Template:Growth potential crow extended

Growth Potential

The failure intensity remaining in the system at the end of the test will depend on the management strategy given by the classification of the Type A and Type B failure modes. The engineering effort applied to the corrective actions determines the effectiveness factors. In addition, the failure intensity depends on [math]\displaystyle{ h(t) }[/math] , which is the rate at which problem failure modes are being discovered during testing. The rate of discovery drives the opportunity to take corrective actions based on the seen failure modes and it is an important factor in the overall reliability growth rate. The reliability growth potential is the limiting value of the failure intensity as time [math]\displaystyle{ T }[/math] increases. This limit is the maximum MTBF that can be attained with the current management strategy. The maximum MTBF will be attained when all Type B modes have been observed and fixed.
If all seen Type B modes are corrected by time [math]\displaystyle{ T }[/math] , that is, no deferred corrective actions at time [math]\displaystyle{ T }[/math] , then the growth potential is the maximum attainable with the Type B designation of the failure modes and the corresponding assigned effectiveness factors. This is called the nominal growth potential. In other words, the nominal growth potential is the maximum attainable growth potential assuming corrective actions are implemented for every mode that is planned to be fixed. In reality, some fixes to modes might be implemented at a later time due to schedule, budget, engineering, etc.
If some seen Type B modes are not corrected at the end of the current test phase then the prevailing growth potential is below the maximum attainable with the Type B designation of the failure modes and the corresponding assigned effectiveness factors. If all Type B failure modes are seen and corrected with an average effectiveness factor, [math]\displaystyle{ d }[/math] , then the maximum reduction in the initial system failure intensity is the growth potential failure intensity:

[math]\displaystyle{ {{\lambda }_{GP}}={{\lambda }_{A}}+\left( 1-d \right){{\lambda }_{B}} }[/math]

The growth potential MTBF is:

[math]\displaystyle{ {{M}_{GP}}=\frac{1}{{{\lambda }_{GP}}} }[/math]

Note that based Eqns. (lambda GP), (lambda initial) and (msr), the initial failure intensity is equal to:

[math]\displaystyle{ {{\lambda }_{I}}=\frac{{{\lambda }_{GP}}}{1-d\cdot msr} }[/math]