Search results for "polymer composites"
showing 10 items of 21 documents
The effects of water absorption and salt fog exposure on agglomerated cork compressive response
2022
The replacement of synthetic foams with agglomerated cork in sandwich composites can meet the increasing environmental concerns. Its peculiar morphology and chemical composition lead to outstanding dimensional recovery that endorsed a broad investigation of its compressive behavior. The knowledge of neat material response is fundamental to obtain a reliable design dataset, but it is necessary to consider all the environmental factors (water, moisture and sunlight) that significantly modify material mechanical properties. In view of this, the present work investigates the effect of distilled and seawater absorption and salt fog exposure on the compressive behavior of two agglomerated corks w…
Green composites: A brief review
2011
The rising concern towards environmental issues and, on the other hand, the need for more versatile polymer-based materials has led to increasing interest about polymer composites filled with natural-organic fillers, i.e. fillers coming from renewable sources and biodegradable. The composites, usually referred to as "green", can find several industrial applications. On the other hand, some problems exist, such as worse processability and reduction of the ductility. The use of adhesion promoters, additives or chemical modification of the filler can help in overcoming many of these limitations. These composites can be further environment-friendly when the polymer matrix is biodegradable and c…
Dynamic Mechanical Behavior Analysis of Flax/Jute Fiber-Reinforced Composites under Salt-Fog Spray Environment
2020
Over the last decades, natural fiber-reinforced polymer composites (NFRPs) gained great attention in several engineering fields thanks to the reduction of the environmental impact and the end-of-life cost disposal. Unfortunately, the use of NFRPs is limited, mainly due to their weak resistance against humid environments. Since limited literature is available about the evolution of the dynamic mechanical response of NFRPs under aggressive environments, this paper aims to investigate the damping properties of flax, jute and flax/jute epoxy composites exposed to salt-fog up to 60 days. Furthermore, sodium bicarbonate fiber treatment was performed to improve the composites&rsquo
Glass-basalt/epoxy hybrid composites for marine applications
2011
Abstract The aim of this work is to evaluate the influence of uniaxial basalt fabric layers on the mechanical performances of a glass mat/epoxy composite used for marine applications. Polymer composites, reinforced by glass mat (GFRP), and hybrid ones, reinforced by glass mat and unidirectional basalt fabric, have been produced by vacuum bagging technique. Three points bending and tensile tests have been carried out in order to evaluate the effect of number and position of basalt layers on the mechanical properties of the investigated structures. The experimental tests have showed that the presence of two external layers of basalt involves the highest increase in mechanical properties of hy…
Durability assessment of basalt fiber polymer as reinforcement to expanded clay concrete in harsh environment
2021
Basalt fiber-reinforced polymer composites are receiving considerable attention as they represent a low-cost green source of raw materials. In most cases, fiber-reinforced polymer composites face harsh environments, such as chloride ions in coastal marine environments or cold regions with salt deicing. The resistance of fiber-reinforced polymers subjected to the above environments is critical for the safe design and application of such composites. This research aims to develop a framework to investigate the durability properties of the lightweight expanded clay basalt fiber polymer reinforced concrete exposed to the NaCl environment. The specified quantity of concrete structural elements wa…
The Reinforcement Effect of Strain Gauges Embedded in Low Modulus Materials
2013
The reinforcement effect of electrical resistance strain gauges is well-described in the literature, especially for strain gauges installed on surface. This paper considers the local reinforcement effect of strain gauges embedded within low Young modulus materials. In particular, by using a simple theoretical model, already used for strain gauges installed on the surface, it proposes a simple formula that allows the user to evaluate the local reinforcement effect of a generic strain gauge embedded on plastics, polymer composites, etc. The theoretical analysis has been integrated by numerical and experimental analyses, which confirmed the reliability of the proposed model.
Effect of aggregation of a dispersed rigid filler on the elastic characteristics of a polymer composite
1986
We proposed a method for describing the effective elastic characteristics of a polymer composite with a rigid aggregating filler. An important feature of such a medium is the variable coupling of the inclusion phase in relation to its volume content. A change in the degree of coupling of the filler is accounted for by introducing an additional parameter. We examined a method of determining the coupling parameter from the results of statistical modeling of the geometry of the medium. Using the example of a calcite-HDPE composite, we showed that aggregation has a significant effect on the dependence of the elastic modulus on the volume content of filler; satisfactory agreement was obtained be…
A probabilistic model of the tensile strength of a UD flax-fabric-reinforced polymer composite
2016
In order to fully realize the efficiency of bast fibers or their yarns as reinforcement of polymer composites, they should be aligned. Tensile strength of such composites in the direction of reinforcement has been found to exhibit size effect commensurable with that of unidirectionally reinforced (UD) composites with inorganic fibers, necessitating a probabilistic modeling approach. Strength distribution of a polymer matrix composite reinforced with aligned twisted bast fiber yarns is considered allowing for the strength scatter of elementary fibers, the presence of defects in the form of adjacent fiber breaks, and twist of the yarns. The model is applied to predicting the strength of flax/…
A continuum damage model to simulate failure in composite plates under uniaxial compression
2007
Experimental investigations and numerical simulations are performed in order to numerically predict the buckling behaviour of thin composite laminated specimens. Experiments are aimed at two objectives: the first is to completely characterize the carbon/epoxy material under simple loading configurations, the second is to test this material in buckling and post-buckling situations. The data collected with the first campaign of experiments are used to obtain the strength parameters required to define a damage model based on the failure theory by Tsai-Wu. This model is implemented in a Finite Element (FE) code and numerical simulations of buckling are executed for unidirectional and cross-ply …
Accceleration of Fatigue Tests of Polymer Composite Materials by Using High-Frequency Loadings
2004
The possibility of using high-frequency loading in fatigue tests of polymer composite materials is discussed. A review of studies on the use of high-frequency loading of organic-, carbon-, and glass-fiber-reinforced plastics is presented. The results obtained are compared with those found in conventional low-frequency loadings. A rig for fatigue tests of rigid materials at loading frequencies to 500 Hz is described, and results for an LM-L1 unidirectional glass-fiber plastic in loadings with frequencies of 17 and 400 Hz are given. These results confirm that it is possible to accelerate the fatigue testing of polymer composite materials by considerably increasing the loading frequency. The n…