Modeling flews

[mech5190]

Hi! I try to construct a model of flaw at Patran. First i make a two domention (2D) model of flaw. In this i design a square shape and in this i make the flaw as thin brill. At the end i analyse this geometry with its loads but when i try to load the xdb file, the Patran send me a below message: "Begin: attach xdb file" and it doesn't make results.
The same behavor, it has with 3D model which i construct after.

What is it occured?

There is a special method which i can get solution at problems of flaws?

Kostas p.

 

[40818]

How familiar are you with finite modelling? and using nastran.

 

[mech5190]

i use "quade" finite elements for surfase and "hex" for solid geometry. Why dont it find a solution? Must i use a special finete element?

 

[40818]

Upload you input file (.bdf) and i will take a look at it.
i take it your using nastran.

 

[mech5190]

ok. Until afternoon, i will have upload.

 

[mech5190]

i try to solute other geometries with some gibbocities but the end is occured the same state. ? don' t know what happen here but it may need more boundary contitions for solution.
i Sent you this simply geometry which i make. Is 2D. I want to take the field of stress where challenge the force.
At properties i have input the 2d solid type. Not shell.

Can you solute this geometry..?
Can you say me some tips which we use at these geometries?

 

[40818]

You have supplied the database, not the bulk data file!!

Anyway, the first thing i did was to equivalance the nodes (which were needed for 55 node positions).
You also need boundary conditions which will prevent the model flying off into infinity, and failing to run, so you need to constrain to prevent rotations about the global Y axis.
There are 2 elements (81 and 83) which are collapsed and need deleting. After these then your model will run.

However, your element choice and modeling technique really does need a lot of improving. Your using the wrong types of elements and need a much better mesh to get any repsectable answers. I take it that your new to this stuff??