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G. E. Hudson

Bio: G. E. Hudson is an academic researcher. The author has contributed to research in topics: Deformation (engineering) & Diaphragm (mechanical device). The author has an hindex of 1, co-authored 1 publications receiving 54 citations.

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TL;DR: In this paper, a theory was developed in an attempt to describe the observed motion and plastic deformation of clamped metal diaphragms used in certain underwater explosion experiments and in certain mechanical gauges.
Abstract: The theory presented in this article was developed in an attempt to describe the observed motion and plastic deformation of clamped metal diaphragms used in certain underwater explosion experiments and in certain mechanical gauges. The theoretical attack on this problem enables one to set up certain equations of motion, which may be solved in finite form under certain conditions. The solutions enable one to specify, for instance, the final deformed diaphragm profile, the distribution of thickness after deformation, the swing‐time, which is the total time for deformation to take place, and many other quantities.The simplest case, termed the ``elementary approximation,'' turns out, except for relatively minor details, to describe adequately for many purposes the motion and final shape of the diaphragm; it is found that the deformed diaphragm shape is conical, the thickness distribution shows a marked dimpling at the center of the diaphragm, and the swing‐time ts is, to this order of approximation tS=a/c, wh...

56 citations


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TL;DR: In this article, the theoretical predictions and experimental work on the deformation of thin plates subjected to impulsive loading are reviewed. But the experimental results are not discussed. And the experimental correlations between the deflection-thickness ratio and a function of impulse, plate geometry, plate dimensions and material properties are discussed.

233 citations

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TL;DR: In a previous report, it was demonstrated that the forming limits of BCC interstitial free iron could be significantly increased by forming at high strain rates which were induced using a technique known as electrohydraulic forming as discussed by the authors.
Abstract: In a previous report it was demonstrated that the forming limits of BCC interstitial free iron could be significantly increased by forming at high strain rates which were induced using a technique known as electrohydraulic forming In that report two possible reasons for the increased formability were discussed: (1) a change in the material constitutive law at high rate, making it more formable, and (2) inertial forces slowing the growth of imperfections Because the material's hardness was similar at the same strains at low and high rates, and inertial forces were demonstrably large, it was suggested that inertial effects were likely to be responsible for the increased forming limits Here, more evidence is presented that inertial forces are responsible for the formability increase and it is suggested that this effect is both large and general Specifically the authors have used similar procedures to examine two FCC materials (annealed and quenched 6061 aluminum and annealed oxygen-free high-conductivity (OFHC) copper) Both these materials show very similar increases in formability at high workpiece velocities A simple model is presented that shows that high workpiece velocities are expected to increase forming limits The required velocities are accessible with existing technology

198 citations

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TL;DR: In this paper, the authors report the results of formability testing of dual phase steels in EHF conditions and provide an explanation of the observed formability improvement based on analysis of the experimental results and through the use of a modeling technique developed as part of this work for simulating the EHF process.

103 citations

Journal ArticleDOI
TL;DR: In this paper, it was shown that very large increases in the formability of three materials are observed in the electrohydraulic forming of a conical section and moderate increases are observed by the electromagnetic expansion of aluminum rings.

103 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigate the mechanics of deformation localization and fragmentation in ductile materials at strain rates between 4000 and 15,000 s−1, using the expanding ring experiment as the primary tool for examining the material behavior in this range of strain rates.
Abstract: In this series of papers, we investigate the mechanics of deformation localization and fragmentation in ductile materials. The behavior of ductile metals at strain rates between 4000 and 15,000 s−1 is considered. The expanding ring experiment is used as the primary tool for examining the material behavior in this range of strain rates. In Part I, the details of the experiment and the experimental observations on Al 6061-O were reported. Statistics of necking and fragmentation were evaluated and the process was modeled through the idea of the Mott release waves both from necking and fragmentation. Finally, it was shown that the strain in the ring in regions that strained uniformly never exceeded the necking strain. In the present paper, Part II, we address the issue of strain hardening and strain-rate sensitivity. Specifically, we examine different materials—Al 1100-H14, and Cu 101—in order to determine the role of material constitutive property on the dynamics of necking. These experiments reinforce the conclusion presented in Part I that the onset of necking essentially terminates the possibility of further straining in other parts of the ring and even more importantly that there is no influence of material inertia on the strain at the onset of necking in this wide range of materials. Furthermore, the effect of aspect ratio of the specimen is evaluated; this reveals that as the aspect ratio increases beyond about five, in addition to or instead of diffuse necking, localization into the sheet necking mode is observed; in this mode, the effect of ring expansion speeds is demonstrated to result in an increase of the strain at the onset of localization. In addition, an absolute size effect is observed: larger specimens exhibit localization at larger strain levels. These observations are explained in terms of plastic wave propagation and reproduced with finite element simulations. In future contributions as part of this sequel, we will explore the effect of other geometrical constraints and the effect of a compliant cladding or coating on the development of necking and fragmentation.

86 citations