Life Data Tab

The Life Data tab is visible when you view a Weibull++ standard folio data sheet for life data analysis.

Analysis

Calculate estimates the parameters of the chosen distribution, based on the current data set and the specified analysis settings.

Plot creates a new sheet in the folio that provides a choice of applicable plot types. For standard folios, this includes plots such as reliability vs. time, failure rate vs. time, probability plot, etc.

Quick Calculation Pad opens the Weibull++ Quick Calculation Pad, which allows you to calculate results, such as the mean life and the probability of failure, based on the analyzed data sheet.

Distribution Wizard opens the Distribution Wizard, which helps you select the distribution that best fits your data based on the selected parameter estimation method (i.e., RRX, RRY or MLE).

3D Plot creates a 3D graph of the surface plot of the likelihood function. It plots the likelihood values (LK values) with respect to the estimated parameters of a distribution. The shape of the plot may help you to evaluate the amount of variability in the parameter estimates. A small surface (tall, tower-like peak) suggests that there is less uncertainty in the parameter estimates at the maximum LK value, while a large surface suggests that there is a large uncertainty in the parameter estimates. You can create a 3D plot of the likelihood function for any of the available distributions in Weibull++ except for 1-parameter Weibull, mixed Weibull, Bayesian-Weibull or Weibull using competing failure modes distribution.

Options

Batch Auto Run opens the Batch Auto Run window, which allows you to quickly extract data from an existing data set based on the subset ID.

Specify Points opens the Specify Points window, which allows you to adjust the way that the line is fitted to the points for a rank regression analysis. The ranks will be calculated based on all of the data points but the regression line will be fitted only to the points you have specified.

Alter Parameters gives you two options for manually editing the value of the calculated parameters. Alter Parameters (w/o Recalculation) allows you to alter the value of one (or more) parameters, while keeping the original values of the rest of the parameters and the variance/covariance matrix the same. Alter One Parameters (and Recalculate) allows you to alter one of the parameter values, and then have the software estimate the other parameter values that would result in a good fit for the model. For both options, the LK value, solution line on plots and all subsequent analyses will be based on the modified set of parameters.

Fill Median Ranks is available only if the data type is free-form. It allows you to experiment with median ranks and see how they affect the solution of the analysis. Enter the time-to-failure values in the "X-Axis value" column, then choose this command. The "Y-Axis value" column will be filled with the corresponding median ranks.

Auto Group Data opens the Auto Group Data window, which allows you to group together data points with the same failure/suspension times. Grouping data significantly speeds up calculations when you have a very large data set.

Goodness of Fit Results opens the Goodness of Fit Results utility, which uses different tests to determine how well the parameters of the distribution fit the data.

Folio Sheets

Insert Data Sheet inserts a new blank data sheet into the currently active folio and opens the Weibull++ Folio Data Sheet Setup window, which allows you to select what types of data to include in the new data sheet.

Insert Additional Plot inserts an overlay plot in the currently active folio. This allows you to display in a single plot results from multiple data sheets within the folio. This provides an easy visual method to compare analyses. For example, you may wish to show the reliability plots of two product designs in the same plot.

Insert General Spreadsheet inserts a new blank general spreadsheet into the currently active folio.

Select Sheet opens the Select Sheet window, which allows you to select which sheet in the current folio you want to be active.

Move or Copy Sheet opens the Move/Copy window, which allows you to move or copy any of the sheets within the currently active folio. Select the sheet that you wish to move and then click (move to end) to move the selected sheet to the end of all the sheets in the folio. Select Create a Copy to create a copy of the selected sheet.

Format and View

Alter Data Type opens the Weibull++ Folio Data Sheet Setup window, which allows you to change the data entry columns in the current data sheet. Note that when you change the setup, you may lose information already entered in the data sheet. For example, switching the data sheet from one that supports interval data to one that supports only right censored data will remove all the inspection times.

Override Plot Color opens the Override Plot Color window, which allows you to ignore the default colors of the plotted line and points, and apply a color that you specify. This setting is activated in the source data sheet of the plot. This means that when you enable the setting for a particular data sheet, it applies only to the plots that you create for that data sheet and not the plots for all other data sheets that may be within the same folio. Note that only the colors of the lines and points are affected. Other settings such as the line style and thickness, or the point size and shape are based on the settings that you have specified in the Plot Items page of the Plot Setup window.

Set Headers as Default sets the column headers in the currently active data sheet as the default headers for all Weibull++ standard folio data sheets with the same data type (i.e., times-to-failure or free-form data).

Apply Default Headers uses the default column headers for the columns of the currently active data sheet.

Add/Remove Columns allows you to add or remove subset ID columns in the currently active data sheet.

Color Data Values allows you to apply different font colors to the entries in the data sheet for easy visualization. The following commands are available:

Note that whenever you edit or add new data to the data sheet, you must choose one of the Color Data Values commands again in order to apply the correct font colors.

Synthesis

Publish Model allows you to use the results of the life data analysis (life distribution and parameters) as a resource object and make it available for unlimited use anywhere within the project, in any Synthesis application that has a need for that type of object.

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