Adam Sobey

1
Concurrent Engineering in the Context of FRP Boats
Fluid and Structure Interactions Research
Group, School of Engineering Sciences
Adam Sobey
Supervisory team Prof. R. A. Shenoi, Dr. J. I.
R. Blake
School of Engineering Sciences, University of
Southampton, UK
2. Aims
1. Background
The strategic aim of this project is to develop a
concurrent engineering system, consisting of a
number of tools and a design environment, for use
in the field of leisure boat design.

• The margin between a profitable and
  non-profitable design and build are small.
• Foreign companies have a larger percentage of
  the yacht market than British companies.
• This requires that UK companies become more
  innovative in design and try to use new materials
  and structures and production technologies in
  order to generate new, market-leading designs
  that are cost effective to manufacture.

4. Structural Optimisation

• A tool to optimise the mass and cost of stiffened
  panels is in development.
• Optimisation of the panels relies on changing the
  stiffener spacing, the stiffener size and
  thicknesses as well as the panel thickness.
• Panels can then be optimised using a genetic
  algorithm (GAs) for mass and cost.

• It has been estimated that design costs only
  10-15 but that as much as 70 of the cost of a
  manufactured part is decided at this stage.
• Boat designs, therefore, should take into account
  important factors like production and
  manufacture.
• Rapid and timely production of new designs can
  open up sales opportunities in other areas.

• GAs are based on evolutionary biology and are a
  type of global search heuristic.
• The advantages of using genetic algorithms are
  that they search a large search space quickly
  without getting stuck at local optima.
• Problems can occur where the genetic algorithm
  may not fully reach the optimum value and are
  slower than direct methods.
• This can be resolved by doing a general search
  using Gas and finishing the search using direct
  methods.

T1015 Fast Super-yacht made by Sealine
Process of genetic algorithm optimisation
3. Methodology

• Using the above technique it is also possible to
  constrain the model to coincide with Lloyds
  rules
• Optimisation for bottom panels has been started
  constraining the sea conditions, and therefore
  the forces, and the overall size of the hull.
• A comparison has been done between Lloyds rules
  and grillage method.

• Concurrent Engineering is the process of
  designing, in parallel, to increase quality and
  reduce costs
• It has been successfully used in many different
  industries including aerospace, astronautics, F1
  and shipbuilding.
• The design process can be broken down into areas
  of concept design, detailed design and production
  all of which will be integrated into a concurrent
  engineering environment.
• These areas start with a concept design and end
  in a iterative spiral optimising design and
  production until the final design is complete.
• These areas can be broken down into smaller tasks
  and it is important to find tools in these areas
  that can best help the designer.

Stiffened panel in ANSYS
Results
Method Max. Moments (Nm) Max stiffness (N/mm2 ) Max Stress (Mpa) Deflection (mm) Cost () Mass (kg)
Lloyds Rules 7.8 58 308 1.293 125.69 167.34
Grillage Method 24.16 150 299.9 0.5 84.34 45.59
Results comparing Lloyds rules with Grillage
method

• Discrepancies occur between the two sets of
  values as Lloyds rules builds in safety factors.
• The safety factors constrain the minimum
  thicknesses of the panels meaning that Lloyds
  rules normally create a heavier hull.
• Using thicknesses below that of the Lloyds
  minimum thickness is costly to get accepted
  meaning large benefits would be required to
  justify the use of a first principles approach.

Process of design split into three main topics

5. Collaboration
Tools to be developed Techniques to be used
Structural Tools Genetic Algorithms, Pareto Functions and Direct Optimisation Methods
Design Histories Neural Networks, Fuzzy Logic and XML Schema
Concurrent Engineering Hub Internet Based Excel Hub Embedded in SharePoint

• The project is sponsored by EPSRC and the British
  Marine Federation who are coordinating the
  project with industry.
• The project will involve collaboration with a
  number of boat yards including Princess, Oyster,
  Green Marine and VT Halmatic

Acknowledgements Project sponsored by the British
Marine Federation and EPSRC
Current tools to being developed and techniques
to be used