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mahmood seraji's blog

Tensile stress of the concrete

Submitted by mahmood seraji on

 Dear friends

 The obtained results from my model show that the ultimate load is higher
than the expected one. after checking the results, I found out that the
tensile stress of concrete is much higher than input value for the
tensile yield stress. "concrete damaged plasticity model"  is applied.

your help is highly appreciated.

Displacement control VS. force control in Abaqus

Submitted by mahmood seraji on

Dear friends,



I have modeled a simply supported beam, using wire and the circle section of 1mm and a length of 110mm. I did two analyses


1) I used the distributed load of 0.2 N/mm (where the beam behaves in
the elastic area) and got the maximum displacement (at center).   

2) I used the obtained max displacement (from first analysis) as a
displacement control. the results of the reaction forces are supposed to
like the distributed load at first analysis, but it is much lower.

supports in Abaqus

Submitted by mahmood seraji on

Dear friends



I am modeling a
plate subjected to the vertical loading. the problem is, when the analysis goes
to the nonlinear part, the reactions in some nodes get negative value, while the
plate must be free to move upwards. so there must be no negative value
for reaction. i was wondering, if someone help me define the support in a way
that the plate would be free to move upward and constrain it for the downward
movwement.



Best Regards

Spring in Abaqus

Submitted by mahmood seraji on

Dear all



When i assign the springs between pair points in two
plate over each other, the spring definitely acts in one direction only
(perpendicular to the plates), but they must be assigned in such a way
that the springs work in three orthogonal directions. it is important to
mention that the two plate is fastened using screws, where the spring
has been used for screw.

how can i overcome this problem?

 

Best Regards

"bending stress-strain curve" or "compression stress-strain curve"?

Submitted by mahmood seraji on

Hi 

I want to model the lightweight slab and since i do not have the material behaviour of the slab, i have to do testing. i was searching in internet and i got two different concept: "bending stress-strain curve" and "compression stress-strain curve". i do not know which one should i follow? and is there any difference?

Regards.

spring in Abaqus

Submitted by mahmood seraji on

Hi

I am modelling two plates that have been attached to each other using screws. i have modelled some springs for the screws. the shell element has been used for the plates. i want to assign the spring element (say SPRINGA) for the screws but i do not know how.

thank you.

Concrete Smeared Cracking model in Abaqus

Submitted by mahmood seraji on
Hi
I order to model the cement board material, i am going to use "Concrete Smeared Cracking" model available in Abaqus. I think I have to adjust some variables affecting the properties of the concrete to get the numerical load-deformation response close to that of the cement board.
I will be thankful if anyone help me.