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