What does this negative crack width mean ? Does it have any physical significance?]]>

I'm try to modeling a I section beam with shear force at the middle point. However the analysis failed at step 1. I already read the Troubleshooting 2.4.4. , still fail to solve the problem. Here is part of the informaiton I get.

(*) Invalid master-slave BC, selections for master(s) $N$M402653188S603979797, for slave(s) $N$M402653191S603979823 : 42.2222% slave nodes could not be constrained as required, specified in support id: 1, load case id 738197511, name: VOLUME 402653191 SURFACE 603979823 to VOLUME 402653188 SURFACE 603979797; BC ignored. More details in the Atena .err file.

(x) CCFEModelExc: CCPardiso solver error: zero pivot, numerical factorization or iterative refinement problem, (possibly in equation: 0, node: 0, dof 0) in phase 33.

]]>I'm modeling beams under four point reversed cyclic loading, I have assigned the bond strength-slip material for my reinforcement however I'm not sure about the unloading curve for the material. Does it regain it's strength while unloading ?

If so how can I not allow that to happen?

Also in my experiment, we went beyond yielding and crushing of concrete. In ATENA, the model stops as soon as crushing of concrete occurs how can I push the model further ?

Thank you for your support.

]]>I'm trying to simulate the interface failure test example provided in the documentation in ATENA 2D, Although I'm using same input conditions and keeping the boundary conditions also same, I'm not getting the correct/expected shear stress at the concrete-concrete interface.

Can you please help me with the following questions?

-Where are the monitoring points located in the analysis for plotting the load-displacement curve?

-What is the load step multiplier for both type of prescribed deformations; compression and lateral force?

-What is the solution method used for the analysis? Newton-Raphson or modified NR and how many iterations?

-What is the thickness of the macroelements and the interface?

-Will there be any difference in the results if instead of using SBETA material I'm using non linear cementitious 2 material properties?

These details are not provided in the manual.

Awaiting response on the above queries.

Additionally, what is the formulation adopted by atena3d for geometrically non linear models? Incompatible mode elements?

Thanks

Giovanni

]]>so I'm running a my beam under prescribed deformation and at step 7 for some reason the analysis is stopping and giving me this message: "CCFEModelExc: CCPardiso solver error: zero pivot, numerical factorization or iterative refinement problem in phase 22." I have read the troubleshoot file 2.4.6 yet still I'm not figuring out what is wrong, the model looks normal and nothing seems unusual.

I tried changing the solution parameter from NR to AL on the 7th step and yet I'm encountering the same problem.

Looking forward for your response,

Thank you]]>

" CCInpFExc: Syntax error reading ATENA input, line: 101, file: , data being processed:

1.717000e-002

yvalues "

I have modeled the CFRP as stated in the troubleshoot manual

Thank you]]>

I am modelling a prestressed concrete beam with ATENA 3D and I have a question concerning the data Output of the postprocessing tool. Is it possible to obtain nodal strain values for a previously defined cut section? I would like to integrate the strain values over the cut section in order to obtain the overall compressive concrete force for this section. Is this possible or is there an even better way to obtain the compressive concrete force?

Kind regards,

Sv

]]>I received the following message when my models are runnig through REMOTE DESKTOP of Windows

"CCException: HASP - program is running remotely on a Terminal Server

Continuing in DEMO mode"

However, it's not happen when I do this connection through TEAMVIEWR

How can I solve this problem?

Best regards

]]>I'm simulating a four-point bending test on a slab, for which I am using symmetry and only modelling half of the slab. When I use regular Newton-Raphson method (each iteration/tangent) results don't agree with the experimental conditions. Whereas, when I use modified Newton-Raphson method (each step/elastic), there is some similarity with the experimental results.

-Why is there a significant difference between these two methods?

Furthermore, I simulate results using modified N-R, but now, I varied the number of iterations in two different cases. In first case, I used 40 iterations and in second case, I used 100 iterations.

-Which of these two different iteration values should I rely on? What should be an ideal value for the number of iterations to get good results?

]]>For modelling a 3D GAP interface (mohr-coulomb) in GID, should i use the contact volume elements and subsequently assign the interface material model? Or should i use the conditions->GAP load for volume? and whats the difference?

The goal is to model an interface similar to the GAP interface in Eng 2D.

Thanks in advance!

]]>I work with ATENA 3D as part of my master thesis and try to describe my problem. Basically, I simulate a beam from an experiment and then do a parameter study. The beam is a prestressed T-beam with a total length of 12 m and 2 symmetrical fields with a length of 6 m each. The beam is reinforced differently in both fields and is uniformly loaded in both fields by a single load. In the experiment, the weaker-reinforced field (Field 1) was strengthened shortly before failure with the help of 5 traverses above and below the beam which are connected with threaded rods, so Field 1 could not fail due to shear force. Subsequently, the beam was further loaded in both fields until the failure of the more reinforced field (Field 2). In this way 2 experiments could be carried out on one beam.

My question: Is it possible to simulate the modification of Field 1 as in the experiment? The Field 1 must continue to be able to twist, as the load attacks eccentrically. However, the Field 1 must not fail due to shear force under further load.

I have already considered that the entire beam is modeled once only with the reinforcement as in field 1 and once with the reinforcement as in Field 2, but I'm not sure if the overall load behavior is not different. I would like to picture the beam as realistically as possible.

Many thanks for the help.

Regards.

]]>i would like to ask, how can i modify the stiffness of some certain finite elements or assign these elements a new kind of material? Can i do it through GUI? Can i add some code directly in the *.inp file.

Thanks very much.

]]>I'm modelling a four-point bending test with interfaces using ATENA Engineering 2D. When I given interface properties to the line as 'No connection' the model is not running properly, that is I'm getting zero displacement but a very little increase in the reaction force, when I plot the force vs. displacement curve.

Contrary to this, when I give interface properties to the same line as 'tensile strength = 0, cohesion = 0, friction = 0.5', then I obtain a proper force vs. displacement curve but still values aren't satisfactory.

My main concern is with these two methods I mentioned above. What exactly is the difference between these two techniques, as I want to check the behavior of a composite concrete slab in case of a perfect bond and also when there is no bond between the two concrete layers?

Also, when I'm assigning different values to the interface properties, the results I get don't vary with each other.

I expected some change in the load carrying capacity of the composite slab undergoing 2 point loads (four-point bending test), when I vary the interface properties!

I build up a reinforced concrete model which similar to the example model in Atena Science tutorial. I would like to know how to apply cyclic load on the beam, the beam is under the cyclic load which is ranged from 21kN to 74 kN at frequencies of 3 Hz.

could you give me some hint about it ?

Thanks

]]>