# DLOAD non-uniform loading

**URL:** <https://calculix.discourse.group/t/dload-non-uniform-loading/261>\
**Category:** Uncategorized\
**Created:** [October 16, 2020, 12:17pm UTC](https://calculix.discourse.group/t/dload-non-uniform-loading/261 "2020-10-16T12:17:52Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![tmfx25](https://avatars.discourse-cdn.com/v4/letter/t/73ab20/32.png) [@tmfx25](https://calculix.discourse.group/u/tmfx25)\
**Post date:** [October 16, 2020, 12:17pm UTC](https://calculix.discourse.group/t/dload-non-uniform-loading/261/1 "2020-10-16T12:17:52Z")

</div>

I need to implement a spatially and temporally changing pressure load.

I did that initially using non-uniform loading method with a custom dload.f file. Then called the same as shown below in the INP file.

\*Dload  
EP, P3NU, 1.

However, this non-uniform loading is not the same all the time. So had to recompile the solver all the time (CCX 2.16, Windows, using Cygwin).

A solution to the problem I thought was to us uniform loading and specify a max magnitude (for the step) at each element, then scale the same using an amplitude card.

\*Amplitude, name=Amp-2  
0.0, 0.0, 1.0, 0.25, 2.0, 1.0, 3.0, 0.

\*Step, nlgeom=YES, inc=10000000  
\*Dynamic  
1e-05,3.0,1e-07,0.01  
\*DLOAD, AMPLITUDE=Amp-2  
1, P3, 706.177781  
2, P3, 743.433408  
5, P3, 820.932715  
…

However, displacement result from both methods is different by a huge margin (almost 2 times).

> Is there an error in my logic? How do I rectify the same?

> Any other method of giving a non-uniform loading to the solver without reading a file (too slow) dynamically, like through the INP file?

Thank you

---

<div class="post-metadata">

**Author:** ![vicmw](https://avatars.discourse-cdn.com/v4/letter/v/6de8d8/32.png) [@vicmw](https://calculix.discourse.group/u/vicmw)\
**Post date:** [October 16, 2020, 11:33pm UTC](https://calculix.discourse.group/t/dload-non-uniform-loading/261/2 "2020-10-16T23:33:12Z")

</div>

It looks right to me. Try a simpler model (eg. static, single element, small displacements) so you can isolate which method is wrong and what feature is causing that.

---

<div class="post-metadata">

**Author:** ![tmfx25](https://avatars.discourse-cdn.com/v4/letter/t/73ab20/32.png) [@tmfx25](https://calculix.discourse.group/u/tmfx25)\
**Post date:** [October 17, 2020, 7:41am UTC](https://calculix.discourse.group/t/dload-non-uniform-loading/261/3 "2020-10-17T07:41:23Z")

</div>

Thank you, I will try a simple model to test.