Report Format When printing a Project file report, the Report Format entered here is
automatically selected, but this may be overridden at the time of report generation.
Parts Table
Format Provides the ability to customize the appearance of the Parts Table. Allows you to specify which fields are used, and the order for data entry.
FMEA Input
Format Provides the ability to customize the input windows for FMEA data. Allows you to specify which fields are used and the order during FMEA data entry.
System Tree
Format Provides the ability to customize the format of the System Tree window. Allows you to specify which fields are used, and the order for data entry.
Fault Tree
Format Provides the ability to customize the format of the Fault Tree Table window.
Allows you to specify which fields are used and the order for data entry.
Fault Tree
Report Format When printing a Fault Tree file report, the Fault Tree Report Format entered here is automatically selected, but this may be overridden at the time of report generation.
RBD Report Format
When printing an RBD file report, the RBD Report Format entered here is automatically selected, but this may be overridden at the time of report generation.
Project Definitions Tab
Figure 3 - . Project File Properties, Project Definitions Tab
The data on the Project Definitions tab is used to specify global information that applies to the entire project.
Property Description
Failure Rate
Multiplier Specifies the units for calculating failure rate. Generally, the MIL-HDBK-217 calculations are based on failures per million hours (the value in the field would be 1,000,000); Telcordia (Bellcore) calculations are based on failures per billion hours (the value in this field would be 1,000,000,000). The unit that you select here is used for all items in the Project file.
Note: MTBF is always in hours.
Maintainability
Data The following options are used for maintainability predictions only:
Procedure 5A. When enabled, the maintainability calculations that are performed are based on MIL-HDBK-472 Procedure 5A. If disabled, all calculations are based on MIL-HDBK-472 Procedure 5B.
Repair Time. Allows the selection of units to be used in the entry of repair times. You may select between minutes or hours.
Results Time. Allows the selection of units to be used in the entry of results time. You may select between minutes or hours.
Repair Times
Adjustment The following options are related to maintainability predictions only.
None. When enabled, there is no adjustment to the repair time.
Multiply. When enabled, the entered repair times are all multiplied by the value.
Add. When enabled, the value is added to the entered repair times.
Property Description
Frequency of Type 1 False Alarms
Used for maintainability predictions only. The frequency of occurrence of type 1 false alarms is expressed in ratio units (a value from 0 to 100) of type 1 false alarms to actual failures. Type 1 false alarms are detected during normal operation but cannot be repeated during the fault isolation process. This information is used in the Mean Maintenance Hours per Maintenance Action, Mean Maintenance Hours per Operating Hour, and Mean Maintenance Hours per Flight Hour calculations.
Frequency of Type 2 False Alarms
Used for maintainability predictions only. The frequency of occurrence of type 2 false alarms is expressed in ratio units (a value from 0 to 100) of type 2 false alarms to actual failures. Type 2 false alarms are detected and isolated to a removable item when the removable item does not have an actual fault. This information is used in the Mean Maintenance Hours per Maintenance Action, Mean Maintenance Hours per Operating Hour, and Mean Maintenance Hours per Flight Hour calculations.
FMEA Tab
Figure 3 - . Project File Properties, FMEA Tab
The FMEA tab is used to specify global information that applies to Relex FMEA only. It provides the ability to customize your FMEA.
Property Description
Criticality Matrix Options
Criticality Matrix X Axis. The choice list can be used to select the criteria for the X-axis of the criticality matrix.
Criticality Matrix Y Axis. The choice list can be used to select the criteria for the Y-axis of the criticality matrix.
High Risk Graph Options
High Risk X Level. The point where the high risk line crosses the X-axis.
High Risk Y Level. The point where the high risk line crosses the Y-axis.
Low Risk
Graph Options Low Risk X Level. The point where the low risk line crosses the X-axis.
Low Risk Y Level. The point where the low risk line crosses the Y-axis.
Severity
Options The Severity provides a measure of the worst potential consequences resulting from the failure mode's occurrence. A sample definition of severity levels based on MIL-STD-1629 is (this is the Relex default):
I. Catastrophic. A failure which may cause death or system loss (i.e. aircraft, tank, missile, ship, etc.)
II. Critical. Failures that may cause severe injury, major property damage, or major system damage that result in mission loss.
III. Marginal. Failures that may cause minor injury, minor property damage, or minor system damage that result in delay or loss of availability or mission degradation.
IV. Minor. A failure not serious enough to cause injury, property damage, or system damage, but which results in an unscheduled maintenance or repair.
Name. Used to specify the name of the severity level. For automotive FMEAs, the names are normally a number from 1 to 10. Relex allows you to define descriptive text also.
Value. Used to specify the value of the severity level. 10 signifies the most critical level, and 1 signifies the least critical. For automotive FMEAs, the values range from 1 to 10. The values associated with each severity level are used in the calculation of RPN.
Property Description
Occurrence
Options Basis. The choice list allows you to select the basis of the occurrence value. You can select from a choice list including: None, Mode Criticality, Occurrence Rank, Failure Mode Probability and Process Variation.
None – Selecting this option allows you to build a criticality matrix based on the Occurrence field. The Occurrence field in Relex FMEA is a choice list which allows you to select from the following predefined list of entries:
A – Frequent
B – Reasonably Probable C – Occasional
D – Remote
E – Extremely Unlikely
For each of the remaining options, the occurrence is determined from the specified or calculated value. Relex considers the occurrence definition (Name and Level). For example, an occurrence name may be A – Frequent and its value 100. If mode criticality is used as the basis for the occurrence, then if the specified or calculated mode criticality is greater than or equal to 100 (the defined Value), then the occurrence for that mode is considered to be A – Frequent.
Each of the occurrence basis option equations are described as follows:
Mode Criticality = Effect Probability * Mode Failure Rate * Operating Time Occurrence Rank = Severity * Occurrence * Detection
Failure Mode Probability = 1 – e-t, where is the Mode Failure Rate and t is the Mission Time
Process Variation – The probability that an item parameter is out of specification due to variations in the manufacturing process (based on the Process Capability Index, CPK).
Name. Specifies the name of the occurrence level. For automotive FMEAs, the names are normally a number from 1 to 10. Relex allows you to define descriptive text also.
Value. Specifies the value of the occurrence level. 10 would signify the most critical level, and 1 would signify the least critical. For automotive FMEAs, the values range from 1 to 10.
Detection Options
Name. Specifies the name of the detection level. For automotive FMEAs, the names are normally a number from 1 to 10. Relex allows you to define descriptive text also.
Value. Specifies the value of the detection level. 10 would signify the most critical level, and 1 would signify the least critical. For automotive FMEAs, the values range from 1 to 10.