Session: 03-03-02: Damage, Fatigue, and Fracture

Paper Number: 110899

110899 - Hydrogen-Assisted Fatigue Crack Growth Model for Life Prediction With Pre-Existing Corrosion 

Hydrogen is becoming an increasingly appealing energy carrier and with diversifying usages of hydrogen, the hydrogen industry is set to grow rapidly in the coming years. However, hydrogen is known to degrade metals and lead to a significant loss in ductility, a mechanism known as hydrogen embrittlement. As a result, several studies were conducted under gaseous and electrochemically charged hydrogen environments. However, most of these studies focused on virgin material degradation under hydrogen environment but did not incorporate the effect of pre-existing damage due to aging, such as corrosion. This study focuses on a hydrogen-assisted fatigue crack growth model that can capture the fatigue crack growth rate behavior for various line pipe steels (X52, X70, and X100) at various operating conditions (hydrogen gas pressure, loading frequency, and stress ratio). Pre-existing corrosion (both general material loss and pitting) effects are naturally included as surface irregularities in the form of roughness. Standard profile roughness parameters (such as average roughness and peak-to-valley height roughness) along with modified stress intensity factor solutions are integrated with a crack growth kinetics function for the prediction of fatigue life. Model predictions are validated against in-house as well as experimental data collected from the open literature. Several future research directions are recommended based on the current findings.

Presenting Author: Kaushik Kethamukkala Arizona State University

Presenting Author Biography: Kaushik Kethamukkala is a first year PhD student in the Department of Mechanical Engineering at Arizona State University. He is working under the supervision of Dr. Yongming Liu, studying the effects of gaseous hydrogen on the fatigue behavior of pipeline steels.

Authors:

Kaushik Kethamukkala Arizona State University
Yongming Liu Arizona State University