A PROBABILISTIC ANALYSIS OF A NONLINEAR STRUCTURE USING RANDOM FIELDS TO QUANTIFY GEOMETRIC SHAPE UNCERTAINTIES

Engineers at Los Alamos National Laboratory (LANL) are currently developing the capability to provide a reliability-based structural evaluation technique for performing weapon reliability assessments. To enhance the analyst's confidence with these new methods, an integrated experiment and analysis project has been developed. The uncertainty associated with the collapse response of commercially available spherical marine float is evaluated with the aid of the non-linear explicit dynamics code DYNA3D coupled with the probabilistic code NESSUS. Variations in geometric shape parameters and uncertainties in material parameters are characterized and included in the probabilistic model. Inherent anomalies and variations in geometry and material properties, which were collected from the set of test specimen, are included in the numerical model in the form of random fields and probability density functions (PDF's). A comprehensive analysis of the parameter correlations is performed to determine appropriate correlation functions to use for the geometric random fields.