Sudip Dinda

Date of Award


Degree Name

Master of Science in Engineering


Mechanical and Aerospace Engineering


Mechanical and Aeronautical Engineering

First Advisor

Dr. Daniel Kujawski

Second Advisor

Dr. Philip Guichelaar

Third Advisor

Dr. Judah Ari-Gur

Access Setting

Masters Thesis-Open Access


The prediction of fatigue crack growth rate of a structural material is an important aspect by which we can predict the critical or safe crack length and, therefore, avoid the sudden failure of components and structures.

There are numerous models which claim to predict the fatigue crack growth rate, but with the exception of the highly published "crack closure methodology" no other model lived up to the expectation of correlating the fatigue crack growth data or predicting the fatigue crack growth rate for different R-ratios.

In order to find an effective solution to the above problem a study has been conducted to discuss the difficulties associated with the existing crack closure,

∆Keff methodology. A simplified fatigue crack driving force parameter, K*=Kmax

α(CK+) (1 • α) is proposed to predict the crack growth rate for different R - ratios.

A validation on the effectiveness of the proposed crack growth parameter K * relative to the existing crack closure approach, ∆Keff, is done based on published experimental data.

In addition, another model is developed called the "master curve" approach, which also predicts the R-ratio effects on crack growth rate.