This thesis is made in cooperation with the Swedish Defense ResearchAgency (FOI) and the Swedish Defense Material Administration (FMV). Partof the report is classified and is only published in a classified appendix.
The purpose of the thesis was to study the influence on RCS (Radar-Cross-Section) due to permanent deformation on ships hulls made of metal. Thedeformation studied is occurring on the plating between the web and thelongitudinals, commonly called “starved horse pattern” (see cover picture!).A comparison was made between a metal and an ideal flat compositestructure.
The main tool used for the study is the RCS program, OPTISCAT, developed by Kockums. Data has been gatered from several different ships meeting the operating profile for YS-NY. The data has then been processed by using Cubic splines and has then been interpolated to describe the deformation. The deformed panels has then been benchmarked against ideally flat panels, the latter simulating the composite case.
The results are quite astonishing, but in some way they are ecpected. The RCS is greatly effected by the deformations.At the Swedish Defence Material Administration, FMV, the work to produce the next generation of surface ships (YS-NY), for the Royal Swedish Navy, has begun. The question has been asked just how good, or bad, a metal hull supported by framing versus a composite hull is in a RCS sense. A ship built by steel (or metal in general), will develop deformations called "Starved Horse Patterns". These patterns may occur during the building process, but are most certainly also generated by the heavy dynamic preassures generated by waves. These patterns affect on the RCS are studied in this thesis.
2003. , 88 p.