168easy
Industrial
- Aug 15, 2015
- 1
hi there friends of APDL,
I was quite a while as a observer in this forum - now I need help and hope somebody would be so kind to discuss my problem with me! I'm an student from germany and for my graduation thesis I'm using APDL v.14.0 for an modal analysis and nonlinear stress test- target is one wing of a windmill ( CK220
First I build my model bottom up and could succesfully do a modal analysis. The first 8 frequencies look allright,I've done measurements FFT so I have values to compare. Ansys says total mass is 5,6kg which exactly represents my orignial wing
Well after that my task was to compare another "stress" measurment. I pushed the wing with a newton meter and recorded the actual displacement from my push. I stayed in the linear area so I can assume Hooke's Law is valid. (range 10- 40 N, example : 30N-4mm)
"The value of ROTX at node 2356 is 2917362.35. It is greater rhan the current limit of 1000000. This generally indicates rigid body motion as a result of an unconstrained model. Verify that your model is porperly constrained."
I guess I have no rigid body motion. There is contact between my two materials (always bonded) but my first frequency is at 62Hz.
Where do i have to go from here? I also use SOLID72 with doesnt support "large deflection" is this important?
My last idea is convergency.
- increase pinball radius at contact
- decrease contact stiffness at contact
Do i need to change this at every contact?
And maybe change the properties of convergency?
- NSUBST up
- DELTIM down
Put my code into attachments if needed I can post my ansys output too.
Would appreciate any suggestions since I'm only since 2 months into APDL
Best regards
Eugen
I was quite a while as a observer in this forum - now I need help and hope somebody would be so kind to discuss my problem with me! I'm an student from germany and for my graduation thesis I'm using APDL v.14.0 for an modal analysis and nonlinear stress test- target is one wing of a windmill ( CK220
First I build my model bottom up and could succesfully do a modal analysis. The first 8 frequencies look allright,I've done measurements FFT so I have values to compare. Ansys says total mass is 5,6kg which exactly represents my orignial wing
Well after that my task was to compare another "stress" measurment. I pushed the wing with a newton meter and recorded the actual displacement from my push. I stayed in the linear area so I can assume Hooke's Law is valid. (range 10- 40 N, example : 30N-4mm)
"The value of ROTX at node 2356 is 2917362.35. It is greater rhan the current limit of 1000000. This generally indicates rigid body motion as a result of an unconstrained model. Verify that your model is porperly constrained."
I guess I have no rigid body motion. There is contact between my two materials (always bonded) but my first frequency is at 62Hz.
Where do i have to go from here? I also use SOLID72 with doesnt support "large deflection" is this important?
My last idea is convergency.
- increase pinball radius at contact
- decrease contact stiffness at contact
Do i need to change this at every contact?
And maybe change the properties of convergency?
- NSUBST up
- DELTIM down
Put my code into attachments if needed I can post my ansys output too.
Would appreciate any suggestions since I'm only since 2 months into APDL
Best regards
Eugen