List of Contributors

Bai, Yun; Batra, R.C.; Dai, L.H.; Dodd, Bradley; Couque, H.; Meyer, Lothar; Meyers, Marc A.; Pursche, Frank; Sulem, Jean; Swallowe, G. M.; Walley, S. M.; Wright, Thomas W.; Xu, Yuanyuan

doi:10.1016/b978-0-08-097781-2.00017-4

Cited by 2 publications

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“…These strips go along the direction of rolling of the copper rod and look like small depressions consisting mainly of small grains less than 3 µm in size, as shown in Figure 8 . It is well known from the literature that up to 90% of the entire plastic deformation of the material can be concentrated in shear bands, whose formation is of great interest [ 96 , 97 , 98 , 99 , 100 ]. Shear bands have a complex structure of strongly deformed material and contain structures of dislocations and nanocrystalline grains [ 101 , 102 , 103 , 104 , 105 ].…”

Section: Resultsmentioning

confidence: 99%

Modified Taylor Impact Tests with Profiled Copper Cylinders: Experiment and Optimization of Dislocation Plasticity Model

et al. 2023

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Current progress in numerical simulations and machine learning allows one to apply complex loading conditions for the identification of parameters in plasticity models. This possibility expands the spectrum of examined deformed states and makes the identified model more consistent with engineering practice. A combined experimental-numerical approach to identify the model parameters and study the dynamic plasticity of metals is developed and applied to the case of cold-rolled OFHC copper. In the experimental part, profiled projectiles (reduced cylinders or cones in the head part) are proposed for the Taylor impact problem for the first time for material characterization. These projectiles allow us to reach large plastic deformations with true strains up to 1.3 at strain rates up to 105 s−1 at impact velocities below 130 m/s. The experimental results are used for the optimization of parameters of the dislocation plasticity model implemented in 3D with the numerical scheme of smoothed particle hydrodynamics (SPH). A Bayesian statistical method in combination with a trained artificial neural network as an SPH emulator is applied to optimize the parameters of the dislocation plasticity model. It is shown that classical Taylor cylinders are not enough for a univocal selection of the model parameters, while the profiled cylinders provide better optimization even if used separately. The combination of different shapes and an increase in the number of experiments increase the quality of optimization. The optimized numerical model is successfully validated by the experimental data about the shock wave profiles in flyer plate experiments from the literature. In total, a cheap, simple, but efficient route for optimizing a dynamic plasticity model is proposed. The dislocation plasticity model is extended to estimate grain refinement and volume fractions of weakened areas in comparison with experimental observations.

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Section: Resultsmentioning

confidence: 99%

Modified Taylor Impact Tests with Profiled Copper Cylinders: Experiment and Optimization of Dislocation Plasticity Model

et al. 2023

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“…Also the failure mode can be affected by the strain-rate. This is the case for the titanium alloy Ti-6Al-4V which is known to be very sensitive for the formation of adiabatic shear bands (ASB) and subsequent failure [1,2]. This is mainly due to its low density and heat conduction.…”

Section: Introductionmentioning

confidence: 99%

High-Strain-Rate Shear Testing Applied to Ti-6Al-4V

Peirs

Verleysen

Degrieck

2010

AMR

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In this contribution, two experimental techniques to study the dynamic shear behaviour of metals are presented and applied to Ti-6Al-4V. For bulk materials hat-shaped specimens are subjected to a high-strain-rate load in a split Hopkinson compression bar set-up. For sheet materials a purpose-developed, novel shear specimen geometry, is loaded in a Hopkinson tensile bar set-up. The value of both techniques to assess the dynamic material behaviour is discussed. The experiments are optimized by means of numerical simulations. Digital image correlation is used to extract the specimen deformation from high speed camera recordings. It is shown that the dynamic behaviour, including fracture of Ti-6Al-4V differs considerably from the static behaviour. Both experimental techniques gain complementary information.

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Cited by 2 publications

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Modified Taylor Impact Tests with Profiled Copper Cylinders: Experiment and Optimization of Dislocation Plasticity Model

Modified Taylor Impact Tests with Profiled Copper Cylinders: Experiment and Optimization of Dislocation Plasticity Model

High-Strain-Rate Shear Testing Applied to Ti-6Al-4V

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