| Applies To | |||
| Product(s): | AutoPIPE, | ||
| Version(s): | ALL | ||
| Environment: | N/A | ||
| Area: | Dynamic Analysis | ||
| Original Author: | Bentley Technical Support Group | ||
Problem:
What value would be entered into the Time history dialog screen for "Duration"?
Solution:
Please see the following AutoPIPE help section:
Help > Contents> Contents Tab> Modeling Approaches> Modeling Approaches> Water Hammer (Time History) Example> Executing Water Hammer Example (apham1).
Highly suggested as one of your first time history analysis that you read the entire section on this example and actually perform the example as explained in the online help, the file is located at C:\Bentley\AutoPIPE V8i SELECTseries\ Example\Apham1.dat.
After performing this example you will understand clearly how to calculate the time history duration.
For those time sensitive people, as mentioned in step #11 of the Executing Water hammer (time history) example document, "Duration" = 0.443 (First period, 0.384 sec, plus water hammer duration 0.059 sec),
These values can be found :
a: Water hammer duration value 0.059 sec comes from the THL file:
B. First period 0.384 sec comes from the Frequency output report
Under some circumstances, this duration time may need to be increased to ensure to capture all the time needed for the transient and 1st period to occur. The results should not change if a longer duration than needed is specified.
Question:
For each time history load case user can assign 4 transient files. What Duration Time should be used if more than 1 transient file is assigned to a Time history load case.
Answer:
Yes, the duration should include the total time of the transient + first mode.
Locate the highest time value found in 1 of 4 *.THL files; under "TIME AT END OF FLUID TRANSIENT". Add to this "time of the first period from Frequency report" as outlined above.
See Also
Dynamic "Time History" Analysis