Naturally, good design doesn't stop at aesthetics and functionality.
There are other, important considerations such as: How am I going
to manufacture this? How easily can this product be serviced and
maintained? Have I taken into account all the physical and environmental
factors that will be brought to bear on this product? Clearly,
it is very difficult to predict all eventualities, but the economic
consequences of getting it wrong can be very burdensome indeed.
We've all heard of recalls in the automotive sector, or designs
that have ultimately failed because they are too difficult or expensive
to manufacture. Good design practice, aided by innovative software
tools, is best illustrated by taking a look at a couple of high-profile
case studies from the automotive and aerospace sectors.
When Land Rover was developing the new Discovery, which went on
worldwide sale towards the end of last year, the digital surface
model data generated in ICEM Surf (www.icem.com) from 3D scans
of the clay styling model was made available to the tooling engineers
very early on in the development process. This simple expedient
enabled them to begin tooling development well before the 'design
freeze' stage had been reached, and as the vehicle design was refined,
the tooling department had immediate access to any modifications.
The data was used directly within Land Rover's Catia CAD/CAM system,
enabling tooling design to be updated in parallel with the evolving
design of the vehicle's body skin and interior trim, and ensuring
that unforeseen manufacturing problems arising from late design
changes were avoided. Land Rover has calculated that it achieved
$10m in savings, compared with previous vehicle programmes, by
taking this approach.
Maintaining a modern fighter aircraft is no trivial matter, which
is why BAE Systems considers 'design-for-maintenance' to be a vital
process in the development of the F-35 Joint Strike Fighter. The
company is using a software product from Dassault Systemes subsidiary,
Delmia (www.delmia.com), called Envision Ergo, which ensures that
90% of all selected maintenance tasks on the aft fuselage can be
carried out by all of the pre-determined maintenance personnel.
The simulation toolset ascertains clearances for maintenance of
the fuselage once the aircraft is in use - particularly access
to fasteners and equipment, which was determined using collision
detection in simulated maintenance bays. Envision was also used
to analyse the aft fuselage assembly operations, the simulations
allowing clearances for manufacturing and equipment installation
to be examined in detail and design changes to be made in good
time for the final assembly of the structure - thousands of miles
away in Fort Worth, Texas!
Accurate structural modelling of assemblies is a challenge for
any designer. Quite sophisticated technology is required to model
spot welds and other joining techniques, for example, in order
to gain an accurate assessment of product performance and lifespan.
Catia users can now take advantage of Abaqus for Catia V5, Version
2.1, which adds an advanced finite element analysis (FEA) capability
to this top-range CAD product. In addition to analysing connections
and joints within assemblies, Abaqus' (www.abaqus.com) non-linear
FEA technology can also be used to study the performance of a wide
range of materials specified for assemblies modelled in the Catia
5 environment, including the thermal stress analysis of metal components
and the structural behaviour of composite panels.
Other products to look out for include The Mathworks' (www.mathworks.co.uk)
new Simulink verification and validation module, which lets designers
and test engineers perform continuous testing and verification
throughout the product development process for early identification
of design problems, and a new data exchange facility that allows
designers to create solid models in Kubotek's (www.kubotekusa.com)
KeyCreator environment and then capture the exact geometry in Algor
(www.algor.com) for mechanical, thermal and other analyses. Or
if you're looking for a complete discrete-event simulation package
to model and optimise the manufacturing process, there's Micro
Saint Sharp (http://microsaint.adeptscience.co.uk) which lets you
view your models as a network diagram or a 2D or 3D animation.
Dr Know's recommended download is Micro Saint Sharp Demo - download
yours today.