scholarly journals Development and Evaluation of Crack Band Model Implemented Progressive Failure Analysis Method for Notched Composite Laminate

2019 ◽  
Vol 9 (24) ◽  
pp. 5572
Author(s):  
Donghyun Yoon ◽  
Sangdeok Kim ◽  
Jaehoon Kim ◽  
Youngdae Doh
Keyword(s):  
Failure Analysis ◽  
Failure Criterion ◽  
Composite Laminate ◽  
Progressive Failure ◽  
Numerical Results ◽  
Band Model ◽  
Failure Initiation ◽  
Progressive Failure Analysis ◽  
Crack Band ◽  
Tension And Compression

Progressive failure analysis (PFA) is widely used to predict the failure behavior of composite materials. As a structure becomes more complex with discontinuities, prediction of failure becomes more difficult and mesh dependence must be taken into account. In this study, a PFA model was developed using the Hashin failure criterion and crack band model. The failure initiation was evaluated using the Hashin failure criterion. If failure initiation occurred, the damage variables at each failure mode (fiber tension and compression; matrix tension and compression) were calculated according to linear softening degradation and they were then used to derive the damaged stiffness matrix. This matrix reflected a degraded material, and PFA was continued until the damage variables became “1,” implying complete material failure. A series of processes were performed using the finite element method program ABAQUS with a user-defined material subroutine. To evaluate the proposed PFA model, experimental results of open-hole composite laminate tests were compared with the obtained numerical results. The strain behaviors were compared using a digital image correlation system. The obtained numerical results were in good agreement with the experimental ones.

Micromechanical Progressive Failure Analysis of Fiber-Reinforced Composite Using Refined Beam Models

2017 ◽  
Vol 85 (2) ◽  
Author(s):  
I. Kaleel ◽  
M. Petrolo ◽  
A. M. Waas ◽  
E. Carrera
Keyword(s):  
Failure Analysis ◽  
Progressive Failure ◽  
Computational Cost ◽  
Band Model ◽  
Beam Model ◽  
Fiber Reinforced ◽  
Band Theory ◽  
Progressive Failure Analysis ◽  
Crack Band ◽  
The Matrix

An efficient and novel micromechanical computational platform for progressive failure analysis of fiber-reinforced composites is presented. The numerical framework is based on a recently developed micromechanical platform built using a class of refined beam models called Carrera unified formulation (CUF), a generalized hierarchical formulation which yields a refined structural theory via variable kinematic description. The crack band theory is implemented in the framework to capture the damage propagation within the constituents of composite materials. The initiation and orientation of the crack band in the matrix are determined using the maximum principal stress state and the traction-separation law governing the crack band growth is related to the fracture toughness of the matrix. A representative volume element (RVE) containing randomly distributed fibers is modeled using the component-wise (CW) approach, an extension of CUF beam model based on Lagrange type polynomials. The efficiency of the proposed numerical framework is achieved through the ability of the CUF models to provide accurate three-dimensional (3D) displacement and stress fields at a reduced computational cost. The numerical results are compared against experimental data available in the literature and an analogous 3D finite element model with the same constitutive crack band model. The applicability of CUF beam models as a novel micromechanical platform for progressive failure analysis as well as the multifold efficiency of CUF models in terms of CPU time are highlighted.

scholarly journals Open-Hole 3D Braided Composites Strength Prediction and Stress Analysis

2020 ◽  
Vol 38 (4) ◽  
pp. 889-896
Author(s):  
Shuangqiang Liang ◽  
Chenglong Zhang ◽  
Ge Chen ◽  
Qihong Zhou ◽  
Frank Ko
Keyword(s):  
Failure Analysis ◽  
Progressive Failure ◽  
Failure Criteria ◽  
Element Analysis ◽  
Braided Composite ◽  
Failure Initiation ◽  
Geometry Model ◽  
Progressive Failure Analysis ◽  
3D Braided Composites ◽  
Open Hole

The stress concentration caused by notches is a common engineering issue for composite structure application. 3D braided composite possess excellent damage tolerance compared to common laminates. The tensile properties of 3D braided composite with open-hole and un-notched were experimentally examined. The mechanic properties of 3D braided composite in other directions are predicted using FGM (Fabric Geometry Model) and finite element analysis. The stress distributions around the hole and perpendicular to the loading direction are analyzed based on Abaqus software. The simulation results were compared with Lekhnitskii's analytical study. The open-hole strength of 3D braided composite was predicted respectively using Average stress failure criteria, Point stress failure criteria (PSC), and also the progressive failure analysis based on different failure criteria. The predicted strength results were compared to the experimental values. The results show the PSC predicted strength matched the experiment, while the progressive failure analysis can predict the failure initiation, propagation and final failure mode.

scholarly journals PROGRESSIVE FAILURE ANALYSIS OF HELICOPTER ROTOR BLADE UNDER AEROELASTIC LOADING

Aviation ◽  
2020 ◽  
Vol 24 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Kamran Ahmad ◽  
Yasir Baig ◽  
Hammad Rahman ◽  
Hassan Junaid Hasham
Keyword(s):  
Failure Analysis ◽  
Composite Structures ◽  
Composite Laminate ◽  
Progressive Failure ◽  
Constitutive Relations ◽  
Metal Structure ◽  
Failure Criteria ◽  
Helicopter Rotor ◽  
Progressive Failure Analysis ◽  
Failure Location

Unlike metal structure, composite structures don’t give any clue till the fatal final collapse. The problem is more complicated when applied load on the structure is aeroelastic in nature. Under such loading, composite laminate experiences stresses. The first layer failure happens when stresses in the weakest ply exceed the allowable strength of the laminate. This initial layer-based failure changes overall material characteristics. It is important now to degrade the composite laminate characteristics for the subsequent failure prediction. The constitutive relations are required to be updated by the reduction in stiffness. The rest of the undamaged laminates continue to take the load till the updated strength is reached. In the present work, layer wise progressive failure analysis under aeroelastic loading has been performed by the inclusion of different failure criteria which allow for the identification of the location of the failure. ANSYS APDL environment has been used to model geometry of helicopter rotor. Under the loading conditions, stresses are calculated in the blade. Using stress tensor and failure criteria, failure location and modes have been predicted. It has been found that failure starts at higher speeds and failure starts from the root chord and tend towards the tip chord.

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