About the development of the FEM module/workbench.

Moderator: bernd

HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

Re: Concrete branch ready for testing

bernd wrote:
Wed May 29, 2019 5:54 am
@harry:

Do you know some better names for the reinforced materials added? Are these real standard materials? https://github.com/berndhahnebach/FreeC ... a582d7c00b
Do you mean the names of material parameters Bernd, like:

Code: Select all

``````AngleOfFriction = 30 deg
CompressiveStrength = 15.75 MPa
Density = 2500 kg/m^3
PoissonRatio = 0.17
YoungsModulus = 32000 MPa
``````
If so, the names I am most familiar with are:

Code: Select all

``````Friction Angle
Uniaxial Compressive Strength
Density
Poisson Ratio
Young’s Modulus
``````
bernd
Posts: 11096
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Concrete branch ready for testing

no the material name itself (or we havet to stay with harrys beton and harrys reinforcement ) like Beton C25/30 or Beton Standard or whatever as well as Rebar B500B or Reinforcement Standard or whatever
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

Re: Concrete branch ready for testing

Ah

We could simply use the eurocode classification, e.g.

“Concrete C35/45” for a concrete with a characteristic uniaxial compressive strength of 35MPa (cylinder test), which is equivalent to 45MPa (cube test)

However this may not be very helpful for users outside Europe.
bernd
Posts: 11096
Joined: Sun Sep 08, 2013 8:07 pm
Location: Zürich, Switzerland

Re: Concrete branch ready for testing

HarryvL wrote:
Wed May 29, 2019 1:24 pm
Ah

We could simply use the eurocode classification, e.g.

“Concrete C35/45” for a concrete with a characteristic uniaxial compressive strength of 35MPa (cylinder test), which is equivalent to 45MPa (cube test)

However this may not be very helpful for users outside Europe.
I am fine with these names. On my ToDo is to add swiss standard concrete and reinforcement anyway. Since FreeCAD is worldwide we may have hundrdeds of concretes one day, may be may be not ... Do you know which concrete and reinforcement you used for the wall example (the two harry materials)? Since FreeCAD does not know about safety factor we have to add them to the material parameter directly. I may add a comment inside the material card about this.

bernd
HarryvL
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Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

Re: Concrete branch ready for testing

C 35/45

0.6*0.75*35 =15.75 (CIB shear wall with opening)
bernd
Posts: 11096
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Location: Zürich, Switzerland

Re: Concrete branch ready for testing

HarryvL wrote:
Wed May 29, 2019 2:42 pm
C 35/45

0.6*0.75*35 =15.75 (CIB shear wall with opening)
and the reinforcement https://github.com/berndhahnebach/FreeC ... e598de4R14 Here we have 500 MPa 1.15 =435 MPa
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

Re: Concrete branch ready for testing

Not sure Bernd. The CIB report quotes the factored strength as 315 MPa
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

Re: Concrete branch ready for testing

I had another close look at the FIB report. It uses a factored strength of 420MPa, but then states: “A strength reduction factor of 0.75 was used to all struts, ties and nodes to account for variations in construction quality and workmanship”. So I used 0.75 * 420 = 315 MPa. By implication the steel used has an unfactored yield strength of 315 / 0.75 * 1.15 = 486MPa (?), which is an odd starting point.
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

Re: Concrete branch ready for testing

HarryvL wrote:
Sat Jun 01, 2019 8:12 am
I had another close look at the FIB report. It uses a factored strength of 420MPa, but then states: “A strength reduction factor of 0.75 was used to all struts, ties and nodes to account for variations in construction quality and workmanship”. So I used 0.75 * 420 = 315 MPa. By implication the steel used has an unfactored yield strength of 315 / 0.75 * 1.15 = 483 MPa (?), which is an odd starting point.
HarryvL
Posts: 1071
Joined: Sat Jan 06, 2018 7:38 pm
Location: Netherlands

Re: Concrete branch ready for testing

Perhaps a material factor of 1.2 was used? It doesn’t mention the value used. So 0.75 * 500 / 1.2 would give 312.5 rounded to 315 MPa.