Cumulative Damage in Composites

1990 ◽  
Vol 112 (3) ◽  
pp. 358-361 ◽  
Author(s):  
H. A. Whitworth
Keyword(s):  
Experimental Data ◽  
Fatigue Damage ◽  
Stress Level ◽  
Present Model ◽  
Damage Model ◽  
Fatigue Loading ◽  
Damage Function ◽  
Epoxy Composites ◽  
Remaining Life ◽  
Cumulative Fatigue Damage

The problem of cumulative fatigue damage in composites is analyzed based upon the development of a phenomenological damage model. In this modeling, a damage function is defined based on the degradation of the residual stiffness and used to predict the remaining life of composite specimens subjected to dual stress level fatigue loading. Available experimental data for graphite/epoxy composites are compared with the predictions of the present model.

scholarly journals New Nonlinear Cumulative Fatigue Damage Model Based on Ecological Quality Dissipation of Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Hongsong Li ◽  
Yongbao Liu ◽  
Xing He ◽  
Wangtian Yin
Keyword(s):  
Fatigue Life ◽  
Cyclic Loading ◽  
Fatigue Damage ◽  
Damage Model ◽  
Fatigue Loading ◽  
Ecological Quality ◽  
Aircraft Structures ◽  
Variable Amplitude ◽  
Fatigue Damage Accumulation ◽  
Cumulative Fatigue Damage

The failure of many aircraft structures and materials is caused by the accumulation of fatigue damage under variable-amplitude cyclic loading wherein the damage evolution of materials is complicated. Therefore, to study the cumulative fatigue damage of materials under variable-amplitude cyclic loading, a new nonlinear fatigue damage accumulation model is proposed based on the ecological quality dissipation of materials by considering the effects of load interaction and sequence. The proposed new model is validated by the test data obtained for three kinds of material under multilevel fatigue loading. Compared with the Miner model and Kwofie model, the proposed model can more effectively analyse the accumulative damage and predict fatigue life of different materials under variable-amplitude cyclic loading than others. The study provides a basis for predicting fatigue life accurately and determining reasonable maintenance periods of aircraft structures.

scholarly journals Progressive failure mechanism of laminated composites under fatigue loading

2020 ◽  
Vol 55 (1) ◽  
pp. 137-144
Author(s):  
Ghalib R Ibrahim ◽  
A Albarbar ◽  
Khaldoon F Brethee
Keyword(s):  
Experimental Data ◽  
Fatigue Damage ◽  
Damage Mechanics ◽  
Cohesive Zone Model ◽  
Laminated Composites ◽  
Progressive Failure ◽  
Damage Model ◽  
Fatigue Loading ◽  
Zone Model ◽  
Lap Joint

A cohesive zone model for delamination propagation in laminated composites under static and fatigue loading has been derived and validated with experimental data under different mode conditions. This study presents a new approach to quantify fatigue delamination degradation based on damage mechanics to evaluate the rate of fatigue damage ([Formula: see text]). The static damage evaluation and fatigue damage degradation are derived from damage surface concept. Both static and fatigue damage linked each other to establish fatigue crack growth formula in the laminated composites. A user-defined subroutine, UMAT, has been employed to develop and implement a damage model in ABAQUS. Two different specimens; a double cantilever beam and a single lap joint were used to investigate the effectiveness of the new method. The simulation results revealed that the developed model had good agreement with experimental data available in literature.

A novel non-linear cumulative fatigue damage model based on the degradation of material memory

2019 ◽  
Vol 29 (4) ◽  
pp. 610-625
Author(s):  
Jie Zhou ◽  
Hong-Zhong Huang ◽  
Miles V Barnhart ◽  
Guoliang Huang ◽  
Yan-Feng Li
Keyword(s):  
Experimental Data ◽  
Fatigue Damage ◽  
Residual Life ◽  
Damage Model ◽  
Loading History ◽  
Material Parameters ◽  
Life Estimation ◽  
Damage Models ◽  
Proposed Model ◽  
Cumulative Fatigue Damage

Many fatigue damage models have been investigated based on the S– N curve or modified S– N curve; however, a number of them require additional efforts to determine the material parameters or do not consider the loading history (loading interactions, loading sequences, loading levels, etc.). These limitations can result in extreme deviations for estimating the fatigue life in real-world scenarios. To address these limitations, a new fatigue damage model is developed based on the material memory, which can be described as the degradation of mechanical properties under cyclic loadings. Comparisons with three models are used to demonstrate the validity of the proposed model. Furthermore, four sets of experimental data under two-stress and four-stress levels are carried out to verify the validation of the proposed model, which improves the residual life estimation over the three existing models used for comparison.

A Multi-Level Low Cycle Fatigue Damage Model for Forging Die Material

2006 ◽  
Vol 514-516 ◽  
pp. 804-809
Author(s):  
S. Gao ◽  
Ewald Werner
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Low Cycle Fatigue ◽  
Damage Model ◽  
Fatigue Loading ◽  
Cycle Fatigue ◽  
Die Material ◽  
Multi Level ◽  
Loading Sequence ◽  
Forging Die

The forging die material, a high strength steel designated W513 is considered in this paper. A fatigue damage model, based on thermodynamics and continuum damage mechanics, is constructed in which both the previous damage and the loading sequence are considered. The unknown material parameters in the model are identified from low cycle fatigue tests. Damage evolution under multi-level fatigue loading is investigated. The results show that the fatigue life is closely related to the loading sequence. The fatigue life of the materials with low fatigue loading first followed by high fatigue loading is longer than that for the reversed loading sequence.

Nonlinear Cumulative Fatigue Damage Model

2011 ◽  
Vol 328-330 ◽  
pp. 1440-1444
Author(s):  
Hua Zou ◽  
Qiang Li ◽  
Shou Guang Sun
Keyword(s):  
Mathematical Model ◽  
Aluminum Alloy ◽  
Fatigue Life ◽  
Fatigue Damage ◽  
Welded Joint ◽  
Damage Model ◽  
Reasonable Explanation ◽  
Curve Method ◽  
Cumulative Fatigue Damage ◽  
Damage Rule

Cumulative fatigue damage is an important consideration in determining the fatigue life of structures. A cumulative linear damage rule cannot provide a reasonable explanation for cumulative fatigue damage, but a damage curve method based on nonlinear cumulative fatigue damage model can give a reasonable explanation. In this paper, a specific mathematical model is put forward, which is based on the damage curve method. In the model, miner formula is modified properly and an exponent formula is give out to fit the damage accumulate. According to a two-step fatigue test of aluminum–alloy welded joint, the comparison between the calculated results and the testing results is less than 5%. It shows that the model is reasonable and accuracy.

Fatigue Damage Evaluation in CFRP Woven Fabric Composites Through Dynamic Modulus Measurements

2004 ◽  
Author(s):  
Hideaki Kasano ◽  
Osamu Hasegawa ◽  
Chiaki Miyasaka
Keyword(s):  
Fatigue Damage ◽  
Material Properties ◽  
Elastic Moduli ◽  
Fatigue Loading ◽  
Damage Function ◽  
Fatigue Tests ◽  
Woven Fabric ◽  
Damage Development ◽  
Dynamic Elastic Moduli ◽  
Number Of Cycles

Advanced fiber reinforced composite materials offer substantial advantages over metallic materials for the structural applications subjected to fatigue loading. With the increasing use of these composites, it is required to understand their mechanical response to cyclic loading [1–4]. Our major concern in this work is to macroscopically evaluate the damage development in composites during fatigue loading. For this purpose, we examine what effect the fatigue damage may have on the material properties and how they can be related mathematically to each other. In general, as the damage initiates in composite materials and grows during cyclic loading, material properties such as modulus, residual strength and strain would vary and, in many cases, they may be significantly reduced because of the progressive accumulation of cracks. Therefore, the damage can be characterized by the change in material properties, which is expected to be available for non-destructive evaluation of the fatigue damage development in composites. Here, the tensiontension fatigue tests are firstly conducted on the plain woven fabric carbon fiber composites for different loading levels. In the fatigue tests, the dynamic elastic moduli are measured on real-time, which will decrease with an increasing number of cycles due to the degradation of stiffness. Then, the damage fimction presenting the damage development during fatigue loading is determined from the dynamic elastic moduli thus obtained, from which the damage function is formulated in terms of a number of cycles and an applied loading level. Finally, the damage function is shown to be applied for predicting the remaining fifetime of the CFRP composites subjected to two-stress level fatigue loading.

Cumulative fatigue damage for 3-D angle-interlock woven composite under three-point bending cyclic loading

2012 ◽  
Vol 22 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Limin Jin ◽  
Baozhong Sun ◽  
Bohong Gu
Keyword(s):  
Cyclic Loading ◽  
Fatigue Damage ◽  
Stress Level ◽  
Three Dimensional ◽  
Woven Composite ◽  
Damage Development ◽  
Static Test ◽  
Three Point Bending ◽  
Cumulative Fatigue Damage ◽  
Number Of Cycles

This article presents the quantitative characterization of cumulative fatigue damage behavior for the three-dimensional angle-interlock woven composite undergoing three-point bending cyclic loading. The S–N curve was obtained to demonstrate the fatigue life of the three-dimensional angle-interlock woven composite under different stress levels. The increment of cycles for each 5% interval of stress level was reported to show the difference of fatigue resistance performances of the three-dimensional angle-interlock woven composite among the high, middle, and low intervals of stress level. In addition, the Cumulative Fatigue Damage versus Number of Cycles (D–N) curve and the Deflection Index versus Number of Cycles (F–N) curve were deduced to characterize the three-stage cumulative fatigue damage. Furthermore, the damage morphologies of the three-dimensional angle-interlock woven composite after fatigue tests were photographed to compare with those in quasi-static test. The cracks initiation and propagation in the three-dimensional angle-interlock woven composite during the process of cyclic loading were summarized to find the mechanisms of fatigue damage development.

Sign in / Sign up

Export Citation Format

Share Document