SEDL / STP / STP1059-EB / STP24121S

Influence of Load Levels on Damage Growth Mechanisms of Notched Composite Materials

Razvan, A
Graduate project assistant and Reynolds Metals professorassistant professor, Engineering Science and Mechanics, Materials Research Group, Virginia Polytechnic Institute and State UniversityPennsylvania State University, BlacksburgUniversity Park, VAPA

Bakis, CE
Graduate project assistant and Reynolds Metals professorassistant professor, Engineering Science and Mechanics, Materials Research Group, Virginia Polytechnic Institute and State UniversityPennsylvania State University, BlacksburgUniversity Park, VAPA

Reifsnider, KL
Graduate project assistant and Reynolds Metals professorassistant professor, Engineering Science and Mechanics, Materials Research Group, Virginia Polytechnic Institute and State UniversityPennsylvania State University, BlacksburgUniversity Park, VAPA

Pages: 19    Published: Jan 1990

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Abstract

The effect of cyclic load amplitudes is studied using X-ray radiography and ply level electron microscopic analysis. The influence of fatigue-induced damage on the final fracture of the laminate is presented. From the findings, it is clear that delamination and fiber fracture have well-defined roles in the final fracture of both center-notched quasi-isotropic [0/45/90/-45]^s4 and orthotropic [0/45/0/-45]^s4 laminates under high- and low-amplitude fully reversed cyclic loading (R = -1). Depending on the material system (eight-harness satin weave Celion 3000/PMR-15, quasi-isotropic T300/5208, and quasi-isotropic and orthotropic AS4/1808), and the load level used, interaction modes between delamination, fiber fracture, localization, and the extent of fiber fracture distribution throughout the damaged zone were found to vary. The load level was also found to influence the interaction between the adjacent fibers in the satin weave Celion 3000/PMR-15 unidirectional system.