手法を比較

	二次信頼性解析法 (SORM)	レインフロー計数法
分野	信頼性工学	信頼性工学
系統	Process / pipeline	Process / pipeline
提唱年	1979	1974
提唱者	Bernd Fiessler	Tatsuo Endo
種類	Reliability analysis method	Cycle counting algorithm
原典	Fiessler, B., Neumann, H. J., & Rackwitz, R. (1979). Quadratic limit states in structural reliability. Journal of the Engineering Mechanics Division, 105(4), 661-676.	Goodman, J. (1899). Mechanics Applied to Engineering. Longman, Green and Co.
別名	SORM, Second-order approximation	Rainflow cycle counting, RFC
関連	4	4
概要	The Second-Order Reliability Method (SORM) is an extension of FORM that improves failure probability estimates by accounting for the curvature of the limit-state surface at the design point. Introduced by Fiessler, Neumann, and Rackwitz in 1979, SORM provides more accurate approximations for nonlinear failure surfaces while remaining computationally efficient. It has become the standard refinement when FORM accuracy is insufficient.	Rainflow counting is a fatigue cycle counting method that converts a complex stress history into individual cycles for damage assessment. Developed by Tatsuo Endo and colleagues in 1974, it provides the most physically realistic representation of fatigue damage when combined with Miner's linear cumulative damage hypothesis. The algorithm has become the industry standard in reliability engineering and vibration analysis.