ACCELERATIONFACTOR

Description: Returns the value of the acceleration factor. Available only for stress-dependent models. A value for Time is required only for a Cumulative Damage model with time-varying stresses.

Syntax: ACCELERATIONFACTOR(Data_Src, [Time], [Confidence Level], [US_1], [AS_1])

Data_Src is the source data sheet from which the value is taken.

Time determines the operation duration under the time-dependent stress profile. For example, if the selected stress profile uses 100 degrees from 0 to 100 hours and 200 degrees from 100 to 200 hours, then if you enter 150 for the time, you will get the acceleration factor for the operation duration of 150 hours. (This field is required only when the source data sheet uses the Cumulative Damage model with time-varying stresses.)

Confidence Level is the percentage (entered as a decimal value) for the 1-sided confidence bounds.

US_1 is the use stress level for each stress type. The number of use stress inputs is determined by the number of stress types in the specified data sheet.

AS_1 is the acceleration stress level for each stress type. The number of stress inputs is determined by the number of stress types in the specified data sheet.

Remarks:

The Data_Src can be one of the following values:

If using a default data source, it must be either 1, 2, 3 or 4, as selected from the Data Source Index drop-down list.
It can take a data sheet name (e.g., "Folio1!Data 1").
It can take a variable name defined in the Defined Names window (e.g., datasource).

Time is a required value if the data sheet uses the cumulative damage life-stress model and any use stress (US_1) and/or acceleration stress (AS_1) value is set to a time-varying stress. In all other cases, this input is not used. It must be greater than 0.

Note: If you are using the Function Wizard to enter this function, the Time field will be visible only if a) the data source is an ALTA standard folio with a time-dependent stress profile used to assign at least one stress level and b) you have selected a stress profile for at least one of the fields in the Stress Levels area.

Confidence Level is an optional value and, if specified, must be greater than 0 and less than 1.

US_1 is an optional value. The default value is the value specified in the Use Stress Level window, but you can change the value to any desired number. If the data sheet uses the Cumulative Damage model, you can also use a stress profile for this value.

AS_1 is an optional value. The default value is US_1*1.1 (110% of US_1). If the data sheet uses the Cumulative Damage model, you can also use a stress profile for this value.

Example:

ACCELERATIONFACTOR("Folio1!Data 1",,0.9,300,330) = 0.4129

Note that this value will vary depending on the source data set.