GROUND SHOCK ISOLATION OF BURIED STRUCTURES

1959 ◽  
Author(s):  
Eugene Sevin
Keyword(s):  
Buried Structures ◽  
Shock Isolation ◽  
Ground Shock

A Doubly Asymptotic, Nonreflecting Boundary for Ground-Shock Analysis

1987 ◽  
Vol 54 (3) ◽  
pp. 489-497 ◽  
Author(s):  
I. C. Mathews ◽  
T. L. Geers
Keyword(s):  
Finite Element ◽  
Mass Matrix ◽  
Equations Of Motion ◽  
Element Model ◽  
Solution Procedure ◽  
Buried Structures ◽  
Soil Medium ◽  
First Order ◽  
Ground Shock ◽  
Limiting Value

This paper desribes the formulation and implementation of a nonreflecting boundary for use with existing finite-element codes to perform nonlinear ground-shock analyses of buried structures. The boundary is based on a first-order doubly asymptotic approximation (DAA1) for disturbances propagating outward from a selected portion of the soil medium surrounding the structure of interest. The resulting set of first-order ordinary differential equations is then combined with the second-order equations of motion for the finite-element model so as to facilitate solution by a staggered solution procedure. This procedure is shown to be computationally stable as long as the time increment is smaller than a limiting value based on the finite-element mass matrix and the DAA-boundary stiffness matrix. Computational results produced by the boundary are compared with exact results for linear canonical problems pertaining to infinite-cylindrical and spherical shells.

scholarly journals Experimental and Numerical Investigation of the Ground Shock Coupling Factor for Near-Surface Detonations

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Timothy W. Shelton ◽  
John Q. Ehrgott ◽  
Ramon J. Moral ◽  
Michele Barbato
Keyword(s):  
Numerical Simulations ◽  
Coupling Factor ◽  
Shock Propagation ◽  
Buried Structures ◽  
Near Surface ◽  
Ground Shock ◽  
Particle Velocities ◽  
Development Center ◽  
Depth Of Burial ◽  
Physical Quantities

This paper presents the results of recent ground shock experiments conducted by the U.S. Army Engineer Research and Development Center to further investigate the adequacy of the coupling factor approach to shallow-buried or near-surface detonations. Comparisons between these recent experimental results and results of numerical simulations of the ground shock propagation in soil are presented. It was found that the coupling factor curve currently adopted in design of buried structures does not accurately represent the actual ground shock propagation in soil and that different coupling factor curves are needed for different physical quantities of interest in design. The results presented in this paper also suggest that the coupling factor curves are functions of several parameters in addition to the depth of burial and that numerical simulations can capture reasonably well the ground shock propagation of soil stresses and particle velocities.

An Infrared Microscope for Use on a Focused Ion Beam for Circuit Edit and Backside Edit Applications

2015 ◽  
Author(s):  
Alexander Richards ◽  
Matthew Weschler ◽  
Michael Durller
Keyword(s):  
Focused Ion Beam ◽  
Near Infrared ◽  
Ion Beam ◽  
Visible Spectrum ◽  
Camera System ◽  
Buried Structures ◽  
Ir Camera ◽  
Area Of Interest ◽  
Near Ultraviolet ◽  
Infrared Microscope

Abstract To help solve the navigational problem, i.e., being able to successfully locate a circuit for probing or editing without destroying chip functionality, a near-infrared (NIR), near-ultraviolet (NUV), and visible spectrum camera system was developed that attaches to most focused ion beam (FIB) or scanning electron microscope vacuum chambers. This paper reviews the details of the design and implementation of the NIR/NUV camera system, as instantiated upon the FEI FIB 200, with a particular focus on its use for the visualization of buried structures, and also for non-destructive real time area of interest location and end point detection. It specifically considers the use of the micro-optical camera system for its benefit in assisting with frontside and backside circuit edit, as well as other typical FIB milling activities. The quality of the image obtained by the IR camera rivals or exceeds traditional optical based imaging microscopy techniques.

Guaranteeing Anticipating Control in a Shock Isolation Problem

2018 ◽  
Vol 481 (4) ◽  
pp. 381-385
Author(s):  
N. Bolotnik ◽  
◽  
V. Korneev ◽  
Keyword(s):  
Shock Isolation

Monte Albán's Hidden Past: Buried Buildings and Sociopolitical Transformation

2020 ◽  
pp. 1-23
Author(s):  
Marc N. Levine ◽  
Scott W. Hammerstedt ◽  
Amanda Regnier ◽  
Alex E. Badillo
Keyword(s):  
Ground Penetrating Radar ◽  
Electrical Resistance ◽  
Early History ◽  
Buried Structures ◽  
Systematic Survey ◽  
Monte Alban ◽  
Ground Penetrating ◽  
Shed Light

In this article, we present the most significant results of the Monte Albán Geophysical Archaeology Project. Using ground-penetrating radar, gradiometry, and electrical resistance, we carried out a systematic survey of the site's Main Plaza to identify buried prehispanic features that might shed light on Monte Albán's early history. The most important discoveries include three buried structures dating between the Danibaan (500–300 BC) and Nisa phases (100 BC–AD 100). We argue that the largest structure, measuring 18 × 18 m, was probably a temple platform and that all three of the structures were razed and buried by the end of the Nisa phase at the latest. Furthermore, we contend that these events were part of a major renovation and expansion of the site's Main Plaza that occurred during a pivotal period of dramatic sociopolitical transformation in the Zapotec capital.

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