Behavior Of Polymer Matrix Composites Research Articles

Effect of load on the wear behaviour of polypropylene/carbonized bone ash particulate composite

The effect of applied load on the wear behaviour of polymer matrix composites produced using carbonized bone particles (CBp) as reinforcement has been studied. The addition of the CBp ranges from 5 to 20 wt% in the polypropylene matrix. The composites were produced by compounding and compressive moulding. The wear test was conducted by varying the applied load from 5 to 15 N. Microstructures of the worn surface were assessed with high resolution scanning electron microscopy (HRSEM/EDS). The wear rate increased with increases in applied load from 5 to 15 N and decreased with increasing in CBp from 0 to 15 wt%. The work has established that carbonized bone can be use in increasing the wear resistance of polypropylene composites.

Effect of Redmud on Dry Sliding Wear Behavior of Polymer Matrix Composites: Taguchi Approach

Effect of Redmud on Dry Sliding Wear Behavior of Polymer Matrix Composites: Taguchi Approach

Study of Internal Response of Epoxy due to Compressive Load via Experiment and Simulation Using Abaqus FEA Software

Epoxy is widely used primarily as a matrix material in the manufacture of Polymer Matrix Composites (PMC). Epoxy behavior under compression load has to be understood before the mechanical behavior of PMCs can be accurately predicted. Simulation model combined with experiment and image analysis are used to investigate internal response of epoxy resins polymeric materials subject to compressive loads. To investigate epoxy response to compressive load, small carbon-based material rods are inserted in the epoxy. The samples are held in one side and subjected to compressive load on the other side. All the samples swell at load sides. Image analysis on the carbon-based rods figures out the internal response, which seems to be isotropy in lateral direction. The results are compared to simulation results using Abaqus FEA. Similar condition is obtained when a brittle thin material is stuck to the top of the model.

Thermomechanical viscoelastic response of a unidirectional graphite/polyimide composite at elevated temperatures using a micromechanical approach

In this work, the thermomechanical viscoelastic response of a high temperature polymer matrix composite system made up of T650-35 graphite fibers embedded in PMR-15 resin is studied through a micromechanical model based on the assumptions of simplified unit cell method within a temperature range of 250–300℃ corresponding to aerospace engine applications. The advantage of this particular micromechanical model lies in its ability to give closed-form expressions for the effective viscoelastic response of unidirectional composites as well as each of their constituents. Using the experimental data of the creep behavior of thermostable PMR-15 polyimide, the micromechanical model is first calibrated to account for the effect of temperature. The resulting elastic and viscoelastic responses are found to be in good agreement with the existing experimental data. The validated model is then used to predict the behavior of the composite material under different combinations of thermal and mechanical loadings. The results clearly demonstrate the importance of accounting for the viscoelastic effect of the matrix material as the temperature increases. Current works on modeling temperature-dependent viscoelastic behavior of polymer matrix composites are mainly based on the assumption of thermorheologically simple material. However, through the present approach where the matrix is modeled as a thermorheologically complex material, the effect of temperature on the elastic and viscoelastic response of the composite system can be individually investigated.

Mechanical and Electrical Behavior of Polymer Matrix Composite and their Hybrids Reinforced with (Carbon Black–Boron) Particles

The work is designed to study experimentally the mechanical and electrical behavior of polymer matrix composites and their hybrids which reinforced by carbon black particles with constant volume fraction (10)% and boron particles with different volume fractions (0,2,4,and 6)% which are bounded with unsaturated polyester resin. Number of mechanical tests were done, they include (hardness, Charpy impact,and bending strength), which done at room temperature in Iraq .Results of the work show that the values of hardness increased with volume fractions of boron powder ,the best values of impact strength and elasticity of modulus present at (4)% .On the other hand,dielectric constant (έ) decreases with increasing applied frequency, and alternating electrical conductivity(σa.c) increases as the applied frequency increases up to 1MHz, While (έ) and (σa.c) increased as increasing of temperature.

Nanoparticle surface polarity influence on the flow behavior of polymer matrix composites

The influence of three different nanosized titanias with opposite surface polarity and different particle morphology, dispersed in an unsaturated polyester matrix, on the resulting composite flow behavior was investigated systematically. In addition the maximum filler load was estimated by use of established empirical models. It is known from composites containing microsized particles that a surface polarity conversion from a hydrophilic to a more hydrophobic character allows higher solid loads due to a pronounced viscosity reduction. In this work it was derived from viscosity measurements that a large hydrophobic nanoparticle surface area caused a pronounced attractive interaction between the filler and the polymer matrix reducing the maximum accessible filler load in contrast to a similar hydrophilic nanoparticle. For comparison a highly agglomerated hydrophilic nanosized titanium dioxide with very large specific surface area was investigated also, the large agglomerates with particle sizes in the micrometer range allowed higher solid loads in contrast to the both “real” nanosized titania. POLYM. COMPOS., 34:1425–1432, 2013. © 2013 Society of Plastics Engineers

Fiber Cross-Section Shape Effect on Rate-Dependent Behavior of Polymer Matrix Composites with Fbgs Sensors

The micromechanical investigation of fiber cross-section shape effect on the rate sensitive nonlinear behavior of a glass/epoxy was performed at 10-5/s and 1/s, which considering four shapes, square, cross, circle and ellipse. With the strain of different rate loadings measured by Fibre Bragg gratings (FBGs) sensors, the rate-dependent inelastic constitutive relationship of epoxy is built by using an internal state variables viscoplasticity model. Then, through homogenizing the properties of unit cells, the responses of resin and its composites at 30° and 60° off-axis loadings are predicted by a micromechanical model compared with the experiments data. The effect of fiber cross-section fiber on the 30° and 90° off-axis responses are discussed with respect to the viscoplastic parameters of the resin determined. The results indicate that the micromechanical model accurately calculates the behavior of the PMCs employed. The square fiber causes the largest flow stress and plastic strain in the four cases. And the influences on overall responses for the four fiber shapes are enhanced with raising off-axis angles but weaken with the rate increase. However, the elliptical fiber yields the highest modulus in linear elastic stage. The square fiber is the most effective and the elliptical fiber is the least effective in the nonlinear deformation stage. Besides, the elastic properties are unaffected by loading rates when it is less than 1/s.

Fiber Cross-Section Shape Effect on Rate-Dependent Behavior of Polymer Matrix Composites with Fiber Bragg Grating Sensors

A strain measurement system with fiber Bragg grating (FBG) sensors is developed to monitor the quasistatic/dynamic strain in a glass/epoxy for the experimental analysis of the rate-dependent behavior of polymer matrix composites (PMCs). The rate-dependent inelastic constitutive relationship of epoxy is built using an internal state variable viscoplasticity model with experimental responses. The micromechanical investigation of fiber shape effect on the rate-dependent behavior of glass/epoxy for various off-axis angles is performed at 10–5 and 1/s. The results indicate that a higher strain rate causes a greater flow stress in PMCs. The fiber shape evidently affects the inelastic deformation at large off-axis angle with the biggest stiffness provided by the square fiber, but has little impact on the elastic deformation for all off-axis angles. The effect of fiber shapes on overall responses is enhanced with increasing off-axis angles but weakens with increasing strain rate.

Effect of bagasse ash reinforcement on dry sliding wear behaviour of polymer matrix composites

The tribological behaviour of recycled low density polyethylene (RLDPE) polymer composites with bagasse ash particles as a reinforcement was studied using a pin-on-disc wear rig under dry sliding conditions. The influence of wear parameters like, applied load, sliding speed, sliding distance and percentage of bagasse ash fillers, on the wear rate were investigated. A plan of experiments was performed to acquire data in a controlled way. Scanning electron microscope was used to analyse the worn surface of the samples. Linear regression equation and analysis of variance (ANOVA) were employed to investigate the influence of process parameters on the wear rate of the samples. The predicted wear rate of the RLDPE and it composites were found to lie close to that experimentally observed ones. The confirmation of the experiments conducted using ANOVA to verify the optimal testing parameters show that sliding speed and applied load had significant effect on the wear rate. The results showed that the addition of bagasse ash as filler materials in RLDPE composites increase the wear resistance of the composite greatly.

Modeling of the mechanical loading effects on the effective diffusive behavior of polymer matrix composites

In this study, the effect of a mechanical loading on the diffusion process in a polymer matrix composite is discussed. The application of an external loading is expected to modify the microstructure of the material and cause change in effective diffusive behavior as the diffusion in the polymer matrix is dependent on the free volume. On the basis of the free volume theory, the mechanical problem imposed on the representative volume element (RVE) is solved and then the volume fraction of free volume is determined. The effect of external mechanical loading on the moisture content and diffusion coefficient was first examined and finally the corresponding local stresses in the RVE are calculated.

Preparation and wear behavior of polymer matrix composites with an interpenetrating network structure derived from natural sponge

Natural sponge was used as a template to produce carbon/epoxy resin and (carbon+silicon carbide)/epoxy resin composites with interpenetrating network structures. Carbon with a network structure was first obtained by pyrolysis of the natural sponge. The composites were then obtained by injecting epoxy resin and silicone resin into the carbon. Their microstructures and wear properties were analyzed. The results show that the natural structure of sponge controlled the interpenetrating network structures of the composites. The netlike carbon in the composites reduced the wear rate of the epoxy resin. Compared with the carbon/epoxy resin composite, the (carbon+silicon carbide)/epoxy resin composite shows better wear resistance.

Three-Body Abrasive Wear Behaviour of Polymer Matrix Composites Filled with SiC Particles

Effect of filler material on three-body abrasive wear behaviour of Glass – Epoxy composites has been investigated. The abrading distance, applied load and sliding speed are the parameters used for the study. A L9 orthogonal array and ANOVA were used to identify the contribution of individual parameters. The result shows that the weight loss increases with increase in load, sliding speed and abrading distance. The abrading distance has more effect on the wear compared to other parameters. The filler material (SiC) contributes a significant wear resistance of the G–E composites.

Influence of material nonlinearity on thermal distortion of polymer matrix composite panels

Abstract This paper discusses the influence of material nonlinearity on thermal distortion of polymer matrix composite panels. The load is transverse temperature gradient introduced by one-sided heat exposure, e.g., fire. For such low thermal conductivity materials, when there are no external mechanical loads, the transverse thermal gradient induces non-uniform thermal expansion along the thickness that results in transverse deformation field, known as thermal distortion. The power form stress–strain relation and the Ramberg–Osgood form stress–strain relation are discussed to include the temperature dependent behavior of polymer matrix composites. The degradation of polymer matrix composites at elevated temperature, thermal softening, is discussed. The variations of the reference stress and the reference strain with temperature are specified to describe the temperature dependent constitutive relationships. Semi-analytical simulation and finite element simulation are carried out for panels with roller end support condition. Results suggest that, while the material nonlinearity has insignificant influence on the transverse displacement of the panel, it has strong influence on local stress and strain. The stress and strain can go beyond the yield stress and the yield strain into plastic stage in certain circumstances.

Effect of Filler Materials on Dry Sliding Wear Behavior of Polymer Matrix Composites – A Taguchi Approach

The tribological behaviour of glass epoxy polymer composites with SiC and Graphite particles as secondary fillers was studied using a pin-on-disc wear rig under dry sliding conditions. The influence of wear parameters like, applied load, sliding speed, sliding distance and percentage of secondary fillers, on the wear rate were investigated. A plan of experiments, based on the techniques of Taguchi, was performed to acquire data in a controlled way. An orthogonal array and analysis of variance (ANOVA) were employed to investigate the influence of process parameters on the wear of these composites. The results showed that the inclusion of SiC and Graphite as filler materials in glass epoxy composites will increase the wear resistance of the composite greatly.

Self‐lubricating and self‐protecting properties of polymer composites for wear and friction applications

AbstractBased on the well‐known pin‐on‐disc test rig, a new test setup has been developed for online measuring of the wear and friction behavior of polymer matrix composites. Contrasting with a traditional friction and wear test rig, a steel pin and composite disc are presently used to study the influence of wear debris and fiber orientation. This test setup has a main influence on the results. The polymer materials, a thermoset polyester, and a thermoplastic polyphenylene sulfide were reinforced with glass and carbon fibers, respectively. The results show two different promising aspects of “new” materials for wear and friction applications and more specific to different machine components, namely self‐lubricating and self‐protecting ability. The self‐lubricating ability exists from creating a polymer film on the surface which reduces the coefficient of friction, and the self‐protecting behavior is because of the creation of a protecting carbon film on the surface. The self‐lubricating ability depends on the test parameters, while the self‐protecting ability was due to the material and the structure. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers

Impact Mechanics of Composite Materials for Aerospace Application

Next-generation aircraft engines made of lighter and stronger fiber-reinforced polymer composites are envisioned to replace the conventional metal ones. To certify these engines, ballistic impact tests and related computational analyses should be performed to simulate a “blade-out” event in a catastrophic engine failure. To meet this objective, several papers on extensive numerical computational models derived from basic constitutive relations to failure analyses and experimental evaluation of strain-rate-dependent behavior of resin matrix are presented in the first series in this two-series July and October 2008 special issue on Impact Mechanics and High-Energy Absorption Materials. Goldberg and his coworkers conducted a combined experimental and analytical study to evaluate the loading and unloading behavior of polymers. In particular, the effects of strain rate and hydrostatic stress on the nonlinear regions of the deformation response were characterized. The load and unload tests of polymers under tension, compression, and shear at several strain rates were performed, and a modified constitutive law based on the state variable originally developed for metals was considered to model the nonlinear unloading behavior. A good correlation between the experimental results and analytical constitutive modeling was observed in their study. Zhu, Chattopadhyay, and Goldberg presented a modified Hashin failure model to characterize different failure modes related to high-velocity impact of composite laminates, and their computational study showed that the model is capable of simulating shear failure, delamination, and tearing failure of composite laminates under high-velocity impact. Zheng and Binienda incorporated the rate dependence of elastic modulus of the polymer matrix constituent in an existing constitutive model originally developed for metal and analyzed the nonlinear, strain-rate-dependent deformation behavior of polymer matrix composites. The state variable-based viscoplastic equations were modified to account for the effects of hydrostatic stresses in the polymer matrix, and they were implemented within a strength-of-materials-based micromechanics method to predict the nonlinear, strain-rate-dependent deformation of the polymer matrix composites. The proposed models were then input in LS-DYNA as user-defined materials UMATs to simulate the deformation behaviors of polymers and polymer matrix composites for a wide range of strain rates. Cheng and Binienda developed a simplified methodology to model 2D triaxially braided composite plates under impact of a soft projectile using an explicit nonlinear finite-element

Influence of Re-adhesion on the Wear and Friction of Glass Fibre–Reinforced Polyester Composites

Based on the well-known pin-on-disc test rig, a new test setup for online measuring of wear and friction behaviour of polymer matrix composites has been developed. In contrast to a traditional friction-and-wear test rig, a steel pin and composite disc are used for studying the influence of wear debris and fibre orientation. During sliding, a thin adhesive film is possibly formed on the wear track of a composite disc, consisting of wear debris that is squeezed under the steel pin and that finally smoothens onto the composite surface. By optical microscopy, it was observed that most of the debris particles originate from the edges of the wear track. The thin film deforms continuously, with large and dark wear particles observed at the edge of the wear track. A lower coefficient of friction is achieved when the particles are re-adhered to the mating surface. The film formation mechanism depends on the normal force, sliding velocity, and bulk composite structure: because pultruded composite profiles are presently used with a layered structure, a change in film properties is observed depending on the wear depth.

Simulation of Time-Dependant Deformation of Polymer Matrix Composites Based on Short-Term Data

This paper presents an effort for simulating time-dependant deformation behaviour of polymer matrix composites analytically and experimentally. The proposed models were developed on the basis of the classic lamination theory and the viscoelastic approach with consideration of the anisotropic deformation of fibre reinforced polymer (FRP) composite materials. A series of shortterm creep and recovery tests were conducted to provide the basic material properties and to verify the predictive models. It was found that a fairly good agreement has been achieved between the proposed models with the creep testing data of a cross-ply carbon fibre/urethane resin composite laminate under different loading orientations.

Low-cycle fatigue of unidirectional composites:: Bi-linear S– N curves

Low-cycle fatigue (LCF) behavior of polymer matrix composites (PMCs) is investigated in an experimental study of unidirectional glass/epoxy composites subjected to axial tensile loading along longitudinal 0° orientation of fibers. Under high LCF loads, fatigue life of PMCs is found to be less than 10 4 loading cycles due to the high property degradation rates that are noticeably higher than those seen during high-cycle fatigue (HCF). In PMC response, unique LCF features have been identified and linked with damage accumulation patterns in unidirectional composites. At high loads near the ultimate strength of specimens, large strains and finite strain rates are found to be significant under semi-rectangular loading so the LCF behavior is affected. Lower and upper limits for the LCF life impose some restrictions on the S– N curves that are obtained for the LCF life assessment. A bi-linear S– N curve is used to approximate the data in the LCF and HCF regions. The bi-linear S– N relationship and the associated fatigue model are described by a proposed analytical formula. The concept of pre-LCF damage state is introduced.

Fiber distribution effects in linear viscoelastic behavior of polymer matrix composites: Computation modelling and experimental comparison

Fiber distribution effects in linear viscoelastic behavior of polymer matrix composites: Computation modelling and experimental comparison