Dear all
I’m studying hypo-plastic constitutive law from beginning concepts
I traced concepts successfully until i faced **rate independent topic**
i read this topic in the prof. Wolfgangs paper (hypo-plasticity for beginners)
he said that “Rate-independence means that the gradient of the curve (stiffness) does not depend on the strain rate, Thus the stress rate must be precisely twice as large for a double strain rate” and in the fallowing he said that “the constitutive law may not have terms like (strain rate^2) (strain rate square )”
as you know the hypo-plastic constitutive law is non-linear in strain rate
my question is that how hypo-plastic constitutive law can fulfill the non-linearity (in strain-rate) with no term like (strain rate^2)
Related Articles
-
Calibration the UMAT sand hypoplastic parameters
Dear all, I’m facing trouble in calculating NO. 16 parameter in the UMAT for sand hypoplasticity by Dr. Masin, any help will be really appreciated especially with an example. Best […] -
Cyclic simple shear test simulation with hypoplasticity
Dear All, I am using sand hypoplastic model in my research and I have encountered some problem when looking into cyclic simple shear test in the range of small strains. […] -
Hypoplastic model for Granular soil
Hello everyone, Could you please anyone tell me that how I can define the hypoplastic constitutive model for granular soil in ABAQUS 6.13. With Regards, Naveen. -
Automatic calibration software ExCalibre has been launched
On behalf of the team of developers I am happy to announce that, after more than four years of development and testing, ExCalibre has just been launched. ExCalibre is a […] -
Regarding FRIC : As a beginner
Sir, As a beginner of FRIC I am facing some difficulties to implement it. The downloaded FRIC code has been added to my pile soil friction model and trying to […] -
Book “Modelling of soil behaviour on hypoplasticity” has been published
Hardcopies of my new book “Modelling of Soil Behaviour with Hypoplasticity – Another Approach to Soil Constitutive Modelling” just arrived. The book is available for hardcover or pdf orders at https://www.springer.com/us/book/9783030039752 -
Clay Hypoplastic Model ABAQUS UMAT
Hi, I wanted to ask if the variables/parameters defined in the online Hypoplastic model manual for PLAXIS (https://web.natur.cuni.cz/uhigug/masin/plaxumat/node6.html) are the same for the ABAQUS UMAT? -
Sanisand model
Is the Sanisand constitutive model 3 dimensional? Could it be used for dry sand cases using C4D8 elements? (drained sand) Is it possible to apply it in a dynamic implicit […]
Supporting Organisations
Recent posts
-
Hypoplasticity & Recent Stress History 20.1.2020
-
hypoplasticity models in free Tochnog Professional 14.1.2020
-
Problems with the UMAT subroutine check_parms_DM of the SANISAND constitutive model 11.1.2020
-
Tochnog Professional overview movie in youtube 29.12.2019
-
Tochnog Professional becomes free 18.12.2019
Dear Sobhan, hypo equation is defined as stressrate=L:strainrate * N||strainrate||. Here, ||strainrate|| is Euclidean norm of strainrate, that is sqrt(strainrate:strainrate). You see that the equation is non-linear in strainrate (if strainrate changes direction, stressrate changes direction differently as the term with N only quantifies strainrate size, not direction). You also see that actually, units of ||strainrate|| are still 1/time, as there is sqrt(strainrate^2) involved, thus it is consistent with comment by prof. Wolffersdorff which you cited. I suggest to have a loom into my book “Modelling of Soil Behaviour with Hypoplasticity”, where fundamentals of hypoplasticity are explained in (hopefully) clear way. Regards David
thank you so much!