Investigation of Fracture in Transparent Glass Fiber Reinforced Polymer Composites Using Photoelasticity

2002 ◽  
Author(s):  
Sanjeev K. Khanna ◽  
Marius D. Ellingsen ◽  
Robb M. Winter
Keyword(s):  
Composite Materials ◽  
Fatigue Cracks ◽  
Large Body ◽  
Mechanical Analysis ◽  
Pressure Vessels ◽  
High Ratio ◽  
Material Behavior ◽  
Engineering Structures ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Polymer Composites

Composite materials are widely used in mechanical structures where a high ratio of strength or stiffness to weight is desired. Not only are composite materials widely used in building recreational equipment such as skis, snowboards or even sports cars, but also multiple types of military aircraft are built from composite materials. Airplane bodies are in principle cyclically loaded pressure vessels and are susceptible to the formation of fatigue cracks, and it is necessary to possess knowledge of how the material behaves with a crack present. In fact, all engineering structures have to be designed with the presence of crack like defects in mind. For traditional engineering materials such as steel and aluminum there exists a large body of knowledge regarding material behavior in the presence of a crack. Furthermore, their isotropic nature eases the process of mechanical analysis. Photoelasticity, an optical method, has been widely used to study fracture in isotropic transparent materials (Irwin, 1962, 1980; Dally, 1979; Daniel, 1984; Kobayashi, et al, 1973; Chona, 1987).

scholarly journals Exposure of Glass Fiber Reinforced Polymer Composites in Seawater and the Effect on Their Physical Performance

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 807 ◽  
Author(s):  
Matteo Cavasin ◽  
Marco Sangermano ◽  
Barry Thomson ◽  
Stefanos Giannis
Keyword(s):  
Glass Fiber ◽  
Oil And Gas ◽  
Sea Water ◽  
Mechanical Analysis ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Chemical Action ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Polymer Composites ◽  
Water Effects

An innovative testing methodology to evaluate the effect of long-term exposure to a marine environment on Glass Fiber Reinforced Polymers (GFRPs) has been investigated and is presented in this paper. Up to one-year ageing was performed in seawater, to simulate the environment for offshore oil and gas applications. The performance of an epoxy and epoxy-based GFRP exposed at different temperatures from 25 to 80 °C was quantified. The materials were also aged in dry air, to de-couple the thermal effect from the seawater chemical action. Gravimetric testing and Dynamic Mechanical Analysis (DMA) were conducted in parallel on progressively aged specimens. The effect of specimen geometry and the anisotropic nature of diffusion are comprehensively discussed in this paper. For the quasi-infinite specimens, the results show an exponential increase in the seawater absorption rate with temperature. The methodology allowed for the prediction of the diffusivity at a temperature of 4 °C as 0.23 and 0.05 × 10−13 m2/s for the epoxy and the epoxy-based composite, respectively. The glass transition temperature reduces as sea water is absorbed, yet the sea water effects appear to be reversible upon drying.

Influence of Plastic Prestrain on the Fatigue Crack Growth Resistance (da/dN vs. ΔK) of ASTM A36 Structural Steel

2015 ◽  
Author(s):  
Gustavo Henrique B. Donato ◽  
Fábio Gonçalves Cavalcante
Keyword(s):  
Mechanical Properties ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Growth Rates ◽  
Fatigue Cracks ◽  
Pressure Vessels ◽  
Engineering Structures ◽  
Fatigue Crack Growth Resistance ◽  
Crack Growth Rates

High responsibility components operating under cyclic loading can have their resistance against initiation and growth of fatigue cracks highly influenced by previous thermomechanical processing. Within the interest of the present work, different manufacturing processes and installation techniques incorporate cold plastic straining to engineering structures; two typical examples on the oil and gas fields are: i) the offshore pipelines installation method called reeling; ii) the fabrication of pipes using the UOE method and pressure vessels through calendering. Within this scenario, this work investigates the effects of plastic prestrain on the fatigue crack growth rates (da/dN vs. ΔK) of a hot-rolled ASTM A36 steel. Different from previous results from the literature, in which prestrains were applied directly to machined samples, in this work uniform prestraining was imposed to steel strips (1/2” thick) and specimens were then extracted to avoid (or minimize) residual stress effects. Prestrain levels were around 4, 8 and 14% and C(T) specimens were machined from original and prestrained materials according to ASTM E647 standard. Fatigue crack growth tests were carried out under load control in an MTS 810 (250 kN) equipment using R = 0.1. Results revealed that plastic prestraining considerably reduced crack growth rates for the studied material, which was expected based on the literature and hardening behavior of the studied material. However, results also revealed two interesting trends: i) the larger is the imposed prestrain, the greater is the growth rate reduction in a nonlinear asymptotic relationship; ii) the larger is imposed ΔK, the more pronounced is the effect of prestraining. Crack closure effects were also investigated, but revealed no influence on the obtained mechanical properties. Consequently, results could be critically discussed based on effective crack driving forces and elastic-plastic mechanical properties, in special those related to flow and hardening. The conclusions and success of the employed methods encourage further efforts to incorporate plastic prestrain effects on structural integrity assessments.

Bird Strike Modeling in Fiber-Reinforced Polymer Composites

2017 ◽  
Vol 17 (06) ◽  
pp. 1750065
Author(s):  
Maurício V. Donadon ◽  
Mariano A. Arbelo
Keyword(s):  
Composite Materials ◽  
Polymer Composites ◽  
Numerical Study ◽  
Material Model ◽  
Material Behavior ◽  
Fiber Reinforced Polymer ◽  
Bird Strike ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites

The present paper describes a numerical modeling approach to predict impact resistance and residual Shear Strength After Impact (SSAI) of fiber reinforced polymer composites subjected to bird strike loading. An improved damage mechanics based on material model, previously developed by the authors, is combined with an equation of state to simulate the progressive failure in composite aerostructures subjected to bird strike loading. A series of bird strike impacts on flat panels fabricated from low cost woven glass composite materials are used to validate the material model for practical composite component applications. A numerical study on the residual SSAI of a typical composite shear web is also presented. The panels are modelled with shell elements only. The proposed material model formulation accounts for the strain rate enhancement to strength and shear nonlinearities observed in composite materials. A hydrodynamic model for the bird, based on 90% water and 10% air, is derived to represent the behavior of the bird for all impact scenarios considered. The bird is heterogeneous in nature. However, a uniform material behavior is assumed with a geometry based on a 2:1 length to diameter ratio with a cylindrical body and spherical end caps using Lagrangian mesh. Appropriate contact definitions are used between the bird and the composite panel. The simulations results are compared to experimental results and conclusions drawn.

scholarly journals Matrix and Filler Recycling of Carbon and Glass Fiber-Reinforced Polymer Composites: A Review

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3817
Author(s):  
Roberto Scaffaro ◽  
Alberto Di Bartolo ◽  
Nadka Tz. Dintcheva
Keyword(s):  
Composite Materials ◽  
High Performance ◽  
Value Added ◽  
Composite Fiber ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Frp Composites ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Polymer Composites

Fiber-reinforced polymers (FRPs) are low-density, high-performance composite materials, which find important applications in the automotive, aerospace, and energy industry, to only cite a few. With the increasing concerns about sustainability and environment risks, the problem of the recycling of such complex composite systems has been emerging in politics, industry, and academia. The issue is exacerbated by the increased use of FRPs in the automotive industry and by the expected decommissioning of airplanes and wind turbines amounting to thousands of metric tons of composite materials. Currently, the recycling of FRPs downcycles the entire composite to some form of reinforcement material (typically for cements) or degrades the polymer matrix to recover the fibers. Following the principles of sustainability, the reuse and recycling of the whole composite—fiber and polymer—should be promoted. In this review paper, we report on recent research works that achieve the recycling of both the fiber and matrix phase of FRP composites, with the polymer being either directly recovered or converted to value-added monomers and oligomers.

Influence of filler hybridization on thermomechanical properties of hemp/silver epoxy composite

2020 ◽  
pp. 096739112097811
Author(s):  
Munjula Siva Kumar ◽  
Santosh Kumar ◽  
Krushna Gouda ◽  
Sumit Bhowmik
Keyword(s):  
Thermal Conductivity ◽  
Silver Nanoparticles ◽  
Epoxy Polymer ◽  
Hybrid Composites ◽  
Conductive Filler ◽  
Weight Fraction ◽  
Mechanical Analysis ◽  
Thermomechanical Properties ◽  
Material Behavior ◽  
Good Crystallinity

The polymer composite material’s thermomechanical properties with fiber as reinforcement material have been widely studied in the last few decades. However, these fiber-based polymer composites exhibit problems such as fiber orientation, delamination, fiber defect along the length and bonding are the matter of serious concern in order to improve the thermomechanical properties and obtain isotropic material behavior. In the present investigation filler-based composite material is developed using natural hemp and high thermal conductive silver nanoparticles (SNP) and combination of dual fillers in neat epoxy polymer to investigate the synergetic influence. Among various organic natural fillers hemp filler depicts good crystallinity characteristics, so selected as a biocompatible filler along with SNP conductive filler. For enhancing their thermal conductivity and mechanical properties, hybridization of hemp filler along with silver nanoparticles are conducted. The composites samples are prepared with three different combinations such as sole SNP, sole hemp and hybrid (SNP and hemp) are prepared to understand their solo and hybrid combination. From results it is examined that, chemical treated hemp filler has to maximized its relative properties and showed, 40% weight % of silver nanoparticles composites have highest thermal conductivity 1.00 W/mK followed with hemp filler 0.55 W/mK and hybrid 0.76 W/mK composites at 7.5% of weight fraction and 47.5% of weight fraction respectively. The highest tensile strength is obtained for SNP composite 32.03 MPa and highest young’s modulus is obtained for hybrid composites. Dynamic mechanical analysis is conducted to find their respective storage modulus and glass transition temperature and that, the recorded maximum for SNP composites with 3.23 GPa and 90°C respectively. Scanning electron microscopy examinations clearly illustrated that formation of thermal conductivity chain is significant with nano and micro fillers incorporation.

Review on glass fiber reinforced polymer composites

2021 ◽  
Author(s):  
Priyadarsini Morampudi ◽  
Kiran Kumar Namala ◽  
Yeshwanth Kumar Gajjela ◽  
Majjiga Barath ◽  
Ganaparthy Prudhvi
Keyword(s):  
Glass Fiber ◽  
Polymer Composites ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Polymer Composites

scholarly journals High-Speed Time- and Frequency-Domain Terahertz Tomography of Glass-Fiber-Reinforced Polymer Laminates with Internal Defects

2021 ◽  
Vol 11 (11) ◽  
pp. 4933
Author(s):  
Ji-Sang Yahng ◽  
Dae-Su Yee
Keyword(s):  
Composite Materials ◽  
Glass Fiber ◽  
High Speed ◽  
Nondestructive Inspection ◽  
Fiber Reinforced Polymer ◽  
Glass Fiber Reinforced Polymer ◽  
Tomographic Images ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Thz Tomography

Composite materials are increasingly being utilized in many products, such as aircrafts, wind blades, etc. Accordingly, the need for nondestructive inspection of composite materials is increasing and technologies that allow nondestructive inspection are being studied. Existing ultrasound methods are limited in their ability to detect defects due to high attenuation in composite materials, and radiographic examination methods could pose a danger to human health. Terahertz (THz) wave technology is an emerging approach that is useful for imaging of concealed objects or internal structures due to high transmittance in non-conductive materials, straightness, and safety to human health. Using high-speed THz tomography systems that we developed, we have obtained THz tomographic images of glass-fiber-reinforced polymer (GFRP) laminates with artificial internal defects such as delamination and inclusion. The defects have various thicknesses and sizes, and lie at different depths. We present THz tomographic images of GFRP samples to demonstrate the extent to which the defects can be detected with the THz tomography systems.

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