The Origins of the Hopkinson Bar Technique

Walley, S. M.

doi:10.1007/978-3-319-71919-1_1

Cited by 6 publications

(3 citation statements)

References 56 publications

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“…The number of crystalline systems that have been studied is limited, and many commonplace alloys of practical interest lack experimental studies of dislocation mobility, even at low speeds. The challenges for direct measurements of high speed dislocations are many: the loading rates at which they are expected to occur are accessible only through set-ups such as Hopkinson bar [149,150], plate impact [151] or laser shock experiments [152] where in-situ microscopy is difficult. Equally, the required temporal and spatial resolution pushes current imaging capabilities to its limits, particularly for supersonic dislocations.…”

Section: The Three Regimes Of Dislocation Motionmentioning

confidence: 99%

The mechanics and physics of high-speed dislocations: a critical review

Gurrutxaga-Lerma

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Dini

2020

International Materials Reviews

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High speed dislocations have long been identified as the dominant feature governing the plastic response of crystalline materials subjected to high strain rates. They allegedly control deformation and failure response of industrial processes in a large range of applications, including machining, laser shock peening, punching, drilling, crashworthiness, foreign object damage,etc. Despite decades of study, achieving a consensus on the role and influence high speed dislocations have on the materials response observed at the macro-scale by the means of rigorous mechanistic grounding remains elusive. This article reviews both experimental and theoretical efforts made to address this issue in a systematic way. The lack of experimental evidence and direct observation of high speed dislocations means that most work on the matter is rooted on theory and simulations. This article offers a critical review of the competing theoretical accounts of high speed mechanisms, their underlying hypothesis, insights, and shortcomings. It explores the role that the speed of sound plays in the modelling of high speed dislocations, the way dislocations are modelled in the elastic continuum and how this approach can be used to study plasticity at high strain rates. The role atomistic models of dislocations have played in clarifying high speed motion mechanisms, and how they have led to the development of dislocation velocity-stress relations describing dislocation mobility is then also discussed. The article also reviews modelling efforts aimed at describing high speed dislocation mobility, and how different proposed physical mechanisms believed influence the motion. The article closes with an overview of the current state of the art and suggestions for key developments needed to improve our fundamental understanding in future research.

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Section: The Three Regimes Of Dislocation Motionmentioning

confidence: 99%

The mechanics and physics of high-speed dislocations: a critical review

Gurrutxaga-Lerma

Verschueren

Dini

2020

International Materials Reviews

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“…The propagation of the compression wave along the rod (Figure 1), simulating the implementation of the Hopkinson method [18,53], was performed in the ANSYS AutoDyn environment. The optical cladding of the fiber, having a diameter of 125 µm, was replaced by a parallelepiped with a square cross-section (100 µm × 100 µm) made of the same material (i.e., fused quartz) as the cladding of the fiber to simplify modeling.…”

Section: Modeling Of Mechanical Waves In a Rodmentioning

confidence: 99%

Numerical Simulation and Measurement of Deformation Wave Parameters by Sensors of Various Types

Smailov,

Koshkinbayev,

Tashtay

et al. 2023

Sensors

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The results of applications of various methods for measuring the parameters of high-speed loading using a strain gauge, a fiber Bragg grating located on a metal measuring rod and an interferometer monitoring the movement of the free boundary of the end of the rod are presented. Numerical simulation confirmed the adequacy of the description of the shock-wave process according to experimental data and showed that, with the thickness of the adhesive layer fixing the fiber Bragg grating and the strain gauge on a dimensional rod up to 100 µm, the deformation parameters of the sensors correspond to the parameters of the stress–strain state of the rod. Experimentally, a good correspondence of the results of measuring the magnitude of the relative deformation at a pulse duration of 10–100 µs using sensors of various types is shown, and an estimate of the limit values of the measured values of the deformation wave parameters is given.

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“…This has led to Stephen to writing a number of published research reviews on a wide range of topics including: experimental methods at high rates of strain [76,77], elastic wave propagation in materials [78,79], impact sensitivity of explosives [67,80], shear localization [81,82], indentation hardness [83] solid particle erosion [14], and the high rate properties of ceramics [84] and glasses [85]. This set Stephen up well for his retirement where he has continued to write historical reviews on various topics to do with the high-rate mechanical properties of materials [86][87][88][89][90][91][92].…”

Section: Stephen M Walley Research Associate Cavendish Laboratory University Of Cambridge Phd Awarded 1982-erosion Of Polyethylene By Solmentioning

confidence: 99%