摘要：Goal based and limit state design is nowadays a well-established approach in many engineering *** construction rules started introducing such concepts since early ***,classification societies’rules do not provide hints on how to verify limit states and to determine the structural layout of submerged thin-walled stiffened cylinders,whose most prominent examples are ***,they generally offer guidance and prescriptive formulations to assess shell plating and stiffening *** marine structures are studied,designed and built up to carry payloads below the sea *** the concept-design stage,the maximum operating depth is the governing hull scantling *** dimensions are determined based on the analysis of operational *** study proposes a practical conceptdesign approach for conceptual submarine design,aimed at obtaining hull structures that maximize the payload capacity in terms of available internal volume by suitably adjusting structural layout and stiffening members’scantling,duly accounting for robustness and construction constraints as well as practical fabrication *** proposed scantling process highlights that there is no need of complex algorithms if sound engineering judgment is applied in setting down rationally the hull scantling problem.A systematic approach based on a computer-coded procedure developed on purpose was effectively implemented and satisfactorily applied in design practice.

摘要：To further exploit the potential of marine composites applications in building ship hulls,offshore structures,and marine equipment and components,design approaches should be improved,facing the challenge of a more comprehensive and explicit assessment of appropriately defined limit *** structure ultimate/limit conditions shall be verified in principle within the whole structural domain and throughout the ship service *** above calls for extended and reliable materials characterization on the one hand and for accurate and wide-ranging procedures in structural *** paper presents an overview of recent industrial developments of marine composites limit states assessments and design approaches,as available in open literature,focusing on pleasure crafts and yachts as well as navy ships and thus showing a starting point to fill the gap in this *** a general introduction about composites characterization techniques,current design practice and rule requirements are briefly *** inter-ply and intra-ply failure modes and corresponding limit states are then presented along with recently proposed assessment ***-dimensional aspects in failure modes and manufacturing methods have been identified as the main factors influencing marine composite *** review highlighted also fire resistance and hybrid joining techniques as significant issues in the use of marine composites.

摘要：The hydrodynamic analysis of a new semi-small waterplane area twin hull （SWATH） suitable for various applications such as small and medium size passenger ferries is presented. This may be an attractive crossover configuration resulting from the merging of two classical shapes： a conventional SWATH and a fast catamaran. The final hull design exhibits a wedge-like waterline shape with the maximum beam at the stem; the hull ends with a very narrow entrance angle, has a prominent bulbous bow typical of SWATH vessels, and features full stern to arrange waterjet propellers. Our analysis aims to perform a preliminary assessment of the hydrodynamic performance of a hull with such a complex shape both in terms of resistance of the hull in calm water and seakeeping capability in regular head waves and compare the performance with that of a conventional SWATH. The analysis is performed using a boundary element method that was preliminarily validated on a conventional SWATH vessel.

摘要：Despite the non-contact underwater explosion phenomena(UNDEX)have been studied for decades and several numerical methods have been proposed in literature,its effects on military structures,especially composite ones,are even nowadays matter of *** early design phases,it is not always possible to verify the shock resistance of hull structures modelling the whole phenomenon,in which fluid,gas and solid properties must be properly set in a fully coupled fluid-structure interaction(FSI)numerical *** ones are extremely complex to set,computationally demanding and certainly not suitable for everyday design *** this paper,a simplified finite element(FE)model,easy to use in an early design phase,is ***,the structure and the fluid are *** this approximation,the fluid behaviour is simplified,using special finite elements,available in a commercial software *** choice reduces the computational time and numerical efforts avoiding the problem of combining computational fluid dynamics(CFD)and FE domains and equations in a fully coupled fluid-structure interaction model.A typical parallel body block of a minesweeper is modelled,using two-dimensional multi-layered shell elements to properly account for the composite materials *** the fluid instead,three dimensional volumetric elements,directly coupled to the structural elements,are *** addition,the same calculation is performed,modelling separately fluid in the CFD environment and structures in the finite element ***,realizing a fully coupled fluid-structure interaction *** results obtained by applying both numerical models are compared with the structural response measured on board of a composite ship during a full-scale shock *** simplified proposed procedure provides results in satisfactory agreement with experiments,allowing the validation of the *** are discussed and differences with the real phenomenon and fully coupled CFD+