Tech Briefs
The Iterative Solver in ADINA for 3D Models
In the News of April 30, 2006 we demonstrated already the use of the new iterative solver in ADINA for the analysis of solids. This solver has been released in ADINA 8.4. It can be very effective when considering 3D large models, in linear and nonlinear analyses, including contact.
The solver is used with the higherorder brick and tetrahedral elements in ADINA (but these element meshes may also contain other elements). The higherorder brick and tetrahedral elements need frequently be used to predict stresses accurately. We illustrate the effectiveness of the solver on a one processor machine in the example considered below.
 Cube modeled with 27node brick elements, linear static analysis, one step
 Use of 3Diterative solver and sparse solver for different mesh densities

Runs made on HPUX Itanium computer, 1 processor, 8 GB RAM; all runs made
incore for ease of illustration
Cube modeled with 27node brick elements, fixed at the top and
subjected to gravity loading
Plots of normalized CPU time vs. number of DOFs for sparse solver
and 3Diterative solver
Plots of memory used vs. number of DOFs for sparse solver and 3Diterative solver
While we consider here a mesh of equal sized
The important points to notice are that for the iterative solver
 the solution time increases practically linearly with the number of DOFs
 the memory used increases practically linearly with the number of DOFs
 both quantities are much smaller than when using the direct sparse solver.
This makes it possible to estimate quite accurately the CPU time and memory required for a solution, when using the iterative solver.
Of course, the memory used and the solution time for the sparse solver
become rapidly very large as the number of DOFs increases and the ADINA
For further information and some nonlinear analyses using the iterative solver, see the News of April 30, 2006.