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Daining Fang - One of the best experts on this subject based on the ideXlab platform.
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a constitutive model for elastoplastic damage coupling effect of unidirectional fiber reinforced Polymer Matrix Composites
Composites Part A-applied Science and Manufacturing, 2020Co-Authors: Yanfei Chen, Yong Tao, Yunong Zhao, Yazheng Yang, Daining FangAbstract:Abstract In this paper, an elastoplastic-damage coupling constitutive model for unidirectional fiber-reinforced Polymer Matrix Composites (UD FRPs) is presented, which both considers the plastic-hardening and damage-softening processes. Tension-compression asymmetry and shear strength increase due to transverse compression are observed under off-axis tensile/compressive tests of UD E-glass/YPH-200. Therefore, a four-parameter plastic yield criterion considering these two effects is proposed. Applying this model to predict the off-axis tensile/compressive responses of present tests provides good agreement with experimental curves. In addition, we give a novel definition of shear damage variable based on Puck failure theory and discuss it in detail. Further, we develop a four-parameter Matrix failure criterion for UD FRPs and exactly predict the off-axis failure strength.
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yield and failure theory for unidirectional Polymer Matrix Composites
Composites Part B-engineering, 2019Co-Authors: Hongshuai Lei, Daining Fang, Yanfei Chen, Yunong Zhao, Liqun TangAbstract:Abstract This paper presents a unified theory of yield and failure criteria for unidirectional Polymer-Matrix Composites (UD PMCs). This interactive unified theory considers the effect of normal stress on the shear strength by introducing a coupling term ( q 3 σ 22 | τ 21 | ). The coefficient q 3 of the coupling term is an empirical value and equals to 0.2. The predictions of the unified theory are well agreeable with present and existing experiments. Furthermore, Tao theory has been improved by adding the limiting condition that the ratio of compressive strength to shear strength should be greater than two.
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experimental and theoretical studies on inter fiber failure of unidirectional Polymer Matrix Composites under different strain rates
International Journal of Solids and Structures, 2017Co-Authors: Yong Tao, Haosen Chen, Kai Yao, Hongshuai Lei, Yongmao Pei, Daining FangAbstract:Abstract Polymer-Matrix Composites (PMCs) are widely used in many fields. However, the accurate characterization of their failure behavior is still a challenge. At present, the inter-fiber failure of unidirectional PMCs under compression is not well predicted, and the corresponding strain rate dependent failure theory remains less explored. This paper aims to study and characterize the inter-fiber failure behavior of unidirectional PMCs under different strain rates. Unidirectional glass/epoxy specimens with various off-axis angles were tested at three strain rates (quasi-static, 383 and 646 s−1), and the measured strain rate dependent strength is modelled by an empirical formula. To evaluate the test results, a new failure theory that incorporates strain rate effects is proposed. The theory is developed based on three different failure modes, with each represented by a new and simple formula. Comparison shows that the predicted failure envelopes and fracture angles are in excellent agreement with the experimental results.
Deborah D.l. Chung - One of the best experts on this subject based on the ideXlab platform.
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Processing-structure-property relationships of continuous carbon fiber Polymer-Matrix Composites
Materials Science and Engineering R: Reports, 2017Co-Authors: Deborah D.l. ChungAbstract:This paper reviews the processing-structure-property relationships of continuous carbon fiber Polymer-Matrix Composites, which are important for lightweight structures. Such relationships constitute the guiding principles in materials design, development and tailoring. Although much research has been performed for decades on the mechanical behavior of continuous fiber Composites, the functional behavior (electrical, electromagnetic, dielectric, thermal, thermoelectric, vibration damping, etc.) of these materials are quite new, with research activities that are rapidly growing in recent years due to the importance of multifunctional structural materials and smart structures. In addition, the combined use of continuous fibers and nanofillers such as nanofibers and nanotubes is a relatively new direction that has provided hierarchical or multi-scale Composites with attractive properties. The properties addressed in this review relate to the mechanical (static, dynamic, fatigue, wear), viscoelastic, thermal expansion, thermal conductivity, electrical, piezoresistive, dielectric, electromagnetic, thermoelectric and environmental durability behavior, as well as the effects of temperature, humidity, strain and damage. The structure/processing parameters relate to the fiber arrangement, interlaminar interface, curing pressure, fiber type, fiber treatments, fiber volume fraction, fillers, interlayers, coatings, through-thickness rods, Polymer Matrix and the fastening-relevant interface between contacting unbonded Composites. In addition, this paper reviews the rapidly broadening applications of this class of materials.
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electromagnetic interference shielding using continuous carbon fiber carbon Matrix and Polymer Matrix Composites
Composites Part B-engineering, 1999Co-Authors: Deborah D.l. ChungAbstract:A carbon-Matrix composite with continuous carbon-fibers was found to be an excellent electromagnetic interference (EMI) shielding material with shielding effectiveness 124 dB, low surface impedance and high reflectivity in the frequency range from 0.3 MHz to 1.5 GHz. The shielding effectiveness of Polymer-Matrix Composites with continuous carbon-fibers was less and that of Polymer-Matrix Composites with discontinuous fillers was even less. The addition of 2.9 vol.% discontinuous 0.1 μm diameter carbon-filaments between the layers of conventional 7 μm diameter continuous carbon-fibers in a composite degraded the shielding effectiveness. The dominant mechanism of EMI shielding for both carbon-Matrix and Polymer-Matrix continuous carbon-fiber Composites is reflection.
Xiaoming Bai - One of the best experts on this subject based on the ideXlab platform.
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erratum corrigendum to high fidelity micro scale modeling of the thermo visco plastic behavior of carbon fiber Polymer Matrix Composites composite structures 2015 134 132 141
Composite Structures, 2016Co-Authors: Xiaoming Bai, Miguel A Bessa, Antonio R Melro, P P Camanho, Licheng Guo, Wing Kam LiuAbstract:The authors regret to inform that one of the modifications proposed in the article “High-fidelity micro-scale modeling of the thermo-visco-plastic behavior of carbon fiber Polymer Matrix Composites” [1] was found to be unnecessary: the paraboloid yield criterion is sufficient to describe the shear behavior of the epoxy Matrix considered (Epoxy 3501-6). The authors recently noted that the experimental work [2] used to validate the pure Matrix response considered engineering shear strain instead of its tensorial counter-part, which caused the apparent inconsistency with the paraboloid yield criterion.
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high fidelity micro scale modeling of the thermo visco plastic behavior of carbon fiber Polymer Matrix Composites
Composite Structures, 2015Co-Authors: Xiaoming Bai, Miguel A Bessa, Antonio R Melro, P P Camanho, Licheng Guo, Wing Kam LiuAbstract:Abstract An experimentally validated micro-scale analysis of the visco-thermo-mechanical behavior of Polymer Matrix Composites under different loads is proposed. A new constitutive law for the Matrix material is developed taking into account the pressure dependence of the material as well as strain-rate and temperature dependence. Capturing the Matrix behavior under multi-axial stress states is concluded to be essential to accurately predict the composite material behavior, even when considering simple load cases such as transverse compression and/or shear. Without any calibration procedure at the composite level, good agreement with the experimental data is observed for different loading conditions, including strain-rate dependency. Using this validated micro-scale model, a three-dimensional simulation of the formation of a kink band under longitudinal compression of the composite is conducted. A new evidence at micro-scale is found supporting the hypothesis that shear stresses transferred between fibers and Matrix are particularly important in the formation of the kink band.
Amos Gilat - One of the best experts on this subject based on the ideXlab platform.
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implementation of an associative flow rule including hydrostatic stress effects into the high strain rate deformation analysis of Polymer Matrix Composites
Journal of Aerospace Engineering, 2005Co-Authors: Robert K Goldberg, Gary D Roberts, Amos GilatAbstract:A previously developed analytical formulation has been modified in order to more accurately account for the effects of hydrostatic stresses on the nonlinear, strain rate dependent deformation of Polymer Matrix Composites. State variable constitutive equations originally developed for metals have been modified in order to model the nonlinear, strain rate dependent deformation of Polymeric materials. To account for the effects of hydrostatic stresses, which are significant in Polymers, the classical J2 plasticity theory definitions of effective stress and effective inelastic strain, along with the equations used to compute the components of the inelastic strain rate tensor, are appropriately modified. To verify the revised formulation, the shear and tensile deformation of a representative Polymer are computed across a wide range of strain rates. Results computed using the developed constitutive equations correlate well with experimental data. The Polymer constitutive equations are implemented within a stren...
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implementation of an associative flow rule including hydrostatic stress effects into the high strain rate deformation analysis of Polymer Matrix Composites
Journal of Aerospace Engineering, 2005Co-Authors: Robert K Goldberg, Gary D Roberts, Amos GilatAbstract:A previously developed analytical formulation has been modified in order to more accurately account for the effects of hydrostatic stresses on the nonlinear, strain rate dependent deformation of Polymer Matrix Composites. State variable constitutive equations originally developed for metals have been modified in order to model the nonlinear, strain rate dependent deformation of Polymeric materials. To account for the effects of hydrostatic stresses, which are significant in Polymers, the classical J2 plasticity theory definitions of effective stress and effective inelastic strain, along with the equations used to compute the components of the inelastic strain rate tensor, are appropriately modified. To verify the revised formulation, the shear and tensile deformation of two representative Polymers are computed across a wide range of strain rates. Results computed using the developed constitutive equations correlate well with experimental data. The Polymer constitutive equations are implemented within a strength of materials based micromechanics method to predict the nonlinear, strain rate dependent deformation of Polymer Matrix Composites. The composite mechanics are verified by analyzing the deformation of a representative Polymer Matrix composite for several fiber orientation angles across a variety of strain rates. The computed values compare well to experimentally obtained results.
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incorporation of mean stress effects into the micromechanical analysis of the high strain rate response of Polymer Matrix Composites
Composites Part B-engineering, 2003Co-Authors: Robert K Goldberg, Gary D Roberts, Amos GilatAbstract:The results presented here are part of an ongoing research program, to develop strain rate dependent deformation and failure models for the analysis of Polymer Matrix Composites subject to high strain rate impact loads. A micromechanics approach is employed in this work, in which state variable constitutive equations originally developed for metals have been modified to model the deformation of the Polymer Matrix, and a strength of materials based micromechanics method is used to predict the effective response of the composite. In the analysis of the inelastic deformation of the Polymer Matrix, the definitions of the effective stress and effective inelastic strain have been modified in order to account for the effect of hydrostatic stresses, which are significant in Polymers. Two representative Polymers, a toughened epoxy and a brittle epoxy, are characterized through the use of data from tensile and shear tests across a variety of strain rates. Results computed by using the developed constitutive equations correlate well with data generated via experiments. The procedure used to incorporate the constitutive equations within a micromechanics method is presented, and sample calculations of the deformation response of a composite for various fiber orientations and strain rates are discussed.
Wing Kam Liu - One of the best experts on this subject based on the ideXlab platform.
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erratum corrigendum to high fidelity micro scale modeling of the thermo visco plastic behavior of carbon fiber Polymer Matrix Composites composite structures 2015 134 132 141
Composite Structures, 2016Co-Authors: Xiaoming Bai, Miguel A Bessa, Antonio R Melro, P P Camanho, Licheng Guo, Wing Kam LiuAbstract:The authors regret to inform that one of the modifications proposed in the article “High-fidelity micro-scale modeling of the thermo-visco-plastic behavior of carbon fiber Polymer Matrix Composites” [1] was found to be unnecessary: the paraboloid yield criterion is sufficient to describe the shear behavior of the epoxy Matrix considered (Epoxy 3501-6). The authors recently noted that the experimental work [2] used to validate the pure Matrix response considered engineering shear strain instead of its tensorial counter-part, which caused the apparent inconsistency with the paraboloid yield criterion.
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high fidelity micro scale modeling of the thermo visco plastic behavior of carbon fiber Polymer Matrix Composites
Composite Structures, 2015Co-Authors: Xiaoming Bai, Miguel A Bessa, Antonio R Melro, P P Camanho, Licheng Guo, Wing Kam LiuAbstract:Abstract An experimentally validated micro-scale analysis of the visco-thermo-mechanical behavior of Polymer Matrix Composites under different loads is proposed. A new constitutive law for the Matrix material is developed taking into account the pressure dependence of the material as well as strain-rate and temperature dependence. Capturing the Matrix behavior under multi-axial stress states is concluded to be essential to accurately predict the composite material behavior, even when considering simple load cases such as transverse compression and/or shear. Without any calibration procedure at the composite level, good agreement with the experimental data is observed for different loading conditions, including strain-rate dependency. Using this validated micro-scale model, a three-dimensional simulation of the formation of a kink band under longitudinal compression of the composite is conducted. A new evidence at micro-scale is found supporting the hypothesis that shear stresses transferred between fibers and Matrix are particularly important in the formation of the kink band.