Effect of interfacial debonding on stress transfer in graphene reinforced polymer nanocomposites

2017 ◽  
Vol 27 (7) ◽  
pp. 1105-1127 ◽  
Author(s):  
Meghdad Heidarhaei ◽  
M Shariati ◽  
HR Eipakchi
Keyword(s):  
Shear Stress ◽  
Polymer Nanocomposites ◽  
Applied Stress ◽  
Volume Fraction ◽  
Axial Stress ◽  
Interfacial Shear Stress ◽  
Stress Transfer ◽  
Interfacial Shear ◽  
Zone Model ◽  
Reinforced Polymer

A shear-lag analysis hybrid cohesive zone model is employed to investigate the stress transfer from polymer matrix to the graphene by considering the interfacial damage and debonding phenomena in graphene reinforced polymer nanocomposites. The applied stress can produce three cases for interface treatment: entirely intact, damaged and debonded. By using analytical derived relations, the distribution of axial stress in the graphene and interfacial shear stress at the three-mentioned states is determined and the applied stress to the nanocomposite which leads to damage and debonding initiation at the interface is evaluated. In addition, a sensitivity analysis is performed and the effects of graphene length, interfacial shear strength and graphene volume fraction on the axial stress of graphene, damage and debonding threshold stress along the interface and interfacial shear stress are studied. The results show that after applying a stress called second critical stress, the stress transfer between graphene and matrix at the bulk of graphene length (about 75% of the interface) stops due to debonding of this zone.

Study on the Interfacial Shear Stress Distribution Characteristics of Geotechnical Prestressed Anchorage Structure

2014 ◽  
Vol 919-921 ◽  
pp. 773-776
Author(s):  
Si Feng Zhang ◽  
Long Zhang ◽  
Lin Li ◽  
Xiu Guang Song
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Model Test ◽  
Axial Stress ◽  
Interfacial Shear Stress ◽  
Tensile Load ◽  
Interfacial Shear ◽  
Shear Stress Distribution ◽  
Distribution Characteristics ◽  
Axial Stress Distribution

The ultimate bearing capacity of prestressed anchorage structure is directly related to the interfacial shear stress distribution characteristics of the inner anchorage section. Firstly, the axial stress distribution characteristics of the inner anchorage section for the geotechnical prestressed anchorage structure under tensile load are further studied by indoor similarity model test, and the corresponding fitting formula is established. Based on this result and the force equilibrium conditions of rod body’s micro-segment, the rod body interfacial shear stress distribution characteristics formula is also derived, which fits well with the results of the indoor model test. The research achievements have important significance for the further study on stress distribution characteristics of the inner anchorage section.

An Analytical Model of Stress-Transfer in the Nano-Composites with Debonding Interface

2010 ◽  
Vol 163-167 ◽  
pp. 4599-4603
Author(s):  
Wen Liang Zhu ◽  
Dong Mei Luo ◽  
Ying Long Zhou ◽  
Wen Xue Wang
Keyword(s):  
Shear Stress ◽  
Analytical Model ◽  
Load Transfer ◽  
Polymer Matrix Composites ◽  
Axial Stress ◽  
Interfacial Shear Stress ◽  
Stress Transfer ◽  
Matrix Composites ◽  
Load Transfer Efficiency ◽  
First Time

An improved shear-lag analytical model has been established to study stress transfer in carbon nanotube (CNT) reinforced polymer matrix composites with and without debonding interface. The Poisson’s effect and radial effect of matrix is considered in the model for the first time, and a simplified 2D representative volume element (RVE) is modeled using a four-phase composite composed of matrix, nanotube, bonded, and debonded interfaces in this analysis, and the axial stress for CNT and matrix and interfacial shear stress along the CNT is predicted. The results show that load transfer efficiency in CNT reinforced composites is affected by the debonding length, and the abrupt change of shear stress is existent at the tip of debonding interface.

Stress Distribution of the Composites Reinforced by Slub-Like Short Fibers

2007 ◽  
Vol 353-358 ◽  
pp. 389-391 ◽  
Author(s):  
Li Xin Dong ◽  
Guang Ze Dai ◽  
Xian Feng Zhou ◽  
L.L. Liu ◽  
Qing Qing Ni
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Textile Industry ◽  
Axial Stress ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Reinforced Composites ◽  
Stress Distributions ◽  
Short Fibers ◽  
The Matrix

The model of slub-like short fibers reinforced composites is suggested from the viewpoint of bamboo in the nature and patterns characteristic of simulated silk PET used in textile industry. The stress distributions in the enlarged-end fiber and in the matrix are analyzed. The axial stress in the fiber and matrix is found to increase and the interfacial shear stress decrease with the radius of the enlarged end.

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.

Interfacial micromechanics in model composites using laser Raman spectroscopy

1993 ◽  
Vol 440 (1909) ◽  
pp. 379-398 ◽  
Keyword(s):  
Shear Stress ◽  
Carbon Fibre ◽  
Load Transfer ◽  
Interfacial Shear Stress ◽  
Stress Transfer ◽  
Fibre Surface ◽  
Interfacial Shear ◽  
Laser Raman Spectroscopy ◽  
Laser Raman ◽  
Balance Of Forces

The mechanisms of load transfer in single carbon-fibre/epoxy-resin model composites, are investigated. The composites are subjected to incremental tensile loading and the fibre fragmentation process is continuously monitored. The fibre strain distribution along the fibre fragments is derived through the Raman spectrum of the carbon fibre and its strain dependence. In turn, the interfacial shear stress distribution is evaluated by means of a balance of forces analysis. The effect of fibre surface treatment and fibre modulus upon the stress transfer profiles and the distribution of the interfacial shear stress along the fibre, are also examined. Finally, the importance of parameters, such as, fibre/matrix debonding and interphasial yielding at the vicinity of fibre breaks, is discussed.

Study on Interfacial Shear Stress in RC Beams Strengthened with Prestressed FRP Laminates

2008 ◽  
Vol 33-37 ◽  
pp. 507-514 ◽  
Author(s):  
J.H. Xie ◽  
Pei Yan Huang ◽  
Jun Deng ◽  
Yi Yang
Keyword(s):  
Shear Stress ◽  
Interfacial Shear Stress ◽  
Interfacial Shear ◽  
Bridge Engineering ◽  
Interfacial Stress ◽  
Fiber Reinforced Polymer ◽  
Rc Beams ◽  
Longitudinal Stress ◽  
Reinforced Polymer ◽  
Strengthening Technique

Reinforced concrete (RC) beams strengthened with prestressed fiber-reinforced polymer (FRP) laminates has been proved to be a rather effective strengthening technique in the field of bridge engineering. However, debonding failure usually occurs at the end of FRP in the strengthened beams on releasing the prestress due to the high interfacial shear stress. Analytical method to calculate the interfacial stress is developed in this paper. Through the establishment of mathematical model for the interfacial shear stress, the distribution of the interfacial shear stress and the longitudinal stress of FRP are presented explicitly in an analytical way. Moreover, the maximum prestress level is estimated to prevent debonding failure on releasing the prestress. Finally, experimental results of eight strengthened beams validate the analytical solution for the FRP longitudinal stress.

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