How to calculate the size of the speckle pattern using our spreadsheet to ensure a good measurement quality?
In a previous article, we discussed how to choose the size of the speckle spots for your experiment. We introduced the necessary parameters to control in order to optimize the size of your speckle for each of your tests. As mentioned, although the quality of a speckle pattern can only be analysed with respect to…
Mastering self-calibration with EikoTwin-DIC
To provide accurate digital image correlation (DIC) results, the EikoTwin-DIC software must first calibrate the camera system. This is made using images of the structure in its reference state (unloaded). Using these images, the software determines the intrinsic parameters (the cameras focal lengths, optical centers, skews) and extrinsic parameters (camera positions and orientations in the…
High-temperature tests for ceramic matrix composites
Context As a new member of EikoSim team, I was offered the opportunity to present an overlook of my thesis work dealing with high-temperature experiments for SiC/SiC composites, which was carried out in LMT under the supervision of F. Hild and in collaboration with Safran Ceramics under the supervision of V. Herb and B. Lacombe.…
What is a good DIC speckle pattern ?
In another article, we talked about the different techniques for creating a speckle pattern in digital image correlation, including the ability to vary the size and nature of the spots projected on the piece. But what size should your speckle pattern be? There is no “good” or “bad” speckle, or rather one cannot judge the…
Speckle patterns and Digital Image Correlation
Context The principle of image correlation is based on tracking information from a so-called “reference” image in the following images, often called “distorted images”. All of the images form a film, from which we seek to extract a measure. We can therefore see the correlation of images as following points over the entire observed surface:…
Designing a multi-camera structural test using pre-visualization
Written by Matthieu Vitse Matthieu Vitse is a freelance scientific visualization expert. He has a PhD in computational mechanics from ENS Paris-Saclay, and his main activity now focuses on the post-treatment and visualization of large complex data simulations and experiments. More info at www.sciviz.fr (from Vitse et al. Toward virtual design and optimization of a…
Understanding and controlling the sources of discrepancy between tests and simulations
Adjustment and validation of simulations Simulations play an enhanced role in the design, the qualification and the certification of industrial products by forming the basis of strategic decisions. Therefore, the role devolved to experimental testing has also been modified. These tests were the essential part of the demonstration of compliance, but now they become references…
Instrumenting structural tests with imaging techniques: what benefits?
It is quite simple to assess the benefits of using digital image correlation. For test engineers, DIC makes it feasible to prospect a larger area, to better understand the physical phenomena at stake by using a non-intrusive measuring method. For engineers working on numerical simulations, it is now possible to validate their models using vaster…
Virtual design of experiments with Blender
Blender as a supporting tool for 3D DIC experiments Have you ever heard of Blender? Blender is a comprehensive, open-source, cross-platform 3D creation suite that can be used to create photo-realistic renders, animations, or even full-length movies. Blender’s render engine can produce physically based photo-realistic renders of any 3D environment. In particular, it can be used…
Digital Image Correlation – The basics
Digital Image Correlation (DIC) is a measurement technique that processes pictures taken from cameras to track and record the surface motion of a deforming solid. In the mechanical engineering field, it has been widely used to monitor and process test data in both research and industrial contexts, for applications ranging from common material testing to…
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