Technical Discussion of the PIPENET Interface - CAESAR II - Help

CAESAR II Users Guide

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English
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CAESAR II
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CAESAR II Version
12

Normal piping system operating procedures such as pump start-up and shutdown, valve closure, and unexpected events such as power failure, may produce unsteady pressure-flow conditions. A piping system with rapid pressure-flow variations must be carefully designed to prevent devastating results.

PIPENET performs the analysis and simulation of the unsteady flow situations for a particular liquid piping system, and generates the piping load time histories for the pressure transient of this particular liquid piping system.

In the dynamic analysis module of CAESAR II, a response spectrum can be generated from the input of time history pulse. However, there are typically too many data points from a time history analysis to manually input the data into CAESAR II. The CAESAR II PIPENET Transfer Interface bridges the gap between PIPENET and the CAESAR II dynamic analysis module.

After the time history loads have been generated by PIPENET, the CAESAR II PIPENET Interface extracts the dynamic pipe forces from the PIPENET generated file, and computes the response spectrum. Afterward, the response spectrum can be used as the DLF curve for the dynamic analysis in CAESAR II.

The response spectrum is a plot giving the maximum response of all possible linear, one-degree of freedom systems because of a given input, which is a force. The abscissa of the spectrum is the frequency axis, and the ordinate is the maximum response, such as dynamic load factor (DLF). The DLF is the ratio of the dynamic deflection at any time to the deflection that would have resulted from the static application of the load. In cases where the applied load is not constant, the maximum load, which occurs at any time during the period of interest, is taken.

The dynamic load factor is non-dimensional and independent of the magnitude of load.