Effect of degree of cure on viscoplastic shear strain development in layers of [45/−45]s glass fibre/ epoxy resin composites

2018 ◽  
Vol 52 (24) ◽  
pp. 3277-3288 ◽  
Author(s):  
Liva Pupure ◽  
Sibin Saseendran ◽  
Janis Varna ◽  
Margherita Basso
Keyword(s):  
Epoxy Resin ◽  
Shear Strain ◽  
Glass Fibre ◽  
Final Phase ◽  
Strain Development ◽  
Degree Of Cure ◽  
Residual Stress State ◽  
Viscoelastic Strain ◽  
Applied Shear Stress ◽  
Observed Behaviour

Effect of degree of cure on irreversible (viscoplastic) shear strain development in layers of glass fibre/ epoxy resin (LY5052 epoxy resin) [+45 °/−45 °]s laminate is studied performing a sequence of constant stress creep and viscoelastic strain recovery tests. For fixed values of degree of cure in range from 79.7% to 100%, the viscoplastic strains were measured as dependent on time and stress and Zapa's integral representation was used to characterize the observed behaviour. It is shown that at all degrees of cure the viscoplastic behaviour can be described by Zapa's model with parameters dependent on degree of cure. It is shown that for degree of cure lower than 80% the viscoplastic strains grow much faster and are much more sensitive to the increase of the applied shear stress. These irreversible strains developing in the final phase of the curing can significantly alter the residual stress state in the composite structure.

scholarly journals INVESTIGATION OF RESIDUAL STRESSES AND DEFORMATIONS OF A PULTRUDED THIN BEAM PROFILE

2021 ◽  
Vol 3 ◽  
pp. 232-235
Author(s):  
Endija Namsone
Keyword(s):  
Chemical Analysis ◽  
Residual Stresses ◽  
Epoxy Resin ◽  
Glass Fibre ◽  
Mechanical Analysis ◽  
Beam Profile ◽  
Degree Of Cure ◽  
Thin Beam ◽  
Linear Elastic ◽  
Applied Approach

In the present study, a coupled 3D transient thermo-chemical analysis together with 2D plane strain mechanical analysis is carried out for the pultrusion process. For the mechanical analysis, a cure hardening instantaneous linear elastic (CHILE) approach is used of a thin beam profile made of glass fibre and epoxy resin. The applied approach is efficient and fast to investigate the residual stresses and deformations together with the distributions of temperature and degree of cure obtained from the thermo-chemical analysis. 

Orthotropic Characteristics of Glass-Fibre-Epoxy Laminates under Plane Stress

1973 ◽  
Vol 15 (2) ◽  
pp. 102-108 ◽  
Author(s):  
R. M. Ogorkiewicz
Keyword(s):  
Tensile Strength ◽  
Epoxy Resin ◽  
Uniaxial Tension ◽  
Plane Stress ◽  
Glass Fibre ◽  
Orthotropic Material ◽  
Glass Fibres ◽  
Degree Of Anisotropy

Deformational characteristics of laminates of unidirectionally arranged glass fibres and epoxy resin under plane stress are shown to correspond very closely under uniaxial tension and, to a lesser extent, under shear to the theroetical pattern of stiffness of an orthotropic material. The anisotropy in stiffness is also shown to be accompanied by an even greater degree of anisotropy in tensile strength.

Viscoelastic behavior of an epoxy resin during cure below the glass transition temperature: Characterization and modeling

2018 ◽  
Vol 53 (2) ◽  
pp. 155-171 ◽  
Author(s):  
Alice Courtois ◽  
Martin Hirsekorn ◽  
Maria Benavente ◽  
Agathe Jaillon ◽  
Lionel Marcin ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Epoxy Resin ◽  
Viscoelastic Behavior ◽  
Mechanical Analysis ◽  
Strain History ◽  
Model Parameters ◽  
Degree Of Cure ◽  
Model Predictions

This paper presents a viscoelastic temperature- and degree-of-cure-dependent constitutive model for an epoxy resin. Multi-temperature relaxation tests on fully and partially cured rectangular epoxy specimens were conducted in a dynamic mechanical analysis apparatus with a three-point bending clamp. Master curves were constructed from the relaxation test results based on the time–temperature superposition hypothesis. The influence of the degree of cure was included through the cure-dependent glass transition temperature which was used as reference temperature for the shift factors. The model parameters were optimized by minimization of the differences between the model predictions and the experimental data. The model predictions were successfully validated against an independent creep-like strain history over which the temperature varied.

Stretch Formability Behaviour of Glass Fibre Reinforced Nanoclay on Fiber Metal Laminated Composites

2018 ◽  
Vol 10 (2) ◽  
Author(s):  
K. Logesh ◽  
V.K Bupesh Raja ◽  
C. Krishnaraj
Keyword(s):  
Ductile Fracture ◽  
Epoxy Resin ◽  
Glass Fibre ◽  
Weight Ratio ◽  
High Strength ◽  
Core Material ◽  
Fibre Metal Laminates ◽  
Sem Image ◽  
Pull Out ◽  
Fibre Metal

Innovations and research in material processing have brought forward new and improvised materials that are applied in body panels of automobiles, aircraft cabins and railway wagons. These materials are used widely is because of their good mechanical properties and their high strength to weight ratio. In this paper Fibre Metal Laminates (FMLs) were added with organo modified montmorillonite (MMT) commonly known as nanoclay along with epoxy resin. The homogeneous dispersion of nanoclay in epoxy resin is accomplished by a hand stirrer dispersion method in ethanol. The FML material was processed by hand layup method. In this study the aluminium alloy 5052-H32 was used as a skin material and glass fibre (woven roving) used as core material which is bounded by epoxy with 5 wt.% nano clay (closet 30B). The fabricated sandwich material was cut by using water jet machine as per IS standards for testing. The fabricated material subjected to erichsen cupping test and was observed under Scanning Electron Microscope (SEM). The results from SEM image analysis indicated that the FML had fibre pull out and surface cracks were obtained in the skin material. Progressive loading resulted in ductile fracture which is absorbed in the specimen. Fibres came across brittle failure and the skin through ductile fracture. Non-uniform distribution of reinforcement is observed in the material, SEM micrographs revealed fibre cracks which were oriented in line to the direction of crack growth on the skin material. This study shows that these fibre metal laminates can be safely applied in automotive field.

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