A new effective approach for computation of reliability index in nonlinear problems of reliability analysis

In reliability analysis, locating design point and computing reliability index is still a challenge. In this paper a simple and efficient reliability algorithm is proposed. The proposed algorithm tries to approach design point purposefully during the iterations. This iterative algorithm works based on the effective use of the represented search direction vectors with appropriate step sizes. In the first part of the proposed algorithm, a search direction vector is represented to locate the general vicinity of design point. In the second part, two search direction vectors are represented such that an effective search around design point is carried out. This search is actually like a damped oscillating movement around design point, from safe to failure domain and vice versa. By such a movement, the distance with design point is reduced until it is found. Generally, in representing the search direction vectors and step sizes of two parts of the proposed algorithm, the main focus is on creating a simple and fast movement towards design point. The proposed algorithm is implemented in several numerical nonlinear examples, among the commonly used examples of the literature, to show its strong performance.