Begell House Inc.
Composites: Mechanics, Computations, Applications: An International Journal
CMCA
2152-2057
11
2
2020
RESEARCH OF ACTIVATION ENERGY OF THERMAL BREAKDOWN OF POLYMER COMPOSITES MODIFIED BY 4-AMINOBENZOIC ACID
99-112
10.1615/CompMechComputApplIntJ.2020030906
A. V.
Buketov
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
Andriy G.
Kulinich
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
A. V.
Akimov
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
S. A.
Smetankin
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
V. N.
Gusev
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
R. N.
Levkivskyi
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
activation energy
thermogravimetric analysis
Broido method
modifier
epoxy composite
properties
Calculation of the effective activation energy of thermo-oxidative breakdown (E) of modified epoxy composite materials is carried out on the basis of thermogravimetric analysis using the Broido double logarithmic method. The maximum values of activation energy (E = 152.1 kJ/mol and 152.3 kJ/mol) were found experimentally for composite materials modified by 0.25 wt.% and 0.50 wt.% of 4-aminobenzoic acid, respectively. The values obtained indicate a significant effect of modifier on the activation energy of epoxy composite materials. The results found experimentally show the formation of relatively thermally stable intra- and intermolecular bonds, which indicates the improvement of cross-linking of epoxy composite macromolecules. Improving the cross-linking of epoxy composite macromolecules leads to an increase of thermal stability, which as a result, has an effect on increasing the materials durability.
INFLUENCE OF THE STRUCTURE OF EPOXY COMPOSITE FILLED WITH DISCRETE FIBERS ON IMPACT FRACTURE OF VEHICLE PARTS
113-127
10.1615/CompMechComputApplIntJ.2020031192
A. V.
Buketov
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
А. V.
Sapronova
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
O. O.
Sapronov
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
N. M.
Buketova
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
V. V.
Sotsenko
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
Mykola V.
Brailo
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
Serhii V.
Yakushchenko
Kherson State Maritime Academy, 20 Ushakova Ave., Kherson, Kherson Oblast 73009, Ukraine
P. О.
Maruschak
Ternopil Ivan Puluj National Technical University, 56 Ruska Str., Ternopil,
46001, Ukraine
S. V.
Panin
Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences, 2/4 Akademicheskii Ave., Tomsk, 634055, Russia; National Research Tomsk Polytechnic University, 2A Lenin Ave., Bld. 11,
Tomsk, 634028, Russia
Sergey O.
Smetankin
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
Andriy G.
Kulinich
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
Viacheslav G.
Kulinich
Kherson State Maritime Academy, 20 Ushakov Ave., Kherson, 73009, Ukraine
mixture of discrete fibers
epoxy composite
IR spectral analysis
mechanical strength
destruction surface
vector of crack propagation
The influence of the content of a mixture of discrete organic fibers on the mechanical strength and nature of destruction of epoxy composites is investigated. It is proved that the introduction of fiber additive into an epoxy binder at an optimum content (q = 0.01 wt.%) increases the impact strength of polymer composites 1.8 times in comparison with the epoxy matrix. It is shown that the growth of impact strength is connected with self-regulation of the structure of composites filled with discrete fibers during the cross-linking process of polymer composites. To determine the resistance of the developed composite materials to impact shocks, changes in spectra of crack propagation during impact shocks with time are investigated and deformation dependences of specimens on shocks are found. The destruction surface of composite materials filled with fiber additive is investigated by the optical microscopy method. An ordered structure of composite materials at the optimum content of a mixture of discrete organic fibers (without fragile areas on the destruction surface and visible granules) is found, which allows one to state the thermodynamic equilibrium in heterogeneous systems after their cross-linking. This additionally indicates a high index of mechanical strength of developed epoxy composites.
RELATIONSHIP BETWEEN THE APPLIED STRESS TRANSFER AND THE NANOFILLER AGGREGATION LEVEL FOR POLYMER/ CARBON NANOTUBES NANOCOMPOSITES
129-135
10.1615/CompMechComputApplIntJ.2020034572
Georgii V.
Kozlov
Kh. M. Berbekov Kabardino-Balkarian State University, 173 Chernyshevsky Str.,
Nal'chik, Kabardino-Balkarian Republic, 360004, Russia
I. V.
Dolbin
Kh. M. Berbekov Kabardino-Balkarian State University, 173 Chernyshevsky Str.,
Nal'chik, Kabardino-Balkarian Republic, 360004, Russia
Yulia N.
Karnet
Institute of Applied Mechanics, Russian Academy of Sciences,7 Leningradsky Ave., Moscow, 125040, Russia
Alexander N.
Vlasov
Institute of Applied Mechanics, Russian Academy of Sciences, 7 Leningradsky Ave., Moscow, 125040, Russia
nanocomposite
carbon nanotubes
stress transfer efficiency
structure
aggregation
fractal dimensionality
reinforcement degree
The relationship was studied between the parameter important for the formation of the properties of polymer nanocomposites, namely, the transfer efficiency of the mechanical stress applied to the sample from the polymer matrix to the nanofiller, and the structure of carbon nanotubes formed in this matrix. It has been found that the indicated efficiency, controlled by the level of interfacial adhesion of the nanofiller-polymer matrix, critically depends on the main negative process for all nanocomposites, that is, aggregation of the nanofiller, an increase in the degree which reduces the efficiency of stress transfer. For the nanocomposites under consideration, the process of carbon nanotubes aggregation takes place in the form of emergence of their annular formations that are fractal objects, which has been confirmed experimentally. This fact allows characterization of the carbon nanotubes structure in a polymer matrix using a fractal dimensionality. It has been found that an increase in the fractal dimensionality of the annular formations of carbon nanotubes, reflecting an upgrowth in the degree of their aggregation unambiguously reduces the efficiency of mechanical stress transfer as well as the nanofiller ability to generate interfacial regions.
MODELING AND NUMERICAL SIMULATION OF THE STATIC BEHAVIOR OF MAGNETO-ELECTRO-ELASTIC MULTILAYER PLATES BASED ON A WINKLER-PASTERNAK ELASTIC SUPPORT
137-158
10.1615/CompMechComputApplIntJ.2020031221
Mustapha
Hamidi
Team M2I, Laboratory of Sciences and Engineering, ENSAM, Moulay Ismail
University, Meknes, Morocco
S.
Zaki
Team M2I, Laboratory of Sciences and Engineering, ENSAM, Moulay Ismail
University, Meknes, Morocco; Team M2AI, Mechanical Mechatronics and Control Laboratory, ENSAM,
Moulay Ismail University, Meknes, Morocco
Mohamed
Aboussaleh
Team M2I, Laboratory of Sciences and Engineering, ENSAM, Moulay Ismail
University, Meknes, Morocco
multilayer plates
magneto-electro-elastic
elastic support
Winkler-Pasternak
state space method
static behavior
In this paper, the state space method is used to analyze the static behavior of laminated magneto-electro-elastic rectangular plates with simply supported boundary conditions based on an elastic support. The mathematical formulation is elaborated in a general form and an arbitrary number of layers as well as the orthotropic behavior can be considered. The methodology is based on the mixed formulation, in which basic unknowns are formed by collecting displacements, stresses, electrical displacements, electrical potential, magnetic induction, and magnetic potential. As a special case, a multilayered rectangular plate is analyzed under the surface loading with simply supported boundary conditions based on an elastic support. The mathematical procedure, elaborated in this paper, allows the study of the effects of the elastic support parameters on the static behavior of these materials. The effectiveness of the proposed methods has been demonstrated by performing variant numerical tests.
MODELING NORMAL WAVES IN FUNCTIONALLY GRADED LAYERS BASED ON THE UNIFIED HIERARCHICAL FORMULATION OF HIGHER-ORDER PLATE THEORIES
159-185
10.1615/CompMechComputApplIntJ.2020034542
Sergey I.
Zhavoronok
Department of Mechanics of Smart and Composite Materials and Systems,
Institute of Applied Mechanics of Russian Academy of Sciences, Moscow, Russian
Federation; Department of Applied Mathematics and Informatics, Moscow State
University of Civil Engineering, Russian Federation
functionally graded plates
higher-order theories
analytical dynamics
Lagrangian formalism
normal wave dispersion
phase frequencies
wave forms
orthogonal polynomials
semianalytical finite elements
convergence
The normal wave dispersion in functionally graded plates investigated by implying the hierarchical theory of plates−improving contribution to the Vekua-Amosov theory. The combined use of the Lagrangian formalism of the analytical dynamics of continuum, dimensional reduction method, and of the biorthogonal expansion technique allows one to obtain the hierarchical traditional, as well as semianalytical finite element models under the unified general variational formulation. The comparative analysis of the convergence of approximate solutions of the wave dispersion problem for the isotropic homogeneous plate is performed for the locking phase frequencies. The wave dispersion in power graded plates with symmetric through-thickness structure is considered, the convergence of solutions is analyzed for both orthogonal polynomial and finite element approximation, and the dependence of the locking frequencies on the power index is studied.