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George Papazafeiropoulos's blog

Newton optimization algorithm made 10x faster. From necessity to reality.

Submitted by George Papazaf… on

A new optimization concept is introduced which involves the gradient-based optimization of any nonlinear structure by using gradients calculated from a linear equivalent, leading thus to significant computational savings compared to the classical Newton-type optimization algorithms which require gradient information from the nonlinear structure itself.

Frequency analysis of space frame with distributed mass

Submitted by George Papazaf… on

Dear all,



I want to do a frequency analysis of a 3d frame which has three beam elements (2 columns and one beam). There are no lumped masses in the model. I want to assign mass to all three elements equal to m per unit length of the members.



When I assigned nonzero density in the beam section definition (equal to m/A, where A is the cross section area),

When I changed from beam elements into frame elements

When I changed from beam of linear geometric order to beam of quadratic geometric order (standard element libraries)

Linking ABAQUS with Fortran

Submitted by George Papazaf… on

Dear all,

I have installed ABAQUS 6.10-1  and Intel Visual Fortran Compiler Professional Edition 11.1 for Windows. The installation of the last requires the previous installation of Microsoft Visual Studio 2008. My operating system is Windows XP 32bit x86.

I am running the abaqus job and abaqus subroutine files in Abaqus Command (allowing ABAQUS to perform the compiling by including -user on the command line) and I get the following error message:

Book request...

Submitted by George Papazaf… on

Dear all,

I am searching for the following book:

"Some basic problems of the mathematical theory of elasticity" by Nikolai Ivanovich Muskhelishvili.

If somebody has a softcopy I would appreciate it if he sent it to me. If someone has a hardcopy and can lend it to me for a few days, I would be grateful...

Thanks in advance,

George Papazafeiropoulos