scholarly journals Influence of Fiber Distribution and Interfacial Strength on Transverse Compressive Strength of Unidirectional Composites

2019 ◽  
Vol 37 (3) ◽  
pp. 443-448
Author(s):  
Xiaopeng Wan ◽  
Guangmeng Yang ◽  
Meiying Zhao
Keyword(s):  
Compressive Strength ◽  
Cohesive Zone Model ◽  
Interfacial Strength ◽  
Interface Element ◽  
Zone Model ◽  
Fiber Distribution ◽  
Interfacial Damage ◽  
Unidirectional Composites ◽  
The Matrix ◽  
Damage Process

The representative volume element(RVE) of the computational micromechanics is established with random fiber distribution being generated by random sequential expansion algorithm. The plasticity of matrix and interfacial decohesion are simulated by using Drucker-Prager model and cohesive zone model respectively. The effects of the random fiber distribution and interfacial strength on the transverse compressive strength of unidirectional composites are analyzed. The results show that the random fiber distribution is a factor to cause the instability of the transverse compressive strength. Meanwhile, the matrix plastic shear damage and non interfacial damage is dominated in compression failure. Therefore, the RVE model without interface element adopted can clearly predict the compressive strength and the damage process of unidirectional composites, which contributes to simplify the modeling without considering the value of interfacial parameters.

The influence of fiber surface profile and roughness to fiber–matrix interfacial properties

2019 ◽  
Vol 54 (11) ◽  
pp. 1441-1452
Author(s):  
Ichsan Setya Putra ◽  
Bentang Arief Budiman ◽  
Poetro Lebdo Sambegoro ◽  
Sigit Puji Santosa ◽  
Andi Isra Mahyuddin ◽  
...  
Keyword(s):  
Composite Structures ◽  
Cohesive Zone Model ◽  
Surface Profile ◽  
Interfacial Strength ◽  
Fiber Surface ◽  
Interfacial Properties ◽  
Zone Model ◽  
The Matrix ◽  
Fiber Matrix ◽  
New Perspective

This work investigates the influence of fiber surface profile and roughness to fiber–matrix interfacial properties. A series of the push-out test is performed using specimens with different fiber surface profile and roughness. Numerical simulation is then carried out by employing a finite element method to fit the experimental data. The model contains an indenter which pushes in a single fiber from the matrix, while the cohesive zone model is applied to represent the interface resulting in force–displacement curves. Our results suggest that continuous cavities formed in graphite-based fiber may not be beneficial to interfacial properties since it can accelerate a debonding process along with the interface. In contrast, scattered cavities on the fiber surface create strong mechanical locking, which increases the interfacial strength. These results broaden the understanding of the surface profile, which would shed light on a new perspective in designing composite structures.

scholarly journals FINITE ELEMENT MODELING OF THE CRACK PROPAGATION IN RC BEAMS BY USING ENERGY APPROACH

2015 ◽  
pp. 211-217
Author(s):  
Shahriar Shahbazpanahi ◽  
Chia Paknahad
Keyword(s):  
Finite Element ◽  
Crack Propagation ◽  
Cohesive Zone Model ◽  
Process Zone ◽  
Mesh Size ◽  
Energy Dissipation Rate ◽  
Energy Approach ◽  
Interface Element ◽  
Zone Model ◽  
Steel Bars

In present study, an interface element with nonlinear spring is used to simulate cohesive zone model (CZM) in reinforced concrete (RC) beam for Mode I fracture. The virtual crack closure technique (VCCT) is implemented to model the propagation of the fracture process zone (FPZ). This model can be calculated the energy release rate by using new method from energy approach. Energy dissipation rate by steel bars is obtained to affect on the crack propagation criterion to implement in finite element method. The numerical results are compared with references result available in the literature. It is observed that the FPZ is increased linearly and then stay constant. It may be due to effect of steel bars or inherent behavior of FPZ. The results show that the proposed model does not depend on mesh size.

Interfacial Debonding and Stress Field Analysis on a Single Fiber Composite Using FEM

2008 ◽  
Author(s):  
Yi Pan ◽  
Assimina A. Pelegri
Keyword(s):  
Stress Field ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Fiber Composite ◽  
Interfacial Strength ◽  
Interfacial Debonding ◽  
Field Analysis ◽  
Zone Model ◽  
Linear Elastic ◽  
Bonded Composite

Fiber debonding in a bundled fiber reinforced polymer composite is investigated by using finite element method and cohesive zone model. Fiber and matrix are modeled as isotropic and linear elastic materials. Fiber/matrix interface is represented by a cohesive zone model governed by the traction-separation law. Effects of interfacial strength on interfacial debonding and stress field in the bundled fiber composite are examined. The stress field of the debonding composite is compared to that of perfectly bonded composite.

scholarly journals Nonlinear XFEM Modeling of Mode II Delamination in PPS/Glass Unidirectional Composites with Uncertain Fracture Properties

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3548
Author(s):  
Damoon Motamedi ◽  
Mahdi Takaffoli ◽  
Abbas S. Milani
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Cohesive Zone Model ◽  
Polyphenylene Sulfide ◽  
Mode Ii ◽  
Zone Model ◽  
Extended Finite Element ◽  
Fracture Properties ◽  
The Matrix ◽  
Mode Ii Loading

Initiation and propagation of cracks in composite materials can severely affect their global mechanical properties. Due to the lower strength of the interlaminar bonding compared to fibers and the matrix, delamination between plies is known to be one of the most common failure modes in these materials. It is therefore deemed necessary to gain more insight into this type of failure to guide the design of composite structures towards ensuring their robustness and reliability during service. In this work, delamination of interlaminar bonding in composite end-notched flexure (ENF) samples was modeled using a newly developed stochastic 3D extended finite element method (XFEM). The proposed numerical scheme, which also incorporates the cohesive zone model, was used to characterize the mode II delamination results obtained from ENF testing on polyphenylene sulfide (PPS)/glass unidirectional (UD) composites. The nonrepeatable material responses, often seen during fracture testing of UD composites, were well captured with the current numerical model, demonstrating its capacity to predict the stochastic fracture properties of composites under mode II loading conditions.

Peeling Rate Dependency of Delamination Behavior of Adhesives

2008 ◽  
Vol 33-37 ◽  
pp. 339-344 ◽  
Author(s):  
Ryota Masuda ◽  
Hirotsugu Inoue ◽  
Kikuo Kishimoto
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Cohesive Zone Model ◽  
Base Material ◽  
Interfacial Strength ◽  
Video Camera ◽  
Zone Model ◽  
Rate Dependency ◽  
Element Analysis ◽  
Rate Region

Adhesives are widely used in our life and industrial world. However, it is difficult to characterize their mechanical properties because those strongly depend on environmental and mechanical conditions such as temperature, humidity or strain rate. In this paper, we focus on the strain rate dependence of the interfacial strength and investigate the interfacial strength by peel tests under several peel rates. The results show that, in lower rate region (under 1.0 mm/s), the interfacial strength is constant and, in transition region (1.0 to 10 mm/s) the interface strength increased with the peel rate. In middle rate region (10 to 103 mm/s), the interfacial strength is constant again. Over 103 mm/s region, the interfacial strength drops and became lower than those in middle rate cases. From the observation of peeling front by a high speed video camera, the deformation behavior of adhesives changes with the peel rate.􀀁Finite element analysis by using cohesive zone model is also conducted, and influence of the rate dependency of adhesive and base material is discussed.

Estimating the Cohesive Zone Model Parameters of Carbon Nanotube–Polymer Interface for Machining Simulations

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Lingyun Jiang ◽  
Chandra Nath ◽  
Johnson Samuel ◽  
Shiv G. Kapoor
Keyword(s):  
Carbon Nanotube ◽  
Cohesive Zone ◽  
Cohesive Zone Model ◽  
Interfacial Strength ◽  
Weight Fraction ◽  
Model Parameters ◽  
Zone Model ◽  
Fe Model ◽  
Polymer Interface ◽  
Two Parameters

The failure mechanisms encountered during the machining of carbon nanotube (CNT) polymer composites are primarily governed by the strength of the CNT–polymer interface. Therefore, the interface should be explicitly modeled in microstructure-level machining simulations for these composites. One way of effectively capturing the behavior of this interface is by the use of a cohesive zone model (CZM) that is characterized by two parameters, viz., interfacial strength and interfacial fracture energy. The objective of this study is to estimate these two CZM parameters of the interface using an inverse iterative finite element (FE) approach. A microstructure-level 3D FE model for nanoindentation simulation has been developed where the composite microstructure is modeled using three distinct phases, viz., the CNT, the polymer, and the interface. The unknown CZM parameters of the interface are then determined by minimizing the root mean square (RMS) error between the simulated and the experimental nanoindentation load–displacement curves for a 2 wt. % CNT–polyvinyl alcohol (PVA) composite sample at room temperature and quasi-static strain state of up to 0.04 s−1, and then validated using the 1 wt. % and 4 wt. % CNT–PVA composites. The results indicate that for well-dispersed and aligned CNT–PVA composites, the CZM parameters of the interface are independent of the CNT loading in the weight fraction range of 1–4%.

The Research of the Effective Moduli of Particle Reinforced Polymer Composites Based on Interface Debonding

2009 ◽  
Vol 413-414 ◽  
pp. 211-217
Author(s):  
Xin Long Chang ◽  
Bin Jian ◽  
Chang Ouyang
Keyword(s):  
Polymer Composites ◽  
Cohesive Zone Model ◽  
Volume Fraction ◽  
Micromechanical Model ◽  
Interface Debonding ◽  
Zone Model ◽  
Effective Moduli ◽  
Reinforced Polymer ◽  
The Matrix ◽  
Particulate Size

This paper is devoted to studying influences of matrix/particle interface debonding and particulate size in micromechanical predictions of the effective moduli of particulate reinforced polymer composites (PRPC). The PRPC is regarded as a three-phase composite that includes the matrix, particle and interphase. The formulation for the effective moduli of the interphase is derived by the cohesive zone model, and combined with the Mori-Tanaka method, the micromechanical model for the effective moduli of the PRPC is formulated with emphasis on the effects of the matrix/particle interface, particulate size and volume fraction. The numerical example shows that the interface debonding, the particulate size and volume fraction have significant influences on the effective moduli of PRPC. The effective moduli of the PRPC can be used to characterize its damage degree.

Numerical Analysis on the Influence of Interface on the Mechanical Behavior of Unidirectional Fiber Composites under Different Loads

2013 ◽  
Vol 575-576 ◽  
pp. 188-193
Author(s):  
Peng Qu ◽  
Yu Xi Jia ◽  
Guo Wei Zhu ◽  
Yun Li Guo ◽  
Xiao Chen Sun
Keyword(s):  
Mechanical Behavior ◽  
Cohesive Zone Model ◽  
Interfacial Strength ◽  
Unidirectional Composite ◽  
Transverse Load ◽  
Failure Behavior ◽  
Zone Model ◽  
Failure Strength ◽  
Multi Scale ◽  
Representative Unit Cell

On the smallest structural scale in the multi-scale structure composites, namely fiber scale, a numerical model was proposed for the analysis on the mechanical properties of unidirectional composites through the representative unit cell (RUC). The progressive method was used to simulate the failure behavior of fiber and matrix, and the debonding between fiber and matrix was characterized by the cohesive zone model (CZM). The failure strength of the unidirectional composite was predicted, and the influence of the interfacial strength on the mechanical behavior of unidirectional composite was discussed. It is shown that fiber dominates the failure strength of the material under the longitudinal load, whereas under the transverse load interfacial properties play an important role in the mechanical behavior of the material. The increase of the interfacial strength can significantly improve the capability of transverse compression and shear resistance.

A Quasi-Static Delamination Model with Rate-Dependent Interface Damage Exposed to Cyclic Loading

2018 ◽  
Vol 774 ◽  
pp. 84-89 ◽  
Author(s):  
Roman Vodička ◽  
Katarína Krajníková
Keyword(s):  
Numerical Analysis ◽  
Cyclic Loading ◽  
Cohesive Zone ◽  
Cyclic Load ◽  
Cohesive Zone Model ◽  
Zone Model ◽  
Interface Damage ◽  
Domain Structures ◽  
Rate Dependent ◽  
Damage Process

A model for numerical analysis of interface damage which leads to interface crack initiationand propagation in multi-domain structures under cyclic loading is considered. Modelling of damagetakes into account various relations between interface stresses and displacement gaps providing theresponse of a cohesive zone model, additionally equipped by a kind of viscosity associated to theevolution of the interface damage. Together with repeating loading-unloading conditions, it makesthis damage process to have a fatigue-like character, where the crack appears for smaller magnitudeof the cyclic load than for pure uploading.

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