topic Re: Why is the reduced result for panels NRx value different to the reactions integral value? in Robot Structural Analysis Forum

Why is the reduced result for panels NRx value different to the reactions integral value?

HRahmanMKEP2 — Wed, 10 Sep 2025 09:25:47 GMT

So I have a small building model which for information is not orthogonal to the global work-plane. When I calculate the reactions I am getting discrepancy in results between the integral reaction value and the reduced results for panels NRx value.

For one panel here is the results:

Integral reaction on this panel = 407.92 kN

Same panel the reduced results NRx = -370 kN see below:

I have also took the cut length of the panel to work out line load reaction using the NRx/cut length

and this is still different to the average reaction.

Does anyone know the explanation behind this discrepancy and does the work plane play a role in this?

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

Simau — Wed, 10 Sep 2025 12:05:11 GMT

Hi @HRahmanMKEP2

please zip and share your model

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

HRahmanMKEP2 — Wed, 10 Sep 2025 14:28:52 GMT

Please see zipped attachment of the robot model without results thanks 🙂

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

Simau — Wed, 10 Sep 2025 18:20:23 GMT

Hi @HRahmanMKEP2

Work-plane orientation has nothnig to do with the results. Results accurency depends on mesh size.

Some warning messages were fixed

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

HRahmanMKEP2 — Thu, 11 Sep 2025 07:46:13 GMT

In the snapshot you have shown for both mesh sizes why is there a difference in the NRx value and the Fz I thought they were the same?

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

Simau — Thu, 11 Sep 2025 08:49:21 GMT

You will never get 100% accurancy.

The smaller size the better accurancy

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

HRahmanMKEP2 — Fri, 12 Sep 2025 09:47:57 GMT

Makes sense. What actually is the difference between Fz and NRx in this case so how is it calculating differently. Is NRx the benchmark to use for design?

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

Simau — Fri, 12 Sep 2025 12:26:34 GMT

Robot uses NRx to design wallss

Re: Why is the reduced result for panels NRx value different to the reactions integral value?

HRahmanMKEP2 — Fri, 12 Sep 2025 12:48:11 GMT

thanks I'll close the thread 🙂