Mathematical modeling and dimensional analysis

1992 ◽  
pp. 93-119
Author(s):  
J. Molenaar
Author(s):  
Matthew Pope ◽  
Bradley Martin ◽  
David Lambert ◽  
Stanley E. Jones ◽  
Jonathan Muse

A “soft catch” is a device with which an explosively formed projectile can be decelerated to zero velocity without sustaining significant damage. The recovered projectile provides data, via metallurgical analysis, on the deformation conditions found within the explosively formed projectile. At Eglin AFB, FL, the soft catch consists of a sequence of sections (Figures 1–3), each roughly one meter long, filled with various soft media. Velocity screens are placed at the entrance and exit of each section. This enables investigators to experimentally determine the time at which the projectile passes each station in the catch. Based on these experimental measurements, average velocity estimates for each section of the soft catch can be made. The purpose of this paper is to support the soft catch design process with a one-dimensional analysis. The mathematical modeling is based on observations presented in studies by Allen, Mayfield, and Morrison [1,2]. Their work addresses the penetration of sand, but their modeling is appropriate for materials in the soft catch. The current paper describes application of their model to interpreting three soft catch experiments where Tantalum projectiles with initial velocities of approximately 1400 m/s were successfully recovered.


Author(s):  
S. Naka ◽  
R. Penelle ◽  
R. Valle

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.


2009 ◽  
Author(s):  
Rumi Price ◽  
Gregory Widner ◽  
William True ◽  
Monica Matthieu

2015 ◽  
Vol 46 (S 01) ◽  
Author(s):  
R. Lampe ◽  
N. Botkin ◽  
V. Turova ◽  
T. Blumenstein ◽  
A. Alves-Pinto

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