ResearchActivities

Optical Deformation Measurement and Digital Image Analysis in Experimental Mechanics

The Optical Deformation Measurement and Digital Image Analysis research group focuses on advancing experimental mechanics through cutting-edge optical techniques. Our team specializes in developing and applying digital image correlation (DIC) and other optical measurement methods to analyze deformation across various applications, such as material testing, design optimization and validation, finite element models calibration and validation. The research emphasizes integrating DIC with multiple domains of experimental mechanics, including vibrations, fracture mechanics, and residual stress analysis.

In the field of residual stress research, we are focused on applying optical deformation measurement techniques using DIC in conjunction with the hole-drilling method. This full-field optical measurement approach significantly enhances the evaluation of residual stresses, offering more comprehensive and accurate insights. However, the process is challenging, as the deformations being measured are at the threshold of the observable limit, requiring precise instrumentation and meticulous analysis.

We also widely use DIC in biomechanics, particularly for measuring samples of human tissues and biomaterials, disease research, or evaluating the effectiveness of various treatment methods. Additionally, it is utilized in orthopaedics for the development and testing of different types of joint and bone replacements, as well as in studying the stability of implants.

Our research delves into creating innovative methodologies and algorithms for analyzing structural behaviour under both static and dynamic conditions. We harness the power of Digital Image Correlation (DIC) as a cornerstone of our experimental work, capturing detailed displacement and strain data with exceptional precision. Beyond that, we push the boundaries by implementing advanced techniques for operational modal analysis using DIC, while also pioneering AI-driven features like K-means clustering to uncover and evaluate the nuances of modal shapes. In some cases, our AI advancements are designed to replace the need for human operators, automating and enhancing the analysis process for greater efficiency and accuracy.

Projects
TAČR FW03010653 Optical deformation analysis with artificial intelligence

Publications

APOSTOLOPOULOS, V.; BOHÁČ, P.; MARCIÁN, P.; STANICZKOVA ZAMBO, I.; PAZOUREK, L.; MAHDAL, M.; NERADIL, J.; NÁVRAT, T.; TOMÁŠ, T. Micro-CT, Mechanical, and Histological Examination of the Effect of Local Adjuvants on Porcine Cortical Bone Following Intralesional Curettage of Bone Tumors. ANNALS OF SURGICAL ONCOLOGY, 2024, vol. 31, no. 2024, p. 6282-6290. ISSN: 1068-9265.

HALABUK, D.; NÁVRAT, T. Universal Procedure for Correction of Plasticity Effect in Hole-Drilling Uniform Residual Stress Measurement. EXPERIMENTAL MECHANICS, 2022, vol. 62, no. 8, p. 1267-1287. ISSN: 0014-4851.

Laboratory Equipment

  • machine vision cameras with various resolutions (2 MP – 20 MP)

  • telecentric lenses with various magnifications (0.5x – 1x)

  • various machine vision entocentric lenses

  • various LED lights with power from 4.5 W up to 500 W

  • calibration targets with unit distances from 0.1 mm up to 24 mm

  • various mounting systems and manual stages

More information
https://www.visionlab.tech/

Contact person
doc. Ing. Tomáš Návrat, Ph.D.