First-order reliability method explained

The first-order reliability method, (FORM), is a semi-probabilistic reliability analysis method devised to evaluate the reliability of a system. The accuracy of the method can be improved by averaging over many samples, which is known as Line Sampling.^{[1] [2]}

The method is also known as the Hasofer-Lind Reliability Index, developed by Professor Michael Hasofer and Professor Niels Lind in 1974.^{[3] [4]} The index has been recognized as an important step towards the development of contemporary methods to effectively and accurately estimate structural safety.^{[5] [6]}

The analysis method depends on a "Most Probable Point" on the limit state ^[7]

See also

• EN 1990
• Fast probability integration
• Stress–strength analysis

Notes and References

1. Verderaime, V. (1994) "Illustrated Structural Application of Universal First-Order Reliability Method", NASA Technical Paper 3501.
2. Cizelj, L.; Mavko, B.; Riesch-Oppermann, H. (1994) "Application of first and second order reliability methods in the safety assessment of cracked steam generator tubing", Nuclear Engineering and Design, 147.
3. Hasofer, Abraham M., & Lind, Niels C. (1974). "An Exact and Invariant First Order Reliability Format." ASCE Journal of the Engineering Mechanics Division. Vol. 100. EM1. Feb 1974. 111-121
4. Huang, Jinsong, and D. V. Griffiths. "Observations on FORM in a simple geomechanics example." Structural Safety 33, no. 1 (2011): 115-119.
5. Dudzik, A., and U. Radoń. "The reliability assessment for steel industrial building." Advances in Mechanics: Theorectical, Computational and Interdisciplinary Issues (2016): 163-166.
6. Choi, Chan Kyu, and Hong Hee Yoo. "Uncertainty analysis of nonlinear systems employing the first-order reliability method." Journal of Mechanical Science and Technology 26, no. 1 (2012): 39-44.
7. C Annis. "How FORM/SORM is Supposed to Work"