Effect of Ply Constraint on Fatigue Damage Development in Composite Material Laminates

2009 ◽  
pp. 64-64-21 ◽  
Author(s):  
WW Stinchcomb ◽  
KL Reifsnider ◽  
P Yeung ◽  
J Masters
Keyword(s):  
Composite Material ◽  
Fatigue Damage ◽  
Damage Development

The Fatigue Performance of Notched Composite Material Systems

1990 ◽  
Vol 204 (1) ◽  
pp. 57-69 ◽  
Author(s):  
S Kellas ◽  
J Morton ◽  
P T Curtis
Keyword(s):  
Composite Material ◽  
Fatigue Damage ◽  
Residual Strength ◽  
Characteristic Parameter ◽  
Fatigue Performance ◽  
Material System ◽  
Epoxy System ◽  
Damage Development ◽  
Material Systems

In this work results are reported from an experimental fatigue programme. The role of the constituent materials upon the fatigue performance of a given composite material system was studied. This involved comparisons of the residual strength, damage development, and in some cases fatigue life. A new method of approach, based upon a unique characteristic fatigue parameter, termed the damage transition stress, St, was also introduced. It has been shown that the employment of the characteristic parameter can simplify the comparison of different material systems considerably. Four graphite reinforced material systems were evaluated: (a) standard epoxy system, (b) toughened epoxy system, (c) thermoplastic system and, (d) high temperature system. It was found that three of the four material systems examined (a, b, and d) were more sensitive to hygrothermal environments, so far as the development of fatigue damage is concerned. In general, the tensile residual strength, in all material systems, showed a marked improvement, whereas the effect of environment and fatigue damage combination upon the compressive strength was more complex. Presentation of the fatigue data in the form of linear S-N plots allowed the determination of St, and its dependence upon environment and material systems. A material dynamic toughness was also identified.

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.

Computation of Interaction Between Deepwater Risers: Collision Statistics and Stress Analysis

2002 ◽  
Author(s):  
Kjell Herfjord ◽  
Tore Holma˚s ◽  
Bernt Leira ◽  
Mads Bryndum ◽  
Tor Hanson
Keyword(s):  
Composite Material ◽  
Stress Analysis ◽  
Fatigue Damage ◽  
Material Properties ◽  
Relative Velocity ◽  
Post Processing ◽  
Time Step ◽  
Processing Operation ◽  
Deepwater Risers ◽  
Actual Stress

A methodology for computing the dynamics of interacting risers is presented. During the time simulations, riser impacts (if any) are recorded. The relative velocity and angle between the axes of the risers are recorded at each hit, so that the actual stress and accumulated fatigue damage may be computed in a post-processing operation. Detailed material properties, such as properties of coating, the actual composite material properties, etc. are used in that process. The methodology is based on a pre-established database of forces acting on the cylinders. At each time step, all riser elements are loaded with a combination of in-line and transverse forces, depending on local relative distance to the neighbouring riser. This imply that the methodology is based on quasi-static assumptions. The paper presents a validation of the computed force database by comparison with measured results. Examples of results from simulation with top tensioned risers on a TLP are given.

Damage development in a noncrimp-glass fabric reinforced epoxy composite material

2009 ◽  
Vol 30 (12) ◽  
pp. 1800-1808 ◽  
Author(s):  
G. Cruz-Santos ◽  
J. Rodríguez-Laviada ◽  
C.R. Rios-Soberanis
Keyword(s):  
Composite Material ◽  
Epoxy Composite ◽  
Glass Fabric ◽  
Damage Development

scholarly journals Assessment of fatigue damage development in power engineering steel by local strain analysis

2016 ◽  
Vol 52 (05) ◽  
pp. 269-277 ◽  
Author(s):  
D. KUKLA ◽  
Z. KOWALEWSKI ◽  
P. GRZYWNA ◽  
K. KUBIAK
Keyword(s):  
Fatigue Damage ◽  
Strain Analysis ◽  
Local Strain ◽  
Power Engineering ◽  
Damage Development ◽  
Engineering Steel

scholarly journals Fatigue Damage Characterization of Braided and Woven Fiber Reinforced Polymer Matrix Composites at Room and Elevated Temperatures

2021 ◽  
Author(s):  
John Montesano
Keyword(s):  
Elevated Temperature ◽  
Prediction Model ◽  
Fatigue Damage ◽  
Polymer Matrix ◽  
Elevated Temperatures ◽  
Polymer Matrix Composites ◽  
Stiffness Degradation ◽  
Woven Composites ◽  
Matrix Composites ◽  
Damage Development

The use of polymer matrix composites (PMC) for manufacturing primary load-bearing structural components has significantly increased in many industrial applications. Specifically in the aerospace industry, PMCs are also being considered for elevated temperature applications. Current aerospace-grade composite components subjected to fatigue loading are over-designed due to insufficient understanding of the material failure processes, and due to the lace of available generic fatigue prediction models. A comprehensive literature survey reveals that there are few fatigue studies conducted on woven and braided fabric reinforced PMC materials, and even fewer at elevated temperatures. It is therefore the objective of this study to characterize and subsequently model the elevated temperature fatigue behaviour of a triaxial braided PMC, and to investigate the elevated temperature of fatigue properties of two additional woven PMCs. An extensive experimental program is conducted using a unique test protocol on the braided and woven composites, which consists of static and fatigue testing at various test temperatures. The development of mechanically-induced damage is monitored using a combination of non-destructive techniques which included infrared thermography, fiber optic sensors and edge replication. The observed microscopic damage development is quantified and correlated to the exhibited macroscopic material behaviour at all test temperatures. The fiber-dominated PMC materials considered in this study did not exhibit notable time or temperature-dependent static properties. However, fatigue tests reveal that the local damage development is in fact notably influenced by temperature. The elevated temperature environment increases the toughness of the thermosetting polymers, which results in consistently slower fatigue crack propagation rates for the respective composite materials. This has a direct impact on the stiffness degradation rate and the fatigue lives for the braided and woven composites under investigation. The developed analytical fatigue damage prediction model, which is based on actual observed damage mechanisms, accurately predicted the development of damage and corresponding stiffness degradation for the braided PMC, for all test temperatures. An excellent correlation was found between the experimental the predicted results to within a 2% accuracy. The prediction model adequately captured the local temperature-induced phenomenon exhibited by the braided PMC material. The results presented in this study are novel for a braided composite material subjected to elevated temperature fatigue.

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