Analytical Quick Calculation Pad (QCP)

BlockSim includes a Quick Calculation Pad (QCP) for computing useful metrics. You can access the QCP by choosing Analysis > Analysis > Analytical QCP or by clicking its icon on the Analytical page of the diagram control panel.

To perform a calculation, select the appropriate option and enter any required inputs in the Input area, then click Calculate. For more detailed information on how to use the QCP in general, see Quick Calculation Pad (QCP).

Calculates the probability that a new system will operate without failure for a given period of time. Enter the time at which you wish to calculate the reliability in the Mission End Time field. The mission is assumed to start at time = 0.

For example, a reliability of 90% for a mission end time of 3 years means that if 100 identical systems are fielded, then 90 of them will still be operating at the end of 3 years.

Note: Reliability calculations are available even when the linked RBD or fault tree contains static blocks. If the diagram contains one or more static blocks (i.e., blocks that use a constant model), the mission end time for the static blocks is assumed to be equal to the time for which the fixed reliability value has been defined.

Calculates the probability that a new system will be failed in a given period of time. Enter the time at which you wish to calculate the probability of failure in the Mission End Time field. The mission is assumed to start at time = 0.

Probability of failure is also known as unreliability and it is the inverse of the reliability. For example, a probability of failure of 10% for a mission end time of 3 years is equivalent to a 90% reliability.

Calculates the probability that a system will successfully operate at a specific time interval given that it has operated successfully up to a specified time. Enter the start time of the interval in the Mission Start Time field and enter the duration of the interval in the Mission Additional Time field.

For example, a system may have a reliability of 90% for 3 years. If the system has operated for 2 years without failure, the conditional reliability for an additional year (for a total of 3 years of operation) may be 95%.

Note: This assumes that all components start with the same accumulated age; that is, all components start life at 0 and age to the Mission Start Time value. It is possible to consider an individual component that has already accumulated some age (i.e., a used component) in the same formulation by changing the block's Current Age value in the Block Properties window.

Calculates the probability that a system will be failed at a specific time interval given that it has not failed up to a specified time. Enter the start time of the interval in the Mission Start Time field and enter the duration of the interval in the Mission Additional Time field.

For example, a product may have a 10% probability of failure for 3 years. If the product has operated for 2 years without failure, the conditional probability of failure for an additional year (for a total of 3 years of operation) may be 5%.

Calculates the estimated time at which a specified reliability value will be achieved. Enter the reliability goal in the Required Reliability field. For example, a goal of 90% reliability with a reliable life of 4 years means that if 100 identical systems are fielded, then 90 of them will be still be operating at the end of 4 years.

What's Changed? In previous versions of BlockSim, this calculation was called "Warranty Time."

Calculates the estimated time at which a specified probability of failure will be achieved. Enter the probability of failure in the BX% Information At field. For example, a B10 life of 4 years means that the system has a 10% probability of failure in 4 years of operation (note that this is equivalent to a 90% reliability with a reliable life of 4 years).

Note: In the early days of reliability engineering, bearing manufacturers used the term "B10 life" to refer to the time by which 10% of the components would fail. Keeping with tradition, ReliaSoft retained this nomenclature but replaced "10" with "X," since the software allows you to get this information at any percentage point and not just at 10% (e.g., B1, B5, etc.).

Calculates the mean time to failure for the non-repairable system in the diagram.

Note: The mean life is a performance index and does not provide any information about the behavior of the failure distribution of the system.

Calculates the instantaneous number of failures per unit time that can be expected at a certain time given that the system survives to that age. Enter the time at which you wish to calculate the failure rate in the Time field.

For example, a failure rate of 0.01 at 100 hours means that a system that survives to 100 hours has approximately a 1% probability of failure in the next hour.