Thermal Analysis of Composite Slab - DASSAULT_ ABAQUS FEA Solver - Eng-Tips

12/11/2014Thermal analysis of composite slab - DASSAULT: ABAQUS FEA Solver - Eng-Tips Home > Forums > Engineering Computer Programs > Simulation > DASSAULT: ABAQUS FEA Solver Forum Thermal analysis of composite slab thread799-370570 Share This Fnct or Escr testing Full notch creep/stress crack resistance by UKAS accredited lab bothul (Structural) (OP) 26 Aug 14 12:54 Dear All, I am trying to model a fiber reinforced concrete slab on steel beams. I have applied the load in the first step and applied thermal conditions (convection and radiation) in the second step. The analysis reached 400seconds (tops) ( I was expecting 7000s). I have modeled the structure with solids. Slab tied to the beam. the analysis was run with Abaqus Standard. I have tried the same model using Explicit but the second step won't even start due to convergence. I tried contact between slab and beam. I have tried the same structure with shell elements but still "no go". Does anyone have references related to the topic? I would be glad to have someone to discuss to. Regards everyone, corus (Mechanical) 26 Aug 14 13:49 Presumably it failed in the second step when you applied temperatures. Again, presumably it's a coupled temperature displacement model so are there significant displacements that could cause convergence problems during the thermal loads? Have you tried just running a thermal model alone assuming tied surfaces and then loading the temperatures into a general static model? What was the error message when the job failed? http://www.eng-tips.com/viewthread.cfm?qid=370570 1/5 Eng-Tips bothul (Structural) (OP) 27 Aug 14 8:38 Thank you Corus for reply! For both Standard and Explicit I have used: "static. after running the Standard model again without structural loading.12/11/2014 Thermal analysis of composite slab . Best! bothul (Structural) (OP) 28 Aug 14 14:23 Hello. Your message gave me an idea. examples or materials on scaling? Do I have to scale mass or time. Thank you! Best! http://www.. The message is : ***ERROR: TIME INCREMENT REQUIRED IS LESS THAN THE MINIMUM SPECIFIED I tried the explicit model but I am pretty sure I don't do the scaling correctly.DASSAULT: ABAQUS FEA Solver .. I will be back with the results..com/viewthread. Do you think this can be the cause of "in-convergence". the model stops at 600s.8s from the 7000s of the step time while the OUT file is 665GB. Maybe the expansion in the steel beam is cracking the concrete slab. I tried the analysis without structural load (pressure on the slab) and I just want to see how it behaves due to expansion. only with thermal conditions.so I stopped it. Now the analysis is running. Due to the fact that I have also temperature in the elements I think the mass scaling is not advised.cfm?qid=370570 2/5 . So. I obseerved that the beam is expanding (at the bottom flange)more than 12mm while the slab expands 1mm. Can you guide me to some tutorials. it was still running and it reached 0. The concrete model I have tried is Concrete Damaged Plasticity. For the Standard part the error is: "Time increment required is less than the minimum specified" For the Explicit (by mass scaling) after 20h. general" analysis for the first step and "coupled temperature-displacement" analysis for the second step.eng-tips. See the status file for further details. I have modeled the composite slab using shell elements. I have tied the beam to the slab. finite sliding.12/11/2014 Thermal analysis of composite slab . I run the analysis and it can be observed that the slab and the top flange of the beam are distanced at the beginning of the step. Both the file option and the data line format option are used for the *temperature in the same step.com/viewthread. bothul (Structural) (OP) 1 Sep 14 13:39 Hello everybody. If so you'd have to review your mesh and how you apply the contact definition. The warnings I got are: The option *BOUNDARY. For a given node the values given on the data line will take precedence if op=mod parameter is specified or if op=new parameter is used to specify new values for the removed field Do you have any advice regarding these warnings? Thanks! Best http://www. It could be your model fails due to contact 'chattering' causing smaller and smaller time steps. I defined a contact between the beam and the slab: Tangential= Frictionless and Normal= hard contact .eng-tips. My advice would be to keep the model as simple as possible and to introduce more complexity after you've got some results. I works faster now with sequentially analysis. Kinematic contact method. Contact: Surface to surface.Eng-Tips corus (Mechanical) 30 Aug 14 3:05 If you run the thermal transient separately from the structural model then you can scale the mass in the structural model without any problems.TYPE=DISPLACEMENT has been used with a jump in displacements at the nodes in node set WarnNodeDispBCJump-Step1 at the beginning of the next step. Dear Corus. A couple temperature displacement model takes a lot longer to run and is ill advised to carry out unless your temperatures are significantly dependent upon the displaced shape. The temperatures in the slab are OK.DASSAULT: ABAQUS FEA Solver . all jumps in displacement across steps are ignored. The analysis stopped due to over stress in the beam due to compression ( the beam is expanding more than the slab). are less than the predefined field of 20C in initial step and the temperature are not increasing according to the heat transfer analysis. Thank you for your advice. also the temperatures in the slab after 250s.cfm?qid=370570 3/5 . etc. concrete slab with steel beams. solving http://www. the same integration points. I also choose the same time interval in the structural model as the thermal model though I think that's not strictly necessary. values are correct when reading in the temperatures. I have performed a sequentially coupled thermal analysis of the slab (with 7 integration points) and then a mechanical analysis. The thermal analysis has one step with 9000s and for bstep I used 1 and for estep also 1.12/11/2014 Thermal analysis of composite slab . and then viewing them from the structural odb file. I was checking the temperatures given by the thermal analysis and the temperatures in the mechanical analysis. case-setup. bothul (Structural) (OP) 3 Oct 14 10:32 Dear Corus.DASSAULT: ABAQUS FEA Solver . BCs.Eng-Tips corus (Mechanical) 2 Sep 14 3:29 You can check that the temperatures have been read in correctly by requesting the temperature as an output variable in the structural analysis.eng-tips.I didn't defined the beggining and end increment Do you know what might be the cause of this temperature difference between the two analysis when comparing NT11 and NT17? Thank you Best wishes! CastNet for CalculiX Non-linear FEA based on CAD input: Meshing. I only changed the element type. Also check your bstep. I am analyzing the same structure described above.600(NT17) degrees across the thickness of the slab and in the mechanical analysis the temperatures between the two faces are close (differ only 50 degrees) and are about 600 C.cfm?qid=370570 4/5 .dear all. The temperatures in the thermal analysis varies from 200(NT11) .com/viewthread. If your mesh isn't the same between the thermal and structural model then you can get errors in the results unless you used the incompatible mesh option. I have used the same mesh for both analysis. estep. eng-tips.12/11/2014 Thermal analysis of composite slab .DASSAULT: ABAQUS FEA Solver . http://www.Eng-Tips Join | Indeed Jobs | Advertise Copy right © 1998-2014 ENGINEERING. Unauthorized reproduction or link ing forbidden without expressed written permission. Inc.cfm?qid=370570 5/5 . A ll rights reserv ed.com.com/viewthread.