Hello, does anyone know what the ref energy value is that Abaqus is looking for in Hysteresis Energy damage simulations? Abaqus presents an error without a value being included; however, the user manual doesn't mention anything about it. I would like to know what this value represents physically so that I can confidently understand what Abaqus is trying to do.
***NOTE: DUE TO AN INPUT ERROR THE ANALYSIS PRE-PROCESSOR HAS BEEN UNABLE TO
INTERPRET SOME DATA. SUBSEQUENT ERRORS MAY BE CAUSED BY THIS OMISSION
*damageevolution, type=HYSTERESISENERGY
***ERROR: THE REF ENERGY PARAMETER MUST BE SPECIFIED. IT IS RECOMMENDED THAT
REF ENERGY, WHICH HAS THE UNITS OF ENERGY DENSITY, BE CHOSEN TO HAVE
THE VALUE OF 1.0 IN THE SYSTEM OF UNITS IN WHICH THE EVOLUTION LAW
IS CALIBRATED TO THE AVAILABLE TEST DATA. IF A DIFFERENT SYSTEM OF
UNITS IS USED, THE REF ENERGY SHOULD BE CONVERTED APPROPRIATELY TO
THE NEW SYSTEM IN ORDER TO ENSURE THAT THE PHYSICAL RESULTS ARE
INVARIANT TO THE CHOICE OF THE UNIT SYSTEM.
Example of what Abaqus thinks is sufficient information....
Data lines to specify damage initiation for CRITERION=HYSTERESIS ENERGY:
First line:
Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than five):
Repeat this set of data lines as often as necessary to define the dependence of material constants on temperature and other predefined field variables.
Optional parameter REF ENERGY is used with TYPE=HYSTERESIS ENERGY to set a reference value of the accumulated inelastic hysteresis energy per cycle. The default walue is 1.0.
https://docs.software.vt.edu/abaqusv2022/English/SIMACAEKEYRefMap/simakey-r-damageevolution.htm#simakey-r-damageevolution__simakey-r-damageevolution-s-paramsoptional1
Please look at the next sections:
Damage initiation criteria for ductile materials https://docs.software.vt.edu/abaqusv2022/English/?show=SIMACAEMATRefMap/simamat-c-damageinitfatigue.htm
Damage evolution based on accumulated inelastic hysteresis energy density https://docs.software.vt.edu/abaqusv2022/English/?show=SIMACAEMATRefMap/simamat-c-damageevolfatigue.htm
Apologies, thank you very much for your help.
So if the damage calibration was done in $\frac{inlb}{in^3}$ and the model is in $\frac{J}{m^3}$ the value of 1 for $\Delta\omega_0$ would be equal to 0.000145? Assuming that 1 $\frac{J}{m^3}$ is equal to 0.000145 $\frac{inlb}{in^3}$. Also, $c_1$ would need to be multiplied by the same factor, is this correct?
A reference value of the accumulated inelastic hysteresis energy density per cycle Δw0=1 lb/in2=4.448222N /(0.0254m)2=6894.76 N/m2. Material constant c1 has unit of CYCLE, so I think it should not be changed.
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