Influence of Fiber-matrix Interphase on the Long-term Behavior of Graphite/ Epoxy Composites

Author(s):  
S Subramanian ◽  
JS Elmore ◽  
WW Stinchcomb ◽  
KL Reifsnider
2019 ◽  
Vol 54 (6) ◽  
pp. 731-743 ◽  
Author(s):  
Dielly Cavalcanti da Silva Monte Vidal ◽  
Heitor L Ornaghi ◽  
Felipe Gustavo Ornaghi ◽  
Francisco Maciel Monticeli ◽  
Herman Jacobus Cornelis Voorwald ◽  
...  

In the present study, different stacking sequences on hybrid carbon/glass/epoxy composites laminate were examined in relation to thermal, dynamic mechanical and long-term behavior. A positive hybrid effect was found for both hybrid composites (interleaved-Hybrid 1 and in block-Hybrid 2) showing that in some cases hybrid composites can properly replace carbon or glass composites. The composite containing all glass fiber in the middle (Hybrid 2) presented similar thermal behavior when compared to glass fiber composite. All hybrid composites presented higher storage modulus when compared to glass composite. Dynamic mechanical analysis showed that both hybrids can satisfactorily perform the requirement in a wide temperature range. The long-term prediction was successfully applied for all composites, showing to be highly temperature-dependent. Hence, depending on the application requirement, both hybrids can be used, saving weight and cost.


2021 ◽  
Vol 1756 ◽  
pp. 147334
Author(s):  
Charles Budaszewski Pinto ◽  
Natividade de Sá Couto-Pereira ◽  
Felipe Kawa Odorcyk ◽  
Kamila Cagliari Zenki ◽  
Carla Dalmaz ◽  
...  

1997 ◽  
Vol 07 (11) ◽  
pp. 2487-2499 ◽  
Author(s):  
Rabbijah Guder ◽  
Edwin Kreuzer

In order to predict the long term behavior of nonlinear dynamical systems the generalized cell mapping is an efficient and powerful method for numerical analysis. For this reason it is of interest to know under what circumstances dynamical quantities of the generalized cell mapping (like persistent groups, stationary densities, …) reflect the dynamics of the system (attractors, invariant measures, …). In this article we develop such connections between the generalized cell mapping theory and the theory of nonlinear dynamical systems. We prove that the generalized cell mapping is a discretization of the Frobenius–Perron operator. By applying the results obtained for the Frobenius–Perron operator to the generalized cell mapping we outline for some classes of transformations that the stationary densities of the generalized cell mapping converges to an invariant measure of the system. Furthermore, we discuss what kind of measures and attractors can be approximated by this method.


2007 ◽  
Vol 133 (9) ◽  
pp. 1307-1315 ◽  
Author(s):  
M. Fragiacomo ◽  
R. M. Gutkowski ◽  
J. Balogh ◽  
R. S. Fast
Keyword(s):  

2021 ◽  
pp. 004051752110519
Author(s):  
Yecheng Fan ◽  
Shen Ziyue ◽  
Shaohua Zeng ◽  
Pengpeng Chen ◽  
Ying Xu ◽  
...  

To improve the interfacial adhesion of glass fiber (GF)/epoxy composites, the GF surface was treated by dispersing aliphatic diamine-functionalized multi-walled carbon nanotubes (MWCNTs). Carboxyl MWCNTs were first modified by aliphatic diamine with different alkyl chain lengths and then deposited on the surface of GF. The effect of aliphatic diamine chain lengths on the MWCNTs’ dispersion and interfacial properties of resultant composites was investigated in detail. The results showed that uniform dispersion of MWCNTs and strong fiber/matrix interfacial adhesion could be achieved, based on the grafting of 1,8-octanediamine onto MWCNTs. Compared with the control sample, the interlaminar shear, flexural, and tensile strengths of the treated composites increased by 41%, 29%, and 30%, respectively; the interlaminar fracture toughness and storage modulus in the glass region were significantly enhanced; and the glass transition temperature increased by more than 8°C. This work demonstrates that the carbon nanotubes functionalized by appropriate chain lengths of amine modifier can improve the fiber/matrix interfacial interactions and thus enhance the strength, toughness, and stiffness of fiber-reinforced composites.


Author(s):  
Panpan Zhang ◽  
Anhui Gu

This paper is devoted to the long-term behavior of nonautonomous random lattice dynamical systems with nonlinear diffusion terms. The nonlinear drift and diffusion terms are not expected to be Lipschitz continuous but satisfy the continuity and growth conditions. We first prove the existence of solutions, and establish the existence of a multi-valued nonautonomous cocycle. We then show the existence and uniqueness of pullback attractors parameterized by sample parameters. Finally, we establish the measurability of this pullback attractor by the method based on the weak upper semicontinuity of the solutions.


2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
F. Nyabadza ◽  
B. T. Bekele ◽  
M. A. Rúa ◽  
D. M. Malonza ◽  
N. Chiduku ◽  
...  

Most hosts harbor multiple pathogens at the same time in disease epidemiology. Multiple pathogens have the potential for interaction resulting in negative impacts on host fitness or alterations in pathogen transmission dynamics. In this paper we develop a mathematical model describing the dynamics of HIV-malaria coinfection. Additionally, we extended our model to examine the role treatment (of malaria and HIV) plays in altering populations’ dynamics. Our model consists of 13 interlinked equations which allow us to explore multiple aspects of HIV-malaria transmission and treatment. We perform qualitative analysis of the model that includes positivity and boundedness of solutions. Furthermore, we evaluate the reproductive numbers corresponding to the submodels and investigate the long term behavior of the submodels. We also consider the qualitative dynamics of the full model. Sensitivity analysis is done to determine the impact of some chosen parameters on the dynamics of malaria. Finally, numerical simulations illustrate the potential impact of the treatment scenarios and confirm our analytical results.


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