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In this article, low-velocity impact characteristics of UHN125C carbon fiber/epoxy composite, including unidirectional (0°), cross-directional (0°/90°), and quasi-isotropic layups, were experimentally measured. The effect of the fiber orientation angle and stacking sequences on impact force and induced strain were measured via an instrumented drop-...
Citations
... Many researchers have reported that LVIs cause internal damages viz. matrix cracking, fibre splitting, and delamination which lead to significant reduction in the local strength of the laminate (Zai et al., 2019;Pai et al., 2022;Sadighi & Alderliesten, 2022a;Safri et al., 2014;Taraghi et al., 2014). Impact loading can be classified into four categories: low velocity (less than 10 m/s), intermediate velocity (between 10 and 50 m/s), high/ballistic velocity (between 50 and 1000 m/s), and hyper velocity (between 2 and 5 km/s) (Safri et al., 2014). ...
The scientific community has taken a particular interest in the study of low-velocity impact (LVI) behavior of fiber-reinforced polymer (FRP) composites due to its application across various domains. LVI is a serious threat to composites since it generates a variety of internal damages as well as complex failure mechanisms, resulting in a significant drop in composite structural characteristics. Several parameters, including fabric architecture, resin toughness, environmental conditions, stacking sequence, and hybridization can affect the impact resistance and damage tolerance of FRP composites. Furthermore, polymer composites in outdoor applications are exposed to various hygrothermal conditions. This results in moisture absorption and leads to physiochemical changes in the matrix material through various mechanisms such as plasticisation, hydrolysis and swelling. The long-term exposure to such environments causes the material property degradation, which affects the overall LVI performance and durability of the structures. Hence, it is crucial to critically review the influence of various parameters and hygrothermal ageing on the LVI response of FRP composites. This paper reviews the primary factors affecting LVI behavior, following, a comprehensive review on the hygrothermal effect on LVI behavior of FRP composites.
Hybrid polymer laminates employed in advanced engineering fields are susceptible to atmospheric conditions, such as moisture and temperature throughout their service life, which may impact their mechanical and damping properties. This research focuses on the influence of three distinct environmental situations: ambient ageing at 25°C, sub-zero ageing at −10°C, and environmental chamber humid ageing at 40°C with 60% RH (relative humidity) on the mechanical and damping characteristics of quasi-isotropic carbon-Kevlar fibre reinforced intraply hybrid composites. Compression molding process was incorporated for the fabrication of the laminates and specimens were aged until the moisture saturation point was reached. The mechanical and vibrational properties of post-aged specimens, including tensile, three-point flexure, short-beam shear strength (SBS), and hammer impact tests, were investigated and compared with pristine specimens. The results showed that the experimental degree of moisture absorption closely followed the Fick’s first law, with a greater moisture diffusion rate in the early phase of ageing and moisture saturation in the laminates were ranging from 1.162% to 4.167%. The study also unveiled that diffusion of moisture has a negative impact on the mechanical and vibrational behaviour of the composites. Mechanical strength deterioration was discovered to be highest in the ambient aged specimens followed by humid and sub-zero aged specimens. To evaluate the damage morphology, post-tensile test coupons were analysed by employing a Scanning Electron Microscope (SEM). The predominant failure mechanisms found in aged composites were fibre fractures, interfacial degradation due to matrix deterioration, matrix cracks, and delamination.
