Compressive fatigue in glass and graphite reinforced composites
Conners, Jeffrey Durnell
McGarry, Frederick J.
MetadataShow full item record
The characteristics of compressive fatigue failure are described for unnotched laminates, with the following rank ordering by compressive strengths determined: [0 degrees/90 degrees] Graphite Epoxy, [ 0 degrees/+ 45 degree/90 degrees] Graphite Epoxy, [0 degrees/45 degrees] Graphite/Epoxy, [0 degrees/90 degrees] Glass Epoxy, [0 degrees/+45 degrees] Glass/Epoxy (0 degrees/+45 degrees/90 degrees] Glass Epoxy, Style 61 E Glass Woven Rovings/Polyester, and 1.5 ounce chopped E Glass Mat/Polyester. A normalized slope parameter with unites of percent decrease of ultimate compressive stress per decade of applied cycles is used to characterize the fatigue resistances of the materials, with the following rank order resulting: [0 degrees/90 degrees] Graphite Epoxy, [ 0 degrees/+ 45 degree/90 degrees] Graphite Epoxy, [0 degrees/45 degrees] Graphite/Epoxy, [0 degrees/90 degrees] Glass Epoxy, [0 degrees/+45 degrees] Glass/Epoxy (0 degrees/+45 degrees/90 degrees] Glass Epoxy. The degradation by water immersion of the Graphite/Epoxy systems is shown to be a loss static compressive strength and a decrease in normalized slope on the order of 10 percent. Multiple Regression Analysis used to quantify the effects of varying unidirectional ply laminate orientation shows that the compressive fatigue resistances of advanced composites cannot be satisfactorily explained only by ply orientation characterizations.. Various physical theories concerning the causes and processes of ultimate failure during compressive fatigue are postulated, based on the microstructures of the specimens and phenomena observed during testing.
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
An investigation of elevated temperature fatigue crack initiation in 2 1/4 Cr-1 Mo low alloy steel Keifer, Orion P. (Monterey, California. Naval Postgraduate School, 1984-06);Environmental effects in elevated temperature fatigue have teen extensively studied and reported in the literature for 2 1/4 Cr-1 Mo steel. The results of cycles to failure (lumped initiation and propagation life) ...
Banazwski, Brian J. (Monterey, California. Naval Postgraduate School, 2011-12);This thesis examines the interplay of residual stress distributions caused by welding and laser peening of marine aluminum alloy 5083. Residual stresses at welds in this alloy can cause fatigue and stress corrosion cracking ...
Wiest, Anthony D. (Monterey, California. Naval Postgraduate School, 1992-09);The thermal strain response of as-cast samples of 40% PI 00 graphite fiber reinforced 6061 Al composites in the unidirectionally reinforced and the [0/90] cross-plied configuration was studied. Thermal strain hysteresis ...