NEi
Nastran V9.0 x64 is a true 64-bit application
capable of accessing memory above 4GB.With
its ability to access larger amounts of memory,
the improvements are twofold:
| • |
Huge
models (such as a 15 million degree of freedom
linear static analysis) can be analyzed; that
would normally be impossible on a 32-bit platform.
|
| • |
Large
models that would normally use virtual memory
in NEi Nastran
32-bit, can now directly access large amounts
of physical memory (if the system is configured
with sufficient RAM).
|
|
These
improvements result in faster solution times since
physical memory is tens to hundreds of times faster
than virtual memory. In addition to these advantages,
NEi Nastran
64-bit contains a new direct parallel solver called
the Parallel Sparse Solver (PSS). Some of the features
of this high-performance solver are:
| • |
Extremely
fast parallel direct solver |
| • |
Parallel
scalability is nearly independent of the shared-memory
multiprocessing architecture (performance
increases of seven times using eight processors
have been observed) |
| • |
Handles
non-positive definite matrices |
| • |
Accuracy
measure output |
| • |
Supported
in all NEi
Nastran solutions |
|
| Case
Studies |
Twisted Cable – Nonlinear Contact Analysis |
| A
twisted cable consisting of 25 individual
strands was modeled to determine the load
and stress distribution within the cable.
Because of the twisted geometry of the cable,
there are no planes of symmetry to take advantage
of (other than lengthwise symmetry). The cables
contact themselves at more than 50 points
within any given cross-section. Ordinarily,
setting up the contact segments for a model
such as this would be extremely difficult
and time consuming. However, taking advantage
of NEi Nastran’s
automatic contact capability, no manual contact
setup was needed.
The
model was setup as a nonlinear static analysis
with an enforced displacement to stretch the
cable by 0.4%. The model consisted of 280,000
HEX elements for a total of 1 million degrees
of freedom (DOF). The analysis was first run
in NEi Nastran
32-bit and the total solution time was 22.4
hours. Then, using the same computer, the
analysis was performed using NEi
Nastran 64-bit with the PSS solver.
The total solution time dropped dramatically
to 10.1 hours. |
 |
 |
 |
1
million DOF nonlinear static analysis
of a twisted cable, 2x speed improvement
on 64-bit |
|
NEi
Nastran 32-bit Solution Time: 22.4 hours
NEi Nastran
64-bit Solution Time: 10.1 hours
|
|
Linear
Static Analysis of an Automotive Crankshaft |
A
crankshaft consisting of 12.3 million degrees
of freedom (2.6 million TET10 elements and
4.1 million nodes) was analyzed in NEi
Nastran 64-bit. A model of this size
would be impossible to run using NEi
Nastran 32-bit.
The
total solution time was 66 minutes on an Intel
Xeon 3GHz CPU with 16GB of RAM.
|
 |
|
12.3
million DOF linear static crankshaft
model solved in 66 minutes. |
|
|
Direct
Frequency Response of a Satellite |
The
following case study was performed to show
that NEi Nastran
64-bit will also speed up medium and small
sized direct frequency response models by
taking advantage of the PSS solver. The PSS
solver is able to take advantage of multiple
CPUs or cores whereas the VSS solver can only
take advantage of a single CPU/core. The satellite
structure has 4,284 elements and consists
mostly of plate and beam elements. The model
consists of 26,382 DOF and was setup to solve
for 100 frequency steps.
NEi
Nastran 32-bit Solution Time: 12.1
minutes (VSS solver)
NEi Nastran
64-bit Solution Time: 6.2 minutes (PSS solver)
By
increasing the mesh density of the model (for
a total of 358,000 DOF) and running the same
100 frequency steps, the power of NEi
Nastran 64-bit is revealed.
NEi
Nastran 32-bit Solution Time: 17.6
hours (VSS solver)
NEi Nastran
64-bit Solution Time: 2.1 hours (PSS solver).
Performance improvement of over 800%
|
 |
|
358,000
DOF direct frequency response of a satellite,
8 times faster on 64-bit. |
|
|
Normal
Modes Analysis of a Piston Assembly |
A
normal modes analysis of a piston assembly
consisting of 2.6 million degrees of freedom
was analyzed. The first 75 modes were extracted,
and the Lanczos eigensolver was used in both
NEi Nastran
32-bit and NEiNastran 64-bit. NEi
Nastran 64-bit was able to perform
a direct Lanczos solution, whereas the 32-bit
solver had to revert to the iterative Lanczos
solver (which requires less memory). The solution
time was over twice as fast using NEi
Nastran 64-bit.
NEi
Nastran 32-bit Solution Time: 13 hours
NEi Nastran
64-bit Solution Time: 5.8 hours |
 |
|
Piston
assembly with 2.6 million DOF, 2x speed
improvement on 64-bit. |
|
|
| Computer
Recommendations |
To
get the most out of NEi
Nastran 64-bit, Noran Engineering, Inc. recommends
the following system specifications:
Operating
System: |
Windows
XP x64 (64-bit) |
CPU: |
Intel
Xeon processor (dual-core or quad-core) or
AMD Opteron (dual-core). |
RAM:
|
4GB
– 16GB depending upon budget |
Video
Card: |
64-bit
Compatible Video card with 256MB of memory
(Example: Nvidia Quadro) |
Hard
Drive(s): |
Primary
standalone HD (for operating system). 2-4
HDs in RAID0 for temporary file storage. Hard
Drives can either be SATA or SAS. |
All the case studies mentioned above were run with
the following system:
| CPU:
|
Intel
Xeon 5160 3.0 GHz (dual-core) |
| Memory: |
16
GB |
| Hard
Disk: |
3
SATA 250 GB (7,200 RPM) in RAID0 |
| Operating
System: |
Windows
XP x64 (64-bit) |
|
