Development Of Composite Materials Research Articles

Multiscale model for bottom-up prediction of failure parameters of unidirectional carbon-fiber-reinforced composite lamina from the atomic to filament-scales, and its application to failure modeling of open-hole quasi-isotropic composite laminates

A multiscale model is developed to comprehensively predict the failure parameters associated with the elasto-plasticity of a unidirectional carbon-fiber-reinforced composite lamina; the prediction is performed according to the resin-matrix design. The developed model involves quantum-chemical reaction-path calculations, molecular-dynamics simulations, and micromechanical analyses at the filament scale. The presented model is further combined with an advanced numerical approach developed based on an extended finite-element method, to analyze composites at the laminate scale. Using the established four-scale model, the open-hole tension and compression of a quasi-isotropic laminate are simulated, starting from the composition of an epoxy resin. The predicted elasto-plastic properties and strengths of a unidirectional lamina are in good agreement with the previously reported experimental results. Furthermore, the strengths predicted for the open-hole tests are also plausible, as they are similar to the experimental values reported in literature. The established multiscale model is expected to be useful in composite-material development as it facilitates rapid and exhaustive analysis.

ИССЛЕДОВАНИЕ ПРОЦЕССА СТРУКТУРООБРАЗОВАНИЯ И ИЗНОСОСТОЙКОСТИ АБРАЗИВНЫХ ИНСТРУМЕНТОВ НА МЕТАЛЛИЧЕСКОЙ СВЯЗКЕ СОСТАВА 51%Fe+9%Ni+32%Cu+8%Sn, ИЗГОТОВЛЕННЫХ ИЗ МЕТАЛЛИЗИРОВАННЫХ ТИТАНОМ АЛМАЗНЫХ ПОРОШКОВ

The process of of structure formation and wear resistance of abrasive tools on the metal bond of composition 51%Fe+9%Ni+32%Cu+8%Sn made from metallized by titanium diamond powders is investigated. The metallographical substantiation is introduced, as well as the wear-resistance and the working capability of abrasive tools are studied. It is shown that the structure is heterophase and consists of five phases, the first of which is a solid solution based on nickel, the second is a solid solution of tin, nickel, and iron in copper, the third is a solid solution of nickel, copper and tin in iron, the fourth and the fifth are intermetallic compounds with a defective structure. It is revealed that in the developed composite material, the volume content of heavy components is approximately 63%, the plastic component occupies approximately 25% of the sample volume, and the intermetallic phases - approximately 12% of the total volume, which are distributed over the entire sample surface. Based on the results of the complex investigation of the operability and wear resistance of diamond tools manufactured according to the developed technology carried out in the laboratory and production conditions for processing non-metallic materials, the optimal modes of manufacturing highly productive and wear-resistant diamond-metal abrasive tools were selected and substantiated: cold pressing pressure P = 600 MPa, free sintering temperature: T = 850°C, holding at this temperature: τ = 45 min. Applying the developed technology as a method for producing a diamond tool ensures the high efficiency of production.

Control of Properties of Composite Materials - Quality Functional

Methodological principles for the development of composite materials with the desiredstructure and properties are proposed. One of the perspective directions of development ofcomposite materials by their representation as multi-purpose systems with the corresponding systemattributes is considered. The structure of quality functional for objective assessment of quality ofkinetic processes of formation of physic-mechanical characteristics of a composite is developed.The technique of synthesis of construction material based on application of lines of equal level ofquality functional is offered.

Mathematical Modeling of the Electron Structure of Polymer Matrix PVDF+PB(ZRTiO3)+(SiO2)6 Hybrid Micro- and Nanocomposite

Developments of composite materials with organic and inorganic components discover the new possibilities in material science. At present, the numerous kinds of polymer materials with various physical mechanical and electro physical characteristics are used as organic matrix. Numerous piezoelectric materials with various properties are as inorganic phase of composites. Such combination of composite components properties allows to create both micro and nanoactive dielectrics. In this paper there have been presented the results of mathematical modeling of the molecular structure of polymer matrix hybrid micro- and nanocomposites materials having three phases: polyvinylidene fluoride (PVDF) molecule, micro particle of Pb(ZrTiO3) piezoelectric and nanoparticle of (SiO2)6 dielectric (PVDF + Pb(ZrTiO3) + (SiO2)6) by using of Parameterized Model number 3 (PM3) semi empirical method. Molecular orbitals energy, potential ionization, the total electronic energy of PVDF + Pb(ZrTiO3) + (SiO2)6 nanocomposite have been calculated. The theoretical models of (SiO2)n nanoparticle, Pb(ZrTiO3) microparticle and polymer matrix of PVDF 2(h-(-chf-chf-)10-h) + (SiO2)6 + PbZrTiO3 hybrid micro- and nanocomposite are constructed. The results of calculations show that PVDF + Pb(ZrTiO3) + (SiO2)6 nanocomposite is solid, electrophile, dielectrical and stable material. The wavelength of radiated photon is l228 nm. The elasticity of PVDF + Pb(ZrTiO3) + (SiO2)6 nanocomposite is more than twice the elasticity of PVDF polymer. They will find a wide application in radio engineering, electronics, optoelectronics and piezo technic, seismic and acoustic technics.

Bounds on Flexural Properties and Buckling Response for Symmetrically Laminated Composite Plates

Nondimensional parameters and equations governing the buckling behavior of rectangular symmetrically laminated plates are presented that can be used to represent the buckling resistance, for plates made of all known structural materials, in a very general, insightful, and encompassing manner. In addition, these parameters can be used to assess the degree of plate orthotropy, to assess the importance of anisotropy that couples bending and twisting deformations, and to characterize quasi-isotropic laminates quantitatively. Bounds for these nondimensional parameters are also presented that are based on thermodynamics and practical laminate construction considerations. These bounds provide insight into potential gains in buckling resistance through laminate tailoring and composite-material development. As an illustration of this point, upper bounds on the buckling resistance of long rectangular orthotropic plates with simply supported or clamped edges and subjected to uniform axial compression, uniform shear,...