Polymeric Composites Tailored by Electric Field

2004 ◽  
Vol 19 (4) ◽  
pp. 1164-1174 ◽  
Author(s):  
GeunHyung Kim ◽  
Yuri M. Shkel
Keyword(s):  
Electric Field ◽  
Glass Fibers ◽  
Tensile Modulus ◽  
Polymeric Composites ◽  
Current Approach ◽  
Functionally Graded ◽  
Epoxy Composites ◽  
Graded Materials ◽  
Ceramic Particles ◽  
Redistribution Effect

A solid composite of desirable microstructure can be produced by curing a liquid polymeric suspension in an electric field. Redistribution effect of the field-induced forces exceeds that of centrifugation, which is frequently employed to manufacture functionally graded materials. Moreover, unlike centrifugational sedimentation, the current approach can electrically rearrange the inclusions in targeted areas. The electric field can be employed to produce a composite having uniformly oriented structure or only modify the material in selected regions. Field-aided technology enables polymeric composites to be locally micro-tailored for a given application. Moreover, materials of literally any composition can be manipulated. In this article we present testing results for compositions of graphite and ceramic particles as well as glass fibers in epoxy. Electrical and rheological interactions of inclusions in a liquid epoxy are discussed. Measurements of tensile modulus and ultimate strength of epoxy composites having different microstructure of 10 vol% graphite, ceramic particles and glass fiber are presented.

Functionally Graded Polymeric Composites Having Micro-Tailored Structure Formed by Electric Field

Materials ◽  
2003 ◽  
Author(s):  
Geun Hyung Kim ◽  
Daniel K. Moeller ◽  
Yuri M. Shkel
Keyword(s):  
Mechanical Properties ◽  
Electric Field ◽  
Functionally Graded Materials ◽  
Applied Electric Field ◽  
Polymeric Composites ◽  
Functionally Graded ◽  
Graded Materials ◽  
Functionally Graded Composites ◽  
Liquid Suspensions ◽  
Redistribution Effect

A solid composite having locally micro-tailored structure can be produced by curing liquid polymeric suspensions in an electric field. The redistribution effect of the field-induced forces exceeds the effect of centrifugation, presently employed to manufacture functionally graded materials. Moreover, unlike centrifugational sedimentation, one can electrically rearrange the inclusions in desired targeted areas. The applied electric field can be employed to produce a composite having uniformly oriented structure or only modify the material in selected regions. This technology enables polymeric composites to be locally micro-tailored for given design objectives. We discuss electrical and rheological inteactions in liquid suspensions. Relationships between microstructure and mechanical properties of the obtained functionally graded composites are presented.

Optimization of Wall Electrodes for Electro-Hydrodynamic Control of Natural Convection Effects During Solidification

Materials ◽  
2003 ◽  
Author(s):  
Marcelo J. Colac¸o ◽  
George S. Dulikravich ◽  
Thomas J. Martin
Keyword(s):  
Natural Convection ◽  
Electric Field ◽  
Solid Phase ◽  
Charged Particles ◽  
Numerical Procedure ◽  
Functionally Graded ◽  
Navier Stokes ◽  
Graded Materials ◽  
Shape Distribution ◽  
B Splines

This paper presents a numerical procedure to reduce and possibly control the natural convection effects in a cavity filled with a molten material by applying an external electric field whose intensity and spatial distributions are obtained by the use of a hybrid optimizer. This conceptually new approach to manufacturing could be used in creation of layered and functionally graded materials and objects. In the case of steady electro-hydrodynamics (EHD), the flow-field of electrically charged particles in a solidifying melt is influenced by an externally applied electric field while the existence of any magnetic field is neglected. Solidification front shape, distribution of the charged particles in the accrued solid, and the amount of accrued solid phase in such processes can be influenced by an appropriate distribution and orientation of the electric field. The intensities of the electrodes along the boundaries of the cavity were described using B-splines. The inverse problem was then formulated to find the electric boundary conditions (the coefficients of the B-splines) in such a way that the gradients of temperature along the horizontal direction are minimized. For this task we used a hybrid optimization algorithm which incorporates several of the most popular optimization modules; the Davidon-Fletcher-Powell (DFP) gradient method, a genetic algorithm (GA), the Nelder-Mead (NM) simplex method, quasi-Newton algorithm of Pshenichny-Danilin (LM), differential evolution (DE), and sequential quadratic programming (SQP). The transient Navier-Stokes and Maxwell equations were discretized using the finite volume method in a generalized curvilinear non-orthogonal coordinate system. For the phase change problems, we used the enthalpy method.

A Study on Modified Mechanical and Wear Characteristics of Epoxy-Particulate Filled Homogenous Composites and Their Functionally Graded Materials

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Siddhartha ◽  
Amar Patnaik ◽  
Alok Satapathy ◽  
Amba D. Bhatt
Keyword(s):  
Theoretical Model ◽  
Functionally Graded Materials ◽  
Sliding Wear ◽  
Functionally Graded ◽  
Epoxy Composites ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Graded Materials ◽  
Wear Characteristics ◽  
Kiln Dust

This article presents the investigations on modified mechanical and wear characteristics of cement kiln dust (CKD) reinforced homogeneous epoxy composites and its functionally graded materials developed for tribological applications. CKD reinforced homogeneous and functionally graded epoxy composites are developed by simple mechanical stirring and vertical centrifugal casting technique, respectively. Mechanical properties of these graded composites are evaluated and compared with those of homogenously filled epoxy composites. Sliding wear tests are conducted over a range of sliding velocities (105–314 cm/s), normal loads (20–40 N), filler contents (0–20 wt %), and sliding distances (0.5–2 km). For this, a pin-on-disk machine and the design of experiments approach using Taguchi’s orthogonal arrays are used. A theoretical model is proposed for estimating the sliding wear rates for homogeneous, as well as graded composites. The results found from the theoretical model so proposed are found to be in good agreement with the experimental values under similar test conditions. This study reveals that the presence of cement kiln dust particles enhances the sliding wear resistance of epoxy resin and the homogeneous composites suffer greater wear loss than the graded composites. scanning electron microscopy micrograph confirms the graded dispersion of CKD particles in the matrix.

scholarly journals Functionally Graded Materials (FGM) for Spacers in Gas Insulated Systems: A Concise Review and Some Comments

2021 ◽  
Vol 11 (6) ◽  
pp. 7887-7891
Author(s):  
K. L. Wong ◽  
M. Danikas
Keyword(s):  
Electric Field ◽  
Functionally Graded Materials ◽  
High Voltage ◽  
Electric Field Distribution ◽  
Industrial Applications ◽  
Functionally Graded ◽  
Graded Materials ◽  
Concise Review ◽  
Viable Solution ◽  
Future Challenges

Functionally Graded Materials (FGMs) present a solution to control electrical stresses in high voltage applications. In this paper, a concise review is presented on the FGMs for spacers in gas-insulated systems. FGMs offer the possibility of a more even electric field distribution and thus a viable solution for industrial applications. FGMs are investigated here primarily as materials for permittivity control. Some aspects of FGMs are discussed as well as some thoughts on future challenges.

An investigation on the mechanical and thermal performance of a novel functionally graded materials–based thermoplastic composites

2018 ◽  
Vol 32 (12) ◽  
pp. 1691-1713 ◽  
Author(s):  
Akant Kumar Singh ◽  
Siddhartha
Keyword(s):  
Functionally Graded Materials ◽  
Glass Fibers ◽  
Solidification Rate ◽  
Hardness Measurement ◽  
Sem Analysis ◽  
Functionally Graded ◽  
Thermoplastic Composites ◽  
Polyamide 66 ◽  
Graded Materials ◽  
Mechanical Fracture

This work investigates the mechanical, fracture toughness, and thermomechanical peculiarity of a novel functionally graded materials (FGMs)–based glass fiber–filled polyamide 66 (PA66) composites. FGMs-based PA66 are fabricated through a particularly designed mold and a punch. Punch is a rotating element of the mold and rotates at 1800 r/min for two min for the fabrication of FGMs. Gradation of fibers takes place in FGMs toward the periphery of the punch cavity due to the centrifugal force. Neat PA66 and homogeneous composites are also fabricated through the same mold for comparative study. Punch remains stationary during the fabrication of neat PA66 and homogeneous composites. PA66 granules filled with 15 wt% and 30 wt% of glass fibers are used to manufacture FGMs and homogeneous composites. Ignition loss test, hardness measurement, and scanning electron microscope (SEM) analysis are used to verify the gradation of glass fibers within FGMs. Result analysis concluded that FGMs performed better as compared to neat PA66 and homogeneous composites. FGMs-based thermoplastic composites have full scope to fabricate polymer gears used in low load applications. This manufacturing route shows a promising potential for fabrication of FGMs-based thermoplastics which otherwise is difficult to manufacture because of their high solidification rate at room temperature.

Tensile Behaviour of Functionally Graded Braided Carbon Fibre/Epoxy Composite Material

2002 ◽  
Vol 10 (4) ◽  
pp. 307-314 ◽  
Author(s):  
Zheng-Ming Huang ◽  
Qiongan Wang ◽  
S. Ramakrishna
Keyword(s):  
Tensile Strength ◽  
Carbon Fibre ◽  
Research Work ◽  
Tensile Modulus ◽  
Primary Objective ◽  
Functionally Graded ◽  
Tensile Behaviour ◽  
Braided Composites ◽  
Graded Materials ◽  
Braiding Angle

The primary objective of this research work was to investigate experimentally the tensile behaviour of Functionally Graded Materials (FGM) made from tubular braided composites and to find out the relationship between the tensile property of the FGM and that of the corresponding non-FGM. Composites were made using tubular braided carbon fibre fabrics and an epoxy resin. The FGM specimens had varying braiding angles and the non-FGM specimens had constant braiding angles. The effect of braiding angle on the composite properties was established from the test results for the non-FGM specimens. It was shown that both the tensile strength and modulus decreased as the braiding angle increased. The tensile behaviour of the FGM specimens was demonstrated to be related to that of the non-FGM specimens. The tensile modulus of an FGM specimen could be estimated from the tensile moduli of a series of non-FGM specimens. The tensile strength of an FGM specimen was a function of its largest braiding angle, and was higher than that of a non-FGM specimen with a braiding angle equal to this largest braiding angle.

Sign in / Sign up

Export Citation Format

Share Document