The Ti/APC-2 hybrid cross-ply nanocomposite laminates were successfully fabricated by the modified diaphragm curing process. The titanium thin sheets were surface treated by chromic acid anodizing to achieve superior bonding with APC-2 laminates. The nanoparticles SiO2 were uniformly spread on the interfaces of APC-2. The tensile tests at room and elevated temperatures were conducted to obtain the mechanical properties. It is interesting to find a knee point in each stress–strain curve. To predict and verify the feature of knee point the residual stresses and strains were calculated by simple methods. Adopting the residual stress effect and rule of mixtures, the analytical stress–strain curves at elevated temperatures were obtained. The data and mechanisms of the knee point in hybrid laminates were verified and highlighted. The predicted results of ultimate strength, longitudinal stiffness and the knee point are all in very good agreement with the experimental data.
The residual strength of notched AS-4/polyetheretherketone (PEEK) composite (APC-2) laminates with a central hole at elevated temperature was systematically investigated by both analytical and empirical methods. First, APC-2 cross-ply [0/ 90] 4s panels were fabricated and cut into samples. A circular hole with one of five diameters was drilled in the center of each sample. The samples were subjected to quasi-static tensile tests at elevated temperatures to measure their mechanical properties -strength and longitudinal stiffness. Stress concentration and high temperature were found to remarkably affect the residual strength of composite. Point stress criterion (PSC) above was found to be unsatisfactory in predicting the residual strength. A modified PSC combined with the equation of thermal degradation was able to predict the characteristic length at elevated temperature. The residual strengths predicted by the extended modified PSC model were in very close agreement with the empirical data.
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.