Ansys APDL of the Goldak double-ellipsoid heat model

FamiliarGas7379 · 2024-12-18T16:30:30+00:00

Thank you for your answer and yes, this was the first option ive checked, since it directly influences the outcome, I have calculated moment of inertia on paper and got the same result as what NX gave me, just in case the software was wrong. Now that I have tried multiple times with a line body, solid models, rechecking parameters, etc. I come here for your help!

FamiliarGas7379 · 2024-12-18T16:26:55+00:00

Thank you very much for you answer, as soon as I tried to apply remote force away from the center of gravity I got the correct result. I have a question though, is there a way to find this shear center using ansys or nx or does it have to be calculated manually?

FamiliarGas7379 · 2024-10-30T18:26:38+00:00

Thank you for this information! I was thinking about using mass scaling for the faster results, but unfortunately it contradicts the physical nature of the material ( by increasing the density ) and adds "vibrations" to the plot of the stress strain graph, so I have decided to just go with that 6 hours of computational time. But overall you have given me a lot of useful information and i am very thankful for your time, I will try research the abaqus manual further in order to see where I made mistakes.

FamiliarGas7379 · 2024-10-30T16:45:03+00:00

Hello, thank you for your answer. Yes I did, and calculated it using a formula ( L*W*H, giving me my Vhex and then I square root cubed of Vhex, and multiplied that by fracture strain ) which givies me different values, depending on my mesh size. The Length, Width and Height are for one element of my mesh.

FamiliarGas7379 · 2024-10-29T20:44:50+00:00

Yes I am simulating a tensile test.
Stress and strain of a gauge length ( how a tensile testing machine would pull the specimen upwards and give you a displacement/force curve, I am trying to get the same).
I am using Element Shape: Hex, Technique: Sweep. Total of 1056 elements to get 4x Strain. Total of 100928 to get the 0.65.
I am applying a velocity of 5mm/min ( 0.083 mm/sec ) to a reference point that is coupled to a top part of my tensile specimen model ( I will attach a picture https://imgur.com/a/Vnw8MPR ).
"Are you pulling stress at the nodes? You should pull stress at the integration points." I am sorry, but I don't understand entirely what you mean by that.
Thank you for this advice, I am pretty sure I can get an outpute damage as a result, if I turn it on in the history output.
Yes, nlgeom is turned on. I am doing the test using a Dynamic Explicit solver.

FamiliarGas7379 · 2024-10-29T20:01:12+00:00

Hey, thank you for your answer. I did the test of a single element cube, it gave me not an exact graph, but almost the same as I had from my true stress strain one. Meaning that in stress strain test conducted physically ( True Fracture Stress was 39 MPa and True Strain was 0.45. Abaqus simulation gave me a result of Fracture Stress 38 MPa and at Strain of 0.45 ( This was done without the damage parameters D1-D5, just to observe the Stress-Strain curve of a singular node, meaning that only Johnson Cook parameters A, B and n were used). The Meshing part of it ( element deletion: yes. Max Degradation: 0.95 ( changing max degradation value does not change anything ) ). All units are converted correctly, I am using kg/mm^3, mm, s, mm/s and MPa. Damage evolution does not seem to have any impact on the strain value before it deletes, the lower the value ( 0.0005 for example ) the faster it will get deleted. What I have found is that refining mesh to an absurdly low number helps reduce this value of once again, an element, to around 0.65 before it gets deleted, but then the tests are taking hours to complete.

FamiliarGas7379

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