Technical Articles

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Simulation correlation with Abaqus: how far we’ve come in linking a solver to our software environment

By Team Eikosim | 2 September 2022

Need to perform correlation between an Abaqus simulation model and measurements automatically? Whether it is by developing a python script, actually using the C++ API or developing our parsers, we have experimented a lot with reading and writing formats related to this solver, whether it is to correlate displacement or deformation fields, or simply strain…

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Mechanical regularization in EikoTwin DIC

By Team Eikosim | 19 May 2022

By Lucas Angénieux, Research engineer at EikoSim In EikoTwin DIC, the calculation of displacement fields is performed on the simulation mesh. However, as this mathematical problem is by nature ill-posed, there is a mechanical regularization parameter that allows the user to add mechanical conditions to the field measurements. Contrary to most digital image correlation software, at…

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Digital image correlation for crack measurement

By Team Eikosim | 29 April 2022

In the context of crack propagation tests on composite material, EikoTwin image correlation solutions were used to meet a customer need. A post-processing script, exploiting the measurement data from EikoTwin DIC, was developed by EikoSim to bring satisfaction to the customer with a tailor-made solution. This work is part of Paul Nicolino’s engineering internship at…

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Sources of measurement errors with digital image correlation

By Team Eikosim | 17 May 2021

By Clara Minguet, Research engineer at EikoSim In digital image correlation as in any measurement process, errors affect measured data. The characteristic of this method lies in the direct dependency between the test and the measurement error [1,2,3]. Indeed, errors need to be estimated for every new test. These errors can be classified in two…

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Camera calibration: principles and procedures

By Team Eikosim | 22 March 2021

By Myriam Berny, R&D engineer at EikoSim The use of a multi-camera system for metrology and accurate measurements requires the calibration of these cameras. They can be represented mathematically by a projection model, in the form of a matrix, allowing the passage of the position of 3D points to their projection in 2D image space.…

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Technical functionality: selection of the measurement mesh

By Team Eikosim | 10 February 2021

By Clara Minguet and Lucas Angénieux, Research engineers at EikoSim On EikoTwin DIC, the measurements are directly expressed on the simulation mesh. In order to choose which areas of interest for the test are visible to the camera(s), the so-called measurement mesh must first be selected. Indeed, this mesh will be the one where the…

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Measurement errors and digital image correlation

By Team Eikosim | 7 January 2021

By Pierre Baudoin, R&D engineer at EikoSim When conducting a test campaign instrumented by digital image correlation, it must be possible to determine the characteristic measurement error for the quantities of interest studied (measured displacement or strain). This analysis is essential to know whether the measurement made is indeed the desired “signal” and not the…

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What are good Digital Image Correlation test practices?

By Team Eikosim | 24 November 2020

By Floriane Soulas, R&D engineer at EikoSim Importance of a good implementation of digital image correlation tests When performing a test by using Digital Image Correlation (DIC), many parameters must be taken into account: brightness, speckle pattern, camera placement. All these steps are essential to achieve the best possible images, in order to get the maximum…

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Hybrid calibration : a robust alternative to self-calibration

By Team Eikosim | 7 October 2020

By Pierre Baudoin, R&D engineer at EikoSim Introduction This article is written as a complement to the article on good calibration practices recently published on our website. In general, it is very often possible to calibrate the camera system in EikoTwin DIC thanks to the knowledge of the geometry of the part, and of the…

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Speckle pattern size: how to calculate it for your DIC test?

By Team Eikosim | 4 September 2020

By Floriane Soulas, R&D engineer at EikoSim In a previous article, we discussed how to choose the size of the speckle pattern 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…