Chapter 3: Degradation Analysis (DA) Module
3.1 DA Analysis List
Degradation analyses will be indicated when there is a procedure for detecting and monitoring the physical variables that could lead the asset to fail, and therefore the operators and maintenance team can stipulate a critical value for those variables.
If the critical point is reached, there is a call for maintenance to apply corrective measures or to replace the item.
This module can be accessed via dashboard or via menu.
All the user’s analyses are listed on the DA menu, where they can be arranged in alphabetical order, number of items order, data order or by last update date. To access each analysis, just click on the view button (magnifying glass with a plus sign on the right side of the analysis information), and to erase it, click on the delete button.
The DA fits the variation of physical parameters measured in inspections in a degradation method: exponential curve, power function, linear or logarithmic curve. Once the fitting is made, the R4All will calculate the Projected Times to Failure, which is an estimation based on the time spent by the degradation of the asset to reach the critical point determined by the team.
These Projected Times to Failure will be instantly inserted in an LDA tab inside the DA analysis so the user can also perform a Life Data analysis over the Projected Times to Failure data set, inside the Degradation Analysis module (there is no need to export data to the LDA module).
3.2 DA Settings
On the “Settings DA” option under the Main Menu to the left, the user can change the standard setting for all the analyses.
The DA requires 3 columns on the data sheet: Inspection Time, Degradation, and Unit ID. That means that each unit will allow more than one inspection time and degradation value combination. The more combinations one unit has, the more the mathematical fitting is precise.
As it is standard in reliability analyses, all units (assets) must be performing the same function and be working in the same usage conditions for the mathematical predictions to be valid. So, in any DA, the degradation being monitored must refer to the same variable.
The Best Fit will calculate which is the best mathematical function to model the item degradation behavior:
By Applying the best model, the calculation for the Projected Times to Failure for each unit will be determined.
3.3 DA – Plot tab
The DA Plot tab will always show a graph containing all curves describing the evolution of each unit degradation, and in which point they cross the red line representing the critical value.
3.4 DA – LDA tab
The Projected Times to Failure points will be placed on the LDA tab in a new, non-editable sheet.
Note: This generated LDA tab is non editable, as it depends on the entries of Projected Times to Failure determined by the degradation analysis.
With these estimated times to failure, on the LDA tab right next to the Plot tab, it is possible to see how the data are arranged and to select a best fitting model to analyze the assets life.
The LDA tab inside the Degradation Analysis module works in a similar way to the Data tab of the LDA module (see chapter 2.4 LDA – Data tab for more details). The only difference is the absence of the Data Type button. That is because the Projected Times to Failure determined by the degradation analysis generated only failures with exact times.
3.5 DA – LDA Plot tab
After the Life Data Analysis over the Projected Times to Failure is performed, the user can use the LDA Plot the same way done on the Plot tab of the LDA module (see chapter 2.5 LDA – Plot tab for more details).
3.6 DA – Report tab
In the DA Report, the user can see the degradation analysis results and the respective degradation curve plot, and if the life data analysis was already performed the report will also present all the LDA results and respective plots.
Some images of the Degradation Analysis Report:
3.7 DA and LDA – Calculator
The DA module includes two different calculators: DA Calculator and LDA Calculator.
The DA Calculator is located on the Data and Plot tab, and it only demonstrates the evolution of the degradation. The user can use it to change the critical value and check projected times to failure for the same degradation model.
The LDA Calculator is also available on DA analysis, and it is located on the LDA and LDA Plot tab. This calculator has the same functionalities as the LDA Calculator of the LDA module (see chapter 2.8 LDA – Calculator for more details).