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Gernold Zulauf - One of the best experts on this subject based on the ideXlab platform.
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Rheology of Plasticine used as rock analogue: the impact of temperature, composition and strain
Journal of Structural Geology, 2004Co-Authors: J. Zulauf, Gernold ZulaufAbstract:Abstract Uniaxial compression tests have been carried out to determine the temperature-dependent rheology of Plasticine commonly used for tectonic modelling. The original Plasticine types ( Kolb brown , Beck's orange , Beck's green , Weible special soft ) are characterized by strain-rate softening with power law exponents ( n ) and apparent viscosities ( η ) ranging from 5.8 to 7.3 and 3.4×10 5 to 2.2×10 7 Pa s, respectively (if e =10%, Ė =4×10 −3 s −1 , and T =25 °C). Beck's orange shows steady-state creep, whereas the other types show strain hardening. The activation energy, determined for 20 °C≤ T ≤35 °C, is ranging from 323±34 to 488±22 kJ mol −1 . A rise in temperature results in linear decreases of n and η and a reduction in the degree of strain hardening. Steady-state creep and major changes in n and η have further been observed at decreasing filler-matrix ratios, the latter being obtained by adding oil to the original Plasticine. The new results suggest that Plasticine can be used to model the deformation of natural rocks undergoing dislocation creep. Various rock analogues with strain hardening or steady-state creep, and prescribed stress exponents ranging from 3.4 to 12.3, can be easily produced by changing the temperature and/or the filler-matrix ratio of commercial Plasticine types.
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Strain-dependent rheology and the memory of Plasticine
Tectonophysics, 2002Co-Authors: Martin P. J. Schöpfer, Gernold ZulaufAbstract:Abstract Plasticine and Plasticine-like materials have been widely used as analogue materials for experimental deformation, but not many workers have conducted detailed investigations on their rheology. The physical properties of Beck's green and black Plasticine , a modelling material made in Gomaringen, Germany, and Plasticine/oil mixtures were investigated by means of uniaxial compression and relaxation tests. Beck's Plasticine is a non-Newtonian fluid characterised by strain rate-dependent plastic yielding and strain hardening. Strain hardening is more pronounced at low strain rates leading to an increase of both stress exponent and viscosity. The addition of oil leads to an increase of the stress exponent and a decrease in viscosity. The strain dependence of viscosity decreases with increasing oil content. Compression tests on preflattened Plasticine were also conducted in order to study possible ‘strain memory’ of the materials. Preflattened Plasticine is characterised by a later onset of yielding and an increase in both stress exponent and viscosity. Our results suggest that Beck's green and black Plasticine is a suitable analogue material for modelling rocks that deform by dislocation creep and exhibit pronounced strain hardening. Nevertheless, plane strain modelling of boudinage has verified analytical solutions for the dominant wavelength at viscosity contrasts of approximately 1.5 and 2.5.
W Webb - One of the best experts on this subject based on the ideXlab platform.
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the use of Plasticine as an analog to explore material flow in friction stir welding
Journal of Materials Processing Technology, 2007Co-Authors: C Liechty, W WebbAbstract:This study investigates Plasticine for use as an analog for modeling material flow in friction stir welding of metals. Different colors of Plasticine are combined in a weld to aid in flow visualization. Several welds are performed in the Plasticine under various rotational speeds and with both a threaded and smooth pin tool. The transient temperature response of the Plasticine shows the same qualitative behavior as welds conducted in metals. Although temperature increases inside the weld region are small during welding of the Plasticine, compression tests show that a relatively small increase in temperature of the clay results in a significant reduction in flow stress. The Plasticine welds are compared to previous visualization data from welds conducted in metals. Transverse sections cut from Plasticine welds show that at a low tool rotational speed, large-scale mixing is absent and the original interface between advancing and retreating side workpieces is clearly discernable. This interface line matches well with a map of the post-welding interface line from an aluminum weld using a marker insert technique. Motion of material in the welding direction is also observed by inserting contrasting color Plasticine markers into the workpiece. The motion of the markers is verified by a similar marker insert technique using aluminum. At high rotational speeds, material rotates several times around the pin, traveling forward with it. Significant vertical motion during welding is also observed in the Plasticine.
Wenbo Chen - One of the best experts on this subject based on the ideXlab platform.
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time and strain rate effects on viscous stress strain behavior of Plasticine material
International Journal of Geomechanics, 2017Co-Authors: Weiqiang Feng, Fei Tong, Wenbo ChenAbstract:AbstractA Plasticine material exhibits the characterized viscous stress–strain behavior with some similarity to the behavior of clayey soils. This paper presents a series of experimental tests, which include oedometer tests, isotropic creep tests, and triaxial multistrain rate compression tests, on a Plasticine material. The test study focuses on effects of time and strain rate on viscous stress–strain behavior of the Plasticine material under one-dimensional (1D) straining, isotropic stressing, and triaxial compression conditions. Values of compression index (Cce), rebounding index (Cre), and creep coefficient (Cαe) are obtained from the 1D straining and 1D stressing test data. The Plasticine material has no primary consolidation period, and creep occurs from the beginning. Values of Cce, Cre, and Cαe are smaller than those of the soft clays. The triaxial multistrain rate compression test data show that the stress–strain behavior of the Plasticine depends on the strain rates and the confining pressures. ...
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Time and Strain-Rate Effects on Viscous Stress–Strain Behavior of Plasticine Material
International Journal of Geomechanics, 2017Co-Authors: Weiqiang Feng, Fei Tong, Wenbo ChenAbstract:AbstractA Plasticine material exhibits the characterized viscous stress–strain behavior with some similarity to the behavior of clayey soils. This paper presents a series of experimental tests, which include oedometer tests, isotropic creep tests, and triaxial multistrain rate compression tests, on a Plasticine material. The test study focuses on effects of time and strain rate on viscous stress–strain behavior of the Plasticine material under one-dimensional (1D) straining, isotropic stressing, and triaxial compression conditions. Values of compression index (Cce), rebounding index (Cre), and creep coefficient (Cαe) are obtained from the 1D straining and 1D stressing test data. The Plasticine material has no primary consolidation period, and creep occurs from the beginning. Values of Cce, Cre, and Cαe are smaller than those of the soft clays. The triaxial multistrain rate compression test data show that the stress–strain behavior of the Plasticine depends on the strain rates and the confining pressures. ...
Hasan Sofuoglu - One of the best experts on this subject based on the ideXlab platform.
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A technical note on the role of process parameters in predicting flow behavior of Plasticine using design of experiment
Journal of Materials Processing Technology, 2006Co-Authors: Hasan SofuogluAbstract:Abstract Since different colors of Plasticine, used to simulate metal forming processes (MFP), are manufactured by adding various agents to a base material, they are different in composition, mechanical properties and in their response to the deformation loads. In addition to selecting appropriate materials and controlling the deformation speed of process, we can also select metal forming lubricants to effectively reduce friction at the interface of die/workpiece. The true characteristics of Plasticine were first clearly identified by designing the compression experiments via 2 k factorial design method with lubrication type, deformation speed, and material type (color) as the main process factors. The obtained data were then analyzed by using analysis of variance (ANOVA) method. The results of this statistical study showed that color of Plasticine, lubricant type used at the interfaces of the die/workpiece and deformation speed of process had a significant and positive effects on the flow behavior of Plasticine as well as two-factor interactions.
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Physical and numerical analysis of three dimensional extrusion process
Computational Materials Science, 2004Co-Authors: Hasan Sofuoglu, Hasan GedikliAbstract:Abstract Three dimensional extrusion process was simulated by utilizing physical modeling technique and numerical method based on the finite element analysis. Plasticine, a soft modeling material, which shows elastic–plastic flow behavior, and conical die were used in the extrusion process for both physical and numerical simulations. The extrusion billet was made from alternating slabs of black and stone color of Plasticine to generate internal grid pattern for the extrusion process. In the finite element analysis, the elastic–plastic behavior was assumed for material and true stress–true strain relation was presented in the form of well-known power law (Holloman) equation. During the extrusion of Plasticine, the extrusion load as a function of ram position and the strain distributions at different extrusion ratios (R) and different semi-cone die angles (α) were obtained from both simulations throughout this study. The obtained experimental and numerical results for the extrusion load showed that they were in good agreement and there were enough reasons for flow behavior of Plasticine to be assumed elastic–plastic.
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Three-dimensional analysis of extrusion process utilizing the physical modeling technique
Journal of Energy Resources Technology-transactions of The Asme, 1993Co-Authors: Hasan Sofuoglu, Jahan RastyAbstract:The purpose of this study was to simulate the metal extrusion processes via three-dimensional physical modeling technique. Plasticine was utilized as the modeling material, while plexiglass was incorporated in the design and fabrication of a lab scale extrusion apparatus. The extrusion setup was designed to accommodate dies of different semi-cone angle while also making it possible to change the extrusion ratio R. Cylindrical billets were prepared utilizing alternating layers of two colors of Plasticine. Extrusion of cylindrical billets was conducted at three different reduction ratios and three different die angles for each reduction ratio. Dissection of the extruded billets along a centroidal plane revealed the internal deformation patterns which were subsequently utilized for determining the effect of the die angle and extrusion ratio on the state of strain in the final product as well as the required extrusion loads.
Weiqiang Feng - One of the best experts on this subject based on the ideXlab platform.
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time and strain rate effects on viscous stress strain behavior of Plasticine material
International Journal of Geomechanics, 2017Co-Authors: Weiqiang Feng, Fei Tong, Wenbo ChenAbstract:AbstractA Plasticine material exhibits the characterized viscous stress–strain behavior with some similarity to the behavior of clayey soils. This paper presents a series of experimental tests, which include oedometer tests, isotropic creep tests, and triaxial multistrain rate compression tests, on a Plasticine material. The test study focuses on effects of time and strain rate on viscous stress–strain behavior of the Plasticine material under one-dimensional (1D) straining, isotropic stressing, and triaxial compression conditions. Values of compression index (Cce), rebounding index (Cre), and creep coefficient (Cαe) are obtained from the 1D straining and 1D stressing test data. The Plasticine material has no primary consolidation period, and creep occurs from the beginning. Values of Cce, Cre, and Cαe are smaller than those of the soft clays. The triaxial multistrain rate compression test data show that the stress–strain behavior of the Plasticine depends on the strain rates and the confining pressures. ...
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Time and Strain-Rate Effects on Viscous Stress–Strain Behavior of Plasticine Material
International Journal of Geomechanics, 2017Co-Authors: Weiqiang Feng, Fei Tong, Wenbo ChenAbstract:AbstractA Plasticine material exhibits the characterized viscous stress–strain behavior with some similarity to the behavior of clayey soils. This paper presents a series of experimental tests, which include oedometer tests, isotropic creep tests, and triaxial multistrain rate compression tests, on a Plasticine material. The test study focuses on effects of time and strain rate on viscous stress–strain behavior of the Plasticine material under one-dimensional (1D) straining, isotropic stressing, and triaxial compression conditions. Values of compression index (Cce), rebounding index (Cre), and creep coefficient (Cαe) are obtained from the 1D straining and 1D stressing test data. The Plasticine material has no primary consolidation period, and creep occurs from the beginning. Values of Cce, Cre, and Cαe are smaller than those of the soft clays. The triaxial multistrain rate compression test data show that the stress–strain behavior of the Plasticine depends on the strain rates and the confining pressures. ...
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Experimental Study on the Behavior of a Plasticine Material
Springer Series in Geomechanics and Geoengineering, 2014Co-Authors: Weiqiang Feng, Fei Tong, Xiaoming Tao, Jian-hua YinAbstract:This paper presents an experimental study, which includes the oedometer test and isotropic creep test, on the compressibility and the creep effect of the Plasticine materials. The Compression Index (Cce), Rebounding Index (Cre) and creep coefficient (C αe ) are obtained from the test results. However, it can be observed that there is almost no loop in unloading-reloading stages of stress-strain relationship, which is different from most soil test results. By means of the Scanning Electron Microscope, it could be found that the compression of the Plasticine is mainly due to the porosity decrease and the structure flocculence, which is nonrecoverable.