Mechanical Behavior of Microwave Processed Polymer Matrix Composites: the Effect Of The Temperature Increase Rate

1996 ◽  
Vol 430 ◽  
Author(s):  
M. Delmotte ◽  
J. Fitoussi ◽  
J. Toftegaard-Hansen ◽  
C. More ◽  
H. Jullien ◽  
...  

AbstractMicrowave processed glass reinforced epoxies or glass reinforced polyesters exhibit mechanical behaviors different from conventionally cured materials, relatively to tensile tests. The faster increases of temperature due to microwaves cause a competition between the matrix flow and the crosslinking reaction which can be estimated by porosity variations. Higher mechanical moduih are also obtained, because of both an effect on chemical kinetics and a more homogenous distribution of temperature in materials. Nevertheless, to provide such specific mechanical behaviors in microwave processed composite materials, a best control of the experimental pressure parameters is requested.

Author(s):  
Fayu Wang ◽  
Nicholas Kyriakides ◽  
Christis Chrysostomou ◽  
Eleftherios Eleftheriou ◽  
Renos Votsis ◽  
...  

AbstractFabric reinforced cementitious matrix (FRCM) composites, also known as textile reinforced mortars (TRM), an inorganic matrix constituting fibre fabrics and cement-based mortar, are becoming a widely used composite material in Europe for upgrading the seismic resistance of existing reinforced concrete (RC) frame buildings. One way of providing seismic resistance upgrading is through the application of the proposed FRCM system on existing masonry infill walls to increase their stiffness and integrity. To examine the effectiveness of this application, the bond characteristics achieved between (a) the matrix and the masonry substrate and (b) the fabric and the matrix need to be determined. A series of experiments including 23 material performance tests, 15 direct tensile tests of dry fabric and composites, and 30 shear bond tests between the matrix and brick masonry, were carried out to investigate the fabric-to-matrix and matrix-to-substrate bond behaviour. In addition, different arrangements of extruded polystyrene (XPS) plates were applied to the FRCM to test the shear bond capacity of this insulation system when used on a large-scale wall.


1994 ◽  
Vol 372 ◽  
Author(s):  
M. T. Kiser ◽  
M. He ◽  
B. Wuj ◽  
F. W. Zok

AbstractThe compressive deformation characteristics of hollow alumina microsphere reinforced aluminum matrix composites have been studied through both experiments and finite element analysis of unit cell models. Tests have been performed on composites containing around 50 volume percent of microspheres. The effects of the matrix flow stress and microsphere morphology (characterized by the ratio of wall thickness to radius) have been examined. The measured strength enhancement due to the hollow microspheres was found to be considerably less than that predicted by the FEM calculations; a result of microsphere cracking. Experiments have been conducted to document the progression of such damage following casting and mechanical deformation. The potential of this class of composite for impact energy absorption applications is also explored.


2010 ◽  
Vol 139-141 ◽  
pp. 84-89 ◽  
Author(s):  
Hong Chang Qu ◽  
Xiao Zhou Xia ◽  
Hong Yuan Li ◽  
Zhi Qiang Xiong

The mechanical behavior of polymer–matrix composites uniaxially reinforced with carbon or glass fibers subjected to compression/tension perpendicular to the fibers was studied using computational micromechanics. This is carried out using the finite element simulation of a representative volume element of the microstructure idealized as a random dispersion of parallel fibers embedded in the polymeric matrix. Two different interface strength values were chosen to explore the limiting cases of composites with strong or weak interfaces, and the actual failure mechanisms (plastic deformation of the matrix and interface decohesion) are included in the simulations through the corresponding constitutive models. Composites with either perfect or weak fiber/matrix interfaces (the latter introduced through cohesive elements) were studied to assess the influence of interface strength on the composite behavior. It was found that the composite properties under transverse compression/tension were mainly controlled by interface strength and the matrix yield strength in uniaxial compression/tension.


2019 ◽  
Vol 24 (No 1) ◽  
pp. 12-19
Author(s):  
S. Vimal Anand ◽  
G. Venkatachalam ◽  
Tushar D. Nikam ◽  
Omkar V. Jog ◽  
Ravi T. Suryawanshi

In the last few years, green composites are becoming more suitable for applications over synthetic composite. There has been a growing interest in recent years in the utilisation of natural fibres in making low-cost building material. However, these natural fibre-based composites are not fully environmentally friendly because the matrix resins are non-biodegradable. In this paper, an attempt is made to fabricate green composites with coir, banana, and aloe vera fibres as reinforcement and hybrid polymer as matrix. The hybrid polymer is prepared from natural and synthetic resins. This work intends to find the vibrational characteristics of these composites. The influence of three parameters, i.e. CNSL in hybrid polymer, fibre volume, and fibre discontinuities on vibrational characteristics are considered. This work is carried out using FEA and the FEA results are validated by experimental results.


2015 ◽  
Author(s):  
Risa Yoshizaki ◽  
Kim Tae Sung ◽  
Atsushi Hosoi ◽  
Hiroyuki Kawada

Carbon nanotubes (CNTs) have very high specific strength and stiffness. The excellent properties make it possible to enhance the mechanical properties of polymer matrix composites. However, it is difficult to use CNTs as the reinforcement of long fibers because of the limitation of CNT growth. In recent years, a method to spin yarns from CNT forests has developed. We have succeeded in manufacturing the unidirectional composites reinforced with the densified untwisted CNT yarns. The untwisted CNT yarns have been manufactured by drawing CNTs through a die from vertically aligned CNT arrays. In this study, the densified untwisted CNT yarns with a polymer treatment were fabricated. The tensile strength and the elastic modulus of the yarns were improved significantly by the treatment, and they were 1.9 GPa and 140 GPa, respectively. Moreover, the polymer treatment prevented the CNT yarns from swelling due to impregnation of the matrix resin. Finally, the high strength CNT yarn composites which have higher volume fraction than a conventional method were successfully fabricated.


1991 ◽  
Vol 6 (11) ◽  
pp. 2463-2473 ◽  
Author(s):  
C.C. Yang ◽  
T. Mura ◽  
S.P. Shah

The mechanism of fracture arrest in brittle-matrix composites with strong, long fibers is analyzed by using the inclusion method. The maximum stress contribution of the matrix in composites is discussed in this paper. A critical volume fraction of fibers fc is theoretically derived. If the volume fraction f is less than fc, then debonding between fibers and matrix occurs before the crack propagates through the whole section. If f is greater than fc, then no debonding occurs before the crack propagates through the whole section. The value of fc depends on the matrix and fiber properties and the bond character of the interface. To verify the analytical predictions, experiments on fiber reinforced cement composites subjected to uniaxial tension were conducted. The results of the theoretical predictions were also compared satisfactorily with other published experimental data.


2013 ◽  
Vol 368-370 ◽  
pp. 683-686
Author(s):  
Ahmad Mubarak Tajul Arifin ◽  
Shahrum Abdullah ◽  
Rozli Zulkifli ◽  
Dzuraidah Abd Wahab

This paper focuses on the characteristic study of polymer matrix composites using a statistical approach, in terms of difference experimental and reflected to difference stacking sequence and orientation of composite lamination. Composite material, have an excellent characteristic and behavior, but with a difference application and materials used, it have a difference phenomenon occurred before the composite structure are collapsed. Therefore, in order to understand the characteristic of polymer matrix composites, it needs to investigate the phenomenon that influences the structure of composite lamination before failures. In this research, polymer matrix composites are produced using difference material and stacking sequence of lamination. The matrix used is thermoset epoxy and polyester resin with chopped strand mat (CSM) and woven roving (WR) as reinforcement materials. It has been produced using hand lay-up technique. The experimental work is carried out using the tension and flexural test accordance to ASTM-D3039 and D-D790 standard. By using a statistical approach, it can clearly show the differential between materials used with a characteristic of composite materials. It is noted, based on this investigation it also showed difference phenomenon failures and damage structure of polymer matrix composites with difference type of experimental.


1999 ◽  
Vol 586 ◽  
Author(s):  
Lawrence T. Drzal

ABSTRACTFiber-matrix adhesion is a variable to be optimized so that optimum composite mechanical properties can be achieved in polymer matrix composites. The contemporary view of adhesion rests on an “interphase” model in which not only the actual chemical and physical interactions between fiber and matrix are considered but also the structure and properties of both the fiber and the matrix in the region near the interface. The optimum design methodology starts with the specification of the fiber and matrix from a structural consideration. Once the constituents are selected, the focus is on the creation of a beneficial fiber-matrix “interphase”. This region where the fiber and matrix interact has to be designed for both “processing” and “performance”. Although no quantitative algorithm is available for interphase optimization, various thermodynamic principles coupled with experimental data can be used to qualitatively design the optimum interphase. Examples will be presented to illustrate how this interface can be engineered with surface treatments and sizings or coatings to insure thorough wetting, protection of the fiber, chemical bonding between fiber and matrix, toughness and desirable failure modes.


2016 ◽  
Vol 858 ◽  
pp. 190-195
Author(s):  
Lenka Markovičová ◽  
Viera Zatkalíková

A composite material is a macroscopic combination of two or more distinct materials, having a recognizable interface between them. Modern composite materials are usually optimized to achieve a particular balance of properties for a given range of applications. Composites are commonly classified at two distinct levels. The first level of classification is usually made with respect to the matrix constituent. The major composite classes include organic – matrix composites (OMC's), metal – matrix composites (MMC's), and ceramic – matrix composites (CMC's). The OMC's is generally assumed to include two classes of composites: polymer – matrix composites (PMC's) and carbon – matrix composites [1]. The composite material used in the work belongs to the PMC's and the composite is formed by the polymer matrix - high density polyethylene. As filler was used hard-magnetic strontium ferrite. Composite samples were prepared with different filler content (0%, 60%, 70%, 80%). Testing of polymer composites included: tensile test, elongation at break, impact test, hardness test.


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