SANDWICH aims to develop novel metal-composite lightweight sandwich panels for primary load-carrying structures in ships and land transport by combining a laser welded metal structure with different core materials. The excellent properties those modular sandwich panels will feature compared to conventional stiffened plates are as follows:
- Weight reduction up to 35% realised during the project;
- max space reduction of 64% at equal weight;
- enhanced fire safety and heat insulation (filled SANDWICH panels have a potential of reaching significant better results than empty ones);
- significantly improved crash resistance (350 mm wide X type SANDWICH wall is as crashworthy as a conventional 1000 mm wide double hull, using about half of the plate thickness);
- reduction of manufacturing cost by accurate pre-manufacturing (much better than conventional but with potential for further improvement);
- easy and fast assembly e.g. for the crash worthy side structure the improvement is in the order of 30%, for decks in the order of 20%; and
- flexible use through modular solutions for panels and joints.
A successful application of the new product, the advanced steel composite sandwich, requires however the solution of a variety of problems. Those are the definition of product properties, the development of design and application guidelines and tools, efficient and reliable production processes as well as the creation of proper structural joints and attachments. The integration of additional functions, like air conditioning, electrical power distribution, fire extinguishing systems and heat insulation into the load-carrying sandwich panels will make them more attractive for a wide range of industrial applications. The SANDWICH project is determined to solve these problems and make the advanced steel-sandwich panels available for industrial use.
Innovative Aspects of the SANDWICH project are e.g.:
- Combining low density materials with steel sandwiches for both design and production;
- development of design data and solutions for all-steel laser welded sandwich panels with enhanced product properties for a wide range of applications in the transport industry;
- development of joints and attachments to integrate the sandwich panels into land and marine vehicles;
- design of integrated multi-functional units based on the sandwich panels;
- development of production and assembly techniques for sandwich panels; and
- the creation of design tools and guidelines with pre-approved solutions accessible via the Internet, which can be used by industrial users to find the optimum sandwich solution for a specific application.
Users from shipbuilding, ship equipment, railway and automotive describe their requirements towards the sandwich panels. A risk analysis will ensure that no major aspects will be missing and that the view of approving bodies has been considered.
Sandwich panels, structural connections, attachments, integrated functional units and prototype solutions will be designed and optimised after the first production, test and calculation feedback is obtained. Multidisciplinary optimisation criteria as well as initial design and acceptance criteria will be defined.
Test specimen and prototypes will be manufactured. Rules for Design for efficient production and assembly will be specified.
Determination of Product Properties:
Specimens will be tested to define the failure mechanisms and the product properties. Tests will be accompanied by parametric studies (calculations). First prototypes will be used to measure operational conditions in transport vehicles and ships. Design algorithms will be derived for the different properties of the advanced sandwich panels. Optimised prototypes will be tested under operational conditions.
A design tool will be developed using the data, algorithms and experiences from the previous work-packages. The tool will be also available via Internet to make it easily accessible for a wide range of users / customers.
Management and Exploitation:
Industry and academia will disseminate the results gained in prototype solutions of the project to support fast and efficient exploitation in all transport areas.
Project findings comprise:
- So far up to 35% weight reduction;
- max space reduction of 64% at equal weight;
- improvements not in the range we expected;
- filled SANDWICH panels reach significant better results than empty ones;
- 350 mm wide X type SANDWICH wall is as crashworthy as a conventional 1000 mm wide double hull;
- much better than conventional but yet not satisfactory accuracy;and
- for the crash worthy side structure the improvement is in he order of 50% for decks in the order of 20%.
Heavily loaded decks and structures: in view of the problems which can not be solved by the SANDWICH project, the application of sandwich panels in these critical areas will be limited and less than expected at the time, when the proposal was written. The development of new structural and functional concepts will be necessary before a breakthrough can be achieved.
Minor components in passenger ships: for minor components, like walls, staircase landings, stairs etc. sandwich panels are an attractive and cost efficient alternative to conventionally stiffened plates. Main benefits are among others, space saving and increased stiffness. Enhanced properties and design algorithms, developed by the SANDWICH project will lead to increased application. Some of the solutions, eg. aiming at supporting new outfitting techniques (pre-manufactured cabins) have already been developed. It is expected, that the application doubles (i.e. approximately 2.400 m2) during the project and in the first two years after the project finishes.
Application in inland-waterway cruise ships: Inland waterway vessels are a new pro-duct line, being produced by a sister company of Meyer Werft. The requirements towards application of sandwich panels in these ships differ significantly from those in large cruise vessels (some requirements are less, others more critical). In the prototype application, sandwich panels have been used in a number of decks in those ships. A number of valuable experiences have been gained from the prototype application, indicating problems in particular in assembly of the ship. Extra investigations have been started as a consequence within the sandwich team and also assembly techniques need further improvements. Up to 3.000 m2 of sandwich panels will be used in decks of inland waterway cruise ships during and immediately after the project terminates. Currently, market forecasts identify a high demand for inland waterway cruise ships, mainly on central European rivers, but also in Russia, where a huge number of similar ships have to be replaced in the next years.
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