Wang, Su Su2016-02-212016-02-21December 22013-12http://hdl.handle.net/10657/1230Fiber composite laminates have been widely used in wind energy and other engineering structures. Three-dimensional deformations and stresses are induced in thick laminates structural joints and ply drops. In addition, weak interlaminar strength often governs complex thick composite laminate failure. Fundamental knowledge of interlaminar mechanical properties and fatigue failure behavior is essential for accurate design and long-term reliability of large composite rotor structures. However, little information on the subject is currently available. In the study, interlaminar fatigue experiments were conducted on composite specimens to determine interlaminar cyclic stress-life relation. Optical and electron microscopy was performed to determine associated fatigue damage mechanisms and failure modes. Interlaminar tensile and shear fatigue stress-life relationships were established for a glass fabric/vinyl ester composite. Both show a fatigue limits below 40% of static interlaminar strengths. Fatigue failure was mostly initiated at the interply interphase which contained the highest amount of defects and stress concentrations.application/pdfengThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).Composite materialsInterlaminar fatigueGlassVinyl esterThrough-thickness2016-02-21Thesisborn digital