Abstract: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 onse… Show more
“…The entirety of the T – T fatigue data used was taken from previous work by Khay et al. 29,30 for comparison purposes. Figure 8.Comparison of the normalized T – C and T – T fatigue S – N curves at 7 Hz under RTD condition (22–25 ℃, dry).…”
Section: Resultsmentioning
confidence: 99%
“…The coupons were manufactured and provided by Bell Helicopter Textron Canada (BHTC) and they were also used by Khay et al. 29,30 in their previous work. The information regarding the dimension and the coupon configuration is shown in Figure 2.…”
Section: Methodsmentioning
confidence: 99%
“…The static ultimate tensile load (UTL) and stress (UTS) values a measured during a previous work by Khay et al. 29,30 using the same type of coupons and hygrothermal conditions were reused as a reference for the load levels in this work.…”
Section: Methodsmentioning
confidence: 99%
“…Coupons made of thermoset epoxy resin CYCOM 5276-1 reinforced with plain-weave carbon fiber G30-500PW by Cytec Engineered Material/Solvay Group were used during fatigue testing. The coupons were manufactured and provided by Bell Helicopter Textron Canada (BHTC) and they were also used by Khay et al 29,30 in their previous work. The information regarding the dimension and the coupon configuration is shown in Figure 2.…”
Section: Materials and Test Samplesmentioning
confidence: 99%
“…The damage characterization of the material is determined using microscopic observations. The results presented in this paper are intended to compare the data obtained from these T-C fatigue tests with those from a previous work conducted by Khay et al 29,30 in T-T fatigue under similar operational conditions using the same apparatus, same specimen geometry, and material.…”
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.
“…The entirety of the T – T fatigue data used was taken from previous work by Khay et al. 29,30 for comparison purposes. Figure 8.Comparison of the normalized T – C and T – T fatigue S – N curves at 7 Hz under RTD condition (22–25 ℃, dry).…”
Section: Resultsmentioning
confidence: 99%
“…The coupons were manufactured and provided by Bell Helicopter Textron Canada (BHTC) and they were also used by Khay et al. 29,30 in their previous work. The information regarding the dimension and the coupon configuration is shown in Figure 2.…”
Section: Methodsmentioning
confidence: 99%
“…The static ultimate tensile load (UTL) and stress (UTS) values a measured during a previous work by Khay et al. 29,30 using the same type of coupons and hygrothermal conditions were reused as a reference for the load levels in this work.…”
Section: Methodsmentioning
confidence: 99%
“…Coupons made of thermoset epoxy resin CYCOM 5276-1 reinforced with plain-weave carbon fiber G30-500PW by Cytec Engineered Material/Solvay Group were used during fatigue testing. The coupons were manufactured and provided by Bell Helicopter Textron Canada (BHTC) and they were also used by Khay et al 29,30 in their previous work. The information regarding the dimension and the coupon configuration is shown in Figure 2.…”
Section: Materials and Test Samplesmentioning
confidence: 99%
“…The damage characterization of the material is determined using microscopic observations. The results presented in this paper are intended to compare the data obtained from these T-C fatigue tests with those from a previous work conducted by Khay et al 29,30 in T-T fatigue under similar operational conditions using the same apparatus, same specimen geometry, and material.…”
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.
[0]16, [90]16, [±45]4s and [+45/0/0/-45/-45/0/0/+45]s were fabricated to study the influence of the different ply lay-up on the moisture absorption and tensile properties of TG800/E207 carbon fiber epoxy resin composite laminates at a hygrothermal environment of 80℃ and 90%RH. Moisture absorption curves, damage morphology after moisture absorption, fracture morphology, load-displacement curves and strength degradation were analyzed. The results show that the moisture absorption curves of TG800/E207 composite laminates present multi-stage phenomenon. The moisture adsorption reached equilibrium at a moisture absorption time of 1 608 hours. The equilibrium moisture content of [90]16 is the lowest and its saturated moisture content is only 0.806%; the equilibrium moisture content of [+45/0/0/-45/-45/0/0/+45]s is the highest and its saturated moisture absorption rate is 0.876%. The failure load of [0]16, [90]16, [±45]4s and [+45/0/0/-45/-45/0/0/+45]s samples decreased by 13.8%, 27.36%, 10.7% and 25.6%, respectively. The saturated moisture absorption of [90]16 is the lowest, but its tensile strength degradation is the most serious.
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