مقایسهٔ روش‌ها

	روش قابلیت اطمینان مرتبه اول (FORM)	روش قابلیت اطمینان مرتبه دوم (SORM)
حوزه	مهندسی قابلیت اطمینان	مهندسی قابلیت اطمینان
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	1969	1979
پدیدآور	Allin Cornell	Bernd Fiessler
نوع	Reliability analysis method	Reliability analysis method
منبع بنیادین	Cornell, C. A. (1969). A probability-based structural code. Journal of the American Concrete Institute, 66(12), 974-985.	Fiessler, B., Neumann, H. J., & Rackwitz, R. (1979). Quadratic limit states in structural reliability. Journal of the Engineering Mechanics Division, 105(4), 661-676.
نام‌های دیگر	FORM, First-order second-moment method	SORM, Second-order approximation
مرتبط	4	4
خلاصه	The First-Order Reliability Method (FORM) is a probabilistic technique for estimating the probability of structural failure given uncertain input parameters. Developed by Allin Cornell in 1969 and refined by Hasofer and Lind in 1974, FORM provides a computationally efficient approximation to the true failure probability by linearizing the limit-state function at the most probable failure point. It has become the cornerstone of modern structural reliability analysis and risk-based design.	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.