13:20
Applications
Chair: Roger Groves
13:20
20 mins
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BEHAVIOUR OF A THERMOPLASTIC COMPOSITE AUTOMOTIVE WISHBONE UNDER MECHANICAL LOADINGS
Patrick Lapeyronnie, Jean-Michel Roche, Pascal Paulmier, Françoise Passilly, Christian Fagiano, Agnès Exertier, Laurent Rota
Abstract: As for aeronautics requirements, automotive industry needs to achieve a weight reduction while keeping equivalent mechanical performances to ones of metallic parts, thanks to the use of composite materials. Moreover this sector meets specific requirements such as a minimization of costs and a high production rate. The objective of this project between CETIM, ONERA and PSA, is to go further with the replacement of a structural steel component of automotive vehicles by a thermoplastic composite part: the wishbone arm. A preliminary design phase is based on the technical specifications of PSA (size limitations, stiffness, weight, etc.) and the manufacturing feasibility by thermoforming and welding. After a mechanical characterization campaign, the final purpose of the project is the validation with accidental test cases on the final composite structure. The experimental results (from image correlation, acoustics, thermal analysis, ultrasonic controls) are validated among themselves and then with numerical simluations.
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13:40
20 mins
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A MULTI-VIEW / MULTI-SURFACE FRAMEWORK USING CAD-BASED STEREO-DIC
John-Eric Dufour, François Hild, Stéphane Roux
Abstract: The calibration of a multi-camera stereo system is performed using
a global approach to Stereo-DIC and the geometric model of the
observed sample, which is composed of several surfaces. As each
camera can see multiple surfaces, a global formulation of the
stereo-matching problem is carried out. 3D shape measurements of
the sample can be performed after the calibration. As for the
calibration step, the formulation has to take into account
multiple cameras seeing multiple surfaces. A proof of concept is
developed using an experiment on a simple geometry with 4 surfaces
and 4 cameras.
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14:00
20 mins
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HIGH PERFORMANCE COMPUTING IN GLOBAL DIC FOR THE ANALYSIS OF LARGE DATASETS
Jean-Charles Passieux, Jean-Noël Périé
Abstract: The computational burden associated to finite element based digital image correlation methods is mostly due to the inversion of finite element systems and to image interpolations. A variable separation technique was recently proposed that alleviate mesh constraints. However, in digital volume correlation, the question of the interpolation of the images remains important. For that, a non-overlapping dual domain decomposition method is proposed to rationalize the computational cost of high resolution finite element digital image correlation measurements when dealing with large datasets. It consists in splitting the global mesh into submeshes and the reference and deformed states images into subset images. It will be shown to combine the metrological performances of finite element based digital image correlation and the parallelisation ability of subset based methods.
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14:20
20 mins
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REAL-TIME MONITORING OF INITIATION AND FATIGUE CRACK GROWTH USING SPECKLE IMAGE CORRELATION METHOD
Alexander Vladimirov, Ivan Kamantsev, Aleksey Ishchenko, Valeriya Veselova, Eduard Gorkunov, Sergei Gladkovskiy, Sergei Zadvorkin
Abstract: The possibility of detecting the moment of fatigue crack initiation and monitoring the kinetics of its propagation during cyclic loading using laser speckle interferometry method is shown.
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14:40
20 mins
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EFFECT OF GAGE LENGTH ON FAILURE STRAIN
Lisa Tang, Carey Walters, Wim van den Heuvel, Etienne van Daelen
Abstract: Failure prediction in crash analyses of ships has traditionally made use of an equation that relates the failure strain to the gage length and material thickness. The equation is derived based on the idea that a neck ( a localization of strain) is a fixed size relative to the thickness and that it can be homogenized over a larger gage section. The fact that DIC allows for the gage length to be retroactively changed after the test (so long as all of the gage section has a random pattern and falls within the view of the camera) allows these hypotheses to be tested. Tests of two different scales have been performed and analyzed with DIC. The results confirm this fundamental assumption that has been at the core of failure modelling in crash analyses.
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