I. System Introduction

1. System Overview

The WT series non-contact video extensometer offers a non-contact optical strain measurement solution. It measures the specimen inTensile TestReal-time longitudinal and lateral strain throughout the process. Utilizing Digital Image Correlation (DIC) technology, it achieves rapid and reliable measurements with sub-pixel accuracy by tracking speckle patterns on the surface of objects. It can communicate with universal material testing machines for synchronized control measurements, featuring portability, speed, high precision, and ease of operation.

Figure: Schematic illustration of the system measurement principle and speckle image tracking process

System Components: System Measurement Head (including 1 industrial camera, lens, with a swivel handle and adjustable LED light source), Camera Synchronization Control Trigger Box, System Calibration Plate, System Mobile Support Stand, Dynamic Data Collection and Analysis Software, Load Pressure Control Communication Interface, Computer System (user optional), etc.

2. Application Scope

• Measurement Object: Equipped with lenses of different focal lengths according to the size of the actual measurement object to achieve various scales of measurement results. Suitable for testing from tiny-sized specimens to large deformation tests of materials like rubber.

• Measurement Environment: Tested under conditions ranging from low temperatures to high temperatures, even extreme ultra-high temperatures; from low-cycle fatigue tests to high-frequency tests.

• Applicable Materials: Ranging from conventional metals to composite materials, rubber, concrete, plastic films, and unconventional materials such as biological骨骼 and muscle tissue.

   

3. Technical Advantages

• Advanced System Technology: Digital Image Correlation 2D and 3D deformation measurement system; core algorithms with independent intellectual property rights, technical specifications reaching international advanced levels.

• Wide application of the system: Suitable for scientific research and engineering measurements in various disciplines such as mechanics, materials, mechanics, architecture, civil engineering, etc., applicable to most materials, and capable of real-time acquisition of coordinates, displacements, and strain data of the measured objects.

• Flexible system configuration: Supports camera interfaces from millions to tens of millions of pixels, from low to high speed, etc., with the system software control module capable of online synchronous data collection.

• Real-time measurement: Strain calculations and results can be performed and displayed in real-time, rather than post-event processing.

• High system compatibility: Compatible with both single-camera 2D measurement and multi-camera 3D measurement.

• Robust auxiliary functions: Equipped with dynamic deformation of circular marker points and motion trajectory posture measurement for rigid bodies.

• Expanded Interface Richness: Equipped with universal testing machine interface for real-time collection of force and displacement signals; features a cup pull test machine interface for measuring material's FLC curve; equipped with a body-type microscope interface for 3D full-field strain detection of objects as small as a few millimeters; supports synchronous measurement by multi-camera setups, enabling simultaneous deformation strain measurement across multiple areas; the system is equipped with multi-channel A/D inputs, multi-channel D/A outputs, multi-channel digital input/output, and can be flexibly expanded.

• Product Performance Stable: Verified by dozens of domestic and international users, with stable performance, including several domestic users (such as the China Aircraft Strength Research Institute, Composite Materials Research Institute No. 43), and universities (like East China University of Science and Technology, Harbin Institute of Technology, Nanjing University of Aeronautics and Astronautics, etc.).

• Technical Support: Self-developed, flexible custom development; our top-tier R&D team provides you with solutions and technical guidance, always standing as a solid technical support for your scientific research and development.

Two、  Extensometer Functional Specifications

The WT series non-contact video extensometer is an important testing method in the field of experimental mechanics, enhancing research methods non-contactly to improve research capabilities. It also provides researchers with a visual testing and analysis tool, simplifying complex issues, making abstract problems more intuitive, and visualizing hidden issues. Its advantages, features, functions, and specifications are as follows:

1. Video Extensometer Advantages and Features

• Non-contact optical measurement: one-touch measurement without interruption; even if the sample breaks, the measuring device will not be damaged.

• High Precision: Based on image correlation technology, sub-pixel matching, accuracy up to sub-pixel level.

• Multi-point simultaneous measurement: simultaneous measurement of axial and lateral strains, even more points.

• Custom Scale: Fixed, conveniently set multiple scales.

• Real-time Calculation: Over 100 frames per second real-time calculation speed; up to 1000 frames.

• Multiple Calibration: Full field distortion correction for measurement field, with the application of scale, for greater accuracy.

• Multiple measurement values: displacement, strain, Poisson's ratio, modulus of elasticity, etc.

• Multiple online interfaces: ADDA, serial port, supporting online measurement for multi-brand testers and temperature units.

• Multiple scenarios: Large deformation, minor deformation, room temperature, high and low temperatures, etc.

• A variety of materials: multiple sizes and specifications.

• Secondary Calculation: Save test data and conveniently modify the gauge length for a recalculation.

• All-Weather Solutions: DIC All-Weather Solutions.
  

• 3D Extensometer (Optional): Supports 3D Extensometer (dual camera) to enhance measurement accuracy in cases of non-negligible off-plane displacement.

2. The main function of the video extensometer

1. Supports real-time calculation and measurement of displacement and strain.

2. Support calculation and measurement of Young's modulus and Poisson's ratio.

3. Supports real-time display of various curve plotting.

4. Supports simultaneous bidirectional tensile and compressive strain measurement.

5. Supports trial alignment assistance feature.

6. Supports automatic scale correction.

7. Support fixed, custom, and free spacing settings.

8. Support real-time image saving and secondary calculation features.

9. Supports data export and reporting features.

10. Supports analog/digital input/output.

11. Supports ADDA, COM online mechanical testing machine function.

12. Supports start/stop of temperature units and data acquisition.

13. Supports full-range strain measurement for DIC.

    * Accompanied mechanical testing machines and temperature units enable various conventional and high/low temperature measurements, including tension, compression, and bending.

     

3. Video Extender Technical Specifications

1. Stress Accuracy: 0.002%

2. Stress Range: 0.002% - 2000%

3. Measurement Resolution: ±1um/±0.5um

4. Field of View: 100mm/50mm

5. Span range: 10-100mm / 5-50mm

6. Data collection rate: 0-100Hz (resolution can be reduced to increase frame rate up to 500)

7. Accuracy meets ISO 9513 standard grade 0.5, ASTM E83 standard grade B-2

Three.  System Detailed Configuration