Kinematic hardening will increase yield in one load direction, but will reduce it in the other load direction regardless if you apply tension or compression first — it will act the same way for both! I think it may be useful for you. It simply expands views on certain things! BTW truth is always a bit more complex! I think Boris will be very happy if you would write few words of encouragement below in the comments.
Also, if you like the idea of guest posts — let me know! Perhaps you would like to write a post on the blog? If so, just drop me an email at: [email protected]! I have over 10 years of practical FEA experience I'm running my own Engineering Consultancy , and I've been an academic teacher for a decade. Here, I gladly share my engineering knowledge through courses, and on the blog! So nice to hear from you. In short This is the first time in my life that I heard about them :.
Nice down to earth explanation, thanks! I also think the choice in hardening rule is highly dependent on the material you are modeling and thus the reason for the various options. Physical testing reveals the applicable rule. Nice article which explains things very well. The only thing I didn't get was how you derived the equation for the change in plastic strain, but hey!
I'm really glad that you like the post. Boris did a really great job : I'm not a big fan of deriving equations myself - I completely understand you there :. It is popular mistake last yeras. Only kinematic hardening near reality. Truth lies near kinematic, not "in-between". Thank you for the suggestion. I will definitely read more about Baushinger effect when my "learning schedule" clears a bit.
Perhaps not from the Wikipedia, but I know what you meant. If this is a mistake, then I apologize If isotropic is wrong, and kinematic is right Are there any new research that could shed some light on that that you are aware of?
I had read too many articles to understood this hardening concept earlier, but i couldn't get clear Idea and this one is excellent and explained in very systemic manner. Many thanks to Boris and Lukasz. I like very much how this subject is written.
It helped me in understanding the differences between these two hardening rules. Thanks for sharing us such great post. I just wonder when should we use isotropic hardening or kinematic hardening while the specimen is subjected to cyclic loads.
I won't even pretend I'm a super-expert on low cycle fatigue and crack propagation. I know my part, but there are limits to this and big ones I guess! Definitely, this will depend on the material you are using in an analysis. All in all, as far as I know, there is no "perfect rule", but in order to solve a specific case or to find a specific answer , it would be best to read some scientific literature on the subject.
So far this was not in my zone of interest, so I won't be able to be more specific than that! Now here's a query: I had read somewhere that isotropic hardening model is good for large strain applications whereas kinematic hardening is good for cyclic loads.
I believe for non-cyclic loads both models should give the same results, hence I don't understand recommendation for large strain applications. This means that all of the deformation caused by loading is fully recoverable and no permanent damage or 'set' is incurred by the material.
This is the case only when the analysis does not generate stresses exceeding the material yield point at any location within the structure. However, if the loading is expected or known to cause stresses beyond yield and, as a result, the effect of plasticity needs to be captured, then we have a decision to make… which Abaqus hardening model should we use?
Fortunately, we published a post a few weeks ago that does exactly that. Plasticity occurs in metals when we introduce enough strain energy that dislocations in the crystal lattice begin to move around, and, once that happens, the material will be deformed permanently. Seems pretty straightforward, right? Until we begin to consider what happens if we unload the material, and then reload either in tension or compression.
We know the material has deformed permanently, but how does that affect the stress-strain behavior upon loading for a second time? To capture this constitutively, we must go back to the yield surface and think about what has happened to it after the yield criterion was met.
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Sun, - kajalschopra I've been trying to figure out difference between isotropic and kinematic hardening. Can anyone explain this more clearly or correct me -with a physical intuition? Computational Mechanics Forum. Kinematic vs. Isotropic Hardening Permalink Submitted by prost on Wed, Kinematic hardening takes Bauschinger effect in account. Just to add: It should be noted that when the loading is monotonic, materials with isotropic hardening and kinematic will behave the same.
Only when unloading is involved, the difference between the two hardening rules will be reflected. Sign In or Register to comment. Commercial Support Ansys customers with active commercial software licenses can access the customer portal and submit support questions.
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