scholarly journals Continuum Damage Micromechanics Model for the Compressive Failure of Flax Fiber Composites and Experimental Validation

2021 ◽  
Author(s):  
V. Tojaga ◽  
A. Prapavesis ◽  
J. Faleskog ◽  
T. Gasser ◽  
A. Vuure ◽  
...  
Keyword(s):  
Experimental Validation ◽  
Fiber Composites ◽  
Flax Fiber ◽  
Continuum Damage ◽  
Compressive Failure ◽  
Micromechanics Model

scholarly journals Dielectric, Thermal and Water Absorption Properties of Some EPDM/Flax Fiber Composites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2555
Author(s):  
Anton Airinei ◽  
Mihai Asandulesa ◽  
Maria Daniela Stelescu ◽  
Niţǎ Tudorachi ◽  
Nicusor Fifere ◽  
...  
Keyword(s):  
Water Uptake ◽  
Electron Beam Irradiation ◽  
Degradation Products ◽  
Fiber Composites ◽  
Flax Fiber ◽  
Relaxation Processes ◽  
Ethylene Propylene Diene Monomer ◽  
Beam Irradiation ◽  
Absorption Properties ◽  
Different Doses

This paper deals with the dielectric and sorption properties of some flax fiber-reinforced ethylene-propylene-diene monomer (EPDM) composites containing different fiber loadings as well as their behavior after exposure to different doses of electron beam irradiation. Three relaxation processes were evinced, a weak relaxation β at sub-Tg temperatures and two α-type relaxations above the Tg. The EPDM/flax composites exhibited higher values of dielectric constant, dielectric loss and conductivity as compared to a pristine EPDM sample. Using thermogravimetric analysis (TG) coupled with Fourier transform infrared spectroscopy (FTIR) and mass spectrometry (MS) (TG/FTIR/MS system), the degradation products can be identified. The water uptake increased as the flax fiber level increased in composites. The water uptake tests of irradiated composites showed that the highest water content was obtained for a flax fiber level of 20 phr.

scholarly journals Influence of Furfuryl Alcohol Fiber Pre-Treatment on the Moisture Absorption and Mechanical Properties of Flax Fiber Composites

Fibers ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 59 ◽  
Author(s):  
Yunlong Jia ◽  
Bodo Fiedler
Keyword(s):  
Mechanical Properties ◽  
Furfuryl Alcohol ◽  
Moisture Absorption ◽  
Natural Fiber ◽  
Tensile Tests ◽  
Fiber Composites ◽  
Flax Fiber ◽  
Moisture Resistance ◽  
Structural Applications ◽  
Pre Treatment

Poor moisture resistance of natural fiber reinforced bio-composites is a major concern in structural applications. Many efforts have been devoted to alleviate degradation of bio-composites caused by moisture absorption. Among them, fiber pre-treatment has been proven to be effective. This paper proposes an alternative “green” fiber pretreatment with furfuryl alcohol. Pre-treatments with different parameters were performed and the influence on the mechanical properties of fiber bundles and composites was investigated. Moisture resistance of composites was evaluated by water absorption tests. Mechanical properties of composites with different water contents were analyzed in tensile tests. The results show that furfuryl alcohol pretreatment is a promising method to improve moisture resistance and mechanical properties (e.g., Young’s modulus increases up to 18%) of flax fiber composites.

MODELING AND SIMULATION OF THE CURING PROCESS OF EPOXY RESINS AND FIBER COMPOSITES

2021 ◽  
Author(s):  
ANASTASIA MULIANA
Keyword(s):  
Constitutive Model ◽  
Residual Stresses ◽  
Elastic Moduli ◽  
Processing Parameters ◽  
Fiber Composites ◽  
Curing Process ◽  
Reinforced Composites ◽  
Micromechanics Model ◽  
Epoxy Curing ◽  
Exothermic Process

This study discusses simulations of the curing process in epoxy and fiberreinforced polymer composites incorporating changes in the thermal and mechanical properties of epoxy during curing at various temperatures. A coupled constitutive model that includes an exothermic process from the cross-linking, heat conduction across the specimen and deformations of the specimen from the thermal expansion and shrinkage effects is formulated. The model is used to capture the curing process in the epoxy resin. The coupled constitutive model is then integrated into a micromechanics model of fiber-reinforced composites and used to study the influence of epoxy curing on the formation of residual stresses in the composites. Furthermore, the micromechanics model is also used to predict the macroscopic properties, i.e., elastic moduli, of the cured composites. The model can then be used to understand the influence of processing parameters, i.e., temperatures and pressure, on the formation of residual stresses and their consequences on the overall properties of cured composites.

Fiber/matrix interface stress analysis of flax-fiber composites under transverse loading considering material nonlinearity

2020 ◽  
Vol 39 (9-10) ◽  
pp. 345-360
Author(s):  
Baris Sabuncuoglu ◽  
Onur Cakmakci ◽  
Fevzi S Kadioglu
Keyword(s):  
Fiber Composites ◽  
Flax Fiber ◽  
Material Nonlinearity ◽  
Transverse Strain ◽  
Matrix Interface ◽  
Transverse Loading ◽  
Stress Concentrations ◽  
Transverse Cracks ◽  
Fiber Matrix Interface ◽  
Fiber Matrix

Distribution of stresses in fiber/matrix interface in UD flax fiber reinforced composites is investigated under transverse loading and compared with conventional synthetic fibers. Micro-scale finite element models with representative volume elements are generated with various fiber packing types and fiber volume ratios. The study is performed for various strain values, which take into account the material nonlinearity of matrix. The results show that significantly lower stress concentrations exist in the case of flax fibers compared to glass fiber composites, explaining the absence of transverse cracks until failure in previously conducted transverse tension tests. Increase in the applied transverse strain causes a further decrease in the stress concentrations due to the nonlinear behavior of the matrix.

Longitudinal Compressive Failure Modes in Fiber Composites: End Attachment Effects on IITRI Type Test Specimens

1985 ◽  
Vol 7 (4) ◽  
pp. 129 ◽  
Author(s):  
KL Reifsnider ◽  
GP Sendeckyj ◽  
SS Wang ◽  
TT Chaio ◽  
W Feng ◽  
...  
Keyword(s):  
Failure Modes ◽  
Fiber Composites ◽  
Compressive Failure ◽  
Type Test

Simulation of Post Failure Response in Fiber Composites

2011 ◽  
Author(s):  
Badrinath Veluri ◽  
Henrik Myhre Jensen
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Constitutive Model ◽  
Failure Mechanism ◽  
Inclination Angle ◽  
Layered Materials ◽  
Fiber Composites ◽  
Finite Element Code ◽  
Compressive Failure ◽  
Localization Of Deformation

This study focuses on the compressive failure mechanism in the form of kinkband formation in fiber composites. Taking into account the non-linearities of the constituents, a constitutive model for unidirectional layered materials has been developed and incorporated as a user material in a commercially available finite element code to study effects of kinkband inclination angle and micro-geometry on kinkband formation. The localization of deformation into a single kinkband is studied. In the post failure regime a state is reached where deformation in the kinkband gets stabilized and the kinkband broadens under steady-state conditions.

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