gauges using rod

[051174]

In general to to evaluate and predict the stress results of gauge readings i read on fem for example the stress on a reference cid along the direction of sensor on quad element taking into account the z1 or z2 face...I think that there is another way to evaluate the sensor value using for fem bar with rod properties...someone can help me to make this more clear to me and in particular what property to use for bar element...what to read then...
Thank in advance.

 

[rb1957]

i'd start by not putting axial straing gauges on a surface, use rosettes. this way both the FEM and the strain gauges can tell you the principal stresses in the surface, so you can compare them.

 

[051174]

Ok. But how simulate rosettes? Can I use rod? I'm tring A=0.001 And material E=1. ni=0.3 dens=0. th-exp=0 also for rosette but i think that it is not correct because this don't take in account the shell z1 or z2 face and so on.
pbeam seems to me more correct i'm tring also I1=I2=0.001....but is it correct? there are other ways? Can you clarify to me the correct approach.
Thank you.

 

[rb1957]

you don't need to simulate a rosette. the stress output of the element is all you need to compare to the strain gauge (since you'll be comparing principal stresses)