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+---
+type: concept
+title: "Midas NFX Fatigue Analysis"
+created: 2026-06-02
+updated: 2026-06-02
+address: c-000181
+aliases:
+  - NFX fatigue analysis
+tags:
+  - concept
+  - finite-element-method
+  - midas-nfx
+  - fatigue
+  - verification
+status: current
+related:
+  - "[[Midas-NFX-Analysis-Manual|Midas NFX Analysis Manual]]"
+  - "[[midas NFX]]"
+  - "[[Finite Element Modeling and Convergence Checks]]"
+  - "[[Abaqus Progressive Damage and Failure]]"
+  - "[[Midas FEA Fatigue Analysis]]"
+sources:
+  - "[[Midas-NFX-Analysis-Manual|Midas NFX Analysis Manual]]"
+---
+
+# Midas NFX Fatigue Analysis
+
+## Definition
+
+NFX fatigue analysis estimates fatigue damage and life from finite element stress or strain histories. The manual covers stress-life, strain-life, and random vibration fatigue approaches.
+
+## Stress-Life Method
+
+The stress-life method uses S-N curves and is positioned for relatively low stress levels where elastic behavior dominates. The manual describes stress amplitude, mean stress, rainflow counting for variable-amplitude histories, S-N curve correction factors, Miner cumulative damage, and life as inverse damage.
+
+## Mean-Stress Corrections
+
+The source includes Goodman, Gerber, Soderberg, Morrow, and Smith-Watson-Topper style mean-stress correction ideas. This matters for solver verification because identical FE stress histories can produce different fatigue lives depending on correction method.
+
+## Strain-Life Method
+
+The strain-life method is positioned for higher stress/strain concentration regions where plastic strain can control life. The manual includes elastic/plastic strain decomposition, cyclic strength/hardening parameters, and Neuber-rule based recovery from linear elastic results.
+
+## Random Vibration Fatigue
+
+For complex load histories, the manual also treats frequency-domain random vibration fatigue. That workflow connects modal/frequency response outputs to fatigue damage rather than relying on explicit time histories.
+
+## Solver Development Use
+
+For a custom solver, fatigue is primarily a postprocessing harness problem. The FE solver must first produce trusted stress/strain histories at documented locations; only then should rainflow counting, S-N/E-N interpolation, mean-stress correction, Miner damage, and random-response fatigue be tested.
+
+## Connections
+
+- [[Finite Element Modeling and Convergence Checks]] connects fatigue accuracy to stress recovery and mesh quality.
+- [[Abaqus Progressive Damage and Failure]] provides a broader damage/failure comparison.
+- [[Midas FEA Fatigue Analysis]] is the sibling MIDAS fatigue reference.