Matrix Analysis of Two Dimensional Bar Structures MABS2D

This program solves bar structures of constant area through matrix analysis of structures.

Description

Input data is the MS Excel file, where the table of nodes, table of elements, nodal external loads vector and boundary conditions are stored.
After running the mabs2d.m file on the Command Window, the program calculates the stiffness matrix in local coordinates kiL (element i). Once the transformation matrix associated to the element is obtained, the stiffness matrix in global coordinates kiG is also calculated. The table of connectivity is automatically generated for the assembly process and then computes the complete stiffness matrix of the structure. Boundary conditions are introduced on the Excel sheet in order to remove the singularity of the stiffness matrix. After solving the matrix system, the nodal displacements vector u and the nodal loads vector P0 (external loads and reactions) are calculated.
Finally, the program returns to the element formulation by transforming the global displacements into local ones to obtain the bar stresses sigmai of the element i and design the each member of the structure.
A plot of the deformed and non deformed structure in static equilibrium is also shown.
This program only considers concentrated loads on the nodes. In case there be distributed loads or thermal loads, they must be calculated separately and then included into the nodal external loads vector.
Flexion and shear effects are not considered. All the elements satisfy the hypothesis of the Finite Element Method (FEM).

• MATLAB release: MATLAB 7.6 (R2008a)

[Karthik kandra]

Find a useful one

[LEONEL LEONEL]

its good man

[Alejandra]

 

[Giancarlo]

Hello,
Sorry to disturb you. I am experiencing some problems on using your matlab code.
Could you help me?
I run mabs2d and then I insert the name of the file but it doesn't work. I don't know why...
this is what my command window show me:

>> mabs2d.m
File name of data importation: example1
??? Error using ==> importdata at 123
Unable to open file.

Error in ==> mabs2d at 72
M=importdata(['nom','.xls']);
 
Let me know, what's wrong. I want just to open the example and then try to modify that one.
Thanks,

[Marcos Cesar Ruggeri]

Giancarlo,

The syntax you typed is correct. There should be no problem if the .xls file is stored in the same current directory.

Keep in mind that this code was programmed, debugged and tested using MATLAB r2008a.

I am not sure if the same built-in functions such as "importdata" were also included in older versions.

Please keep me informed about this issue, and do not hesitate to contact me for further information.

Regards,

Marcos C. Ruggeri

[Bret]

Hi, when I run the examples in Matlab 2007 or 2010, I get errors:
For example1, I get:
??? Index exceeds matrix dimensions.

Error in ==> mabs2d at 166
   if cDOF(I,2)==1

For example2, I get :
??? Error using ==> mtimes
Inner matrix dimensions must agree.

Error in ==> mabs2d at 199
u_red=inv(K)*P_red;

Is there something I'm missing?
 

[Marcos Cesar Ruggeri]

Bret,

I sent you an email about this issue.

Thanks.

Regards.