Further Studies of Computer Simulation of Slamming and Other Wave - Induced Vibratory Structural Loadings on Ships in Waves

Results of analytical modeling and computer simulation of wave-induced structural loadings on ships i!lwaves is presented! with consideration ~f bow flare slamming, bottom impact slamming, and springing. Consideration is given only to the case of head seas, and the outputs are obtained in the form of time histories due to the nature of the nonllnearities and the nonstationary propert~es associated with the slamming phenomena. Springing is considered to be linear and statistically stationary, and output in either time history or spectral foxm is possible, with the same r.m.s. value obtained by either technique. Time history simulation of the slowly-varying direct wave-induced vertical bending moment is also provided% so that relations between constituents making up the total vertical bending moment are demonstrated. The output data is available at rates appreciably faster than real time (80 times or more faster) by use of a large commerc~al general purpose digital computer, thereby allowing rapid analysis of ship structural loads via computer simulation. The present results are primarily demonstrative of capability. Particular refinements in the manner of representing local forces, theoretical techniques for evaluation of such forces, and computational procedures, etc. that are necessary for producing a final completed program for calculation of such loads on a routine basis, are described in the report. The ultimate use of a developed program for vibratory loads, in conjunction with the previously established program for wave-induced bending moments, is a basic tool for application in design and analysis of ship structures.