Development of a Calculation Procedure for Composite High-Speed Vessel. Strength Computations for the First Russian High-Speed Catamaran with a Carbon-Fiber Composite Hull
Area of expertise:
|Keywords||composite shipbuilding, composite structures, composite materials, high-speed catamaran, strength calculations, the direct finite - element modeling|
|Programs in use||ANSYS|
|Project period||2013 г.|
For over 25 years engineers from the SPbPU “Computation Mechanics” laboratory (CompMechLab®) and the Computer-Aided Engineering Centre (CompMechLab®) accomplish finite elements modelling and calculations for products manufactured from composite materials along contracts with leading Russian and international industrial companies.
Dozens of R&D projects on mathematical simulation, calculations, and improvement of composite materials and composite structures in different industrial fields were successfully fulfilled.
For example, the Engineering Centre team developed a new calculation method for high-speed vessels with polymer composite hulls that was used within a project in 2009 devoted to the development of the first Russian high-speed catamaran with a composite hull. This 150-seats passenger catamaran, with LOA of 25 m and full displacement of 66 tons was designed for passenger transportation in the Neva River and the Gulf of Finland.
A 3D Model of 150-seats high-speed passenger catamaran with a composite hull (carbon-fiber composite material). Photo: http://snsz.ru/
Neptun Central Design Bureau was the key developer of the project, and the construction was done at the Sredne-Nevskiy Shipyard (SNSZ, JSC, part of United Shipbuilding Corporation (JSC USC), Pontonniy).
Manufacturing hulls for high-speed vessels from carbon-fiber composite material is a new approach for the Russian shipbuilding industry. Such vessels have many advantages: reduced weight of the structure, extended lifespan, possible integration of new structural and design solutions, etc.
In 2013, Sredne-Nevskiy Shipyard filed an order to the CompMechLab® to carry out finite elements modelling and calculations of structural strength of the high-speed catamaran composite hull. These calculations formed the basis for design validation and a calculation method for high-speed vessels with polymer composite hulls was developed.
The Russian Maritime Register of Shipping rules and regulations have no calculation methods for structural strength of vessels with polymer composite hulls which is why the work was based on international standards on ships design (primarily on Det Norske Veritas, Norway).
"We took into account international experience while developing recommendations and requirements on calculation of composite vessels structural strength. Norway classifier Det Norske Veritas (DNV) rules were taken as a reference because Norway is a leader in applying composite materials in shipbuilding. DNV rules have a large amount of requirements and design cases necessary for structural strength analysis", said Alexander Nemov, deputy head of the Engineering Center of SPbPU, responsible for the project.
International standards allow and sometimes recommend calculating the stress-strain behaviour of various structures using direct finite element (FE) modelling. FE modelling allows avoiding assumptions that are common when using simplified analytical approach and may not be applicable to vessels' unique composite structures to take all hull features into account.
CompMechLab® engineers have world-standard unique transdisciplinary pan-industry computer and supercomputer technologies at hand. The efforts to develop these technologies add up to more than 1,000,000 man-years. Multiple path computations of catamaran composite hull structural strength were fulfilled using the ANSYS finite element analysis system. ANSYS is a well-known international CAE system and is a global leader in computer-aided engineering and finite element solution of linear and nonlinear, dynamic and static of problems of deformable solids mechanics and constructions mechanics for over 40 years.
Full-scale finite element model of catamaran intended for structural strength computation developed within the ANSYS system.
The unique model includes over a half of million multilayer shell elements and considers all load-bearing structural elements and weight loads from equipment, passengers, fuel tanks, engines, etc.
|Finite element model of a catamaran hull fragment.||
Finite element model of the catamaran hull internal structure (fragment).
To take into account all materials used in the composite hull construction its model is developed on the basis of the theory of multilayer shells.
Fragment of the main deck finite element model with each layer having it’s own thickness (different materials are marked with different colours).
Local and general strength of the hull was analysed within this project. Sagging and hogging of a ship's hull at wave, twisting and side loads, etc. were taken into consideration.
Vertical shifts in case of hogging, m.
Both hull deformation and stress-strain state of all structural element were obtained based on finite elements calculations. Besides, some structural assemblies and elements were redesigned according to manufacturer requirements in order to simplify the technology and reduce manufacturing costs.
Laboratory “Computation Mechanics” (CompMechLab®) achieved following results within the project:
- Design-basis justification of hull structural strength of the first Russian high-speed catamaran made of carbon-fiber composite material.
- Development of a structural strength calculation method for high-speed vessels with polymer composite hulls based on finite elements models.
- Finite elements model development method for high-speed vessels with polymer composite hulls, and recommendations on structural strength calculations based on the developed models.
- Redesign of the structure and some elements in accordance with manufacturer requirements aimed at technology simplification and manufacturing costs reduction.
"We are proud of our participation and contribution into design of the the first Russian high-speed passenger vessel made of carbon-fiber composite material", Alexander Nemov, deputy head of the Engineering Center of SPbPU, responsible for the project.