Mechanical Properties Of Composite Materials Research Articles

Effect of Fiber-matrix Interface Decohesion on the Behavior of Thermoset and Thermoplastic Composites Reinforced with Natural Fibers: A Comparative Study

In this article, a comparative study was carried out on two types of thermosetting and thermoplastic matrices to study the effect of the fiber-matrix interface damage on the behavior of thermosetting and thermoplastic composites reinforced by the same natural alfa and wood fibers. The genetic modeling was based on the probabilistic formalism of Weibull. The results have been compared with those obtained by the nonlinear acoustic technique, the two results found to coincide perfectly. The numerical simulation also shows a good concordance with the real behavior of the materials studied, and shows that thermosetting composites are the most resistant to applied thermal stress by 21% compared to thermoplastic composites. Statistical analysis demonstrates that the correlation coefficient values found are very close to 1 (0.964 and 0.973), these values are very satisfactory, and confirm that the results obtained by the genetic model and the nonlinear acoustic technique are in very good agreement with the statistical analysis data. The experimental work presented by Antoine Le Duigou et al. and the work of Bodros et al. have shown that the use of natural fibers greatly improves the mechanical properties of composite materials.

Flame retardancy of silicone rubber foam containing modified hydrotalcite

AbstractSilicone rubber material (silicone rubber foam [SRF]) composites is a new type of polymer foam material, which has the characteristics of high elasticity and high‐temperature resistance, but this material is flammable. In order to improve the flame retardant properties of SRF composites. The co‐precipitation method is used to prepare modified hydrotalcites (LDHs) with different Ce/Al molar ratios for application to SRF composites. X‐ray diffraction, scanning electron microscopy (SEM), and FT‐IR are used to characterize modified LDHs with different Ce/Al molar ratios. The combustion performance, thermal decomposition, and mechanical properties of composite materials are studied through the limiting oxygen index (LOI), vertical combustion test, thermal gravimetric analysis, cone calorimeter test, and SEM. Results show that the LOI value of SRF composite with addition of 3% LDHs at a Ce/Al molar ratio of 0.3:0.7 is 31.2%, and the heat release rate, the smoke production rate, and total smoke production of the SRF composite are reduced by 53.64%, 34.92%, and 66.19%, respectively. Besides, the addition of modified LDHs leads to increase in the thermal stability of the SRF composite. The results obtained from this study can provide guidance for the development of environmentally friendly SRF.

The investigation of hardness and density properties of GFRP composite pipes under seawater conditions

Glass fiber reinforced polymer (GFRP) composite pipes are mostly used in transmission lines of submarine oil, natural gas, and chemical fluids. The alterations in mechanical characteristics of composite pipes used in submarine applications are of great importance to the lifespan of the material. Some important mechanical properties of composite materials are density and hardness value. In this study, the changes in the density and hardness values of GFRP composite pipes which were unexposed to seawater and exposed to seawater for 1, 2 and 3 months were investigated. As a result of the present study, it was deduced that the characteristics of the sample changed with the effect of seawater.

Microstructure Evolution and Mechanical Properties of Needle-like ZrB2 Reinforced Cu Composites Manufactured by Laser Direct Energy Deposition.

Laser additive manufacturing is an advanced material preparation technology, which has been widely used to prepare various materials, such as polymers, metals, ceramics and composites. Zirconium diboride (ZrB2) reinforced copper composite material was fabricated using laser direct energy deposition technology. The microstructure and phase composition of the composite material were analyzed, and the influence of laser energy density on the microstructure and mechanical properties of composite materials was discussed. The results showed that the needle-like ZrB2 ceramic reinforcement was successfully synthesized via an in-situ synthesis reaction. The composites were mainly composed of needle-like ZrB2, Ni dendrites and a Cu matrix. The morphological changes of Ni dendrites could be observed at the interface inside the composite material: cellular crystals → large-sized columnar dendrites → small-sized dendrites (along the solidification direction). The continuous Ni dendritic network connected the ZrB2 reinforcements together, which significantly improved the mechanical properties of the composite material. At a laser energy density of 0.20 kJ/mm2, the average microhardness of the composite material reached 294 HV0.2 and the highest tensile strength was 535 MPa. With the laser energy density increased to 0.27 kJ/mm2, the hardness and tensile strength decreased and the elongation of the Cu composites increased due to an increase in the size of the ZrB2 and a decrease in the continuity of the Ni dendritic.

Elaboration and Characterization of a Plaster Reinforced with Fibers from the Stem of <i>Cola lepidota</i> for Industrial Applications

Current environmental and eco-design issues require the use of environmentally friendly materials. These make up a large share of the building materials market. Natural fibers are already used in various types of materials, such as plastics, concrete and lime-based products. They exhibit different attributes like the right combination of mechanical, thermal and acoustic properties, allowing these types of materials to be used for different applications. The main disadvantage associated with plaster is its fragility, especially under mechanical stress. Therefore, it becomes interesting to study different methods that could improve the mechanical properties of plaster. The addition of fibers to the plaster to obtain a composite material is already recognized as a means of improving the behavior of the product, in particular after the rupture of the matrix. The aim of this work was to study the effects of the addition of natural fibers from the stem of Cola lepidota (CL), on the physical properties and the mechanical behavior of the composite matrix. This study highlights the effects of fiber size and volume fraction. It has been shown that the mass of composites decreases as the percentage and length of fibers increases. The mechanical properties of composite materials are also discussed. Even at low addition rates, CL stem fibers achieved slightly higher values of flexural properties.

Data-driven approach for the prediction of mechanical properties of carbon fiber reinforced composites

Supervised machine learning models are trained on experimental data to predict the mechanical properties of composite materials. Results show that these techniques are reasonably accurate and generalizable.

Experimental investigations on synthesis and characterization of tamarind seed powder reinforced Bio- composites

The entire world is poignant towards the eco-friendly manufacturing stratagem; especially most of the plastic components were slowly replaced by the natural composites. In the automobile sector, some of the popular car manufacturers were concentrated to replace interior plastic materials with natural fiber-based composite materials. A novel development of bio-composite materials augments to reduce global warming and ecofriendly environment. In this research work, the agricultural waste of tamarind seeds powder is used as a bio-composite material, which is blended with Epoxy LY556 in various weight percentages and fabricated. The tamarind seeds powder varies from 5 to 30% with Epoxy resin, Methyl Ethyl Kethone Peroxide is used as an accelerator, and Cobalt is used as a Catalyst. The bio-composite plates were fabricated by the Compression moulding techniques. The mechanical properties of composite materials were studied in the enhancement of Epoxy resin's impact in the weight percentage range.

Design optimization and numerical analyses of composite leaf spring in a heavy-duty truck vehicle

The suspension in automotive has been carried out for years by steel leaf spring. Despite this, the issue of emission and efficiency of fuel in automotive has remained in the forefront as one of the draw backs in automotive industry. This drawback can be solved by providing vehicles that are cost effective and gives fuel efficiency in terms of weight reduction in automobile. This is achievable by replacing steel leaf spring with composite materials with enhanced properties which can compare favorably with steel leaf. This is due to the fact the weight of a vehicle is carried by steel leaf spring. The aim of this research work is to optimize the design of the steel leaf spring by replacing it with composite materials for an extended application in automotive industry. The economic advantage and enhanced mechanical properties of composite materials like carbon epoxy, bamboo polyester, E-glass/epoxy and graphite epoxy made them choicy materials to be compared with the conventional steel leaf. CATIAVR9 and ANSYS software were both used for the model and the numerical analyses of the composite materials and the steel leaf. The results showed that all the four composite materials exhibited weight reduction compared to the conventional steel leaf. The Von Misses stresses of the composite materials were also compared with the conventional steel leaf and the results corroborated. Bamboo polyester showed maximum displacement of 1.5726 mm and followed by Carbon epoxy with deflection of 1.5469 mm. E-glass/epoxy showed the lowest displacement of 1.5172 mm as compared to conventional steel leaf with displacement of 1.2144 mm.

Effect of different hostile solutions on mechanical properties of composite materials

Due to their excellent performances in terms of high specific strength and stiffness, good static and dynamic properties, good corrosion resistance, adjustable properties, competitive cost, and quick manufacture, fibre-reinforced composites have been used in a variety of engineering fields, and this trend is expected to continue. In this context, these materials are subjected to a variety of environmental conditions, which have a major impact on their mechanical characteristics. Although several studies have been published on the influence of hostile solutions on low velocity impact response, the flexural fatigue performance of composite laminates exposure to corrosive solutions still has some lack of studies. As a result, the goal of this research is to investigate the low velocity impact and flexural fatigue evaluation of Kevlar/epoxy laminates after immersion in Sulphuric acid (H2SO4), diesel and seawater. For this purpose, static three-point bending tests were performed at a displacement rate of 2 mm/min. The low velocity impact tests were made using a drop weight testing machine IMATEK-IM10. Flexural fatigue tests were carried out in flexural mode using an Instron servohydraulic machine. Constant amplitude loading tests were performed at room temperature, under a stress ratio of R = 0.05 and frequency of 2 Hz. It was concluded that the different solutions affect flexural and impact behaviour of the studied materials, but the exposure time was determinant on the mechanical properties’ degradation.

Uncertainty quantification and global sensitivity analysis for composite cylinder shell via data-driven polynomial chaos expansion

The mechanical properties of composite material exhibit inherent variation with uncertainty. Uncertainties in material properties propagate and result in uncertainties of mechanical performance of structure made of composite material. Polynomial chaos expansion (PCE) is implemented to carry out uncertainty quantification (UQ) and global sensitivity analysis (GSA) of cylinder shell made of composite material for this paper. A case study concerning eigenvalue buckling load of composite cylinder shell is investigated. Design of experiment (DOE) is conducted by utilizing Latin hypercubic sampling. Then data-driven PCE is established and later validated. Statistical moments (mean and standard deviation) and Sobol sensitivity indices of eigenvalue buckling load are obtained respectively. It is found that the PCE can serve as an efficient approach to handle UQ and GSA in engineering applications.

Processing and properties of flax fibers reinforced PLA/PBS biocomposites

Reinforced plastic materials are widely used in high sophisticated applications. Fiber length has a strong impact on the mechanical properties of composite materials. Being able to reliably and accurately evaluate the residual fiber length distribution of a sample is the key to understand the mechanisms of fiber breakage through experimental investigations, permitting the prediction of properties for flax fiber reinforced components. To optimize the properties of the composites, the greatest average length is sought. The objective is therefore to investigate the effect of the mixing process (single and twin screw extrusion) and the injection shaping process on flax fibers reinforced composites.However, the subsequent image analysis is frequently performed automatically using the fiber length measurement system “FASEP” that can be used to analyze fiber length distributions automatically. After separating the fibers out of the composite material without any damage, and preparing them, statistical analysis can be done. After image processing and analysis with mathematical methods, a complete investigation of the fiber length distribution could be determined. The main results show that a greater concentration of shorter flax fibers was found in the twin screw extruded composite with more than 16% of particles are smaller than 180 μm when compared against the single screw extruded material. However, volume average results of flax fibers are higher for composite manufactured with single screw extrusion. The control of fiber breakage and final morphology is studied by Scanning Electron Microscopy. As a result of the injection step, the lengths of the fibers have been reduced, compared to the dimensions after extrusion. No reliable correlation between fiber length distribution and mechanical properties, measured with tensile test was found. Also, there is no significanteffect of the melt processing types on the tensile properties considering the experimental errors.

Dynamic mechanical behavior of composite materials reinforced by graphene and huntite minerals

Abstract The aim of this study is to investigate the dynamic mechanical properties of composite materials reinforced by mineral experimentally. Graphene and huntite minerals were added to epoxy resin at different weight ratios (wt.-%) as 0.5 weight percent, 1 weight percent and 3 weight percent, to examine the effect of mineral types and percentages on the resulting dynamic mechanical properties. In addition, the effect of non-layered huntite unlike graphene, with a nano-sized grain structure, was investigated. Thus, glass transition temperature (Tg), storage modulus (E’), loss modulus (E”) and damping ratio (tan δ) values were determined and compared. Moreover, a tensile test was performed in order to explain the relation between stress and strain. It was seen that adding different minerals caused different results according to types and proportions. In general, adding minerals to the pure resin increased the storage modulus and loss modulus, whereas the damping ratio (tan δ) decreased compared to the pure resin.

Structural Health Monitoring in Composite Structures: A Comprehensive Review.

This study presents a comprehensive review of the history of research and development of different damage-detection methods in the realm of composite structures. Different fields of engineering, such as mechanical, architectural, civil, and aerospace engineering, benefit excellent mechanical properties of composite materials. Due to their heterogeneous nature, composite materials can suffer from several complex nonlinear damage modes, including impact damage, delamination, matrix crack, fiber breakage, and voids. Therefore, early damage detection of composite structures can help avoid catastrophic events and tragic consequences, such as airplane crashes, further demanding the development of robust structural health monitoring (SHM) algorithms. This study first reviews different non-destructive damage testing techniques, then investigates vibration-based damage-detection methods along with their respective pros and cons, and concludes with a thorough discussion of a nonlinear hybrid method termed the Vibro-Acoustic Modulation technique. Advanced signal processing, machine learning, and deep learning have been widely employed for solving damage-detection problems of composite structures. Therefore, all of these methods have been fully studied. Considering the wide use of a new generation of smart composites in different applications, a section is dedicated to these materials. At the end of this paper, some final remarks and suggestions for future work are presented.

A Review of Prestressed Fibre-Reinforced Polymer Matrix Composites.

This review examines various studies on reducing tensile stresses generated in a polymer matrix composite without increasing the mass or dimension of the material. The sources of residual stresses and their impacts on the developed composite were identified, and the different techniques used in limiting residual stresses were also discussed. Furthermore, the review elaborates on fibre-prestressing techniques based on elastically (EPPMC) and viscoelastically (VPPMC) prestressed polymer matrix composites, while advantages and limitations associated with EPPMC and VPPMC methods are also explained. The report shows that tensile residual stresses are induced in a polymer matrix composite during production as a result of unequal expansion, moisture absorption and chemical shrinkage; their manifestations have detrimental effects on the mechanical properties of the polymer composite. Both EPPMC and VPPMC have great influence in reducing residual stresses in the polymer matrix and thereby improving the mechanical properties of composite materials. The reports from this study provide some basis for selecting a suitable technique for prestressing as well as measuring residual stresses in composite materials.

Applied computer vision for composite material manufacturing by optimizing the impregnation velocity: An experimental approach

The application of the cutting edge industrial solutions in composite manufacturing are optimizing the processes, quality control and resources usage. Computer vision is currently used in many quality control stages, although its potential advantages have not been applied in the process control. In this paper, computer vision is used to control the impregnation velocity in VARI (Vacuum Assisted Resin Infusion) process. As it is known, there is a relationship between the impregnation velocity and the final mechanical properties in LCM (Liquid Composite Manufacturing) processes. Constant and optimum flow front velocity mean optimum mechanical properties, although the nature of the process makes it difficult to keep these conditions. Then, a methodology has been proposed to identify and use the optimum velocity during the manufacturing process. Firstly, the flow front recognition algorithm was calibrated to be used in different reinforcement and fluid systems. Then, tensile and impact specimens have been manufactured and tested at different controlled and uncontrolled velocities. As a result, the tensile modulus has been increased up to 12.6%, as the tensile strength has increased up to 8.7%. Similarly, the maximum reaction force during the impact test has been increased up to 6.5%, as the damaged area has been reduced by 8.8%. For stitched laminates, force results increase up to 3.2%, as the damaged area has been reduced up to 31% when the optimum velocity is used. The experimental results have demonstrated the advantage of using mechanisms to control the impregnation process to achieve improved mechanical properties of composite materials.

The Study of the Dependence of Optimal Structure of Composite Materials Containing Hollow Aluminosilicate Microspheres on Humidity

Background: Experimental data on the conditions for the formation of gravel materials containing hollow aluminosilicate microspheres with a possibility to receive optimum structure and properties depending on humidity with the use of various binders are presented in this article. This article focuses on the scientific study of the possibility to optimize the physical and mechanical properties of composite materials. Objective: The main goal of this research is an exploration of energy-efficient building materials to be used to replace natural materials with industrial wastes and development of the theory and practice of how to obtain light and ultra-light gravel materials based on mineral binders and waste dump ash and slag mixtures of hydraulic removal. The objective of this research is to study the composite material containing hollow aluminosilicate microspheres. Method: The study is based on the application of the separation method for power and heat engineering functions. The method is based on the use of the structure optimality factor that takes the primary and secondary stress fields of the structural gravel material into account. It shows the possibility to obtain gravel material with the most uniform distribution of nano - and microparticles in the gravel material and to form stable matrices with minimization of stress concentrations. Experiments show that the thickness of the cement shell that performs power functions is directly related to the size of the raw granules. At the same time, the cement crust thickness regardless of the binder type has a higher formation rate for larger diameter granules when the moisture content increases. Results: The conditions of formation for gravel composite materials containing hollow aluminosilicate microspheres were studied. The optimal structure and properties of the gravel composite material were obtained. The dependence of the strength function on humidity and the binder type was investigated. The optimal size and shape of gravel material containing aluminosilicate hollow microspheres with a minimum thickness of a cement shell and a maximum strength function were obtained. Conclusion.: The obtained structure enables us to separate power and heat engineering functions in the material and to minimize the content of the aggressive environment centers.

Characterization of mechanical properties of composite materials with filler coconut shell powder and sawdust with coconut fiber reinforcement as an alternative to low loaded brake friction materials

The purpose of the study is to determine the best composition variation of the fifth variation of the composition of the composite material against the wear test, hardness test, tensile test comparing values ​​ with the safety standards of the brake lining composite SAEJ 661. Making the specimens was performed by mixing the ingredients with a mixer for 15 minutes and then do the process of compaction, with a load of 4 tons and detained achieve holding time is desired, then dies (mould) are placed in the oven and do the sintering process at a temperature of 1500 C for 180 minutes and specimens removed from the mould, the process of finishing and testing. These test results show that the composition of the material that is on variation V best price obtained 96.575 HBN hardness, wear rates of 1,29x10-6 gr / (mm2.detik), and a tensile strength of 0.842 MPa, but the brake friction material not meet safety standards SAEJ brake 661.

Characterization of mechanical properties of composite materials with filler coconut shell powder and sawdust with coconut fiber reinforcement as an alternative to low loaded brake friction materials

Characterization of mechanical properties of composite materials with filler coconut shell powder and sawdust with coconut fiber reinforcement as an alternative to low loaded brake friction materials

Study of technological defects arising during automated laying of prepregs (review)

Technologies of automated laying out of fibers (Automated Fiber Placement — AFP) and tapes (Automated Tape Laying — ATL) are used in the manufacture of blanks from polymer composite materials (PCM) for subsequent autoclave or other type of molding. The frequency of defect formation upon laying depends on the complexity of the certain part and the technological parameters (the tape width, speed of laying and idle time, temperature, deviations from the calculated trajectory, etc.). We present a review of the main defects thus formed along with the analysis of the reasons for their appearance and their effect on the physical and mechanical properties of composite materials. It is shown that the defects change the thickness and reduce the strength of the PCM under tension and compression. Moreover, the inaccuracy of fiber placement when using the AFP technology has a negative effect on the quality of the materials. The results presented can be used in the further study of the effect of defects on the PCM properties and reasons for defect formation, as well as in developing promising universal computational program that can provide reduction of the number of corresponding experimental tests.

Denture composite reinforced with short polyethylene terephthalate fibers

AbstractPolymer matrix composite materials have found application in dentistry because of good mechanical properties, aesthetic, easy processing, and possibilities of the repair. Acrylates are materials used to make and repair dentures. Reinforcements in the form of short glass or polymer fibers are added to improve the mechanical properties of dental polymers. In this study, the processing of composite material with a polymer matrix from commercial auto‐polymerized acrylate Simgal, with reinforcement in the form of short poly(ethylene terephthalate) (PET) fibers was examined. Samples were processed in three series: pure Simgal, Simgal/PET 1 wt% and Simgal/PET 3 wt%. The influence of the reinforcement in the form of short PET fibers on the mechanical properties of composite materials was investigated. Strength and hardness were tested by impact testing and Vickers microhardness, and it was shown that there is an increase in absorbed energy and hardness. The modulus was reduced by the addition of PET fibers and by increasing the amount of fibers in the composite. The increase in the amount of PET fibers also resulted in a smaller loss of surface mass of the samples compared to the pure matrix by 63% and 93%, respectively. Cavitation test revealed better cavitation resistance of composites than the pure acrylate.