This study used a DSE (Digital Speckle Correlation) three-dimensional full field strain measurement system, combined with a high-precision material testing machine from Kael Measurement and Control, to achieve accurate quantitative analysis of the full field deformation evolution of materials under compressive loads. By synchronously collecting three-dimensional full field strain distribution data during the loading process, the system reveals the full process strain evolution law of materials from elastic deformation to plastic yield, and even failure, providing high-resolution, non-contact quantitative methods for material mechanical performance evaluation and failure mechanism research.

1、 System Integration and Testing Methods

1. Composition of the experimental system:

Loading equipment: Kyle measurement and control testing machine, providing accurate and stable axial compression load, and real-time recording of load displacement data.

Measurement system: DSE 3D full field strain measurement system, including high-resolution binocular camera, dedicated speckle projection light source, and image processing software. Prepare a high contrast random speckle pattern on the surface of the specimen in advance.

Synchronous control: The synchronization between the testing machine and the DSE system is achieved through triggering signals, ensuring that the mechanical data corresponds to the strain image frames.

2. Experimental procedure:

Install the prepared specimen into the compression fixture of the Kyle measurement and control testing machine.

The DSE system performs dual camera calibration on the specimen and establishes a three-dimensional coordinate mapping relationship.

Set up the loading program for the testing machine (such as displacement control or force control) and start the DSE system for continuous image acquisition.

Start the compression test, and the system synchronously records the load, displacement, and sequence images of the specimen surface.

After the experiment is completed, the image sequence is processed using DSE software to calculate the three-dimensional displacement and strain field of the entire field.

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2、 Accurate quantitative analysis of deformation evolution

1. Visualization of Full Field Deformation:

Displacement field: Obtain the displacement vectors of each point on the surface of the specimen in three-dimensional space, and visually display the overall warping, local buckling, and other phenomena during the compression process.

Strain field: Calculate the full field distribution cloud map including longitudinal compressive strain (ε yy), transverse expansion strain (ε xx, ε zz), and shear strain (ε xy, etc.), clearly presenting the localized strain region.

2. Quantification of key deformation stages:

Elastic stage: The strain field is uniformly distributed, and the macroscopic strain is highly consistent with the displacement data of the testing machine, which can accurately calculate the elastic modulus of the material.

Yield and plastic flow: When the strain field is locally concentrated (such as in the "shear band" or "drum shaped" region), the DSE system can accurately capture the starting point of yield and the evolution process of the plastic zone.

Destruction stage: Real time tracking of crack initiation location, propagation path, and surrounding strain concentration, quantitative analysis of failure mechanism.

3. Data comparison and validation:

Compare the local strain measured by the DSE system with the data from the extensometer or strain gauge of the testing machine to verify its accuracy.

Using full field data, analyze the influence of geometric inhomogeneity or material defects on deformation localization of the specimen.

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3、 Technical advantages

1. High spatial resolution: Overcome the limitations of traditional point measurement (strain gauges), obtain strain information of millions of pixel level data points, and capture local strain concentration without omission.

2. True 3D measurement: capable of measuring both in-plane and out of plane displacements simultaneously, suitable for compression specimens that may undergo buckling or tilting.

3. Non contact measurement: Avoid interference from contact sensors on specimens (especially flexible or small-sized specimens), and is suitable for high and low temperature environments.

4. Dynamic evolution record: Complete recording of the entire deformation process, supporting retrospective analysis of the strain state at any moment.

5. Seamless integration with Kyle measurement and control testing machine: ensuring strict synchronization between mechanical data and optical measurement data, providing multi-dimensional correlation analysis of load strain time.

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4、 Application value

Material constitutive parameter inversion: providing high-precision input for material parameter identification based on full field data.

Failure mechanism research: Accurately locate the origin of damage and quantitatively analyze the damage evolution process.

Simulation model validation: Provide detailed full field deformation data for numerical simulations such as finite element analysis (FEA) for model validation and correction.

Process and structural optimization: Evaluate the performance weaknesses of materials or structures under compressive loads and guide optimization design.

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Conclusion

A precise and efficient material compression deformation analysis platform was constructed by combining the DSE three-dimensional full field strain measurement system with the Kyle measurement and control testing machine. This technology not only provides rich strain field information far beyond traditional methods, but also dynamically and quantitatively reveals the complete evolution process of materials from deformation to failure, providing powerful testing methods for materials science, mechanics research, and engineering applications.