Services

Cooperation With VisionLab

Are you interested in getting access to expert knowledge and modern research facilities for advanced research and innovation in the field of optical measurement of deformations? Are you solving a problem you can’t handle, or you lack the necessary equipment? Or do you want to learn more about the use of optical measuring systems in experimental mechanics?

 

We offer you cooperation on scientific research projects with VisionLab. We will deliver a complex solution for industrial orders with the possibility of including both optical measurement and computational modelling. VisionLab also provides consultations, training, and lecturing in the following areas.

Video Extensometry

The laboratory is equipped with modern video extensometers from the X-Sight company, based on the digital image correlation technique (DIC), for planar measuring of displacements and deformations. We use advanced software tools for tensile testing of a broad portfolio of materials and samples, including everything from standardised specimens to oxidised rebars.

Advantages of Video Extensometers

Video extensometers enable non-contact measurement, excel in high accuracy and flexibility and possess other advantages, especially in comparison to conventional extensometers:

 

  • No influence of extensometer contact and inertia, especially when measuring fragile and thin samples
  • No risk of damage to the measuring device during tests releasing a large amount of elastic energy due to sample failure
  • No result distortion caused by wear of the device’s mechanical parts
  • Effortless analysis of the behaviour of samples in the transversal direction, which is required under some testing standards
  • Easy measuring using thermal chambers and climate chambers
  • Advantage of data storage and post-processing enabling further evaluation
  • Possibility to obtain information on the behaviour of the adjacent surroundings of the specimen, such as the jaws of the testing machine

Video Extensometers Not Just for Tensile Testing

Thanks to special software instruments, video extensometers are suitable for a wide range of applications. Fundamental tests include compression tests (tamping), three-point and four-point flexural tests, torsion, or shear tests.

 

In creep, fracture and fatigue tests, in addition to the standard measurement of deformations and displacements, the length and speed of crack propagation can also be determined. For cyclic testing, the measuring system can be synchronised with the test equipment.

 

In addition to the specialised software tools mentioned above, the displacement field can be measured over the entire sample surface (so-called full-field). This allows, for example, to replace a strain gauge rosette for residual stress measurements by the hole drilling method or to examine specimens with cracks.

Stereoscopic Digital Image Correlation

All the applications and measuring tools mentioned above can be extended to another dimension using a 3D DIC system allowing measuring samples, components, and prototypes of complex shapes subjected to general loading.

 

The sample scale does not present any obstacles for the measuring system. It is possible to measure nanofibers under a microscope or to tackle fieldwork and measure bridge deformations with a wide-angle objective as the train passes.

 

The system also allows measurement of deformations at higher speeds and identifies natural frequencies and operating deflection shapes of a system.

On-Site DIC Measurement

The DIC measuring system is suited for use in conditions outside the test laboratory, with any machine or structure on the factory floor or for on-site measurement of deformations of buildings, trees, statues, bridges, and other civil engineering structures and industrial buildings. For example, to assess the condition of structural elements and operational safety.

Miniature Specimen Testing

As technology progresses towards miniaturisation, new testing techniques must acknowledge the challenges of measuring microscale and nanoscale displacements.

 

Visionlab operates a miniature test machine for measuring flat specimens with a maximum load value of 500 N. The testing machine allows the measuring of mechanical properties of small samples using a video extensometer.

Validation and Verification of Computational Models

Optical measuring systems are an efficient tool for validating computational models. By analyzing the behaviour of a real object, we can verify the validity of the applied boundary conditions, simplifications, and assumptions applied.

 

We offer professional consultations on the verification of your computational models.

Computational Modelling​

We also offer comprehensive computational-experimental solutions to the problems of solid mechanics, mechatronics and biomechanics. We analyse stiffness, strength, fatigue, residual stresses, dynamic properties, noise, vibration, reliability assessment and optimisation of machine parts or structures according to customer requirements.

 

We offer the development of special simulation software. Not to compete with commercial software such as Ansys, which can handle such problems. However, by creating a single-purpose program, we will achieve easier data input, faster calculations, and more efficient results reading.

 

In biomechanics, we offer the analysis of human musculoskeletal, cardiovascular, dental or auditory systems. We also provide calibrations of advanced material models of biological tissues.

 

We deal with calculations, simulations, and optimisation of mechatronic systems and mobile autonomous robotics.

Simulation of Technological Operations

In computational modelling, we offer:

 

Numerical simulations of selected technological operations, such as straightening, are described in this article (Petruška et al., 2016). This article (Nytra et al., 2020) deals with forming operations, specifically forging.

 

Identification of the true stress-strain curve and its extrapolation beyond the ultimate tensile strength, including the influence of temperature and deformation rate. For more information, see the article (Jeník et al., 2017).

 

Design, implementation, and evaluation of experiments for calibration of advanced plasticity models taking into account the response to:

  • cyclic loading by means of kinematic hardening, for more information, see the article (Peč et al., 2019),
  • monotonic loading by means of combined and non-combined plasticity conditions formulated as quadratic and non-quadratic surfaces of plasticity, prismatic and non-prismatic.

 

Design, implementation, and evaluation of suitable experiments and subsequent calibration of ductile failure criteria of bulk materials as well as sheets, both on a microscopic scale and for standard-size test specimens with the possible use of digital image correlation. More on this topic in the article (Kubík et al., 2019).

Measurement of Mechanical Variables and Properties of Systems of Bodies

Within the framework of experimental mechanics, we also provide:

 

  • Experimental stress analysis under static and dynamic loading of machine parts and systems using electrical resistance tensometry
  • Analysis of system properties using structural dynamics (EMA – experimental modal analysis, OMA – operational modal analysis, ODS – operational deflection shapes)
  • Analysis of noise and vibration both in the field of mechanical structures and in the biomedical field
  • Diagnostics of machines and equipment
  • Measurement of residual stresses using the hole drilling method
  • Measurement of mechanical variables (force, torque, displacement, velocity, acceleration, temperature, pressure, rotational speed)