The in-house developed buckling tool enables more efficient structural analysis. This speeds up the process of ship design and creates optimized ship designs with less weight and fully compliant with multiple classification societies.
What is buckling?
The majority of ships built today use steel and aluminum plates for construction. These flat or curved plates are strengthened by primary and secondary stiffening elements. Buckling of the plate panels in between the stiffening elements can occur because of compression or shear. This geometrical instability can occur anywhere in a ship’s structure during:
- Global bending of a ship such as hogging or sagging (in-plane forces)
- Lateral pressure caused by seawater or fluid in a tank (out-of-plane forces)
- Concentrated loads in various directions caused by heavy equipment installations
Standard shipbuilding steel plate can withstand stress of 235 MPa. While the steel will experience structural failure if exposed to stresses greater than this, buckling can occur if the steel if exposed to stresses less than this. The load at which buckling occurs depends on the stiffness of a component and the choice of the structural grid, usually not upon the strength of the material.
Buckling calculations are performed during the basic design phase of each ship. This is to prove the structural integrity for buckling and yield in accordance with the guidelines set out by classification societies.
These calculations involve vast amounts of data. Traditionally, this is done manually in Excel spreadsheets. However, this is labor-intensive – especially with the new rules, constrained by the limits of the software, and is a less than ideal way to present results. Keen to improve this situation, C-Job developed the buckling tool.
The buckling tool
The buckling tool is an in-house developed tool that calculates the stresses in a given structure. The tool uses an automated calculation method to perform buckling analysis of ship designs or any other shell structure. It details the stresses on each elementary plate panel and calculates the buckling capacity of each of the panels. The buckling tool can analyze both unstiffened and stiffened panels.
C-Job’s structural engineers use the buckling tool results to create color-mapped 3D FEM models. These identify the areas that are more susceptible to buckling as well as the areas that are actually underutilized. By utilizing the buckling tool from the earliest stages of concept design, C-Job can define the optimum thickness of panels – resulting in a clearer understanding of plated structures.
The buckling tool enables more efficient structural analysis. This speeds up the process of ship design: producing optimized ship designs with less weight, but still fit-for-purpose, fully functional and class compliant. Streamlined calculations mean that the buckling tool completes in one day what would have normally taken weeks.
The tool meets standards set by classification societies such as Bureau Veritas, DNV GL, and the International Association of Classification Societies (IACS).