Fatigue Behavior of Impacted Plain-Weave Glass/Epoxy Composites under Tensile Fatigue Loading

The goals of this paper are to identify the impact damage behavior of plain-weave E-glass/epoxy composites and predict the fatigue life of the composites with impact-induced damage under constant amplitude loading. To identify these behaviors, the low velocity impact and fatigue after impact tests are performed for glass/epoxy composites having two types of fiber orientations. The impact damage behavior is dependent on the fiber orientation of the composites. The fatigue life of the impacted composites can be identified through the prediction model, which was proposed on the carbon/epoxy laminates by authors regardless of fiber orientations.

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Experimental investigation and phenomenological modeling of hygrothermal effect on tensile fatigue behavior of carbon/epoxy plain weave laminates

Journal of Composite Materials ◽

10.1177/0021998318770505 ◽

2018 ◽

Vol 52 (27) ◽

pp. 3803-3818 ◽

Cited By ~ 2

Author(s):

M Khay ◽

AD Ngo ◽

R Ganesan

Keyword(s):

Fatigue Life ◽

Composite Laminates ◽

Fatigue Behavior ◽

Tensile Load ◽

Fatigue Loading ◽

Stiffness Degradation ◽

Plain Weave ◽

Hygrothermal Effect ◽

Tensile Fatigue ◽

Delamination Propagation

The purpose of this paper is to study the hygrothermal effect on fatigue behavior of quasi-isotropic carbon/epoxy plain weave aerospace laminates containing artificial flaw under axial tension–tension loading. Dry and wet specimens were tested at tensile load-controlled cyclic loading with a stress ratio R = 0.1 and a load frequency of 7 Hz at room temperature (RT) and at 82℃ under different stress levels. Allowable stiffness change as a failure criterion was used to determine the delamination propagation onset threshold under cyclic tensile loading at each environmental condition. The delamination propagation onset was verified using the ultrasonic imaging (C-Scan) technique. The experimental results show that (1) fatigue life of CFRP specimens was more individually affected by moisture than by temperature and (2) combined moisture and temperature cause a drastic decrease in fatigue life. Finally, an investigation of the effect of hygrothermal conditions on stiffness degradation and damage of composite laminates subjected to tensile fatigue loading has been also carried. On the basis of the residual stiffness degradation, a damage variable was presented and phenomenological damage models were proposed by employing fatigue modulus and secant modulus concepts as measure of material damage.

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Effects of defects on interlaminar tensile fatigue behavior of carbon/epoxy composites

Composites Science and Technology ◽

10.1016/j.compscitech.2013.10.006 ◽

2013 ◽

Vol 89 ◽

pp. 194-201 ◽

Cited By ~ 32

Author(s):

Guillaume Seon ◽

Andrew Makeev ◽

Yuri Nikishkov ◽

Edward Lee

Keyword(s):

Fatigue Behavior ◽

Epoxy Composites ◽

Tensile Fatigue

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Effects of environmental conditions on the axial tension–compression fatigue behavior of carbon/epoxy plain-weave laminates containing flaws

Journal of Composite Materials ◽

10.1177/0021998320929411 ◽

2020 ◽

Vol 54 (27) ◽

pp. 4215-4230

Author(s):

Marc-Claudel Deluy ◽

Mohamed Khay ◽

Anh Dung Ngo ◽

Martine Dubé ◽

Rajamohan Ganesan

Keyword(s):

Fatigue Life ◽

Environmental Conditions ◽

Cyclic Load ◽

Fatigue Testing ◽

Fatigue Behavior ◽

Real Life ◽

Compressive Load ◽

Fatigue Loading ◽

Plain Weave ◽

Strain Increase

The objective of this work is to investigate the effects of environmental conditions on the axial fatigue behavior of a carbon/epoxy plain-weave laminate with an embedded flaw subjected to a partially reversed cyclic load (stress ratio R = −0.1) in tension–compression. This specific material is more commonly used in aerospace engineering for the manufacturing of aircraft structural parts, which are directly exposed to various environmental conditions during service. Specific environmental and loading conditions that are appropriate to simulate real-life conditions are considered to observe and collect information about the material's behavior. For the investigation, dry and wet coupons were submitted to room temperature, 82 and 121 ℃ under loading frequencies of 7 and 15 Hz. A maximum allowable strain increase criterion is used to monitor the flaw growth threshold or delamination onset, during fatigue testing. The ultrasonic imaging (C-scan) technique is used to verify and confirm the delamination onset. Results show that the delamination onset strain increase criterion, along with fatigue life, generally decreased as the operating temperature and humidity were increased and that frequency had little effect on the delamination onset fatigue life. The S– N curves obtained from the tension–compression fatigue data were then compared to those of a previous work carried out in tension–tension fatigue loading. Results show a clear degradation in the delamination onset fatigue life of the coupons tested under tension–tension cyclic loading when the minimum tensile component of the cyclic load was replaced with a compressive load of the same magnitude.

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