BS in Materials Engineering
Materials Engineering Department
The design allowables for ten carbon fiber/cyanate ester composites used by Space Systems/Loral for satellite structures were recalculated. This recalculation is done in order to incorporate a growing pool of test data. B-Bases for tensile, compressive, and short beam shear strength (SBS) were generated. Means were calculated for combined modulus (an average of tensile and compressive moduli). Compressive strength B-Bases were higher than current B-Bases for nine of the ten materials, ranging from 27% to 44%. Tensile strength increases ranged from 1% to 18%. SBS changes were mixed, ranging from -39% to +22%. K13D2U tape was the only material which had concerning decreases in B-bases; however, this is not a structural material. Mechanical testing of M55J fabric coupons revealed lower than expected values. This is likely due to a uniform fiber misalignment angle of 4 degrees as well as isolated warpage. Fractured coupons of M55J fabric were analyzed using a FEI Quanta 200 SEM to characterize porosity. Voids were small, spherical and randomly distributed, as was to be expected for an autoclaved aerospace composite. Precise measurements of void content could not be made. Numerical data is proprietary to Space Systems/Loral.