Material characterization of several resin systems for high temperature carbon fiber reinforced composites was
performed through a series of the tensile test, the dynamic mechanical analysis (DMA) test, and the strand test. The
modified tensile specimens and the DMA specimens were used to evaluate the tensile and thermal analysis properties of
resin systems. The strand specimens were used to evaluate the tensile properties and load transfer efficiencies of the
specimens. Four types of resin systems were considered. One was a conventional resin system currently used for filament
wound structures and other three were high temperature resin systems. According to the tensile and DMA test results, the
tensile modulus decreases slightly and the tensile strength decreases rapidly until the temperature reaches glass transition
temperature. The tensile modulus and tensile strength are almost negligible above glass transition temperature. The
tensile modulus obtained from the tensile test is consistent with that from the DMA test at different temperatures. From
the strand test results, considering, the load transfer efficiency is found to be around 87 to 90 % of the tensile strength of
T800H-12K carbon fibers for all resin systems except the specimen with the Type 2. Finally we found that the Type 4 is
the best candidate for high temperature resin system applicable to filament wound structures in the view of the glass
transition temperature as well as the tensile properties.
Phase transformations and crystal structures of nitinol shape memory alloy are investigated by varying with heat treatment conditions through DSC (differential scanning calorimetry) and XRD (X-ray diffraction). Heat treatment conditions are considered as heat treated times of 5min, 15min, 30min, and 45min as well as heat treated temperatures of 400°C, 500°C, 525°C, 550°C, 575°C, 600°C, 700°C, 800°C, and 900°C. In addition, tensile tests are conducted to investigate thermomechanical behaviors of nitinol shape memory alloy through material testing system by varying with heat treated temperatures and environmental temperatures. According to these results, heat treatment conditions are found to be significantly affected on phase transformations, crystal structures, and thermomechanical behaviors of nitinol shape memory alloy.