Response of thick, notched laminates subjected to tension-compression cyclic loadsThe fatigue response of a (0/24/90/-45)s4 T300-5208 graphite-epoxy laminate with a drilled centerhole subjected to fully reversed tension-compression (R=-1, T-C) constant amplitude loading was investigated. Damage evaluation techniques such as stiffness monitoring, penetrant-enhanced X-ray radiography, C-scan, laminate deply and residual strength were used to establish the mechanisms of damage development as well as the relations between this damage and the stiffness, strength and life of the laminate. Damage initiated at the hole as matrix cracking parallel to the fibers in all plies. Matrix cracks had a significant effect on delamination initiation and growth. Delaminations initiated near the surface in the densely cracked region at the hole and grew along major matrix cracks. Compressive properties degraded more rapidly than tensile properties. At the stress levels used, residual tensile strength increased early in the fatigue life and remained approximately constant to near the end of life, when failure was precipitated by excessive laminate instability during the compressive portion of the loading.
Document ID
19860058286
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Bakis, C. E. (Virginia Polytechnic Inst. and State Univ. Blacksburg, VA, United States)
Stinchcomb, W. W. (Virginia Polytechnic Institute and State University Blacksburg, United States)