Delamination onset of the VARTM bond line in Mode I and Mode II cyclic loading
Abstract
In 2006 the United States Marine Corps (USMC) selected Sikorsky to develop an improved version of the CH-53E, a heavy lift helicopter designed to transport personnel, materiel and supplies into combat environments. The CH-53K Super Stallion has been announced as the replacement to the CH-53E and represents a significant increase in operational capability, partly delivered by a substantial increase in the use of lightweight composite materials. As a consequence of its operational environment, the USMC requires an efficient and effective rapid repair capability to maximize the serviceability of the CH-53K throughout its operational life. In order to meet this need, Purdue University has developed a repair patch utilizing the vacuum assisted resin transfer molding process. Throughout 2011-12 a static testing program was conducted to validate the VARTM patch in shear, biaxial and uniaxial loading. This Thesis seeks to further characterize the VARTM bond line fracture toughness by determining the bond line strength under Mode I and II cyclic loading. The methodology from ASTM D6115 was used to determine the strain energy release rate for which delamination onset of the bond line will not occur. It was found that the reduction of strength due to cyclic loading of the VARTM bond line was comparable with the interlaminar strength of common unidirectional composites under similar loading conditions.
Degree
M.S.E.
Advisors
Pipes, Purdue University.
Subject Area
Engineering|Aerospace engineering
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