Yade

About strain and uniaxialstrainer

Asked by John Avoilao on 2019-11-12

Hi to all,
I am a new user. Currently trying to simulate a compression test
I cant completely understand all the components of uniaxial strainer.
1) The strain I get is in (m/m); is it percentage elongation;
eps=(DL/Lo)=(L-Lo)/Lo;;
strain = Current strain value, elongation/originalLength
2) In a uniaxial compression test should I allow blockDisplacements and
blockRotations of boundary bodies;

Thank you all

Question information

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Solved by:
Jan Stránský
Solved:
2019-11-12
Last query:
2019-11-12
Last reply:
2019-11-12
Best Jan Stránský (honzik) said : #1

Hello,

please use question mark (?) at the end of questions.
The current description looks like you are just making statements and then you thank us. Probably not what you wanted to express..

Now **guessing** that 1) and 2) should have been questions:

1), yes, strain is computed as length difference / original length [1].
It is not percentage as it is dimensionless (percentage would be multiplied by 100)

2) depends on what you want to simulate :-)
in certain case you should, in other cases you should not

cheers
Jan

[1] https://gitlab.com/yade-dev/trunk/blob/master/pkg/dem/UniaxialStrainer.cpp#L125

John Avoilao (johnav) said : #2

Thanks Jan Stránský (honzik),

I get the strain concept.

 2) depends on what you want to simulate :-)
 in certain case you should, in other cases you should not

Well im trying to simulate a ucs test;
Are you suggesting anyting?
Like blockDisplacements(=false) and blockRotations(=false)? or maybe true??

Jan Stránský (honzik) said : #3

Hi,

> Are you suggesting anyting?

any suggestion would depend on what you want to simulate.
If you want to simulate blocked transverse displacement of boundary particles, then use blockDisplacements=True, if you want to simulate free transverse displacement of boundary particles, then use blockDisplacements=False.
What is more appropriate depends on real physical test, how it is loaded, what is friction between the loading machine and the specimen .....

You can try both versions and choose :-)

cheers
Jan

John Avoilao (johnav) said : #4

Thanks Jan Stránský, that solved my question.