A study is undertaken to develop a methodology for determining the suitability of various high-cycle fatigue models for metallic structures subjected to combined thermal-acoustic loadings. Two features of this problem differentiate it from the fatigue of structures subject to acoustic loading alone. Potentially large mean stresses associated with the thermally pre- and post-buckled states require models capable of handling those conditions. Additionally, snap-through motion between multiple post-buckled equilibrium positions introduces very high alternating stress. An aluminum beam structure is chosen as the computational test article, with its geometric and material nonlinear response determined via numerical simulation. A cumulative damage model is employed using a rainflow cycle counting scheme and fatigue life estimates are made for 2024-T3 aluminum using various non-zero mean stress fatigue models, including Walker, Morrow, Morrow with true fracture strength, and MMPDS. A baseline zero-mean stress model is additionally considered. It is shown that for this material, the Walker model produces the most conservative fatigue life estimates when the stress response has a tensile mean introduced by geometric nonlinearity, but remains in the linear elastic range. However, when the loading level is sufficiently high to produce plasticity, the response becomes more fully reversed and the baseline, Morrow, and Morrow with true fracture strength models produce the most conservative fatigue life estimates.
Department, Program, or Center
Mechanical Engineering (KGCOE)
Przekop, Adam; Rizzi, Stephen; and Sweitzer, Karl, "An investigation of high-cycle fatigue models for metallic structures exhibiting snap-through response" (2008). Elsevier - International Journal of Fatigue, Vol. 30 (No. 9),Accessed from
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