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Y. S. Yang and S. H. Hsieh
National Taiwan University,
Taipei, Taiwan
December 8, 2000
FE2000: An Object-OrientedFramework For Parallel Nonlinear Dynamic Finite Element Analysis
Develop a parallel FEA test bed
– High performance
– Parallel computing (substructure method)
– Good extensibility & maintainability
Introduction (1/2)
Introduction (2/2)
FE2000– Object oriented– Linear / Geometric nonlinear analysis– Static / Implicit dynamic analysis– Sequential / Parallel computing
Key classes (1/3)
feAssemblage– Uses dynamic arrays for FE objects
• vector<feNode*>
• vector<feElement*>
• ANSI C++ Supported
• Useful for adaptive mesh refinement
Key classes (2/3)
Hierarchy of feElement
feElement
feB8Element
feB20Element feBCElement
feTrussElement
feSuperElement
Key classes (3/3)
2D-frame structure example
feA ssemblageO b jec t
E lem en t # 2E lem en t # 1
N o d e # 2
N o d e # 1 N o d e # 3
feNodeO b jec t # 1
feNodeO b jec t # 1
feNodeO b jec t # 3
feBCE lementO b jec t # 1
feBCE lementO b jec t # 2
(a ) A fin ite e le m n e t a n a ly s is e x a m p le (b ) O b je c t re la tio n sh ip in F E 2 0 0 0
Substructure analysis
Multi-level substructure hierarchy
Iterative mesh partitioning approach– Improved Hsieh-Yang-Tsai (IHYT) approach
for better computational load balance (Yang, 2000)
(a ) In itia l m e sh(le v e l 0 )
(b ) S u b s tru c tu re A(le v e l 1 )
(c ) S u b s tru c tu re B(le v e l 1 )
(d ) S u b s tru c tu re A A(le v e l 2 )
(e ) S u b s tru c tu re A B(le v e l 2 )
(f) S u b s tru c tu re B A(le v e l 2 )
(g ) S u b s tru c tu re B B(le v e l 2 )
Proc 0
Proc 1
Proc 2
Proc 3
Proc 0
Proc 2
Proc 0
Matrix libraries (1/2)
For solving [K]{d}={f}– Extended SPARSPAK (George and Liu, 1981)
• Direct, sequential
• Linear system solution/matrix condensation
– SPOOLES (Ashcraft et al., 1999)
• Direct/Iterative, sequential/parallel
– PETSc (Balay et al., 1997)
• Iterative, sequential/parallel
Matrix libraries (2/2)
Interface between FE2000 and matrix libraries
Validation tests
Static nonlinear analysis
P
V
U
0.01 P
0
1
2
3
0 0.2 0.4 0.6 0.8 1
Displacements V/L
P/P
cr
BC
B20
Dynamic analysis
F
0
0.5
1
1.5
2
0 0.2 0.4 0.6 0.8 1
T (sec)
D/Do
BC
B20
Numerical experiments (1/2)
Nonlinear dynamic analyses– Analysis methods
• Newmark method (avg. accel.)
• Total t = 0.2 sec., Δt = 0.01 (20 time steps)
• Geometric nonlinearity
• Sequential / Parallel multi-level substructure method
– Computing environment• 4 PCs (Pentium II 350) + 100 Mbps network
• Linux Redhat
• FE2000 + Extended SPARSPAK
Numerical experiments (2/2)
2165
675
Seq. Par.
H5-1211,568 BCs25,344 DOFs
4057
1605
Seq. Par.
O1-1235,904 BCs181,152 DOFs
19679
4370
Seq. Par.
M12BD-24,032 B20s64,809 DOFs
2509
9113
Seq. Par.
B20P64162,048 BCs34,767 DOFs
S=2.89 S=2.48 S=3.60 S=3.15
Conclusions & future works
FE2000– An efficient object-oriented parallel nonlinear dynamic
FE package.
Future works– More element types (plate, shell, etc.)
– More material models
– Adaptive mesh refinement
– Pre/post processing