Abstract:T800 carbon fiber/high-temperature epoxy resin composites with holes were subjected to thermal–oxidative aging, and the effects of different aging temperatures and times on the composite properties were investigated. The mass loss, surface topography, open-hole tensile performance, fracture morphologies, dynamic mechanical properties, and infrared spectra were analyzed. The results showed that chemical aging did not occur with thermal–oxidative aging at 70°C and 130°C. However, chemical aging occurred at 190°C… Show more
“…Using the artificial accelerated thermal-oxidative aging test method according to the T g of the unaged specimens, determined as described in “Dynamic mechanical analysis” section, 27,28 thermal-oxidative aging was conducted in a DHG-9140A electrothermal constant temperature blast drying oven (Shanghai Linpin Instrument Stock Co., Ltd, Shanghai, China) at 190°C for 40 days. The change in mass was determined by weighing every day with the ALC-210.4 analytical balance of Sartorius Scientific Instruments Co., Ltd (Beijing, China), and the mass-loss rate was then calculated by…”
The properties of T800 carbon fiber–epoxy composite specimens with a hole were studied in terms of mass change, scanning electron microscopy, glass transition temperature ( T g), heat-resistant temperature, Fourier-transform infrared (FTIR) spectroscopy, open-hole compressive strength at different temperatures, and stereomicroscopic observations after being subjected to hygrothermal aging and thermal-oxidative aging processes. FTIR spectra indicated that after hygrothermal aging at 70°C and 85% relative humidity (RH), chemical aging did not occur, whereas after thermal-oxidative aging at 190°C, the specimens exhibited chemical aging. The unaged specimens had a T g of 229°C and an extreme heat-resistant temperature T gmod of 184°C; after hygrothermal aging, the specimens had a T g and T gmod of 207°C and 143°C, respectively; and after thermal-oxidative aging, the specimens had a T g and T gmod of 252°C and 215°C, respectively. The effects of temperature on open-hole compressive strength were evaluated at room temperature of 23°C, 50°C, 100°C, 150°C, and 200°C. The compressive strengths of the specimens decreased after aging and with the increasing test temperature. At the highest test temperature, the unaged specimens, hygrothermal-aged, and thermal-oxidative-aged specimens retained over 73.7%, 65.5%, and 67.9%, respectively, of their compressive strength. Thus, the T800 carbon fiber–epoxy composite evaluated in this study exhibited good resistance to the effects of aging and high temperature. These results should be beneficial to the understanding of the long-term performance of composites.
“…Using the artificial accelerated thermal-oxidative aging test method according to the T g of the unaged specimens, determined as described in “Dynamic mechanical analysis” section, 27,28 thermal-oxidative aging was conducted in a DHG-9140A electrothermal constant temperature blast drying oven (Shanghai Linpin Instrument Stock Co., Ltd, Shanghai, China) at 190°C for 40 days. The change in mass was determined by weighing every day with the ALC-210.4 analytical balance of Sartorius Scientific Instruments Co., Ltd (Beijing, China), and the mass-loss rate was then calculated by…”
The properties of T800 carbon fiber–epoxy composite specimens with a hole were studied in terms of mass change, scanning electron microscopy, glass transition temperature ( T g), heat-resistant temperature, Fourier-transform infrared (FTIR) spectroscopy, open-hole compressive strength at different temperatures, and stereomicroscopic observations after being subjected to hygrothermal aging and thermal-oxidative aging processes. FTIR spectra indicated that after hygrothermal aging at 70°C and 85% relative humidity (RH), chemical aging did not occur, whereas after thermal-oxidative aging at 190°C, the specimens exhibited chemical aging. The unaged specimens had a T g of 229°C and an extreme heat-resistant temperature T gmod of 184°C; after hygrothermal aging, the specimens had a T g and T gmod of 207°C and 143°C, respectively; and after thermal-oxidative aging, the specimens had a T g and T gmod of 252°C and 215°C, respectively. The effects of temperature on open-hole compressive strength were evaluated at room temperature of 23°C, 50°C, 100°C, 150°C, and 200°C. The compressive strengths of the specimens decreased after aging and with the increasing test temperature. At the highest test temperature, the unaged specimens, hygrothermal-aged, and thermal-oxidative-aged specimens retained over 73.7%, 65.5%, and 67.9%, respectively, of their compressive strength. Thus, the T800 carbon fiber–epoxy composite evaluated in this study exhibited good resistance to the effects of aging and high temperature. These results should be beneficial to the understanding of the long-term performance of composites.
“…This occurred mainly because thermo-oxidative aging volatilized water molecules and low-molecular-weight substances, resulting in the volume contraction of the matrix. 23,24 This generated shrinkage stress due to the different thermal expansion coefficients of the carbon fiber and the resin matrix. The shrinkage stress acted on the interface of carbon fiber composites and caused interfacial failure.…”
Section: Resultsmentioning
confidence: 99%
“…These cracks provided new channels for oxygen to enter the material, which increased the contact area with the resin and accelerated the rate of thermo-oxidative aging. 24,30 This caused the micro-cracks and pore defects to expand, which ultimately led to serious internal damage and performance degradation 31,32 Figure 9.Morphological changes of the internal impact damage of the composite material after different aging times: a-unaged; b-thermo-oxidative aging for 30 d; c-thermo-oxidative aging for 60 d; d-thermo-oxidative aging for 90 d.…”
Section: Resultsmentioning
confidence: 99%
“…These cracks provided new channels for oxygen to enter the material, which increased the contact area with the resin and accelerated the rate of thermo-oxidative aging. 24,30 This caused the microcracks and pore defects to expand, which ultimately led to serious internal damage and performance degradation 31,32 Impact-induced damage…”
Here, the effect of thermo-oxidative aging on domestic T800 carbon fiber/epoxy resin composites was studied using mass loss rate curves, interface morphology, infrared spectroscopy, and dynamic mechanical property analysis. The composites were subjected to thermo-oxidative aging tests after low-velocity impact. Then, the effect of environmental factors on the damage area of the composites and the compression performance after impact were investigated. The results showed that the composites underwent physical and chemical aging at 185°C. Due to the short aging time, the mass loss rate slowly increased. After aging, thermo-oxidative aging caused the matrix to crack, and the sample cracks that formed after impact expanded, and the damage area also slightly increased. The residual compressive strength of the material fluctuated due to the competing reinforcing and destructive effects of the composite during thermo-oxidative aging; however, aging had little effect on the impact damage morphology and compression failure mode. Upon extending the aging time, thermo-oxidative aging caused the tanδ peak to gradually shift to a higher temperature, and the glass transition temperature ( Tg) increased.
“…The analysis of the cutting process showed, that depending on the hole depth the process can be divided in three stages, with increasing depth the cutting process slows down. Xu et al [9] examined thermal ageing in carbon fibre reinforced epoxy composites with ageing cycles of up to 190 • C. Open hole tests were performed to compare intact and aged specimens. Here for all temperatures and ageing times the tensile strength was increased compared to the initial specimen and a maximum strength was found for t = 250 s Chippendale et al [10] describe a modelling approach for the thermal decomposition due to the laser heat input with a focus on the influence on the thermal conductivity.…”
In this contribution a method is introduced that allows for a linkage between the processinduced structural damage and the fracture behaviour. Based on an anisotropic elastic material model, different modelling approaches for initial damage effects are introduced and compared. The approaches are applied to remote laser cut carbon fibre reinforced polymers in order to model various thermally induced damage effects like chemical decomposition, micro-cracks and delamination. The dimensions of this heat affected zone are calculated with 1D-heat conduction. In experiment and simulation milled and laser cut specimens with different process parameters are compared in order to quantify the impact of the cutting technology on the fracture behaviour. For this purpose open hole specimens were used.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
