Reliability analysis of plate elements under uniaxial compression using an adaptive response surface approach

Abstract

This paper presents a reliability analysis of plate elements under uniaxial compression using an adaptive response surface approach. The limit state considered is the buckling collapse failure of the plate elements computed through nonlinear finite element analysis. A response surface model based on second-order polynomials is combined with the first-order reliability method in order to compute reliability estimates at moderate computational time. An adaptive interpolation scheme combined with a Latin hypercube sampling technique is used to define the response surface model iteratively in the region of the basic random variables space that most contributes to the failure probability. Plate elements typical of the deck structure of double hull tankers with random thickness, material properties and amplitude of weld-induced initial distortions are used as case study. The uniaxial compressive load is defined considering extreme values in a reference time period of one year of operation of the ship. The effect of considering constrained or restrained boundary conditions along the longitudinal plate edges as well as corroded plate elements on the reliability analysis results is determined. Sensitivity analyses are performed to identify the relative contribution and importance of each basic random variable to the estimated reliability indices.

Keywords:

• structural reliability analysis
• response surface method
• first-order reliability method
• nonlinear finite element analysis
• unstiffened plate elements
• buckling collapse strength

Acknowledgements

The first author has been funded by the Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia – FCT) under the contract SFRH/BPD/85093/2012. This study was initiated during a visit of the first author to the Center of Mechanics and Structural Dynamics, Vienna University of Technology, Austria, which was funded by the Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia – FCT) under the contract SFRH/BD/39106/2007. This study contributes to the project ‘Adaptive Methods for Reliability Analysis of Complex Structures’, which is funded by the Portuguese Foundation for Science and Technology (Fundação para a Ciência e a Tecnologia – FCT) under the contract PTDC/ECM/115932/2009.