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Theses

Dynamique des tubes parcourus à grande vitesse : influence de la géométrie des tubes et leur environnement sur la justesse et la dispersion

Abstract : Gun accuracy is influenced by several factors during the stages of the ammunition course (internal, intermediate and external ballistics). According to previous studies, internal ballistics are the major contributor to deviations from target. Indeed, this phase determines projectile exit conditions and, consequently, his behavior during the flight. The projectile entry conditions, the weapon and barrel geometry and their movements during firing, can modify the interaction tube / projectile and change ammunition angular rates and its transversal velocities. The purpose of this thesis is to determine the parameters related to barrel and gun geometry, which influence the bias and the dispersion. A statistical analysis was led thanks to the data base of the 25 mm firing results. It was found that some parameters, including barrel straightness, affect accuracy. Subsequently, tests were conducted with a firing appliance in order to isolate the barrel geometry influence on the deviations from the target and to confirm the straightness impact. A tridimensional numerical model was created in order to vary this parameter and to study its influence on the ammunition behavior during internal ballistics. The representativeness of the model was validated using accelerometers embedded in the ammunitions. The firing of these ammunitions has required the development of an optoelectronic system to transmit accelerations in real time. The comparison between experimental and numerical results has shown close amplitudes and similar shapes curves that proves the representativeness of the model. The model can be used now to lead parametric analysis and to determine the straightness shapes the most penalizing for gun accuracy.
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https://tel.archives-ouvertes.fr/tel-03081288
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Submitted on : Friday, December 18, 2020 - 10:02:28 AM
Last modification on : Saturday, December 19, 2020 - 3:28:51 AM

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mathilda_liennard_3186.pdf
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  • HAL Id : tel-03081288, version 1

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Mathilda Liennard. Dynamique des tubes parcourus à grande vitesse : influence de la géométrie des tubes et leur environnement sur la justesse et la dispersion. Autre. Université d'Orléans, 2015. Français. ⟨NNT : 2015ORLE2033⟩. ⟨tel-03081288⟩

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