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Fragmentation of Rings and Shells

Author: Dennis Grady

Publisher: Springer Science & Business Media

Published: 2007-07-13

Total Pages: 375

ISBN-13: 3540271457

For a brief period during the latter part of World War II, Nevill F. Mott led a theoretical group at Fort Halstead in the United Kingdom that tackled scientific issues related to pressing war-time concerns. Among later awards and honors, Mott was knighted and a recipient of the Nobel Prize. While at Fort Halstead, he undertook an effort to theoretically describe the statistical fragmentation of munitions subjected to intense explosive loading. Mott`s original internal reports contain seminal theoretical concepts on the physics and statistics of dynamic fracture and fragmentation, which have provided the inspiration for numerous later modeling efforts and engineering formulae. Some of his most forward-looking thoughts on the micromechanical and molecular aspects of fracture are included in these publications. The present book surveys the theoretical analysis put forth by Mott with particular focus on his efforts to characterize the size and distribution of fragments resulting from a dynamic fragmentation event. Copies of the original internal reports of Mott and his co-workers are included. The book also pursues additional theoretical analysis with the intent of delving further into the physical ideas and unfinished analysis implicit in Mott`s original studies. This book will be of interest to all scientists and engineers concerned with the dynamic fracture and fragmentation of solid bodies subject to intense transient loads imparted by explosive detonation and high-velocity impact from both the historical and modern perspective.

Expansion and Fragmentation

Author: Kees van Kersbergen

Publisher: Amsterdam University Press

Published: 1999

Total Pages: 244

ISBN-13: 9789053564271

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Is the end of the nation-state approaching, now that the international economy takes less and less notice of borders between countries and the European Union has already acquired so much political power? What does national autonomy mean when governments delegate any number of powers to inter-national organizations? Internationalization leads to political change, and the position of the nation-state appears to be undergoing a radical process of erosion. The surprising conclusion of this book is that the political significance of the state will not be lost. The analyses show that both expansion and fragmentation of political power are characteristics of fundamental political change. While it is true that the state is delegating authority and that internationalization is limiting autonomy, the state is also finding new forms of cooperation and coordination, both nationally and internationally, to preserve and even to strengthen its power and autonomy. Contrary to widely held assumptions, the idea of a progressive weakening of the nationstate does not prove tenable.

Heathland fragmentation and the potential for expansion

Author: N R. Webb

Publisher:

Published: 1993

Total Pages:

ISBN-13:

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Cylinder Expansion (Gurney Constant) and Warhead Fragmentation. Part 2. Computerized Data Reduction

Author:

Publisher:

Published: 1972

Total Pages: 78

ISBN-13:

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Development of a cylinder expansion test for use in assessing the metal acceleration capability of explosives is discussed. A precisely manufactured metal cylinder is filled with explosive, and its wall expansion during detonation is observed with a streak camera. The photographic record of the cylinder expansion is analyzed by mechanized film reading and high speed computer techniques. The maximum velocity attained by the wall fragments is taken as a measure of the momentum imparted to the metal by the explosive. Both manual and automated methods of data reduction for attainment of test results are given. When standardized, this test procedure will permit the correlation of the evaluations of explosive compounds between laboratories. The computerized reduction of the pictorial data to tabular listings and graphic displays is also discussed.

Generalized Many-body Expansion

Author: Kuan-Yu Liu

Publisher:

Published: 2019

Total Pages: 105

ISBN-13:

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In this work, we explore several promising aspects of generalized many-body expansion (GMBE) for computing energies and energy responses of large systems. The GMBE is recognized as one of the fragment-based methods and provides a unified view of those methods in electronic structure theory. The four elements shared by other fragment-based methods include a fragmentation method, a capping method, an embedding method, and the number of layer. We utilize the last two elements as well as the screening to approximate the non-additive many-body interactions. We found that energy-based thresholding affords linear scaling and high accuracy without embedding and multi-layer approximations. For the charge embedding scheme, the variational electrostatic embedded one-body approximation alongside symmetry-adapted perturbation theory proves promising for non-covalent interactions with the newly implemented modified Hirshfeld population analysis. We are able to reduce the cost for calculation the charge response term without compromising accuracy. The two prominent results of the GMBE show that we can apply this fragment-based method to relatively large systems due to its excellent parallel ability. Since the preliminary results of frequency calculations show the robustness of finite difference implementation, we are also looking forward to applying this methodology to energy responses such as spectroscopies.

Governance Fragmentation and Urban Spatial Expansion

Author: Silvia Beghelli

Publisher:

Published: 2019

Total Pages:

ISBN-13:

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This study assesses the effects of urban governance structure on the spatial expansion of metropolitan areas. A more fragmented governance structure, represented by a high number of administrative units with decision power on land use per inhabitant, is expected to increase the competition between small towns in the suburbs of metropolitan areas to attract households and workers, which, in turn, induces more land uptake. We study empirically the relationship between administrative fragmentation and the spatial size of cities in a sample of 180 metropolitan areas in the contexts of the US and Europe in the period 2000-2012. Results shed light on the structural differences between the two broad regions and suggest that administrative fragmentation impacts positively on land uptake in both the United States and Europe, although to different extents.

A Fragmentation Model for Cylindrical Warheads

Author: John Pearson

Publisher:

Published: 1990

Total Pages: 49

ISBN-13:

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This report presents a descriptive model for the expansion and fragmentation behavior for the case of a single-point, end-initiated cylindrical warhead. This model divides the overall behavioral process of the warhead case into four distinct zones of behavior which occur between initial case motion and fragment impact. The report describes what is happening in each zone in terms of (1) the physical behavior of the warhead case and (2) the respective velocities of the metal case or fragments. This model is based on the results of numerous experimental studies using high speed photography and fragmentation test arenas. Several examples in the use of the model are presented based on these studies.