Fatigue of composite materials: damage mechanisms and fatigue-life diagrams

1981 ◽  
Vol 378 (1775) ◽  
pp. 461-475 ◽  
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Composite Materials ◽  
Fatigue Limit ◽  
Fatigue Damage ◽  
Fatigue Resistance ◽  
Composite Laminates ◽  
Fatigue Performance ◽  
Basic Pattern ◽  
Damage Mechanisms

The basic fatigue damage mechanisms in composite laminates are reviewed. Based on these mechanisms a pattern in the fatigue-life diagrams is proposed. Several experimental data are shown to agree with this basic pattern. Fatigue ratio is defined in terms of strains, and fatigue limit is shown to exist for unidirectional, cross-plied and angle-plied laminates. The limitations to the fatigue performance of composite laminates are pointed out and suggestions for improving the fatigue resistance are made.

Fatigue Life Assessment of Fastened Composite (FRP and CRP) Plates: A Comparative Study

2011 ◽  
Vol 110-116 ◽  
pp. 1155-1160
Author(s):  
K.N. Pandey ◽  
Yogesh K. Tembhurne
Keyword(s):  
Fatigue Life ◽  
Composite Materials ◽  
Composite Laminates ◽  
Maximum Load ◽  
Butt Joint ◽  
Fatigue Tests ◽  
Life Assessment ◽  
Reinforced Plastic ◽  
Mechanically Fastened ◽  
Subsequent Propagation

Composite materials are now a day most frequently used materials in aerospace structures. Mechanically fastened joints are usually used there for joining process due to number of advantages over other conventional joints. These joints are easy to assemble and dissemble and are cheaper. However, they create stress concentration near the hole, leading to source of nucleation and subsequent propagation of cracks under cyclic loading. They also increase weight of the system tat may nullify the advantages we get from composite materials. The present work intent to find fatigue life of two composite laminates usually employed in spacecraft structures. The composites studies are fiberglass reinforced Plastic (FRP) and Carbon Reinforced Plastic (CRP). After preparing the composites, moisture, tension and fatigue tests were conducted on both composites. To know the behavior under damped condition, absorption tests were conducted. Fatigue tests were done both under as plate and butt joint conditions. It was found that in bolted joint condition, both CRP and FRP plates fails in net tension at minimum load but for maximum load they fail in shear.

A Study of Fatigue Damage and Fatigue Life of Composite Laminates

1996 ◽  
Vol 30 (1) ◽  
pp. 123-137 ◽  
Author(s):  
Wen-Fang Wu ◽  
L. J. Lee ◽  
S. T. Choi
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Composite Laminates

Multi-Axial Fatigue Damage Models of Fiber Reinforced Composites

2004 ◽  
Author(s):  
N. H. Yang ◽  
H. Nayeb-Hashemi ◽  
A. Vaziri
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Fatigue Failure ◽  
Multiaxial Fatigue ◽  
Loading Frequency ◽  
Reinforced Composites ◽  
Damage Models ◽  
Failure Models ◽  
Axial Fatigue

Fiberglass reinforced composites are extensively used in various structural components. In order to insure their structural integrity, their monotonic and fatigue properties under multiaxial stress fields must be understood. Combined in-phase tension/torsion loading is applied to [±45°]4 E-glass/epoxy composite tubes under monotonic and fatigue conditions to determine the effects of multiaxial loading on its failure. Various monotonic and fatigue damage criteria are proposed. These models considered failure mode (failure plane), the energy method and the effective stress-strain method. It is observed for the majority of experiments, the failure initiated at the outer lamina layer at 45° to the tube axis. A damage criterion for multiaxial monotonic loading is proposed considering both normal and shear stress contributions on the plane of failure. The experimental data show an excellent agreement with this proposed model for various loading conditions. Other failure models are currently under investigation utilizing the stresses and strains at the composite laminate as well as stress and strain at the outer lamina layer. Multiaxial fatigue failure models are proposed considering again the plane of failure. Since the plane of the failure is subjected to mean and cyclic stresses (shear and normal) and mean and cyclic strains (shear and normal), the fatigue damage models consider the contributions of these stresses and strains to the fatigue life of the composite tube. In addition to the fatigue damage model based on the plane of failure, a multi-axial fatigue failure model is proposed considering the mean and cyclic energy during fatigue experiments. The experimental data show a good correlation between the proposed damage parameters and fatigue life of specimens with some scatter of the data. Other fatigue failure models are currently under investigation considering the loading frequency and visco-elastic properties of the composite.

Fatigue Life Prediction of Composite Laminate

2012 ◽  
Vol 472-475 ◽  
pp. 591-595 ◽  
Author(s):  
Jun Liu ◽  
Feng Peng Zhang
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Life Prediction ◽  
Plate Theory ◽  
Damage Model ◽  
Prediction Method ◽  
Fatigue Life Prediction ◽  
Fatigue Properties ◽  
Adjacent Layer

Abstract. based on the accumulating fatigue damage model, with single ply plate theory and experiment data as the foundation, consider the interaction between adjacent layer and material degradation, a kind of fatigue life prediction method of fiber reinforced composite laminates is developed. The stiffness decline of each ply during cyclic loading is determined by the fatigue damage variable and the load amplitude and the fatigue life of any laminates can be predicted using the fatigue properties of single ply plate. Using this method a 3D Finite element model is established by ABAQUS software and the fatigue life and the fatigue damage evolution of a T300 / QY8911 laminats are analyzed, the results are more closer to the experimental results.

Fatigue Life Prediction of Composite Laminates Based on Progressive Damage Analysis

2014 ◽  
Vol 1064 ◽  
pp. 108-114 ◽  
Author(s):  
Jun Kang ◽  
Zhi Dong Guan ◽  
Zeng Shan Li ◽  
Zhun Liu
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Material Property ◽  
Composite Laminates ◽  
Life Prediction ◽  
Shear Failure ◽  
Fatigue Life Prediction ◽  
Progressive Damage ◽  
Damage Analysis ◽  
Fatigue Damage Analysis

A three dimensional analysis model is developed on the fatigue life prediction of composite laminates based on a progressive damage analysis. This model consists of stress analysis, fatigue failure analysis and material property degradation. Teserpe’s failure criteria is used to fatigue damage analysis. Fiber tensile/compressive breakage, matrix tensile/compressive cracking, matrix/fiber shear failure and tension/compression delamination are considered in fatigue damage analysis. The methodologies of sudden degradation and gradual degradation are both applied in the material property degradation. The stiffness and strength gradual degradation is based on the Shokrieh fatigue model, which is based on fatigue test for unidirectional laminates. In order to consider the scatter of the material in the practical structures, the stiffness and strength of the material are randomly distributed using normal distribution in the numerical model. The progressive fatigue damage model is developed in finite element code ABAQUS through user subroutine UMAT, which can simulate the fatigue damage process. Fatigue life of different ply stacking sequences and geometries composite laminates under different cycle loading are predicted. The predicted fatigue life is in good agreement with the experimental results.

Rapid Characterization of Fatigue Performance With Application to Additive Manufactured Components

2020 ◽  
Author(s):  
Dino A. Celli ◽  
M.-H. Herman Shen ◽  
Onome E. Scott-Emuakpor ◽  
Tommy J. George
Keyword(s):  
Experimental Data ◽  
Fatigue Life ◽  
Life Prediction ◽  
Prediction Method ◽  
Experimental Tests ◽  
Parameter Selection ◽  
Process Parameter ◽  
Fatigue Life Prediction ◽  
Fatigue Performance ◽  
Cycles To Failure

Abstract The aim of this paper is to provide a fatigue life prediction method which can concurrently approximate both SN behavior as well as the inherent variability of fatigue efficiently with a limited number of experimental tests. The purpose of such a tool is for the quality assessment and verification of components using Additive Manufacturing (AM) processes and other materials with a limited knowledgebase. Interest in AM technology is continually growing in many industries, such as aerospace, automotive, or biomedical. But components often result in highly variable fatigue performance. The determination of optimal process parameters for the build process can be an extensive and costly endeavor due to either a limited knowledgebase or proprietary restrictions. Quantifying the significant variability of fatigue performance in AM components is a challenging task as there are many causes including machine to machine differences, recycles of powder, and process parameter selection. Therefore, a life prediction method which can rapidly determine the fatigue performance of a material with little or no prior information of the material and a limited number of experimental tests is developed as an aid in process parameter selection and fatigue performance qualification. This is performed by using a previously developed and simplistic energy based fatigue life prediction method, or Two Point method, to predict the inherent variability associated with fatigue performance. The proposed approach is verified by using predicted distributions of stress and cycles to failure and comparing with experimental data at 104 and 106 cycles to failure. SN life prediction is modeled via a modified Random Fatigue Limit (RFL) model where the two RFL model parameters are evaluated using Bayesian statistical inference and stochastic sampling techniques for distribution estimation. This is performed in a dynamic way such that the life prediction model is continually updated with the generation of experimental data.

FAILURE PREDICTION OF COMPOSITE MATERIALS USING DEEP NEURAL NETWORKS

2021 ◽  
Author(s):  
ALLYSON FONTES ◽  
FARJAD SHADMEHRI
Keyword(s):  
Experimental Data ◽  
Neural Networks ◽  
Composite Materials ◽  
Composite Laminates ◽  
Deep Neural Networks ◽  
Mean Squared Error ◽  
Failure Criteria ◽  
Failure Strength ◽  
Failure Data ◽  
Frp Composite

Fiber-reinforced polymer (FRP) composite materials are increasingly used in engineering applications. However, an investigation into the precision of conventional failure criteria, known as the World-Wide Failure Exercise (WWFEI), revealed that current theories remain unable to predict failure within an acceptable degree of accuracy. Deep Neural Networks (DNN) are emerging as an alternate and time-efficient technique for predicting the failure strength of FRP composite materials. The present study examined the applicability of DNNs as a tool for creating a data-driven failure model for composite materials. The experimental failure data presented in the WWFE-I were used to develop the datadriven model. A fully connected DNN with 23 input units and 1 output unit trained with a constant learning rate (α=0.0001). The network’s inputs described the laminates and the loading conditions applied to the test specimen, whereas the output was the length of the failure vector (L=(σx+σy+τxy)0.5). The DNN’s performance was evaluated using the mean squared error on a subset of the experimental data unseen during training. Network configurations with a varying number of hidden layers and units per layer were evaluated. The DNN with 3 hidden layers and 20 units per hidden layer performed the best. In fact, the network’s predictions show good agreement with the experimental results. The failure boundaries generated by the DNN were compared to three conventional theories: the Tsai-Wu, Cuntze, and Puck theory. The DNN’s failure envelopes were found to fit the experimental data more closely than the above-mentioned theories. In sum, the DNN’s ability to fit higher-order polynomials to data separates it from conventional failure criteria. This characteristic makes DNNs an effective method for predicting the failure strength of composite laminates.

A New Approach to Fatigue Damage Modeling of Composite Laminates

2011 ◽  
Vol 338 ◽  
pp. 315-318 ◽  
Author(s):  
Peng Gang Mu ◽  
Xiao Peng Wan ◽  
Mei Ying Zhao
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Composite Laminates ◽  
Fatigue Behavior ◽  
Failure Criteria ◽  
Damage State ◽  
Damage Indices ◽  
Model Combining ◽  
Proposed Model ◽  
Fatigue Damage Accumulation

Fatigue damage of composites can be described by the residual stiffness and residual strength, and the same damage state can be described by the two mechanical parameters equivalently. Based on this assumption, a new pair of fatigue damage accumulation models are established to simulate fatigue behavior and predict the fatigue life of composites. Each of two equations contains three parameters and has the similar form, and the power function relationships between the two damage indices are constructed. The proposed model, combining with constant life diagrams and failure criteria are used to estimate the fatigue life of composites, and good agreement is observed between the present model and experimental results.

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