Dear all, i try to modeling a gear and pinion in Abaqus/standard to analysis the contact stress. I defined the reference point in the center of each gear and assigned the kinematic coupling constraint for both of them.
The displacement/rotation (B.c) was defined for reference points and moment load allocated to pinion. the surface to surface contact was assigned to gear and pinion teeth.
the analysis is aborted with these errors
I was wondering if anyone can help me to get over these errors
[Whenever a translation (rotation) dof at a node is constrained by a kinematic coupling definition the translation (rotation) dofs for that node cannot be included in any other constraint including mpcs, rigid bodies, etc.]
[MPCS (EXTERNAL or INTERNAL, including those generated from rigid body definitions), KINEMATIC COUPLINGS, AND/OR EQUATIONS WILL ACTIVATE ADDITIONAL DEGREES OF FREEDOM]
[2 elements are distorted. Either the isoparametric angles are out of the suggested limits or the triangular or tetrahedral quality measure is bad. The elements have been identified in element set WarnElemDistorted.]
[Displacement increment for contact is too big.]
[Excessive distortion at a total of 364 integration points in solid (continuum) elements]
Please check the BC. The rotation you apply should be very small. Try with 0.001 and/or reduce the time step increment.
Franco
I appreciate your quick response franco .
, as you said I applied the rotation (0.001) and the time increment(0.0001) but the errors are still exist.
Hi,
I have simulated the same using PERMAS on a Planetary Gear train combined with a differential.
However, I had to suppress the rotational DOFs of the output gearwheel (the last wheel, if it is a gear-train) in order to attain reaction forces on the gear teeth mesh. There is still some rotation rendered in the results due to flexibility of the material. I agree with Franco that the rotation should be small to avoid geometrical non-linearities in the calculation. But ABAQUS already contains the remedy for it.
The way I simulated the gear teeth contact was by using a rigid coupling (MPC/RBE2) from the gear teeth flank on the input wheel with its guiding node placed at the pitch circle diameter of the corresponding teeth of the output teeth in mesh. Then to create a surface to node contact (master surface of the output teeth flank and slave node being the guiding node of the rigid MPC).
This method is effective only if you wish to attain the deformation of the housings in which the gear-train is installed or just to attain the contact forces in the gear teeth. This method is not suitable to analyze the distribution of stresses on the meshed gear teeth as the transfer of loads is through a single node and not both the mating surfaces of the teeth in mesh.
Furthermore, to calculate the torque and the radial bearing loads, you must use only the radial contact forces from the results, taking into account the helix angle and the pressure angle of the gear teeth. Respectively, it goes for the axial bearing loads.
I hope this would be of help.
Dear franco and Nikhil Dhawan,
I do appreciate your useful answers.
I have done my project successfully.
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