Mechanical performance of carbon-epoxy laminates. Part II: quasi-static and fatigue tensile properties

• Published in: Materials research (São Carlos, São Paulo, Brazil) São Paulo, Brazil), 2006-06, Vol.9 (2), p.121-130
• Main Authors: Tarpani, José Ricardo, Milan, Marcelo Tadeu, Spinelli, Dirceu, Bose, Waldek Wladimir
• Format: Article
• Language: English
• Subjects: carbon-epoxy laminates; composite materials; ENGINEERING, CHEMICAL; MATERIALS SCIENCE, MULTIDISCIPLINARY; mechanical properties; METALLURGY & METALLURGICAL ENGINEERING
• ISSN: 1516-1439; 1980-5373; 1516-1439
• DOI: 10.1590/S1516-14392006000200003

In Part II of this work, quasi-static tensile properties of four aeronautical grade carbon-epoxy composite laminates, in both the as-received and pre-fatigued states, have been determined and compared. Quasi-static mechanical properties assessed were tensile strength and stiffness, tenacity (toughness) at the maximum load and for a 50% load drop-off. In general, as-molded unidirectional cross-ply carbon fiber (tape) reinforcements impregnated with either standard or rubber-toughened epoxy resin exhibited the maximum performance. The materials also displayed a significant tenacification (toughening) after exposed to cyclic loading, resulting from the increased stress (the so-called wear-in phenomenon) and/or strain at the maximum load capacity of the specimens. With no exceptions, two-dimensional woven textile (fabric) pre-forms fractured catastrophically under identical cyclic loading conditions imposed to the fiber tape architecture, thus preventing their residual properties from being determined.