FAILURE ANALYSIS OF BOLTED COMPOSITE JOINTS EXHIBITING INPLANE FAILURE MODES

The Damage Zone Model (DZM) is applied for simultaneous in-plane, net- tension, and shear-out failure analysis of T300/914C graphite/epoxy [0 (alpha)/90(beta)/+/-45(gamma)]-type laminates containing a single, per fect-fit, finger-tight, bolt-loaded hole. DZM is a general in-plane fa ilure model for composites with arbitrarily shaped cutouts or in other ways experiencing stress gradients. The DZM parameters (laminate stre ngth and fracture energy properties), two for each failure mode, are d etermined from the strength of standard notched and unnotched coupon s pecimens. Neither DZM, nor its parameters, are in any way modified or calibrated for bolted-joint application. For the given joint geometry, DZM correctly predicts a dominant shear-out failure for all laminates . The joint strength predictions are well within +/-10% of the experim ental results.