Micromechanics modeling of viscoelastic properties of hybrid composites with shunted and arbitrarily oriented piezoelectric inclusions

In the present work, a combination of experimental and numerical procedure is proposed to study the effects of different hygrothermal conditions on the creep strain, viscoelastic properties of nanocomposites, and mechanical properties of such nanocomposite-based carbon fiber–reinforced polymer (CFRP) hybrid composite materials. Ultrasonic probe sonicator is used to randomly disperse the multiwalled carbon nanotubes into an epoxy to minimize agglomerations. Dynamic mechanical analysis is employed to conduct the creep tests under different hygrothermal conditions of such nanocomposite samples. The Findley power law is used to obtain the long-term creep behavior of nanocomposite materials. Prony series is used to determine the viscoelastic properties of nanocomposite material in the frequency domain. Coefficient of moisture expansion (CME) is independent of moisture concentration; thus, CME of the nanocomposite is also determined. Strength of materials and Saravanos–Chamis micromechanics (SCM) have also been utilized to obtain the mechanical properties of such hybrid composite materials under different hygrothermal conditions. It has been found that the inclusion of multiwalled carbon nanotubes in the nanocomposite and hybrid composites improves storage modulus and loss factor (i.e., tan δ) compared to the conventional CFRP-based composite materials under hygrothermal conditions.

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Dynamic Viscoelastic Properties of Organic / Inorganic Fibres Reinforced lldpe Composites in Molten State

Applied Rheology ◽

10.1515/arh-2001-0014 ◽

2001 ◽

Vol 11 (5) ◽

pp. 258-263 ◽

Cited By ~ 4

Author(s):

Takeschi Kitano ◽

S.A.R. Hashmi ◽

Navin Chand

Keyword(s):

Viscoelastic Properties ◽

Parallel Plate ◽

Hybrid Composites ◽

Loss Modulus ◽

Angular Frequency ◽

Low Density Polyethylene ◽

Rheological Parameters ◽

Low Density ◽

Linear Low Density Polyethylene ◽

Glass Fibres

Abstract Dynamic rheological parameters such as storage modulus, G’, loss modulus, G”, and dynamic viscosity, h’, at 200°C were studied for Kevlar fibres, glass fibres and their hybrids reinforced linear low density polyethylene (LLDPE). Parallel plate rheometer was employed for these tests. G’, G” and h’ increased with the increased reinforcement and angular frequency, w. Two sets of reinforcement, 10 and 20 vol.% of fibres are used in LLDPE. The composition of fibres in hybrid composites was varied. The replacement of glass fibres with Kevlar increases the values of G’, G” and h’. The values of these rheological parameters also increased with the thickness of the composite. This increase was associated with the decreased average orientation of fibres present in the composite. The effects of the change in strain amplitude on G’ and G” is also studied and reported here.

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Enhanced Thermal and Dynamic Mechanical Properties of Synthetic/Natural Hybrid Composites with Graphene Nanoplateletes

Polymers ◽

10.3390/polym11071085 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1085 ◽

Cited By ~ 21

Author(s):

Naveen Jesuarockiam ◽

Mohammad Jawaid ◽

Edi Syams Zainudin ◽

Mohamed Thariq Hameed Sultan ◽

Ridwan Yahaya

Keyword(s):

Mechanical Properties ◽

Viscoelastic Properties ◽

Hybrid Composites ◽

Cocos Nucifera ◽

Research Work ◽

Weight Ratio ◽

Dynamic Mechanical Properties ◽

Differential Scanning Calorimetric ◽

Dynamic Mechanical ◽

Structural Applications

The aim of the present research work is to enhance the thermal and dynamic mechanical properties of Kevlar/Cocos nucifera sheath (CS)/epoxy composites with graphene nano platelets (GNP). Laminates were fabricated through the hand lay-up method followed by hot pressing. GNP at different wt.% (0.25, 0.5, and 0.75) were incorporated with epoxy resin through ultra-sonication. Kevlar/CS composites with different weight ratios (100/0, 75/25, 50/50, 25/75, 0/100) were fabricated while maintaining a fiber/matrix weight ratio at 45/55. Thermal degradation and viscoelastic properties were evaluated using thermogravimetric analysys (TGA), differential scanning calorimetric (DSC) analysis, and a dynamic mechanical analyser (DMA). The obtained results revealed that Kevlar/CS (25/75) hybrid composites at 0.75 wt.% of GNP exhibited similar thermal stability compared to Kevlar/epoxy (100/0) composites at 0 wt.% of GNP. It has been corroborated with DSC observation that GNP act as a thermal barrier. However, DMA results showed that the Kevlar/CS (50/50) hybrid composites at 0.75 wt.% of GNP exhibited almost equal viscoelastic properties compared to Kevlar/epoxy (100/0) composites at 0 wt.% GNP due to effective crosslinking, which improves the stress transfer rate. Hence, this research proved that Kevlar can be efficiently (50%) replaced with CS at an optimal GNP loading for structural applications.

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