Do-itall 3D CAD speeds success

Advanced CAD and PLM is playing a key role in Mitsubishi's three year 2005-2007 revitalisation plan for its rally team in Rugby, which won the FIA World Rally Championship driver's championship four times in succession from 1996 to 1999 and the constructor's championship in 1998. Mitusbishi Motor Sports uses both PTC Wildfire2 CAD and Pro/Intralink 3.4 to control concurrent data usage for the 11 CAD users. Pro/Mechanica is used to perform advanced structural and thermal analysis of wheels, crankshafts and welded and bolted joints. Chief Designer Paul Doe told us that the team originally used SolidWorks but switched to PTC in 2000 because they needed a "Do it all" package able to manage large assemblies, with parametric mechanical analysis and "serious" surface design capabilities. Although the rally car is based on the Mitsubishi Lancer, the only parts that are carried over from the production cars are body shell, engine block and cylinder head and even these are heavily modified. The present car started as a clean sheet design in February 2003 with only 0.2 per cent of parts carried over from the previous car. The first new car was on the test track the following September. Although the team has consistently done well, only winning is considered satisfactory by the owners, and the team has just announced that it is suspending participation from 2006 with the intention to return from 2008. Innovations include using CAD to reduce the number of man hours to install a roll cage from 100 man hours to 40. The design process starts with a skeleton model optimised for stiffness and strength using Pro/Mechanica. The tube surfaces are extruded in Pro/Engineer and unrolled using Pro/Sheetmetal. The output is them sent to a subcontractor as DXF files, and the electronic data used to program CNC lasers to profile the tube ends so they all fit together and to the body shell when they are welded. This greatly reduces assembly time and reduces the chance of error. The suspension is an assembly of hundreds of moving parts with much great travel and required to survive much more arduous conditions than in a normal car. Starting with "stick" models, behavioural modelling is used to optimise the multiple parameters and behaviour is graphed to confirm. The gravel strut, a key component when driving on such surfaces is based on an older design from an outside supplier but has been greatly improved following analysis using Pro/Mechanica. Load cases are derived from experimental data. Several re-design options were looked at. The final version has a 50 per cent reduction in peak Von Mises stress, an 8 per cent increase in stiffness and an 18 per cent reduction in mass, allowing the removal o 500g from each strut. A peculiarity of the business the team is in its keeping a database of components performance, such as the exact dimensions of wishbones as determined on CMM machines. These deform slightly over time requiring mating parts to be made slightly differently. The CMM software, Virtual DMIS from IMS is able to import PTC files, so that any deviations can be marked up on them when they are sent back. Windchill is currently being implemented company wide, and laser scanning is being introduced to produce Pro/Engineer surface data relating to individual driver ergonomic requirements. The team in Rugby is also going to work with the Paris Dakar cross country team which is currently doing crushingly well. More information from www.ralliart.com and www.ptc.com PTC