Tutorial: How to calculate stress triaxiality for damage for ductile metals ?

[@armytwin2]

This is a very informative and well explained video thank you for posting it

[@somethingdifferent1910]

Very usefull content , wish to see more ....

[@yunsongguo584]

A trick: When you wanna calculate stress triaxiality, you can simply use 'pressure', rather than querying and summing s11,s22,s33 separately. In addition, you also can turn on the TRIAX when you set the field/history output， but this may only be suitable for dynamic(I am not sure).

[@hnrwagner]

I have not yet seen this field output, i will check , thanks for the suggestion

[@هندسةميكانيكيةثانويةصلاحالدينب]

thanks for all

[@ismaillakhal9495]

Thank you Doctor

[@hnrwagner]

thanks too

[@ukaszojek1305]

Dear dr, I wonder if I can use stress triaxiality achived this way to determine J-C damage parameters. I have tensile test results for different strain rates and temperatures but samples which were used in tests are simple flat samples with different gage lenght, not like round bars you used in your video about determining J-C damage parameters. Would be grateful for your answer.

[@javadfazelpour1195]

Thank you!!!!🌷🌷🌷

[@张慧乐]

Can you explain the meaning of Equivalent strain to fracture in the cover image? How to obtain this parameter? Thanks

[@hnrwagner]

It's fracture strain to triaxiality

[@张慧乐]

Is it the initial failure strain or the total strain when the failure index is 1?@@hnrwagner

[@davidmichael8179]

Why in your Abaqus model, failure of coupon is not happening at centre of the specimen.

[@hnrwagner]

Why should it? Have seen many tests some start above mid section or near edges

[@davidmichael8179]

@@hnrwagner if it's equal pulling force applied on both ends, where the boundary conditions are fixed and if specimen dimension are uniform. It should fail at mid length or almost near to mid length right ?? Else if the force applied is non uniform, where the force is higher it will break near to that support. Am i right or wrong

[@hnrwagner]

Its a dynamic explicit simulation, there are many simulation and also meshing parameters which also influence the results, in theory it should break in the mid section

[@davidmichael8179]

@@hnrwagner let me ask you one more doubt Why can't we do with a static general simulation

[@hnrwagner]

@@davidmichael8179 as far as i know the static solver cannot handle such large deformations and element deletion as well as explicit solver

[@charitharanwala]

How can u produce the graph??

[@hnrwagner]

you test different test specimen with different stress triaxiality values and determine the frature strain, an example is shown here: kzbin.info/www/bejne/aXq1amhnic6BfcU at 2:30

[@张慧乐]

What does alpha mean?

[@hnrwagner]

that is the plastic strain ratio, it is described in the article which i have linked in the video description

[@هندسةميكانيكيةثانويةصلاحالدينب]

dear dr, can you help me or make video about how to calibrate a material using abaqus as in this paper : 1-s2.0-S2452321616300853-main.pdf

[@hnrwagner]

what is the exact question ? I am not sure

[@هندسةميكانيكيةثانويةصلاحالدينب]

@@hnrwagner : Damage model calibration and application for S355 steel

[@هندسةميكانيكيةثانويةصلاحالدينب]

Based on the triaxial vs. PEEQ dependency plotted for the middle finite element of the dog bone using Abaqus he calibrates the parameters of Johnson and Cook’s equation using for ductile damage but I don't know how he does the calibration in Fig. 9 thanks

[@shuomengzhang9516]

like it.