Authors: Xin Chi Yan, Yuan Hua
Abstract: Because there were many random factors, the failure analysis and reliability analysis of
stochastic structural system was very difficult. In this paper, failure procedure and reliability
analysis flow chart of stochastic structural system based on stochastic finite element were present.
Establishment of the safety margin, reduced member stiffness matrix and opposite sign of the
equivalent nodal force was analyzed in the failure process. Stochastic finite element method was
adopt to solve the structures’ stochastic, and the reliability of structural system is evaluated by
PNET method. According to probabilities of the failure paths redound to probability of failure of the
structural system, the most significant failure paths was determined on the basis of the
branch-and-bound method. Then, a classical 48-bar space truss problem is made as an example to
illustrate the predominance of this algorithm, the calculation shows that the analysis of the failure
process is justified; this methodology is efficient and useful for reliability analysis of large
stochastic structural system.
223
Authors: Yan Gang Zhao, Yue Feng Geng, Kazuhiro Yoshihara
Abstract: In ultimate asseismic design of ductile frame structures, plastic deformation and plastic
hinge are generally permitted, and some preferred failure modes are often selected. It is an
important problem that whether the designed structure collapses according to the designed failure
mode, because of the large uncertainties included in external loads and member strength. In this
paper, an identification procedure of failure modes for frame structures is developed, and the likely
collapse modes of frame structures under uncertain load and member strength are investigated
under assumption of normal distributed and non-normal distributed external loads and member
strength. It is found that the occurrence order of likely collapse mode is much influenced by the
distribution of the random variables. The occurrence order of collapse modes for column over
designed structures are investigated and it is found that the increase of column over-design factor
can effectively avoid the story collapse mode in probabilistic means.
1393
Authors: Bao Chu Yu, Sheng Yong Li
Abstract: A self-anchored suspension bridge is analyzed for its structural system reliability, and the bridge reliability is relatively high under vehicular load. Through seeking the distinct structural system fault modes the relatively weak structural elements can be identified, which can be the basis on its reasonable design and offer the reference to the analysis for the similar bridge structures. The results verify that the global -Unzipping method and the improved difference equivalent recursion algorithm is efficient and applicable for system reliability evaluation of the complex structures such as self-anchored suspension bridges.
1868
Authors: Y.W. Tun, D.M. Pedroso, Alexander Scheuermann
Abstract: Uncertainty estimation and consideration in engineering is an important practice to design reliable structures especially in geotechnical engineering since the level of control with regards to the material parameters is much lower. Research has been conducted in order to assess the reliability of geotechnical works using probabilistic methods where challenges in computing the probability density function and predicting the critical failure region must be first overcome. One method to solve this problem is the Monte Carlo simulation; however it requires a high computational effort. Alternatively, reliability indices such as the Hasofer-Lind (HL) index can approximate the probability of failure Pf with fewer computations. Nonetheless, yet an optimisation problem needs to be solved. In this work, a genetic algorithm is developed to compute the HL index using the limit equilibrium method to search for the critical failure surface. Study cases and the analysis of the Vajont landslide are presented in order to illustrate the method.
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