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# Units in FEMAP

Valued Contributor

Hi everybody!

I prepare a direct transient analysis in work. I have got a important problem because I´m not sure about the units of results. That´s why I`m asking You for help. Have anybody a table or note about the input and output units in FEMAP? Could you explain me how to use a units in FEMAP? Especially I am interesting in a units of frequency and acceleration.

Best wishes

J. Krzesimir

7 REPLIES

# Re: Units in FEMAP

Legend

About the units the user must take care abut them. I use always:

- mass (M): tonnes

- time (T): seconds

- length (L): mm

Then you get stresses in MPa (N/mm2), frequency in Hz (1/sec) and acceleration in mm/sec2

# Re: Units in FEMAP

Legend

Hello Jakub,

Femap doesn't use any units. Units of your results depend of your input units.

For example if you use N as force and mm as lenght unit, you get stress results in MPa (N/mm2). See earlier post, f.e.

or

https://community.plm.automation.siemens.com/t5/3D-Simulation-Femap-Forum/Unit-System/m-p/23001#U230...

Best regards

# Re: Units in FEMAP

Valued Contributor

Thanks for your answer! I would like to ask for something else, what about acceleration? I have to make a half-sine function. And it is a chart acceleration vs. time. Time is in seconds but in which unit shall I signify the second axis to get mm/s2 in result? Now I have got just a m/sec2 but I am getting wrong results.

Best wishes

J. Krzesimir

# Re: Units in FEMAP

Legend
Hello Jakub,

Which length unit do you use in your model?

If you use mm, you should use mm/s2 acceleration. If you use m, you should use m/s2 acceleration.

Best regards

# Re: Units in FEMAP

Legend

Hello Jakub,

If you use as input:

- Mass in tonnes

- length in mm

- time in seconds

acceleration then must be in mm/sec2

the outputs are:

- force in Nw

- stresses in MPa

- acceleration should be in  mm/sec2

# Re: Units in FEMAP

Valued Contributor

Everythink i s clear now.

Thank You very much and have a nice day!

Best regards

J. Krzesimir

# Re: Units in FEMAP

Phenom

Only saw the above post recently...

The short explanation for Femap units (also relevant to any other "unit-free" = "consistent units" FEA code) is here:

http://www.endurasim.com.au/consistent-units-fea/

The detailed explanation including tables of metric / imperial + mech / thermal is here: