Date of Award
2025
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Aerospace Systems Engineering
Committee Chair
Nathan Spulak
Committee Member
Yue Xiao
Committee Member
Nicholas Ginga
Research Advisor
Nathan Spulak
Subject(s)
Steel--Mechanical properties--Simulation methods, Aluminum--Mechanical properties--Simulation methods, Inconel--Mechanical properties--Simulation methods, Finite element method
Abstract
Understanding aerospace materials’ strain rate sensitivity is crucial for accurate designs and analysis for structural performance in dynamic loading conditions, such as rocket launches, airplane collisions, and debris impacts. Three common aerospace face-centered cubic (FCC) metals are evaluated through various strain rate tests and FEA and simulation modeling. Quasi-static and intermediate tests are performed on a hydraulic load frame, and dynamic tests are run on a split-Hopkinson pressure bar, all in tensile motion. This covers the range of strain rates from 1x10-3 s-1 to 1x103 s-1. Results reveal little strain rate sensitivity at room temperature for A286 steel and AL7075 aluminum, while Inconel 718 clearly shows some variations. Finite Element Analysis (FEA) was run with LS-DYNA to simulate tabulated material models and Johnson-Cook constitutive models. Material constants are derived from experimental data, and the simulations are compared to the experimental results. Overall, the tabulated simulations show a more accurate comparison than the mathematical Johnson-Cook model. This research confirms that tabulated, data-derived material models are more accurate than empirical equations and recommends that for the design and analysis of dynamic aerospace structures, tabulated, or tabulated-based, simulations should be used. A full investigation of A286 steel is presented with experimental tests and simulation model results for analysis and conclusions. Future work includes completing the investigation of AL7075 and IN718.
Recommended Citation
Resnick, Sydney Carlota, "Evaluating the accuracy of Johnson-Cook strain rate sensitivity for FCC aerospace structural materials" (2025). Theses. 789.
https://louis.uah.edu/uah-theses/789