Control of distortion in thin ship panels

The increased use of thin section (i.e., less than 10-mm (3/8-in.) thick) steel in ship panel construction has aggravated distortion problems, adding to the costs for fitting and flame straightening. This paper describes the results of a study to evaluate techniques for control of distortion in thin panels used in ship construction. The objective of this project is to identify cost effective techniques for controlling distortion. Buckling is usually the dominant mode of distortion in thin panels, followed by angular distortion. Means of reducing both forms of distortion are discussed. During the design phase relatively small adjustments to the design, such as changing plate thickness or stiffener spacing, can significantly reduce distortion. Improving manufacturing techniques, including reducing weld size, implementing intermittent welding, and restraining the panel during welding, can also make a major impact on reducing distortion. New techniques such as egg-crate construction, laser welding, thermal tensioning, back-side line heating, back-bending, and weld quenching also show promise.