ALTADataSet Class

Provides the functionality of an ALTA standard folio, including entering data in a data set, specifying analysis settings and fitting a distribution and life-stress relationship to the data set. To create plots, use the WAPlots class.

Constructors

• ALTADataSet Creates a new ALTADataSet object with an empty data set name.
• ALTADataSet( String ) Creates a new ALTADataSet object with the user-specified data set name.

Methods

Use these methods to enter data points into a data sheet and analyze them. The settings for the analysis are specified with this class's properties.

Add Stresses and Stress Profiles

• AddStressDefinition( String, [ALTASolverLSR], [Double] ) Adds a stress to the data set, using the specified name of the stress, the stress transformation (if any) and the use stress level.
• AddStressProfile( ALTAStressProfile ) Makes an existing time-varying stress profile available for use in the analysis.

Add/Remove Data

• AddFailure( Double, Integer, Object() ) Adds failure times to the data set, using the specified time, the number of failures at that time and an array of stress values/profiles for all the stresses.
• AddFailure( Double, Integer, Object ) Adds failure times to the data set, using the specified time, the number of failures at that time and a single stress value/profile.
• AddFailure( Double, Integer, Object, Object ) Adds failure times to the data set, using the specified time, the number of failures at that time and two stress values/profiles.
• AddSuspension( Double, Integer, Object() ) Adds suspensions to the data set, using the specified time, the number of suspensions at that time and an array of stress values/profiles for all the stresses.
• AddSuspension( Double, Integer, Object ) Adds suspensions to the data set, using the specified time, the number of suspensions at that time and a single stress value/profile.
• AddSuspension( Double, Integer, Object, Object ) Adds suspensions to the data set, using the specified time, the number of suspensions at that time and two stress values/profiles.
• AddFailureInterval( Double, Double, Integer, Object() ) Adds interval censored failures to the data set, using the specified start/end times, the number of failures during the interval and an array of stress values/profiles for all the stresses.
• AddFailureInterval( Double, Double, Integer, Object ) Adds interval censored failures to the data set, using the specified start/end times, the number of failures during the interval and a single stress value/profile.
• AddFailureInterval( Double, Double, Integer, Object, Object ) Adds interval censored failures to the data set, using the specified start/end times, the number of failures during the interval and two stress values/profiles.
• AddSuspensionInterval( Double, Double, Integer, Object() ) Adds interval censored suspensions to the data set, using the specified start/end times, the number of suspensions during the interval and an array of stress values/profiles for all the stresses.
• AddSuspensionInterval( Double, Double, Integer, Object ) Adds interval censored suspensions to the data set, using the specified start/end times, the number of suspensions during the interval and a single stress value/profile.
• AddSuspensionInterval( Double, Double, Integer, Object, Object ) Adds interval censored suspensions to the data set, using the specified start/end times, the number of suspensions during the interval and two stress values/profiles.
• ClearDataSet Clears all data and stresses in the data set, and removes the fitted model, if any.

Analyze Data

• Calculate Fits the model (i.e., distribution and life-stress relationship) to the current data set using the settings specified in the AnalysisSettings property.

Properties

Use these properties to specify analysis settings and view analysis results, as well as view or edit properties of the data set.

Analysis Settings

• AnalysisSettings (as ALTAAnalysisOptions) Sets some of the control panel analysis settings for use with the ALTADataSet.Calculate method.
• GeneralSettings (as ALTAGeneralOptions) Sets some of the Application Setup calculation options that can apply to the ALTADataSet.Calculate method.
• PlotUseStress( Integer ) (as double) Sets or gets the use stress value of a particular stress for use in plots (not calculations), using the specified stress index.
• StressRelation( Integer ) (as ALTASolverLSR) Sets or gets the stress transformation of a particular stress, using the specified stress index.

Analysis Results

• FittedModel (as cModel) Gets the fitted model from the accelerated life testing analysis.
• AnalysisResults (as ALTAAnalysisResults) Gets the likelihood function value that was estimated from the analysis.

Data Set Properties

• DatasetName (as string) Provides the ability to retrieve or set the name of the data set.
• FailureCount (as integer) Gets the total number of failures in the data set.
• SuspensionCount (as integer) Gets the total number of suspensions in the data set.
• NumStresses (as integer) Gets the total number of stresses in the data set.

Events

The ALTAEvents class contains all the event handlers that can be called by ALTADataSet. To use events, you must inherit the class, override its methods and assign its instance to the Events property of an ALTADataSet. ALTAEvents inheritance is not available in VB6/VBA.

• Message( ALTADataSet, String, String, Boolean ) Called when a message should be displayed. Displays a message.
• Question( ALTADataSet, String, MsgBoxStyle, MsgBoxResult ) Called when an answer to a question is required. Displays a prompt and returns the result.
• UpdateCalculationProgress( ALTADataSet, String, String, Double, Boolean, Long, Boolean ) Called when the calculation progress should be updated. Provides ability to customize the calculation progress display.
• ShowCalculationProgress( ALTADataSet ) Called when calculation progress should be shown. Shows the current calculation progress if the calculation process is running.
• HideCalculationProgress( ALTADataSet ) Called when calculation progress should be hidden. Hides the calculation progress display.

Usage Example

This example demonstrates how to fit three failure times to a model and then use the model to calculate the reliability at a specified time. Full application examples are available at Synthesis_API_Reference#Application_Examples.

 'Initialize a new ALTADataSet object 
 Dim ADS As New ALTADataSet("DataSet1")
 
 'Set analysis settings 
 ADS.AnalysisSettings.ModelType = ALTASolverModel.Arrhenius
 ADS.AnalysisSettings.Distribution = ALTASolverDistribution.Weibull
 ADS.AnalysisSettings.Analysis = ALTASolverMethod.MLE
 ADS.AnalysisSettings.UngroupGroupedData = False
 ADS.AnalysisSettings.SortBeforeCalculations = True
 
 'Set general settings 
 ADS.GeneralSettings.AllowLargeBetaValues = False
 ADS.GeneralSettings.ImplementStressAtTheEndOfTheStep = False
 
 'Add a stress definition 
 ADS.AddStressDefinition("Temperature (K)", , 400)
 
 'Add failure times 
 ADS.AddFailure(248, 1, 406)
 ADS.AddFailure(164, 1, 416)
 ADS.AddFailure(92, 1, 426)
 
 'Fit failure times to the specified model 
 ADS.Calculate()
 
 'Get the reliability at 300 hours 
 Dim Rel As Double
 Rel = ADS.FittedModel.Reliability(300)