Test Data Import Overview

When the calibration app is set to analytic execution or numerical execution mode the test data import tool has two functions. First, it allows you to select and import the test data that you wish to include in a subsequent calibration. Second, it allows you to select a domain (time or frequency), a built-in deformation model, and prescribed conditions, such as temperature, that best captures the experimental conditions under which the test data was collected. For example, if the test data included nominal uniaxial stress and strain from a standard tensile test under monotonic extension you would most likely select the available Uniaxial deformation mode in the Time domain.

See Also
Importing a Set of Experimental Test Data
Importing a Response Data Set

You can select and import the test data for your material calibration using the following process:

  1. Preprocess the raw test data.

    The calibration app has an extensive and specialized set of test data preprocessing tools that can be used to clean up your test data after import (see About Test Data Processing). However, you have the option to preprocess your test data using your own tools before import. From a calibration standpoint good test data should have the smallest number of data points needed to accurately capture the material response, and be free from as much experimental noise as possible. You should confirm that the stresses and strain for time domain test data are zero at time=0.

  2. Import the test data files.

    You can import one or more files of experimental test data into the app. The app supports import from Excel spreadsheets (.xls*), text files (.txt), or comma-separated value files (.csv). Test data must be stored in column format with each row of data corresponding to the same measurement point. For example, a typical test data set from a uniaxial tension experimental test would include the following columns: time, nominal strain, and nominal stress.

  3. Select subsets of test data.

    You can select the rows and columns of test data that you want to import. If you highlight columns that have textual header data, the app automatically disregards headers and starts reading from the first numerical values it finds.

  4. Characterize the imported data.

    Part of the import process is describing what the test data represents. You can describe imported test data sets as follows:

    • Domain: Describes whether the test data is based on time or frequency.
    • Deformation mode: Describes the physical testing procedure (deformation modes) used to collect the data. The app supports: uniaxial tension, biaxial tension, planar tension (pure shear), simple shear, torsion, and volumetric compression.
    • Quantities: Describes the X- and Y-quantities and units for each column of test data.
    • Metadata: Describes any other pertinent information about the test data, such as the lab that performed the testing, the machines that were used, test data, and specimen temperature. If your data does not include time information, you can also specify a strain rate for the data manually. Metadata are optional.

  5. Review plots of the imported data.

    Upon import, the app immediately plots your test data in a dedicated panel. If you have already specified a material model, the app also plots an initial response.

You can also load data files with response data into the app, which enables you to extrapolate material response outside of the range of your test data. Response data only includes time and strain history; therefore, it cannot be used during a calibration. If you do not have response data in a file, you can also specify the response directly; for more information, see Defining Response Data.