Dear all:
I apply ABAQUS to model a steel bar under compressive load, and use displacement control, but the result showed that at the beginning it was compressed, but later on, it was stretched and the structure is tending to deform unreasonable, see the attached picture, can any one do me a favor and tell me what is the reason of that?
Sincerely yours,
Mengli
You should create a constraint as follows:
In the interaction module of Abaqus/CAE, select Create Constraint-> Coupling, select a node at the middle of the surface, define the surface to be node based, then at the window that appears select Coupling type to be Kinematic. Do this for the loaded and the constrained end of the solid beam.
After this you can apply a pin constraint at the reference point of the one end of the beam, and a load (force or moment) at the reference point of the constraint of the other end of the beam.
I tried the above and they work. Of course, there may be other options to impose the conditions you want, of lower or higher complexity.
I hope this helps.
Check the load and the boundary conditions of the model. There is large possibility that the error lies there.
It is true, since only I modified the boundary condition, the result tends to be like this, and can you help me with another question?
I want to use solid element to model a bar under compression, and I want to impose pin end to the bar, but ironically, I just cannot make it....
I mean, for a solid element, there is no rotational DOF, the end of the solid bar can only rotate with the difference of the axial displacement, and I also want to use displacement control to add load, If so, I will set all the nodes on the top surface as a same displacement value, at that time, it cannot rotate, but I want it rotate with displacement control, do you know how I can do that? It is such a dilemma ....
Please help me, I need your suggestion!
You should create a constraint as follows:
In the interaction module of Abaqus/CAE, select Create Constraint-> Coupling, select a node at the middle of the surface, define the surface to be node based, then at the window that appears select Coupling type to be Kinematic. Do this for the loaded and the constrained end of the solid beam.
After this you can apply a pin constraint at the reference point of the one end of the beam, and a load (force or moment) at the reference point of the constraint of the other end of the beam.
I tried the above and they work. Of course, there may be other options to impose the conditions you want, of lower or higher complexity.
I hope this helps.
Okay, thanks very much I will try that one, and when you use kinematic coupling, what DOF you suppressed?
Another thing, I applied Rigid Body to the end of the bar, and impose the load as you said, it also works!
Thank you again, it does help!
Double check you did not introduce a gravity or body force on the system. this would load the system first, and then your displacements would superimpose. this could cause the behavior you are seeing.
Thanks Mr.Brian!
But I did not set any body force and gravity force on the bar, it is so wired, I set comprssive displacement at one end, and another one works well, but only because I set free more DOF at the end surface, it shows like this. (I am modelling a compressive bar with displacement control, and investigate its buckling behaviour)
Thanks very much!
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