Submarine Structure Modeling and Analysis for Life-Cycle Management: Phase 2
Abstract
This report presents results from the nonlinear structural analyses of six cylinder specimens in order to provide validation of the finite element methods of predicting collapse pressures and post collapse behaviour of stiffened cylindrical shells. The six cylinder specimens considered in the present study included a non-corroded short cylinder, two short cylinders with simulated center corrosion, a noncorroded long cylinder, a long cylinder with simulated corrosion in flange and a long cylinder with penetrations. The nonlinear calculations were performed using the VAST finite element (FE) code. In these nonlinear analyses, convergence studies were first conducted to determine the adequate mesh sizes for capturing nonlinear collapse behaviour of cylinders of different geometry. Other factors affecting the nonlinear responses of cylinders, such as material properties, geometric imperfections, boundary conditions, specimen's self weight and some meshing details, were also considered. In order to facilitate direct comparison between measured and predicted strain histories, a FORTRAN program was developed to automatically extract load-strain histories at all strain gauge locations from the FE solutions. FE meshes were produced using SubSAS, a submarine structural analysis program developed for DRDC Atlantic and the UK MoD. Tools for incorporating tapered regions and simulated corrosion were under development in SubSAS at the time of writing, and so specialized FORTRAN programs were written to incorporate these features into the FE models, and to generate shell element meshes for plate junctions that do not contain material overlaps. Very good agreement is obtained between the numerical and experimental results, indicating that the modeling approach and numerical analysis procedures described herein are capable of predicting the collapse behaviour of corroded stiffened cylindrical shells.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2008
- Accession Number
- ADA637983
Entities
People
- John Wallace
- Lei Jiang