Three-Dimensional Elastic Moduli of Graphite/Epoxy Composites

1982 ◽  
Vol 16 (2) ◽  
pp. 153-159 ◽  
Author(s):  
Marvin Knight
Keyword(s):  
Elastic Moduli ◽  
Three Dimensional ◽  
Epoxy Composites

Study of Porosity of Carbon Reinforced Plastic Composites Using Broadband Ultrasound Structuroscopy Techniques

2017 ◽  
Vol 755 ◽  
pp. 44-51
Author(s):  
Anton S. Bychkov ◽  
Alexander A. Karabutov ◽  
Elena V. Savateeva ◽  
Yulia G. Sokolovskaya ◽  
Vasily P. Zarubin ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Metal Matrix ◽  
Elastic Moduli ◽  
Epoxy Composites ◽  
Ultrasonic Spectroscopy ◽  
Isotropic Composite ◽  
Plastic Composites ◽  
Reinforced Plastic ◽  
Local Porosity ◽  
Longitudinal Acoustic Waves

Theoretical assessments are given for the use of the through-transition technique of broadband ultrasonic spectroscopy to determine porosity of heterogeneous materials. Experimental measurements of local porosity of composites using the through-transition technique are presented. Dependences of elastic moduli on the concentration of hardening particles and porosity of metal matrix isotropic composite found. Experimental relationship between the phase velocity of longitudinal acoustic waves and the power of structural noise in samples of graphite epoxy composites is obtained.

Enhanced thermal properties for epoxy composites with a three-dimensional graphene oxide filler

2015 ◽  
Vol 16 (12) ◽  
pp. 2617-2626 ◽  
Author(s):  
Jian Gao ◽  
Jinhong Yu ◽  
Xinfeng Wu ◽  
Baolin Rao ◽  
Laifu Song ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Thermal Properties ◽  
Three Dimensional ◽  
Epoxy Composites

Electromagnetic properties of three-dimensional woven carbon fiber fabric/epoxy composite

2017 ◽  
Vol 88 (20) ◽  
pp. 2353-2361 ◽  
Author(s):  
Wei Fan ◽  
Dan-dan Li ◽  
Jia-lu Li ◽  
Juan-zi Li ◽  
Lin-jia Yuan ◽  
...  
Keyword(s):  
Electromagnetic Wave ◽  
Carbon Fiber ◽  
Electromagnetic Interference ◽  
Three Dimensional ◽  
Woven Fabric ◽  
Epoxy Composites ◽  
Woven Composites ◽  
Carbon Fiber Fabric ◽  
Fiber Fabric ◽  
Wave Properties

To investigate the reinforcement architectures effect on the electromagnetic wave properties of carbon fiber reinforced polymer composites, three-dimensional (3D) interlock woven fabric/epoxy composites, 3D interlock woven fabric with stuffer warp/epoxy composites, and 3D orthogonal woven fabric/epoxy composites were studied by the free-space measurement system. The results showed that the three types of 3D woven carbon fiber fabric/epoxy composites had a slight difference in electromagnetic wave properties and the absorption was their dominant radar absorption mechanism. The electromagnetic wave absorption properties of the three types of composites were more than 90% (below −10 dB) over the 11.2–18 GHz bandwidth, and more than 60% (below −4 dB) over the 8–12 GHz bandwidth. Compared with unidirectional carbon fiber reinforced plastics, the three kinds of 3D woven carbon fiber fabric/epoxy composites exhibited better electromagnetic wave absorption properties over a broadband frequency range of 8–18 GHz. Therefore, the three kinds of 3D woven composite are expected to be used as radar absorption structures due to their excellent mechanical properties and outstanding absorption capacity. The total electromagnetic interference shielding effectiveness of the three types of 3D carbon fiber woven composites are all larger than 46 dB over the 8–12 GHz bandwidth, which is evidence that the three types of 3D carbon fiber woven composites can be used as excellent shielding materials for electromagnetic interference.

Mechanics of Three-Dimensional Printed Lattices for Biomedical Devices

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Paul F. Egan ◽  
Isabella Bauer ◽  
Kristina Shea ◽  
Stephen J. Ferguson
Keyword(s):  
Elastic Moduli ◽  
Nutrient Transport ◽  
Three Dimensional ◽  
Integrated Design ◽  
Mechanical Efficiency ◽  
Lattice Structures ◽  
Effective Elastic Moduli ◽  
Biomedical Devices ◽  
Fully Integrated ◽  
Polyjet Printing

Advances in three-dimensional (3D) printing are enabling the design and fabrication of tailored lattices with high mechanical efficiency. Here, we focus on conducting experiments to mechanically characterize lattice structures to measure properties that inform an integrated design, manufacturing, and experiment framework. Structures are configured as beam-based lattices intended for use in novel spinal cage devices for bone fusion, fabricated with polyjet printing. Polymer lattices with 50% and 70% porosity were fabricated with beam diameters of 0.4–1.0mm, with measured effective elastic moduli from 28MPa to 213MPa. Effective elastic moduli decreased with higher lattice porosity, increased with larger beam diameters, and were highest for lattices compressed perpendicular to their original build direction. Cages were designed with 50% and 70% lattice porosities and included central voids for increased nutrient transport, reinforced shells for increased stiffness, or both. Cage stiffnesses ranged from 4.1kN/mm to 9.6kN/mm with yielding after 0.36–0.48mm displacement, thus suggesting their suitability for typical spinal loads of 1.65kN. The 50% porous cage with reinforced shell and central void was particularly favorable, with an 8.4kN/mm stiffness enabling it to potentially function as a stand-alone spinal cage while retaining a large open void for enhanced nutrient transport. Findings support the future development of fully integrated design approaches for 3D printed structures, demonstrated here with a focus on experimentally investigating lattice structures for developing novel biomedical devices.

A Stochastic Nonlinear Constitutive Law for Concrete

1989 ◽  
Vol 111 (4) ◽  
pp. 443-449 ◽  
Author(s):  
A. Fafitis ◽  
Y. H. Won
Keyword(s):  
Stochastic Model ◽  
Elastic Moduli ◽  
Three Dimensional ◽  
Path Dependency ◽  
Experimental Results ◽  
Constitutive Law ◽  
Induced Anisotropy ◽  
Nonproportional Loading ◽  
Strain Relationship ◽  
Good Agreement

An incremental three-dimensional stress-strain relationship for concrete with induced anisotropy has been developed. The nonlinearity and path-dependency are modeled by expressing the elastic moduli at each increment as function of the octahedral and deviatoric strains, based on a uniaxial stochastic model developed earlier. Predictions of multiaxial response under proportional and nonproportional loading are in good agreement with experimental results.

The Effect of Microstructural Morphologies on the Effective Electromechanical Properties of Piezoelectric Particle Composites

2012 ◽  
Author(s):  
Vahid Tajeddini ◽  
Chien-hong Lin ◽  
Anastasia Muliana ◽  
Martin Lévesque
Keyword(s):  
Mechanical Properties ◽  
Elastic Moduli ◽  
Volume Fraction ◽  
Micromechanical Model ◽  
Three Dimensional ◽  
Particle Sizes ◽  
Reinforced Composites ◽  
Electromechanical Properties ◽  
Particle Volume ◽  
Self Consistent

This study introduces a micromechanical model that incorporates detailed microstructures for analyzing the effective electro-mechanical properties, such as piezoelectric and permittivity constants as well as elastic moduli, of piezoelectric particle reinforced composites. The studied composites consist of polarized spherical piezoelectric particles dispersed into a continuous and elastic polymeric matrix. A micromechanical model generated using three-dimensional (3D) continuum elements within a finite element (FE) framework. For each volume fraction (VF) of particles, realization with different particle sizes and arrangements were generated in order to represent microstructures of a particle composite. We examined the effects of microstructural morphologies, such as particle sizes and distributions, and particle volume fractions on the overall effective electro-mechanical properties of the active composites. The overall electro-mechanical properties determined from the present micromechanical model were compared to those generated using the Mori-Tanaka, self-consistent, and simplified unit-cell micromechanical models.

Sufficient Symmetry Conditions for Isotropy of the Elastic Moduli Tensor

1987 ◽  
Vol 54 (4) ◽  
pp. 772-777 ◽  
Author(s):  
R. M. Christensen
Keyword(s):  
Elastic Moduli ◽  
Fiber Composite ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Dimensional Problem ◽  
Axial Deformation ◽  
Space Network ◽  
Plane Normal ◽  
Rank Tensor ◽  
Three Space

Symmetry conditions are found that assure isotropy of the fourth rank tensor of elastic moduli. Crystallography provides the answer to this problem in the two-dimensional context, namely one axis of three-fold symmetry assures the isotropy of properties in the plane normal to the axis. The present work provides the answer in the three-dimensional problem: 6 axes of five-fold symmetry are sufficient to give isotropy of the elastic moduli. An important restriction must accompany the present result. The derivation is given in the special form appropriate to low density materials which have a microstructure that transmits load according to the axial deformation of a space network of material distributed into micro-struts. The corresponding fiber composite idealization is that of a fiber dominated system, it therefore follows that if the fibers take the 6 specific orientations in three-space then isotropy is obtained.

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