what does time period in step means 1

[Mechanicslearner]

Hello,

Am trying to do simulation using dynamics/explicit and I like to know what time period in step means. Because in static I set to default to 1. But in Dynamic if I set to 1 it takes more simulation time than less than 1. I know we can even set more than 1. My question is in time period values. Does these values means seconds or something else. I tried in manual too but I could not find its definition. So if I want to simulate wind load for a minute , do I have to put value of 60 meaning 60 seconds in Time period?

 

[akabarten]

Hi,

It depends what system unit you choose for your analysis.
Abaqus has no default system unit, it is a user choice.

You have to choose three base units: length/mass/time.
For instance it can be SI system unit [m/kg/s] or [mm/kg/ms], [mm/ton/s].

When you made your decision you have to define all material properties and loads in correct units.
Young module for steel in [mm/kg/ms] will be in GPa so you put value of 210.0, in [mm/ton/s] it will be in MPa so the value is 210.0e+03
The same rule is for time unit, if you are working in [mm/kg/ms] you have to put value of 60000 for [mm/ton/s] it will be 60.
If you decide to use system unit like [mm/kg/min] (a little crazy but possible) you will have to define step for 1.

So the question is what system unit you use in your simulation?

See here: Getting Started with Abaqus: Interactive Edition, 2.3.1 Units.

Regards,
Bartosz

VIM filetype plugin for Abaqus

https://github.com/gradzikb/vim-abaqus

 

[Mechanicslearner]

Hi Bartosz,

Thank you for the explanation. So if I want to see stress acting on a structure due to wind load, where my SI system is m,kg,sec for 10 minutes then I have to give time period value as 600?

 

[akabarten]

Hi,

You are correct, for SI system unit you have to set value of 600.
I have to say it is a lot for explicit analysis which is suitable for transient analysis.
For 10[min] you can expect quite big time of calculation.

Regards,
Bartosz

VIM filetype plugin for Abaqus

https://github.com/gradzikb/vim-abaqus

 

[Mechanicslearner]

Hi Bart,

Thanks for the solution. Is the wind analysis is done using this step or someother step like Implicit analysis? Am asking because which is a good step for that so simulation time will be less?