fitting the cohesive-shear-lag model to our experimental results, the interface properties were identified including interface stiffness (74 Tpa/m), shear strength (0.50 Mpa), and mode II fracture toughness (0.08 N/m). Parametric studies showed that larger interface stiffness and/or shear strength can lead to better stress transfer efficiency, and high fracture toughness can delay debonding from occurring. 3D finite element simulations were performed to capture the interfacial stress transfer in graphene flakes with realistic geometries. The present study can provide valuable insight and design guidelines for enhancing interfacial shear stress transfer in nanocomposites, stretchable electronics and other applications based on graphene and other 2D nanomaterials.

Longitudinal Relaxation of a Thermally Stressed Fiber by Prismatic Dislocation Punching

1990 ◽  
Vol 209 ◽  
Author(s):  
David C. Dunand ◽  
Andreas Mortensen
Keyword(s):  
Fiber Length ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Longitudinal Stress ◽  
Shear Lag ◽  
Shear Lag Model ◽  
Cylindrical Fiber ◽  
The Matrix ◽  
Lag Model ◽  
Critical Fiber Length

ABSTRACTA model predicting the number of prismatic loops dislocation punched at the ends of a cylindrical fiber by thermal mismatch stresses is presented and compared to another based on a mismatching ellipsoid. The longitudinal stress in the fiber and the interfacial shear stress are derived by adapting a shear-lag model to the plastic portion of the interface. In certain cases, the central part of the fiber is strained by plastic and elastic interfacial shear until it exhibits no mismatch with the matrix. This leads to a critical fiber length above which the number of punched loops is constant.

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