PNNL-13501 - Pacific Northwest National Laboratory

subsequently transform them back into the MARC input
format. This capability was crucial to the subsequent
example problems that incorporated remeshing and
multiple analysis steps. Figure 3 shows the second stage
for the stretch forming process. A continuous 2-step
analysis was also performed in MARC to confirm that the
results were for all purposes identical.
Test Problem 2
The second problem added mesh refinement to Test
Problem 1. The goal was to stop the forming analysis,
refine a region of the mesh, remap the intermediate results
to the new mesh, and restart the analysis. Using internally
developed gridding software, NWGrid, we developed data
transformation tools to convert between the common data
format and NWGrid. Modifications to NWGrid were
required to support shell elements with multiple layers
and support the reflection of results. Figure 4 illustrates
the additional data transformation routines that are
required to support the remapping of model results
between different meshes. Figure 5 compares the
equivalent plastic strain distributions at the intermediate
forming stage for the original analysis in Test Problem 1
with the refined mesh in Test Problem 2. Figure 5 also
shows the significant capability in NWGrid to reflect the
results to construct a full 360-degree model from the
previous ¼-symmetry model. This is an important
capability when the forming process is symmetric, but
subsequent operations; such as welding, introduce nonsymmetric
thermal or mechanical loads.
Test Problem 3
The intent of the third problem was to combine and
extend the capabilities developed for test problems 1 and
2 to prepare the meshes for a welding analysis shown in
Figure 6. The schematic of the complete process is
shown in Figure 7. The goal was to map the results of a
forming simulation to a new mesh that included the
necessary mesh detail to simulate joining of a beam to the
hydro-formed part. Mesh refinement is also necessary in
this case to capture the thermal gradients of the welding
analysis. Remeshing the formed part to have coincident
node spacing with the attached beam proved to be an
ambitious goal, and this problem was only partially
completed with the allotted funding. Figure 6 shows a
final thickness plot of the hydroforming analysis and the
combined meshes of the hydroforming analysis and the
beam introduced for welding. However, additional work
is required to generate a mesh at the intersection of these
two geometries that was well defined enough to provide
accurate analysis results. This work was still in progress.
182 FY 2000 Laboratory Directed Research and Development Annual Report
Summary and Conclusions
The software components developed under this effort now
provide scientists and engineers with the ability to
perform integrated multistep finite element analysis using
a small collection of commercial finite element software
applications. The present work to support the use of
NWGrid further promises to extend this capability to
provide robust remeshing/remapping capabilities.
Critical technical issues have been identified and
addressed, providing a robust solution to integrated
modeling and simulation needs of automotive
manufacturing scientists and engineers. Future
development efforts should expand the collection of data
transformation tools to support additional finite element
application formats. Future research efforts should focus
on increasing the ease with which NWGrid can be used
by scientists and engineers, the incorporation of material
properties into the common data format and data pedigree
representations, and the development of a Web-based
architecture for supporting data transformation tools (i.e.,
Web-based translation services).
Presentations
Johnson KI. September 2000. “Integrated Modeling and
Simulation, Joining of Hydroformed Structures, Glass
Process Modeling.” Presented to Reza Sadeghi and John
Long, MSC Software Corporation.
Thurman DA. February 2000. Collaborative Problem
Solving Environments: What Use Are They? Policy and
Management Science Technical Network, Battelle Seattle
Research Center.
Thurman DA and T Peterson. March 2000. Information
Technology to Support Public Involvement Processes.
Puget Sound Chapter of the American Urban Planning
Association.
Thurman DA. April 2000. Collaborative Problem
Solving Environments for Wastewater Management.
Modeling and Assessment Unit, Water Treatment Group,
Department of Natural Resources, King County,
Washington.
Thurman DA. June 2000. Collaborative Environments
and Virtual Facilities. Members of the Battelle/PNNL
Mexican Alliance.