# Using Force instead of Velocity or Stress

**URL:** https://forum.itascainternational.com/t/using-force-instead-of-velocity-or-stress/1739
**Category:** Uncategorized
**Created:** [October 8, 2024, 3:23pm UTC](https://forum.itascainternational.com/t/using-force-instead-of-velocity-or-stress/1739 "2024-10-08T15:23:37Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Adams](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@Adams](https://forum.itascainternational.com/u/Adams)
#### Post date: [October 8, 2024, 3:23pm UTC](https://forum.itascainternational.com/t/using-force-instead-of-velocity-or-stress/1739/1 "2024-10-08T15:23:37Z")

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I am trying to apply a force of 80kN over an area of 1200cm2. I have tried to use velocity and stress but the results are not great. Please how can I apply force directly in Flac?

 ![Screenshot 2024-10-08 110824](https://canada1.discourse-cdn.com/flex031/uploads/itasca/original/2X/0/0f7835d60e2cb2dc985413751a3b836f45594efb.png)

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### Author: ![dblanksma](https://avatars.discourse-cdn.com/v4/letter/d/858c86/32.png) [@dblanksma](https://forum.itascainternational.com/u/dblanksma)
#### Post date: [October 10, 2024, 2:47pm UTC](https://forum.itascainternational.com/t/using-force-instead-of-velocity-or-stress/1739/2 "2024-10-10T14:47:03Z")

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Hello @Adams,  
To apply a force you have a couple options

1. You can use the [zone gridpoint initialize force-applied](https://docs.itascacg.com/itasca910/flac3d/zone/doc/manual/zone_manual/zone_commands/zonegridpoint/cmd_zone.gridpoint.initialize.html?node3232#kwd:zone.gridpoint.initialize.force-applied) command.
2. You can use the [gp.force.load()](https://docs.itascacg.com/itasca910/flac3d/zone/doc/manual/zone_manual/zone_fish/zone.gridpoint_intrinsics/fish_gp.force.load.html?node3358) FISH function.  
\*\* Remember forces are applied only at gridpoints.
3. You can also use the [zone face apply](https://docs.itascacg.com/itasca910/flac3d/zone/doc/manual/zone_manual/zone_commands/zoneface/cmd_zone.face.apply.html?node3214) command to apply a stress to a zone face, which may be more suitable for your application.

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### Author: ![Adams](https://avatars.discourse-cdn.com/v4/letter/a/96bed5/32.png) [@Adams](https://forum.itascainternational.com/u/Adams)
#### Post date: [October 10, 2024, 7:05pm UTC](https://forum.itascainternational.com/t/using-force-instead-of-velocity-or-stress/1739/3 "2024-10-10T19:05:32Z")

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Thank you! @dblanksma Yeah, I later used zone face applied stress and it worked better.