Low Modulus of Elasticity The elastic modulus of FRP is approximately twice as large as that of wood but roughly ten times smaller compared to steel (with an elastic modulus of E=2.1E5). Due to this relatively low modulus, FRP products often lack sufficient stiffness and tend to deform easily under structural loads. This limitation can be addressed by designing thinner shell structures or sandwich constructions. Alternatively, reinforcing elements such as high-modulus fibers or additional stiffeners can help compensate for this weakness. Poor Long-Term Temperature Resistance FRP materials generally cannot withstand prolonged exposure to high temperatures. For example, standard polyester-based FRP tends to lose significant strength when exposed to temperatures above 50°C, with optimal performance usually limited to around 100°C. Similarly, while epoxy-based FRP may perform slightly better, its strength begins to degrade noticeably above 60°C. However, by selecting specialized high-temperature resistant resins, it is possible to achieve long-term operating temperatures ranging from 200 to 300°C. Aging Phenomenon Like many plastics, FRP is prone to aging, which is a natural consequence of environmental factors. Exposure to ultraviolet light, sand, rain, snow, chemical agents, and mechanical stresses can lead to a decline in material properties over time. Regular maintenance and protective coatings can help mitigate some of these effects, though they cannot completely eliminate aging in FRP structures. Low Interlaminar Shear Strength The interlaminar shear strength of FRP relies heavily on the resin matrix, which makes it inherently weak. To improve bonding between layers, careful attention must be paid during manufacturing processes. Using coupling agents and optimizing the layup sequence can enhance adhesion between layers. Additionally, product designs should avoid situations where layers are subjected to excessive shear forces, as this could exacerbate the problem. Dongguan HengTaichang Doors Co, Ltd. , https://www.dghtcdoor.com
Flaws and shortcomings