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Farmer profit can be increased and air quality improved

The coupled flexural-torsional vibration equations of a floating beam model, considering added fluid masses, are developed. The beam has varying bending stiffness, varying torsional stiffness and varying mass distribution; frequencies and mode shapes are calculated using Galerkin’s method. Stiffness for the cracked beam (backbone) has been calculated using an energy procedure. Experimental values have been compared with the results of theoretical predictions and the agreement between the two found to be good. The frequency contour method has been used to identify the crack.`

This paper describes recent head seas slamming tests on four models of the NRC hull form series for fast surface ships. This series has been developed using the Canadian DDE-205 frigate as the 'parent' hull form and is defined by systematic variation of non- dimensional geometric parameters involving ship length, beam, draft, block coefficient, and water plane area coefficient. The series provides a database for preliminary design of high speed ships, and for validation of theoretical hydrodynamic models. The series covers, but is not limited to, contemporary frigate and destroyer hull forms. The test variables include model speed, wave frequency and wave steepness. Most tests were performed in regular waves, but a limited number of irregular wave tests were also performed. Test procedures are reviewed, and an overview of results is presented, including bending moment spectra, impact forces and rise times, impact pressures and rise times, and a comparison of theoretical and calculated form factors.