Date of Award

3-15-2007

Document Type

Thesis

Degree Name

Master of Science in Astronautical Engineering

Department

Department of Aeronautics and Astronautics

First Advisor

Shankar Mall, PhD

Abstract

New composite materials and processing methods are continually being developed for use in high performance aerospace systems. One of these new processing methods is the vacuum assisted resin transfer molding (VARTM) process, which shows promise in producing large structural components that have good properties at a lower cost than traditional manufacturing methods. Future widespread use of components manufactured using the VARTM process depends on understanding how these components perform under service conditions, specifically under impact and fatigue conditions. The tension-compression fatigue behavior of a four-harness satin weave carbon fiber/epoxy (IM7/EPON 862) composite manufactured using the VARTM process is investigated in this research. The results are compared to previous research done to determine the tension-tension fatigue behavior of the same material. An anti-buckling fixture was used to allow a long, thin specimen to be used for the tests without causing a buckling failure when the specimen was under compression loading. The tension-compression fatigue tests were carried out at a percentage of the ultimate compressive strength at room temperature. Failed specimens were examined using an optical microscope and a scanning electron microscope to investigate and document damage mechanisms and failure modes. Fatigue life curves were developed for stress range, maximum stress, and normalized stress. Specimens tested under tension-compression loading were shown to have lower fatigue life than those under tension-tension loading.

AFIT Designator

AFIT-GA-ENY-07-M14

Download

Share

COinS