Comments, Questions, and Answers:

Note: see additional comments about Time history analysis in AutoPIPE on the following WIKI's:

• • • Water Hammer (Time History) Example - Modeling Approach in AutoPIPE

    • Dynamic Analysis - Time History load case in AutoPIPE

Item #1:

On the Load> Time History Location dialog screen, change value at node (ex. C14 N) from Dy = -1 to Dy = -10 and there is no change in the results, but if change Dy = 0, there is a change in the results. Why?

Answer: From the online help:

   DX/DY/DZSpecify the direction cosines or offsets of the time history
            load (i.e., values of 1,0,0 would specify the X-direction as the direction at
            which the time history load is applied.

Therefore, changing Dx =0, Dy = -1, Dz = 0, to Dx =0, Dy = -10, Dz = 0, has no affect on the direction cosines, the load is still going to be applied in the -ve Dy direction regardless if Dy in this case is any  number -1 to -infinity.

In addition, by setting Dx =0, Dy = -1, Dz = 0, to Dx =0, Dy = 0, Dz = 0, will have a significant change on the results as there is now no directional cosine specified for the load.

If there was another direction with a value, Dx =1, Dy = -1, Dz = 0, to Dx =1, Dy = -10, Dz = 0, is a significant change in the directional cosine. Thus changing the results.

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See Also

Bentley AutoPIPE