The Digitization Lab, at NCAC, contains
the equipment necessary to start with a working automobile, take it apart,
construct a detailed digital representation of every part of the vehicle,
and re-assemble the vehicle so that it can be crash tested, and the results
compared with simulation. The model under development was a Chevy C-1500
Pickup Truck. It was completely disassembled and tape lines placed on the
vehicle to represent the finite element mesh that will be created. As the
truck is taken apart, individual parts were digitized using a robotic arm.
The arm is capable of measuring
3-dimensional positions within several thousandths of an inch. Proceeding
from vertex to vertex, the technician instructs a Pentium PC running Autocad
to register the position of each point by pressing a button on the grip
of the arm. As the geometric data from individual parts of the car is compiled,
it is used to construct a complete model of the vehicle on an SGI Indigo2
Extreme running Patran3.
Large and complex models such as
the C-1500 Pickup Truck require a tremendous amount of detail work, which
is greatly facilitated by the close proximity of the modeller and vehicle.
Building such models is also very computationally intensive-the C-1500
model contains over 45,000 elements, and working with such models requires
very high-end CAD workstations equipped with large amounts of disk space,
RAM and 3-D graphics capabilities. Once the geometry has been created,
debugging the model can require days of supercomputer time, which is why
the Digitization Lab is right down the hall from the NCAC Supercomputer
Lab.