addLatent: Add a Latent Component Event

In ftree: Fault Trees and Event Trees for Risk and Reliability Analysis

Description

Modifies an existing fault tree with the addition of a latent component event.

Usage

addLatent(DF, at, mttf=NULL, mttr=NULL, prob="repair", inspect=NULL, 
			name="",description="")

Arguments

DF	A fault tree dataframe such as returned from ftree.make or related add... functions.
at	The ID of the parent node for this addition.
mttf	The mean time to failure. It is the user's responsibility to maintain constant units of time.
mttr	The mean time to repair (restore). It is the user's responsibility to maintain constant units of time.
prob	An underlying probability of the component being in a failed state. This will be additive to the fractional downtime due to inspection interval. A probability value >=0 && <1 can be provided. Often it is known that unavailable risk continues during repair upon inspection detection, so a string value of "repair" is accepted and the Pzero will be calculated as mttr/(mttf/mttr).
inspect	The time interval between inspections for the dormant component. (It will be possible upon future development to enter the string for the named inspection dataframe object. In this case the inspection object will be read to get the inspection interval. An inspection object must be a dataframe with interval and duration columns. If a positive duration value other than zero is found it is taken that the system is at risk during the time of inspection. An unavailable probability calculated as duration/(interval+duration) will be added to the fractional downtime.
name	A short identifying string
description	An optional string providing more detail for the resultant event.

Value

Returns the input fault tree dataframe appended with an entry row for the defined component event.

References

Nicholls, David [Editor] (2005) System Reliability Toolkit Reliability information Analysis Center

O'Connor, Patrick D.T. (1991) Practical Reliability Engineering John Wiley & Sons

Vesely, W.E., Goldberg, F.F., Roberts, N.H., Haasl, D.F. (1981) Fault Tree Handbook U.S. Nuclear Regulatory Commission

Vesely, W.E., Stamatelato, M., Dugan, J., Fragola, J., Minarick, J., Railsback, J. (2002) Fault Tree Handbook with Aerospace Applications NASA

Doelp, L.C., Lee, G.K., Linney, R.E., Ormsby R.W. (1984) Quantitative fault tree analysis: Gate-by-gate method Plant/Operations Progress Volume 3, Issue 4 American Institute of Chemical Engineers

Examples

mytree <-ftree.make(type="and")
mytree <- addLatent(mytree, at=1, mttf=5,mttr=12/8760,inspect=1/26, name="e-gen set fails")

ftree documentation built on May 2, 2019, 4:41 p.m.