The Experts below are selected from a list of 3426 Experts worldwide ranked by ideXlab platform
Somnath Ghosh - One of the best experts on this subject based on the ideXlab platform.
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Micromechanics modeling and validation of thermal mechanical damage in der353 epoxy borosilicate glass Composite subject to high strain rate deformation
International Journal of Impact Engineering, 2020Co-Authors: Zhiye Li, Somnath GhoshAbstract:Abstract With advances in the design and manufacturing of Composite materials, the number of their defense and civil applications has grown significantly. This calls for detailed experiments and modeling of Composite materials for their characterization and performance analysis. Experiments show that adiabatic heating becomes more noticeable at high-strain-rate deformation, causing the stress-strain slopes to become negative. However, most rate-dependent Micromechanics models, e.g. in a previous work by the authors [1], lack an interpretation of the relation between energy dissipation and adiabatic temperature rise. In this study, a continuum damage model (CDM) with adiabatic heating is established to enhance the accuracy of the Micromechanics model under high-strain-rate impacts. The model predicts the behavior of a heterogeneous material and punch shear strength tests are used for validation. The model is calibrated using results from experiments conducted in a split-Hopkinson pressure bar (SHPB). A constitutive law for the DER353 epoxy in the finite rotation framework is presented first, focusing on the connection between the energy dissipation and local temperature rise. Next, the model is implemented in a finite element framework and calibrated using a SHPB experiment. Lastly, the DER353 epoxy model is applied to a unidirectional fiber Composite Micromechanics model as a predictive tool. Results show that damage initiates at the material interface and diffuses into individual phases. In addition, the punch shear experiment results are compared with results from the single-fiber RVE model. The comparison shows that the micromechanical model can be used as a multiscale analysis tool. The findings in this work can be used to explore the performance of more complicated microstructures, e.g. woven Composites.
Zhiye Li - One of the best experts on this subject based on the ideXlab platform.
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Micromechanics modeling and validation of thermal mechanical damage in der353 epoxy borosilicate glass Composite subject to high strain rate deformation
International Journal of Impact Engineering, 2020Co-Authors: Zhiye Li, Somnath GhoshAbstract:Abstract With advances in the design and manufacturing of Composite materials, the number of their defense and civil applications has grown significantly. This calls for detailed experiments and modeling of Composite materials for their characterization and performance analysis. Experiments show that adiabatic heating becomes more noticeable at high-strain-rate deformation, causing the stress-strain slopes to become negative. However, most rate-dependent Micromechanics models, e.g. in a previous work by the authors [1], lack an interpretation of the relation between energy dissipation and adiabatic temperature rise. In this study, a continuum damage model (CDM) with adiabatic heating is established to enhance the accuracy of the Micromechanics model under high-strain-rate impacts. The model predicts the behavior of a heterogeneous material and punch shear strength tests are used for validation. The model is calibrated using results from experiments conducted in a split-Hopkinson pressure bar (SHPB). A constitutive law for the DER353 epoxy in the finite rotation framework is presented first, focusing on the connection between the energy dissipation and local temperature rise. Next, the model is implemented in a finite element framework and calibrated using a SHPB experiment. Lastly, the DER353 epoxy model is applied to a unidirectional fiber Composite Micromechanics model as a predictive tool. Results show that damage initiates at the material interface and diffuses into individual phases. In addition, the punch shear experiment results are compared with results from the single-fiber RVE model. The comparison shows that the micromechanical model can be used as a multiscale analysis tool. The findings in this work can be used to explore the performance of more complicated microstructures, e.g. woven Composites.
Edson Cocchieri Botelho - One of the best experts on this subject based on the ideXlab platform.
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damping behavior of continuous fiber metal Composite materials by the free vibration method
Composites Part B-engineering, 2005Co-Authors: Edson Cocchieri Botelho, A N Campos, E De Barros, L C Pardini, Mirabel Cerqueira RezendeAbstract:Abstract Fiber metal laminates (FML) offer significant improvements over current available materials for aircraft structures due to their excellent mechanical characteristics and relatively low density. Non-destructive testing techniques are being used in the characterization of Composite materials. Among these, vibration testing is one of the most used tools because it allows the determination of the mechanical properties. In this work, the viscoelastic properties such as elastic (E′) and viscous (E″) responses were obtained for aluminum 2024 alloy; carbon fiber/epoxy; glass fiber/epoxy and their hybrids aluminum 2024 alloy/carbon fiber/epoxy and aluminum 2024 alloy/glass fiber/epoxy Composites. The experimental results were compared to calculated E modulus values by using the Composite Micromechanics approach. For all specimens studied, the experimental values showed good agreement with the theoretical values. The damping behavior, i.e. the storage modulus and the loss factor, from the aluminum 2024 alloy and fiber epoxy Composites can be used to estimate the viscoelastic response of the hybrid FML.
S L Phoenix - One of the best experts on this subject based on the ideXlab platform.
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comparison of probabilistic models for stress rupture failure in continuous unidirectional fiber Composite structures
Journal of Materials Science, 2018Co-Authors: Amy Engelbrechtwiggans, S L PhoenixAbstract:Stress rupture is an important failure phenomenon in Composite overwrapped pressure vessels, which is highly unpredictable other than on a statistical basis. Even then, there are several statistical models, with varying bases in Composite Micromechanics and molecular failure mechanisms. Choosing among these models is not trivial, even when micromechanical details of the failure process are reasonably well appreciated, and one has available a reasonably large database of strength and lifetime data. As a result, there is little in the way of guidance to choose the most appropriate model. One important issue is that accurate predictions are desired at relatively low service loads compared to the strength, and low probabilities of failure that are far less, e.g., 10−6, than can be directly confirmed using the data itself. In essence, one needs a robust and accurate statistical model free of inconsistencies associated with such low stress levels and probabilities of failure. This paper performs an in-depth comparison of several current models, which have varying physical bases. The models compared differ in the number of parameters to be estimated from data. The results of this study, however, show that over a broad range of parameter values these models give surprisingly similar failure probability predictions. While practitioners may have a preference for one model over another, the basis for such a choice is not easily established, given the fidelity of typical data.
David K Hsu - One of the best experts on this subject based on the ideXlab platform.
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quantitative estimation of material properties of porous ceramics by means of Composite Micromechanics and ultrasonic velocity
Ndt & E International, 1996Co-Authors: Hyunjo Jeong, David K HsuAbstract:Abstract This paper describes a nondestructive method for the quantitative estimation of property variations due to porosity in advanced ceramics. The method employs a Composite Micromechanics which accounts for the effective density and elastic stiffness of a porous Composite medium with a measurement of ultrasonic velocity. When the measured velocity is coupled with the theoretically predicted velocity, the unknown pore volume fraction is solved, from which other material properties are determined. The Micromechanics model based on the Mori-Tanaka theory can handle ellipsoidal pores with a certain orientation distribution. Given the zero-porosity matrix moduli and the pore aspect ratio, the oblate spheroidal theory is first applied to hot pressed silicon carbide (SiC) samples in the range of about 85–100% of theoretical density and then extended to sintered samples in the density range of 93.6–97.6%. It is shown that the bulk density and elastic modulus of porous ceramics can be estimated accurately by the proposed method.