So sánh phương pháp

	Phương pháp Tin cậy Bậc hai (SORM)	Đếm Dòng Chảy Mưa
Lĩnh vực	Kỹ thuật độ tin cậy	Kỹ thuật độ tin cậy
Họ	Process / pipeline	Process / pipeline
Năm ra đời	1979	1974
Người khởi xướng	Bernd Fiessler	Tatsuo Endo
Loại	Reliability analysis method	Cycle counting algorithm
Công trình gốc	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.
Tên gọi khác	SORM, Second-order approximation	Rainflow cycle counting, RFC
Liên quan	4	4
Tóm tắt	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.