The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Michael Kaliske - One of the best experts on this subject based on the ideXlab platform.
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A thermo-mechanical material model for rubber curing and tire manufacturing simulation
Computational Mechanics, 2020Co-Authors: Thomas Berger, Michael KaliskeAbstract:In this contribution, the phase change of unvulcanized to vulcanized rubber is described by a thermo-mechanical material model within the finite element method (FEM) framework. Before the Vulcanization Process (curing), rubber exhibits an elasto-visco-plastic behaviour with significant irreversible deformations without a distinct yield surface. After exposing rubber to high temperature, the molecular chains build-up crosslinks among each other and its mechanical behaviour changes to stiffer viscoelastic material. The proposed model assumes, that both phases are present during the Vulcanization Process. The ratio changes from the uncured phase at the beginning to the cured phase according to the current state of cure. A constitutive curing formulation is introduced into the model, to capture the shape change during the Vulcanization and to ensure, that the second law of thermodynamics is fulfilled. A multiplicative split of the deformation gradient is assumed to describe incompressible material. Thermal expansion due to the change of temperature is taken into account in the volumetric part, as well as shrinkage during the Vulcanization Process. In the isochoric part, the phase change from elasto-visco-plastic to viscoelastic material is described by micro-macro transition based on the micro-sphere model. The consistent formulation of the material model and its tangent are important for a successful implementation into a three-dimensional finite strain FEM framework. The capabilities of the model are shown by the simulation of an axisymmetric tire production Process starting at the green tire inserted into the heating press up to a post-cure inflation step.
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A thermo-mechanical finite element material model for the rubber forming and Vulcanization Process: From unvulcanized to vulcanized rubber
International Journal of Solids and Structures, 2020Co-Authors: Q. Adam, R. Behnke, Michael KaliskeAbstract:Abstract In this contribution, the transition in the thermo-mechanical properties of unvulcanized rubber during the Vulcanization (curing) Process is modeled by a material model for unvulcanized and vulcanized rubber (two-phase material) in the context of finite strain thermo-mechanics within the finite element method (FEM). For the Vulcanization rate, a constitutive approach with few parameters is proposed representing the monotonic increase of the degree of Vulcanization as a function of current temperature and the curing history. The material model taking into account the two phases of rubber uses different constitutive approaches for the isochoric part and the volumetric part for which a multiplicative split of the deformation gradient is considered. The isochoric part of the model consists of a hyperelastic spring and a dashpot device in series forming a Maxwell element with properties depending on the degree of Vulcanization and temperature. Inelastic isochoric deformations during the forming and Vulcanization Process of rubber parts can be captured. The volumetric part consists of a hyperelastic spring and takes into account volume changes due to mechanical loads and temperature variations (thermal expansion). The proposed material model is formulated based on the displacement field, the temperature field, the degree of Vulcanization and its kinetics. It is implemented into the thermo-mechanically coupled framework of the FEM in 3D for finite strains.
L-q. Zhang - One of the best experts on this subject based on the ideXlab platform.
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Micro-structural evolution of rubber/clay nanocomposites with Vulcanization Process
Express Polymer Letters, 2011Co-Authors: L-x. Mao, L-q. ZhangAbstract:Brominated isobutyl-isoprene rubber/clay nanocomposite (BIIRCN) and ethylene-propylene-diene-monomer rubber/clay nanocomposite (EPDMCN) were prepared by melt blending. The micro-structural evolution of these two kinds of rubber/clay nanocomposites (RCNs) with Vulcanization Process was investigated using wide-angle X-ray diffraction (WAXD) and transmission electron microscope (TEM). The WAXD results revealed that the intercalated structure of organically modified clay (OMC) changed throughout the whole curing Process. The intercalated structure kept on chang- ing beyond the Vulcanization stage of T90. The interlayer space of intercalated silicate in uncured BIIRCN is larger than that in uncured EPDMCN. However, the intercalated structure for EPDMCN changed by a larger extent than that for BIIRCN during the Vulcanization Process, and the interlayer space of the intercalated structure is larger in the cured EPDMCN than that in the cured BIIRCN. It was found that the intercalant (i.e., octadecylamine, ODA) for OMC could shorten the scorch time of the curing reaction, and increase the curing rate, which was attributed to the further intercalation during vulcaniza- tion. TEM results indicated that the spatial distribution of OMC is much better in BIIR (a polar rubber matrix) than that in EPDM (a non-polar rubber matrix). The changes in spatial dispersion structure during Vulcanization for EPDMCN and BIIRCN show different trends. In conclusion, the polarity of the rubber is the determining factor influencing the evolution of both the intercalated structure and the spatial dispersion of clay during Vulcanization.
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micro structural evolution of rubber clay nanocomposites with Vulcanization Process
Express Polymer Letters, 2011Co-Authors: L-x. Mao, L-q. ZhangAbstract:Brominated isobutyl-isoprene rubber/clay nanocomposite (BIIRCN) and ethylene-propylene-diene-monomer rubber/clay nanocomposite (EPDMCN) were prepared by melt blending. The micro-structural evolution of these two kinds of rubber/clay nanocomposites (RCNs) with Vulcanization Process was investigated using wide-angle X-ray diffraction (WAXD) and transmission electron microscope (TEM). The WAXD results revealed that the intercalated structure of organically modified clay (OMC) changed throughout the whole curing Process. The intercalated structure kept on chang- ing beyond the Vulcanization stage of T90. The interlayer space of intercalated silicate in uncured BIIRCN is larger than that in uncured EPDMCN. However, the intercalated structure for EPDMCN changed by a larger extent than that for BIIRCN during the Vulcanization Process, and the interlayer space of the intercalated structure is larger in the cured EPDMCN than that in the cured BIIRCN. It was found that the intercalant (i.e., octadecylamine, ODA) for OMC could shorten the scorch time of the curing reaction, and increase the curing rate, which was attributed to the further intercalation during vulcaniza- tion. TEM results indicated that the spatial distribution of OMC is much better in BIIR (a polar rubber matrix) than that in EPDM (a non-polar rubber matrix). The changes in spatial dispersion structure during Vulcanization for EPDMCN and BIIRCN show different trends. In conclusion, the polarity of the rubber is the determining factor influencing the evolution of both the intercalated structure and the spatial dispersion of clay during Vulcanization.
Xiong Wei - One of the best experts on this subject based on the ideXlab platform.
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Intelligent control system of rubber Vulcanization Process
Computers and Applied Chemistry, 2004Co-Authors: Xiong WeiAbstract:This intelligent control system of rubber Vulcanization Process is based on industry computer.Its functions include data col-lecting,alarming,calculating Vulcanization effect and switching between manual operation and Automation.In the VulcanizationProcess the temperature is controlled by fuzzy rules that improve the control accuracy and quality of Vulcanization products.Software de-sign adopts VC++ language,which uses the multi-thread,Activex component,D11 and so on.Those technologies all help to friendlyinterface between man and computer,and improve the real time quality and stabilization of the control system. Vulcanization Process,intelligent control,VC++,equivalent Vulcanization
L-x. Mao - One of the best experts on this subject based on the ideXlab platform.
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Micro-structural evolution of rubber/clay nanocomposites with Vulcanization Process
Express Polymer Letters, 2011Co-Authors: L-x. Mao, L-q. ZhangAbstract:Brominated isobutyl-isoprene rubber/clay nanocomposite (BIIRCN) and ethylene-propylene-diene-monomer rubber/clay nanocomposite (EPDMCN) were prepared by melt blending. The micro-structural evolution of these two kinds of rubber/clay nanocomposites (RCNs) with Vulcanization Process was investigated using wide-angle X-ray diffraction (WAXD) and transmission electron microscope (TEM). The WAXD results revealed that the intercalated structure of organically modified clay (OMC) changed throughout the whole curing Process. The intercalated structure kept on chang- ing beyond the Vulcanization stage of T90. The interlayer space of intercalated silicate in uncured BIIRCN is larger than that in uncured EPDMCN. However, the intercalated structure for EPDMCN changed by a larger extent than that for BIIRCN during the Vulcanization Process, and the interlayer space of the intercalated structure is larger in the cured EPDMCN than that in the cured BIIRCN. It was found that the intercalant (i.e., octadecylamine, ODA) for OMC could shorten the scorch time of the curing reaction, and increase the curing rate, which was attributed to the further intercalation during vulcaniza- tion. TEM results indicated that the spatial distribution of OMC is much better in BIIR (a polar rubber matrix) than that in EPDM (a non-polar rubber matrix). The changes in spatial dispersion structure during Vulcanization for EPDMCN and BIIRCN show different trends. In conclusion, the polarity of the rubber is the determining factor influencing the evolution of both the intercalated structure and the spatial dispersion of clay during Vulcanization.
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micro structural evolution of rubber clay nanocomposites with Vulcanization Process
Express Polymer Letters, 2011Co-Authors: L-x. Mao, L-q. ZhangAbstract:Brominated isobutyl-isoprene rubber/clay nanocomposite (BIIRCN) and ethylene-propylene-diene-monomer rubber/clay nanocomposite (EPDMCN) were prepared by melt blending. The micro-structural evolution of these two kinds of rubber/clay nanocomposites (RCNs) with Vulcanization Process was investigated using wide-angle X-ray diffraction (WAXD) and transmission electron microscope (TEM). The WAXD results revealed that the intercalated structure of organically modified clay (OMC) changed throughout the whole curing Process. The intercalated structure kept on chang- ing beyond the Vulcanization stage of T90. The interlayer space of intercalated silicate in uncured BIIRCN is larger than that in uncured EPDMCN. However, the intercalated structure for EPDMCN changed by a larger extent than that for BIIRCN during the Vulcanization Process, and the interlayer space of the intercalated structure is larger in the cured EPDMCN than that in the cured BIIRCN. It was found that the intercalant (i.e., octadecylamine, ODA) for OMC could shorten the scorch time of the curing reaction, and increase the curing rate, which was attributed to the further intercalation during vulcaniza- tion. TEM results indicated that the spatial distribution of OMC is much better in BIIR (a polar rubber matrix) than that in EPDM (a non-polar rubber matrix). The changes in spatial dispersion structure during Vulcanization for EPDMCN and BIIRCN show different trends. In conclusion, the polarity of the rubber is the determining factor influencing the evolution of both the intercalated structure and the spatial dispersion of clay during Vulcanization.
Guangsu Huang - One of the best experts on this subject based on the ideXlab platform.
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Vulcanization Kinetics of Graphene/Styrene Butadiene Rubber Nanocomposites
Chinese Journal of Polymer Science, 2014Co-Authors: Maozhu Tang, Wang Xing, Guangsu HuangAbstract:This paper presents the influence of graphene on the Vulcanization kinetics of styrene butadiene rubber (SBR) with dicumyl peroxide. A curemeter and a differential scanning calorimeter were used to investigate the cure kinetics, from which the kinetic parameters and apparent activation energy were obtained. It turns out that with increasing graphene loading, the induction period of the Vulcanization Process of SBR is remarkably reduced at low graphene loading and then levels off; on the other hand, the optimum cure time shows a monotonous decrease. As a result, the Vulcanization rate is suppressed at first and then accelerated, and the corresponding activation energy increases slightly at first and then decreases. Upon adding graphene, the crosslinking density of the nanocomposites increases, because graphene takes part in the Vulcanization Process.
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Vulcanization kinetics of graphene natural rubber nanocomposites
Polymer, 2013Co-Authors: Wang Xing, Guangsu Huang, Maozhu Tang, Yufeng LiuAbstract:Abstract In the present work, the influence of graphene (GE) on the Vulcanization kinetics of natural rubber (NR) with sulfur curing system was investigated in detail for the first time. It is found that on adding graphene the induction period of the Vulcanization Process is remarkably depressed, whereas the Vulcanization rate is enhanced at low graphene loading and then suppressed. As a result, the optimum cure time decreases dramatically at first and subsequently shows a slight increase with increasing graphene loading. At the same time, the crosslinking density of NR increases monotonically, because graphene takes part in the Vulcanization Process. The exothermal peak of the Vulcanization reactions is split into two peaks on adding ≥0.5 phr graphene. It is interpreted in terms of two reaction stages, i.e., chemical reaction controlling stage and diffusion controlling stage. The activation energy of the former stage decreases with increasing graphene loading, while that of the latter stage is higher than the former one and increases with graphene loading. A possible mechanism was proposed to interpret the accelerating effect of graphene and the enhanced crosslinking density of NR.
