Unit conversion

Hi
I have a problem. I am modelling a concrete shell in SAP2000
I did it in (Tn, m) units; I have a moment resultant as follows:

"1.0373" I supouse (Tn-m)/m; when I convert this to (Kg,cm) I get "1037.3"

Didn't I have to find 1.0373*1000*100 (Kg-cm)/m.??

What exactly means, I really cannot figure it out.

Thank you for your time.
Regards.

 

[dlew]

Visitor021,

If the units are kilogram-force and cm, then the moment should be given in kg-cm/cm

1.0373(tn-m/m)*1000*100/100 = 1037.3 kg-cm/cm

 

Not sure what Tn stands for. If you are using metric units, Moment is Force mutiplied by distance or Newton-meter. This is not the same as Kg-m or Kg-cm as this is a mass multiplied by distance. The gravitational constant g is missing. Sorry if this is not much help.

 

Visitor aloha
There is an unit kilogram force and the value is the same as the mass so the constant "g" is not missing.

 

[godoza]

If I well understand, your dimensional formulas is:
[Tn]*[m]/[m]=[Tn]. But this is not a measurement unit for the moment. I can't understand what kind of distributed moment is this. My opinion is to consider the moment in Tn*m only, not in Tn*m/m. Florian Smochina

 

[austim]

Hi,

If your moment is a moment per unit width of shell, as you have concluded, then you are starting with tonne*metres/metre. That is exactly the same as tonne*cm/cm, and the conversion to 1037.3 has given you kgf*cm/cm. (Essentially most formulae for moments in slabs and shells give you moments as force*length/length, and boil down to moments in units of force only).

ie the conversion result is in consistent units of kgf and cm.

If you want to mix your units of length, and work with kgf*cm/metre you must multiply by 1000 to get 1037300.

 

[hyper]

I think S2K transforms all the units, as well as:

internal forces (Tn/m) to (Kg/cm)
resultant moments (Tn*m/m) to (Kg*cm/cm)
and you maybe need (Kg*cm /m) to design so, it is ok
what austim says, but you must multiply by 100 to get
103730, because de Ton to Kg is already converted.

 

[austim]

OOPS! I can't imagine a more public place to drop a factor of 10. hyper is quite right, and the multiplier is 100.

My only excuse is that in Aus no-one uses cm, and all conversions are from mm, so my 1000 went straight in out of habit :-(

 

[jackyyau]

The SAP manual states "It is very important to note that these (for shell elements) stress resultants are forces and moments PER UNIT of in-plane length".

Therefore the second post by dlew is right.

 

[chicopee]

Dlew's value and units are correct eventho he did not showed you how he did it. But Visitor021, if you are an engineer, Dlew did not feel that he had to.
Any way, that's how it should have been presented:

1.0373 Tn-m/m X 1000kg/Tn X 100cm/m X 1m/100cm=
1037.3 Kg-cm/cm

The meaning to the result is that the moment =
1037.3 Kg-cm per lineal centimeter

The lineal centimeter could be along the circumference of the shell that you are addressing. It could also be along the straigth length of a seam. I Just dont know because you did not state where that moment was calculated.

 

[abbver98]

Go to this link, you may found a free converting software :

http://www.joshmadison.com/software/

josh@joshmadison.com

you'll find all quantities (masse, moment, pressure, ....)