Universal Testing Machine Data Integration

This section outlines the requirements for importing external load and displacement data into the DIC analysis workflow.

Overview

Note

Analysis Stage: This data is required only for the final step of the analysis workflow.

The DIC software uses this data to merge the Strain vs. Time history (calculated optically) with the Force vs. Time history (recorded by the machine) to produce the final Stress-Strain curves.

File Format Requirements

The software utilizes a standardized format known as AUTD (Agnostic Universal Testing Data) to decouple the analysis from specific machine manufacturers (e.g., Instron, MTS, Zwick).

Users must ensure their testing machine data is converted to the following specifications before importing.

1. The Data File (.autd)

Status: Mandatory

The primary data file must have the extension .autd. Internally, this is a plain text file using Tab-Separated Values (TSV).

Required Columns: The file must contain a header row with the specific column names listed below.

Column Name	Unit	Description
time_s	Seconds	The common time axis used to synchronize with DIC image timestamps.
force_N	Newton	The instantaneous load recorded by the load cell.
disp_mm	Millimeters	The crosshead displacement (or extensometer data) recorded by the machine.

Example Content:

force_N    disp_mm    time_s
0.00       0.000      0.0
150.25     0.012      0.1
305.50     0.024      0.2
...

2. The Metadata File (.json)

Status: Optional (Reference Only)

The generation script often produces a companion JSON file (e.g., filename_ut.json).

• Usage: This file contains experimental details (e.g., Operator name, Temperature, Humidity, Sample ID).

• Necessity: It is not required for the computation of stress or strain. The analysis software can proceed fully without it; it is preserved solely for user traceability and data archiving.