Bearing Life
Tools -> Bearing Life
Bearing Life option in Tool menu is visible only if there is Adams Machinery or Adams Machinery-Bearing License feature.
For the option: | Do the following: |
|---|---|
Analysis | Select the analysis to perform this calculation. |
Bearings | A multi-select field in which you can select one/more/all of any of the bearings within the model corresponding to the selected analysis. The bearing must be modeled via the "Detailed" modeling method option. |
Start Time, End Time | ■Real number entries for start and end time. ■Start time should be less than end time. ■Both should be within the time range for which the analysis was run. |
Number of Repeats | The number of times this time range in the analysis, as specified by start time and end time, should be repeated for the life calculation. This must be positive integer value and greater than 0. |
Insert | Inserts a row above the selected row (row selection is done by clicking the row number). |
Delete | Deletes the selected row (row selection is done by clicking the row number). |
File Name | Optional: ■If no name provided then no file is exported. ■If name provided then file will be saved in current working directory with given name. |
File Format | "HTML" or "Tab Delimited Text". |
Base Font Size | Control the font size for the HTML option. |
Report | The resulting report will be displayed in the upper-side and updated upon each subsequent click of "Report" button. |
Notes: | ■You can save the bearing duty cycle generated report in .html or .txt format. ■You can load the report in Postprocessor window. |
Formula to calculate service life over the course of the duty cycle
Adams Machinery Bearing calculates a service life estimate at every output step which can be interpreted as the as the predicted service life in hours for the bearing under the loading and rotational speed conditions at that output step. See Bearing Output for details of the inputs to this calculation and Calculation of service life based on the bearing inner geometry (ISO/TS 16281) as for details of the life calculation method according to ISO/TS 16281. The single-value service life estimate provided by this "Adams Machinery Bearing Duty-Cycle Service Life" tool aggregates these individual service life output values from each output step (known as Li in the formulation description, below) over the course of the duty-cycle specified in the dialog box. The formulation used to accomplish this amounts to an "equivalent life" calculation and is described below:
Where:
♦Ltot : single-value service life estimate provided for each bearing by this "Adams Machinery Bearing Duty-Cycle Service Life" tool in units of hours.
♦ti : time length of the Adams output step in hours. For example, if the time from the previous output step to the current output step (the current output step is the one from which Li is taken) is 0.1s, then ti would be 0.1/3600 = 2.778e-5 hours.
♦ri : the number of repeats applied to the given output step as defined in the duty cycle specification.
♦Li : the given output step's life prediction value. It is reported in units of hours.
For more details see "Adams Machinery Bearing Duty-Cycle Service Life within Adams PostProcessor".