Date of Award


Document Type


Degree Name

Master of Science in Aeronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

Shankar Mall, PhD


Effects of a variable contact load on the high cycle fretting fatigue behavior of Ti-6AL-4V were investigated. Experimental tests were performed using a new test setup capable of applying a contact load varying in amplitude, frequency, and phase and independently measuring shear forces on opposite sides of a specimen. Finite element analysis (FEA) of experimental and idealized loading conditions was performed and local mechanistic parameters and the Modified Shear Stress Range (MSSR) fatigue parameter were determined. Correlations between contact width, slip amplitude, fatigue life and a variable contact load were established with variable contact loading shown to have a damaging effect. Predicted values of crack location and orientation using the MSSR parameter were verified experimentally. The MSSR parameter unsuccessfully predicted fatigue life for variable contact loads. A new formulation of the MSSR parameter is proposed.

AFIT Designator


DTIC Accession Number