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You searched for subject:(shock focusing). Showing records 1 – 3 of 3 total matches.

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University of California – San Diego

1. Lakhani, Elesh. Design of Exploding Wire System.

Degree: Structural Engineering, 2018, University of California – San Diego

Shock focusing can lead to extreme conditions in the region, where the shock waves coalesce, called the focal region. These conditions can either be detrimental or beneficial, depending on the circumstances. The phenomenon has found applications in various industries including biomedical, nuclear and anti-terrorism. However, due to the nonlinear nature of shock waves and their interactions, predictions of shock focusing events are far from trivial. A deeper understanding of shock focusing is vital to determine how to both mitigate its harmful effects and enhance its applications. This thesis aims to provide an experimental technique to study shock-shock interaction and shock focusing from multiple synchronized shock waves. The technique utilizes a combination of a capacitor bank and a spark gap switch to pass a large amount of current through very thin conducting wires. The large current causes the wires to undergo substantial thermal changes, leading to their explosion. This results in the generation of shock waves that have decaying flow properties behind the shock front. The number and locations of the shock waves can be easily varied to study a myriad of cases. The technique, in combination with different experimental chambers, provides the flexibility to either constrain the shock waves to propagate in only a 2-dimensional space or allow them to propagate in the entire 3-dimensional space. Additionally, the technique has a very fast turnaround time and allows the user to run up to 30 experiments in a day.

Subjects/Keywords: Fluid mechanics; Exploding Wire System; Shock Dynamics; Shock Focusing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Lakhani, E. (2018). Design of Exploding Wire System. (Thesis). University of California – San Diego. Retrieved from http://www.escholarship.org/uc/item/26z8c0ds

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Lakhani, Elesh. “Design of Exploding Wire System.” 2018. Thesis, University of California – San Diego. Accessed April 19, 2019. http://www.escholarship.org/uc/item/26z8c0ds.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Lakhani, Elesh. “Design of Exploding Wire System.” 2018. Web. 19 Apr 2019.

Vancouver:

Lakhani E. Design of Exploding Wire System. [Internet] [Thesis]. University of California – San Diego; 2018. [cited 2019 Apr 19]. Available from: http://www.escholarship.org/uc/item/26z8c0ds.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Lakhani E. Design of Exploding Wire System. [Thesis]. University of California – San Diego; 2018. Available from: http://www.escholarship.org/uc/item/26z8c0ds

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of Southern California

2. Wang, Chuanxi. Converging shocks in water and material effects.

Degree: PhD, Physics, 2013, University of Southern California

During events of underwater explosions, the resulting shock waves poses extreme mechanical loadings to the nearby naval structures. Therefore this dissertation studies the shock wave dynamics of water inside a solid structure and the dynamical response of such a structure. The goal is to understand the effect of underwater shock wave focusing on materials possessing various mechanical properties with an emphasis on lightweight materials. This research has a direct impact on the material selection and hydrodynamic considerations in naval architecture. ❧ Two steps are taken towards the research goal. First, a special geometry of the confinement structure called logarithmic spiral is chosen. This type of shape will help to focus the shock wave, which will yield the maximum energy at the focal region. Numerical simulations are conducted to confirm the derived characteristics of the geometry. When including weak material coupling with the liquid, both experiments and simulations demonstrate that the shock dynamics in water is sensitive to the coupling. ❧ Secondly, significant coupling effect is introduced by reducing the thickness of the solid structure. Experimental and numerical investigations are both carried out to shed light onto the details of the fluid-structure coupling. The results revealed that the thickness of the material has the most significant impact on both the fluid dynamics and the deformation mechanisms of the structure. Lightweight carbon fiber composite structures are also studied under the same framework. ❧ Along the way, this dissertation also proposes and designs experimental methodologies to enable the study of highly dynamic underwater events. Advisors/Committee Members: Eliasson, Veronica (Committee Chair), Haas, Stephan W. (Committee Member), Dappen, Werner (Committee Member), Däppen, Werner (Committee Member), Daeppen, Werner (Committee Member), Thompson, Richard S. (Committee Member), Redekopp, Larry G. (Committee Member).

Subjects/Keywords: shock focusing; underwater explosion; fluid-structure interaction; Schlieren optics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Wang, C. (2013). Converging shocks in water and material effects. (Doctoral Dissertation). University of Southern California. Retrieved from http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/338110/rec/1652

Chicago Manual of Style (16th Edition):

Wang, Chuanxi. “Converging shocks in water and material effects.” 2013. Doctoral Dissertation, University of Southern California. Accessed April 19, 2019. http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/338110/rec/1652.

MLA Handbook (7th Edition):

Wang, Chuanxi. “Converging shocks in water and material effects.” 2013. Web. 19 Apr 2019.

Vancouver:

Wang C. Converging shocks in water and material effects. [Internet] [Doctoral dissertation]. University of Southern California; 2013. [cited 2019 Apr 19]. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/338110/rec/1652.

Council of Science Editors:

Wang C. Converging shocks in water and material effects. [Doctoral Dissertation]. University of Southern California; 2013. Available from: http://digitallibrary.usc.edu/cdm/compoundobject/collection/p15799coll3/id/338110/rec/1652

3. Giammarinaro, Bruno. Focalisation non linéaire des ondes de choc de cisaillement dans les solides incompressibles : Focusing of shear shock waves in incompressible solids.

Degree: Docteur es, Acoustique Physique, 2016, Université Pierre et Marie Curie – Paris VI

Les ondes de choc de cisaillement dans les solides quasi-incompressibles sont un type d'onde peu exploré car accessible à la mesure seulement depuis une douzaine d'années. Elles se distinguent des ondes de choc de compression par leur non-linéarité cubique au lieu de quadratique. Les faibles vitesses des ondes de cisaillement, de l'ordre du mètre par seconde, permettent notamment d'atteindre des régimes assez fortement non linéaires sur de faibles distances, et de contrebalancer l'absorption relativement importante dans ces milieux. A notre connaissance, ces ondes ont été étudiées presque exclusivement en ondes planes. Or, la focalisation est un phénomène fondamental dans la physique des ondes et ses applications. C'est cette focalisation que l'on s'est attaché à étudier spécifiquement ici, tant du point de vue théorique et numérique, qu'expérimental. L'objectif était de mettre en évidence la focalisation des ondes de choc de cisaillement. Ce travail est en particulier motivé par son application potentielle en biomécanique. On a ici fait l'hypothèse que les ondes de choc de cisaillement pourraient jouer un rôle dans la formation de certaines lésions cérébrales suite à un traumatisme crânien, la géométrie du crâne induisant leur focalisation. Ces considérations nous ont conduits à dimensionner les phénomènes étudiés en conséquence, en termes de fréquence, d'amplitude et de géométrie. La focalisation a ainsi été montrée dans le cas d'un gel simulant un tissu biologique. Les comparaisons avec le modèle théorique et numérique se sont avérées favorables. Pour approfondir l'analyse de l'hypothèse, il resterait à prouver que ces ondes de choc peuvent induire des lésions.

Shear shock waves in quasi-incompressible soft solids have been observed experimentally only twelve years ago. They differ from compression shock waves because their nonlinearity is cubic instead of quadratic. Velocities of shear waves are small, of the order of the meter per second, and thus induce a strong nonlinear behavior over small distances. This allows to counter-balance the quite strong absorption in such media. To our knowledge, these shear shock waves have been studied only for plane waves. However, focusing is a fundamental phenomenon in the wave physics and its applications. This is why our objective is to investigate the focusing of shear waves theoretically, numerically, and experimentally. This work was in particular motivated by a potential application in biomechanics. We have hypothesized that shear shock waves could play a role in the formation of some traumatic brain injuries, the geometry of the skull producing the focusing effect. These hypotheses have governed our studies for the choice of the different parameters such as the frequency, the amplitude and the geometry. The focusing has been demonstrated in a biological tissue-mimicking gel. Comparisons with the theoretical and numerical model have shown a good agreement. Further studies should concern the possible formation of lesions by shear shock waves.

Advisors/Committee Members: Coulouvrat, François (thesis director), Pinton, Gianmarco (thesis director).

Subjects/Keywords: Focalisation; Ondes de choc; Cisaillement; Solides mous; Numérique; Expérimental; Focusing; Shear shock waves; Numerical; Wave physics; 534

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Giammarinaro, B. (2016). Focalisation non linéaire des ondes de choc de cisaillement dans les solides incompressibles : Focusing of shear shock waves in incompressible solids. (Doctoral Dissertation). Université Pierre et Marie Curie – Paris VI. Retrieved from http://www.theses.fr/2016PA066054

Chicago Manual of Style (16th Edition):

Giammarinaro, Bruno. “Focalisation non linéaire des ondes de choc de cisaillement dans les solides incompressibles : Focusing of shear shock waves in incompressible solids.” 2016. Doctoral Dissertation, Université Pierre et Marie Curie – Paris VI. Accessed April 19, 2019. http://www.theses.fr/2016PA066054.

MLA Handbook (7th Edition):

Giammarinaro, Bruno. “Focalisation non linéaire des ondes de choc de cisaillement dans les solides incompressibles : Focusing of shear shock waves in incompressible solids.” 2016. Web. 19 Apr 2019.

Vancouver:

Giammarinaro B. Focalisation non linéaire des ondes de choc de cisaillement dans les solides incompressibles : Focusing of shear shock waves in incompressible solids. [Internet] [Doctoral dissertation]. Université Pierre et Marie Curie – Paris VI; 2016. [cited 2019 Apr 19]. Available from: http://www.theses.fr/2016PA066054.

Council of Science Editors:

Giammarinaro B. Focalisation non linéaire des ondes de choc de cisaillement dans les solides incompressibles : Focusing of shear shock waves in incompressible solids. [Doctoral Dissertation]. Université Pierre et Marie Curie – Paris VI; 2016. Available from: http://www.theses.fr/2016PA066054

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