A high-throughput testbed for parallelized thermal fatigue characterization
Wendsday May 28th 2025 at 14:00
Wolfson Building of Mechanical Engineering, Room 206
Abstract:
Thermal fatigue is a key life-limiting failure mechanism in turbomachinery. This problem is especially severe in the turbine of turbopumps that power new reusable staged-combustion rocket engines, which subject the turbine to extreme thermal transients upon engine startup and shutdown. A candidate approach to mitigating thermal fatigue is to select intrinsically fatigue-resistant materials, often characterized by a combination of low thermal expansion and high ductility. However, reliable thermal fatigue data is scarce and can be expensive and time-consuming to collect. This work addresses this lack of design-relevant data using a novel high-throughput approach for parallelized thermal fatigue testing. The test rig uses a high-speed rotating disk specimen, with edge notches of varying radii uniformly spaced around its perimeter. The specimen is subjected to thermal cycling using induction heating followed by forced convection cooling while the edge notches are imaged in situ with high-rate digital image correlation and IR thermography, providing real-time measurements of the displacement and temperature fields. By tracking the strain at the notch roots and observing the cycles to crack initiation, a single disk specimen can be used to collect a complete strain-life curve. The setup can also be used to directly measure crack propagation rates. In this talk I will describe the design, development, and successful implementation of this high-rate test method. I will also present results from an ongoing DARPA-funded test campaign where we aim to characterize the thermal fatigue properties of 150 alloy variants. The aggregated data provides insights into the effects of material chemistry, microstructure, processing history, and surface finish on thermal fatigue resistance. Further it establishes fatigue-life correlations that can be used to estimate the fatigue behaviors of materials outside those explicitly tested. The talk will conclude with a discussion of how these experimental results are now being used to design fatigue-resistant turbine rotors for reusable rocket engines.
Bio:
Yuval Harduf is a research engineer in the Department of Aeronautics and Astronautics at MIT, where he develops high-throughput material testing methods. He holds a Ph.D. from the Technion – Israel Institute of Technology (2024), where he also earned his master's (2017) bachelor's (2016) degrees, all in mechanical engineering. His studies were part of the IDF’s academic reserve (atuda academit) program "Brakim," through which he served at Rafael Advanced Defense Systems between 2017 and 2022.
