1,721,103 research outputs found
Parametric Evaluation of the Effective Breadth for GRP Beams with FEM Calculation
No full textThe direct scantling of reinforced plates can be performed by simplified grillage theory or
by FEM codes. The first approach gives satisfactory results and better matches
Classification Society Rules. The only problem is represented by the determination of
beam geometry which implies the determination of the shell portion cooperating with the
reinforcement. The width of this strip, called “Effective Breadth Be”, depends on several
geometric characteristics like the shell thickness t, the beam span L, the beam distance B
and the dimensions of the beam transverse section. In the case of steel plates the
relationships between the above parameters and Be is well known and several procedures
are available in literature and provided by the Classification Societies rules for determining
the effective breadth.
More uncertainties exists for what GRP structures are concerned. In this case the only
references are represented by semi empirical Classification Societies formulas which give
Be just as a function of the shell thickness. For this reason, and in cooperation with the
Italian Classification Society, an investigation on this matter has been started by the author
considering both single skin and sandwich shells. The analysis has been performed by
FEM calculations on a number of numerical models each of them obtained by a different
combination of the values of the considered parameters that are: the shell thickness t, the
L/B ratio and the transverse section dimensions of the beam.
The results have been presented on diagrams with Be/B ratio versus L/B ratio with different
combination of the evaluated parameters. A comparison of the curves with the values
provided by Classification Societies has been performed as well. Finally all the results
have been utilised to obtain a regression curve by which it is possible to evaluate the
Effective Breadth by considering all the considered geometric characteristics
Light structure design for an unconventional passenger vessel with low environmental impact
No full textThis paper refers to an unconventional passenger vessel which matches hydrofoil and SWATH principles in order to achieve high transfer speeds, low environmental impact and reduced wave washing phenomena. This new, hybrid vessel, called ENVIROALISWATH, should be able to provide high performances, manoeuvrability and controllability typical of hydrofoils and, at the same time, good sea keeping qualities and low installed power, typical of SWATH solution. The design has been developed through a joint research program between Rodriquez Cantieri Navali S.p.A of Messina and the University of Genova. In this paper the final verifications of the structural design are described.
After a preliminary scantling of the main cross section, carried out by applying existing HSC Rules, the structure has been refined by separate numerical models of the hull and of the submerged body.
The gathered information have been collected in order to setup a finite element model suitable to simulate the behavior of the structure as a whole. Starting from this model subsequent implementations have been carried out improving the investigation of stress and strain distributions. Local and global effects have been considered. For the numerical detailed investigation the two FEM codes Maestro and Ansys have been used and the results compared, so verifying their reliability
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