I am studying now about the fracture mechanics of Axis-symmetric edge crack in cylindrical geometry. I have defied the crack size (a) / cylinder radius(R) , ratio(a/R) from (20% to 80%).
Any comments/suggestions would be appreciated.
Thanks
The K_I or G behaviour depends on the load type. For an end force or stress applied to the end of the cylinder, K_I and G may increase with the increase of crack depth. However, for a displacement applied at the end of the cylinder, you may expect a maximum value for a certain crack depth. You may check a handbook for a known stress intensiti factor solution to validate your calculation.
For elastic materials, G=J=K^2/E’ (E’ is Yong’s modulus taking different values for plane stress and plane strain conditions). You cannot extract G from any energy parameters in ABAQUS.
@Yuebao Lei. I really appreciate your detailed answer. That is interesting to know that Gmax can be expected for displacement control analysis. In my model, I applied uniform tensile stress at the end.
I guess that maximum value for certain depth is key factor when you want to find the critical size to avert the growth of crack. Because, in that case, for one particular size of cylinder, you need to find the Gmax (that makes the critical size calculation independent of crack size).
Therefore, I am looking for to find the way how can I transform my uniform tensile stresses value into corresponding displacements that I would apply to get the Gmax.
Lastly, I wonder as relation of G=J=K^2/E’ depends on plane stress/plane strain (2D case) condition, however how it is calculated for axis-symmetric case (that is kind of 3D geometry)?
Thanks
For axisymmetric problem, the constraint is similar as that under plane strain conditions. Therefore, plane strain conditions should be considered.
In order to seek the stability during crack growth process the energy release rate can decrease. This fact is observe with some specific specimen such as DCB with variable inertia or MMGC specimen for mixed mode ratio. The main objectif of this last specimens is to perform viscoelastic effects during crack growth process. Don't hesitate to contact me for more explications.
Crack growth can be specified based on crack growth resistance curve. One of the ways to evaluate it is by using double cantilever beam technique for interlaminar crack growth. Crack growth resistance behavior is a material property. For most of the materials, crack growth resistance increases initially, and then decreases leading to catastrophic failure.
how to calculate the energy release rate in ABAQQUS ? please
@Fares Mohamed Laid Rekbi: Try the history output setting in Step definition stage
@Fares Mohamed Laid Rekbi: Please, did you get how to obtain the crirtical release strain rates? @Nadeem Qaiser, Please, can you be specific. I think we have to input the value into the critical strain (Mode I, II, III) spaces before closing the property chat. I'm not getting how to obtain the right values.
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