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The effect of cold environment on the buckling behavior of hybrid composites prepared by using carbon/aramid/glass

In this study, the effect of cold environment on the buckling behavior of hybrid composites kept at −18°C for certain periods was investigated. For the buckling tests, hybrid composite plates with different fiber combinations were produced using three different fibers—carbon twill, E-glass twill, and aramid twill—and an epoxy resin (Araldite/Aradur) as the matrix material. Specimens for the buckling experiments were cut from the 12-layer hybrid composite plates and the hybrid composite specimens were then divided into three different groups. The specimens in Groups I and II were kept in a refrigerator for 90 days and 150 days, respectively, while Group III specimens were kept under room conditions as the control group. The hybrid composite specimens were subjected to buckling tests as soon as their waiting times were over. The buckling behaviors of hybrid composites with different stacking sequences were examined on the basis of the data obtained from the buckling experiments. The load–displacement curves obtained from the experiments were used to calculate the critical buckling loads (Pcrs) for each hybrid configuration. The Pcr was found to be highest for the hybrid configuration CAG (carbon/aramid/glass) with the stacking sequence [(0/−90)3]s and lowest for the hybrid configuration CAG45 with the stacking sequence [(45/−45)3]s. The hybrid composite specimens kept in a cold environment were found to have higher Pcrs than those kept under room conditions. The difference was greater in the case of the hybrid specimens kept in the cold environment for 150 days.