Adaptation of COPRAS Algorithm for Reliable Epoxy Matrix Selection for Cryogenic Applications

This work aims to present an experimental framework for material selection purposes for different cryogenic applications that employ thermosetting epoxies. Overall, 9 commercially available epoxy candidates are chosen with varying viscosity and thermal properties. Each candidate is then cast into testing specimens according to ASTM D790 to be tested under three-point bending loading. Mechanical tests were performed both under room temperature and under a cryogenic environment to extract flexural modulus, strain, and strength values. The mechanical response of each candidate is explained case by case with the assistance of fracture surfaces obtained through cryogenic testing. The last effort is to adapt the obtained mechanical response to well-accepted COPRAS material selection criteria to extract the best material candidates for prescribed engineering scenarios. Results suggested that 2 out of 9 candidates performed well both under RT and cryogenic environments. The presented work also aims to provide an example of the adaptation of COPRAS for material selection purposes via three-point bending tests considering the test variances frequently observed in the research conducted with thermosetting plastics.