A new approach for finding the design point of nonlinear systems under random excitation. (November 2017)

• Record Type: Journal Article
• Authors: Salari, Mohsen; Safi, Mohammad
• Is Part Of: Structural safety. Volume 69(2017)
• Page Start: 47
• Page End: 56
• Publication Date: 2017-11
• Subjects: Design point -- Tail equivalent linearization method -- Reliability analysis -- Non-linear random vibration -- Critical excitation; Structural stability -- Periodicals; Safety factor in engineering -- Periodicals; Reliability (Engineering) -- Periodicals; Constructions -- Stabilité -- Périodiques; Coefficient de sécurité en ingénierie -- Périodiques; Fiabilité -- Périodiques; 620.86
• DOI: 10.1016/j.strusafe.2017.07.008
• Languages: English
• ISSNs: 0167-4730

Abstract

Highlights: A new method for finding the design point of a nonlinear system under random excitations has been proposed. The method finds the design point of the nonlinear dynamic system on the basis of the physical characteristics of the system. For nonlinear elastic SDOF systems, the result of the proposed approach is identical to the result of the mirror image excitation method. For nonlinear hysteresis systems, filtered white noise excitations and multi degree of freedom systems, the proposed method yields acceptable approximate results. Abstract: In order to perform nonlinear stochastic dynamic analyses, the tail equivalent linearization method may be employed, which entails the adoption of the first-order reliability method. The major computational challenge posed in this method is related to finding the design point excitation for the threshold corresponding to the failure of the nonlinear system. Furthermore, finding the design point is also a sufficiently challenging problem in some importance sampling techniques. In the present paper, a new approach for finding the design point of nonlinear SDOF systems under white noise excitation is introduced, one that is identical to the mirror image excitation method for a nonlinear elastic system and yields superior results for a nonlinear hysteresis system compared to the results of mirror image excitation method. It is then extended to filtered white noise excitations and multi degree of freedom systems. Some numerical examples are given for confirming the efficiency and accuracy of the proposed method by comparing it to other methods.