Glass Fiber Composite Materials Research Articles

Improved mechanical properties of an epoxy glass–fiber composite reinforced with surface organomodified nanoclays

An organomodified surface nanoclay reinforced epoxy glass-fiber composite is evaluated for properties of mechanical strength, stiffness, ductility and fatigue life, and compared with the pristine or epoxy glass-fiber composite material not reinforced with nanoclays. The results from monotonic tensile tests of the nanoclay reinforced composite material at 60°C in air showed an average 11.7% improvement in the ultimate tensile strength, 10.6% improvement in tensile modulus, and 10.5% improvement in tensile ductility vs. these mechanical properties obtained for the pristine material. From tension–tension fatigue tests at a stress-ratio=+0.9 and at 60°C in air, the nanoclay reinforced composite had a 7.9% greater fatigue strength and a fatigue life over a decade longer or 1000% greater than the pristine composite when extrapolated to 109 cycles or a simulated 10-year cyclic life. Electron microscopy and Raman spectroscopy of the fracture and failure modes of the test specimens were used to support the results and conclusions. This nanocomposite could be used as a new and improved material for repair or rehabilitation of external surface wall corrosion or physical damage on piping and vessels found in petrochemical process plants and facilities to extend their operational life.

Joined-wing test bed UAV

The future green aircraft will be required to meet demanding constraints, including weight reduction, high energy and aerodynamic efficiencies and high performance, to be compliant with pollutant emissions and noise generation regulations. The joined-wing concept is considered a trade-off variant for a green aircraft design with a lower cruise drag and lower structural weight. In addition, the requirements for low pollution and noise could be met using an all-electric aircraft. Hence, the aim of the present study is to design and produce a joined-wing unmanned aircraft test bed or flight laboratory. The basic design incorporates tip-joined front and rear wings with wing-tip vertical joints. The airframe is mainly composed of carbon and glass fibre composite materials. The power plant consists of an electric ducted fan, speed controller and Li-Po batteries. The aircraft integrates the Piccolo II Flight Management System, which offers a state-of-the-art navigation and flight data acquisition. Prior to production and flight testing of the prototype, aircraft aerodynamics and flight dynamics were analysed. Potential models with wind tunnel tests have been used to determine aircraft aerodynamics. One of the major problems found during simulation and flight experiments is the Dutch roll effect. This is thoroughly discussed in the paper. Some problems that concern autopilot tuning are also described.

Influence of Process Parameters on Delamination of Drilling of (GF/PC) Glass Fiber Reinforced Polycarbonate Matrix Composites

Drilling is an important and final operation in the assembly of structural components of aircraft and automobiles. This paper determines the influence of cutting forces in the drilling of GF/PC composites. An assembly, the quality of the drilled holes highly affects the joint of two or more structural components. Drilling of glass fiber composite materials is a vital task for manufacturers. The best methodology for achieving good quality holes during the drilling of glass fiber reinforced plastics is by identify of the cutting forces. Improper cutting forces lead to the damage of composite materials. This paper studies the influence of various feed rate on thrust force, spindle speed and drill bit geometry using Brad and spur drills. This experimental result shows that delamination fully depends on the feed rate. The experimental results have been clearly explained with the help of 3D response graph and Scanning Electron Microscopic (SEM) images.

Analysis of Fiber Glass/Vinyl Ester Composite Subjected to Internal Pressure Loading for Compressed Natural Gas (CNG) Tube Type IV Application

Natural gas in the form of compressed natural gas (CNG) has a pressure of 20 MPa. Glass fiber/vinyl ester composite has potential to be formed into a CNG tube. This study uses a numerical analysis method and tubular approching to assess composite ability to accept internal pressure loading, refered to failure criteria Tsai-Hill. The number of layers and fiber direction are chosen as independent variable. Configuration angle (+70, +25) provided a more optimal result than using a single angle. Composites are in a safe condition on 180th layer. Thus, the glass fiber composite material / vinyl ester is not recommended to apply in the CNG tube manufacture.

흡음재 폐기물의 재활용 방안

흡음재로 널리 사용되는 헤드라이너는 발포성 폴리우레탄(PU foam)과 유리섬유(Glass Fiber,GF) 로 구성된 복합재료로, 제품의 생산 공정을 거치는 동안 부산물 형태의 폐기물이 발생한다. 헤드라이너 폐기물에 대한 효과적인 재활용을 위해 헤드라이너 구성성분에 대한 분리공정이 중요한 문제점이다. 헤드라이너에 대한 열분석결과에 의하면 중량의 감량 비율은 <TEX>$400^{\circ}C$</TEX>까지의 온도범위에서는 발포성 폴리우레탄 > 비발포성 폴리우레탄 > 부직포 > 1st layer > 유리섬유의 순으로 감량이 증가하는 결과를 보이고 있다. HDPE, LLDPE, PP 그리고 Master Batch 에 첨가제 형태로 폐 스크랩 첨가하여 sheet를 제작한 후 DSC 특성을 분석한 결과 PP를 제외한 다른 물질들에서는 결정화에 따른 발열전이가 나타나지 않는 것을 확인 하였다. The headliner was made of polyurethane(PU) and glass fiber(GF) composite materials are widely used as a sound insulation material. A large amount of waste materials occurs as a by-product in the headliner manufacturing process. In order to efficiently reuse the headliner waste materials, separation process of the components are very necessary. According to the results of thermal analysis, weight loss showed increase in the order polyurethane foam> non-foaming polyurethane> non-woven fabric> 1st layer> glass fiber in the range of up to <TEX>$400^{\circ}C$</TEX>. Analysis of the DSC characteristics, HDPE, LLDPE, PP, and Master Batch by adding additives the wasted scrap. As a result, except for the PP, there was no exothermic transition due to the crystallization.

The Development of Modular Electrical Fittings for Transmission Lines in Intelligent Distribution Network

Spacers, for example, this paper introduces the developing process of energy efficient transmission line modular electrical fittings in distribution network. It uses glass fiber composite materials and non-magnetic as the main material which does not produce or produce very little hysteresis and eddy current losses. It has no corona and its energy saving effect is obvious; anti-dancing, high mechanical strength. Refer to the knowledge of aerodynamics to design the structure, not only effectively prevent the connection joint of different materials connected to the wear and tear, and can effectively reduce wind noise, thus reducing friction and shock losses .It not only replaces the expensive and rare metal materials such gold, and provide simple and economical solution for upgrading the distribution network. It meets the transmission line spacers technical indicators, economic and social benefits significantly.

Design of the Hybrid-Propeller Shaft Using Composite Materials

The propeller shaft of rear-wheel drive vehicle transfers power from the engine to rear wheels through the differential gear box. Generally the propeller shaft has a two-piece steel structure of more than 10kg of weight. In this paper, we designed the one-piece hybrid propeller shaft using the aluminum, carbon fiber composite material and glass fiber composite material. Research on the adhesive strength of the hybrid propeller shaft with respect to roughness of aluminum surface was conducted. The one piece hybrid propeller shaft satisfying the performance standards of propeller shaft such as statistic torsion torque strength and first bending natural frequency was manufactured. The manufactured hybrid shaft was assembled with the suitable connecting parts and analyzed for performance verification. This hybrid propeller shaft satisfies all performance standards of propeller shaft for automobile application. The hybrid shaft has vibration characteristics of 237Hz significantly higher than the standard characteristic of 150Hz of the existing two-piece steel structure propeller shaft.

Life cycle assessment of a novel hybrid glass-hemp/thermoset composite

Bio-based materials have come increasingly into focus during the last years, as alternatives to conventional materials such as fossil-based polymers, metals, and glass. The present paper is an application of life cycle assessment (LCA) methodology in order to explore the possibility of improving the eco efficiency of glass fibre composite materials by replacing part of the glass fibres with hemp mats. The main purpose and contribution of this study is the exploration of the eco-efficiency of this new material. To a minor degree, it is also a contribution in the sense that it provides life cycle inventory data on composites, which as yet is scarce in the LCA community. The study is a development of a previous work conducted on a pipe system used to transport cooling sea waters in a Sicilian petrochemical company. A comparative LCA was performed of two different elbow-fittings made of glass fibre/thermoset composite and hybrid (glass fibre-hemp)/thermoset composite, respectively. Primary data were collected mainly for the manufacturing process of the composite, while the Ecoinvent v2.2 database (PRe-Product Ecology Consultants, 2012) was used to model other parts of the system. Significant environmental benefits of using hemp mats were found mainly in the production phase. An LCC was also carried out from cradle to grave to find ways to optimise the costs. Material costs reduction was significant for the hybrid elbow formulation.

Modeling the tribological abrasive wear behavior of woven composite materials using the planning design experimentation approach

This article addresses the experimental characterization of the abrasive wear of two woven fabric carbon fiber and glass fiber composite materials, taking into account the effect of moisture absorption. The composite materials were tested to three level loadings and two sliding speeds. The abrasive used was dry sand of size 0.6 µm, and the time of wear testing was 10 min. In order to study the effects of moisture on wear behavior, another series of samples was introduced into the tank of water during a period of 40 days at ambient temperature. The planning design experimentation approach was applied to obtain a mathematical model taking into account the influencing parameters on the wear behavior of the composites. The wear results have shown that for a higher turn speed and a load, the loss of matter increases. In the case of samples exposed to water absorption, the wear rate increases more than the dry samples. The micrographs of the surface of the samples tested were taken in order to characterize the wear mechanism.

Infrared Thermography Non-Destructive Testing of Composite Materials

To detect the delamination, disbond，inclusion defects of the glass fiber composite materials applied in the solid rocket motor, active infrared thermographic non-destructive testing(NDT) is researched. The samples including known defects are heated by pulsed high energy flash lamp. The surface temperature of the samples is monitored by infrared thermography camera. The results of the experiments show that the active infrared thermography technique is a fast and effective inspection method for detecting the defects of delamination, disbond，inclusion of the composites. The samples are also detected by underwater ultrasonic c-scans. The paper concludes that the active infrared thermography NDT is more suitable to rapidly detect the defect in large-area and the underwater ultrasonic c-scans is more suitable to quantitatively identify the defect in local-area.

SERIAL SECTIONS THROUGH A CONTINUOUS FIBER-REINFORCED POLYMER COMPOSITE

The microstructure of a unidirectional glass-fiber composite material is described seeking especially for the influence of the stitching perpendicular to the reinforcement. Serial cuts are performed through the composite and the microstructure is quantified using global parameters and linear morphological analysis. A key result is that the stitching induces variations in fibers spacing within the yarns and in the matrix volume between the yarns. This can affect noticeably the flow of the resin during the manufacturing process and also the mechanical properties of the composite.

Solution of the Flutter Eigenvalue Problem with Mixed Structural/Aerodynamic Uncertainty

The solution of the flutter eigenvalue problem with mixed structural/aerodynamic uncertainty was examined. A delta-wing wind-tunnel model was used as a test case. The model had a simple structural design and was made of glass-fiber and carbon-fiber composite materials. It had a semispan of 0.88 m and mean chord of 0.70m and was mounted vertically in the low-speed wind tunnel L2000. The numerical analysis was based on a NASTRAN model with shell elements for the wing, mass elements for the missile, and aerodynamic panels for doublet-lattice aerodynamic loads. The relatively stiff missile was modeled as a rigid body attached to the wing tip. The nominal eigenvalue was always an interior point of the corresponding eigenvalue set. A parameter sweep taking only aerodynamic uncertainty into account was performed by solving the eigenvalue problem for a set of parameter values. The eigenvalue sets based on one patch and seven patches, respectively, showed only slight difference.

Strain rate dependent low velocity impact response of layerwise 3D-reinforced composite structures

The performance evaluation of a novel layerwise 3D-reinforced glass–fibre composite material under low velocity impact loading conditions is presented. Firstly, strain rate dependent material properties are determined, for which the experimental procedure is explained in detail on the example of polypropylene and epoxy matrix based composite configurations. The gained orthotropic property-profile provides the input parameters for a numerical low velocity impact analysis of a demonstrator structure. This complex shaped bucket structure, manufactured within a VARTM process, is subjected to various impact scenarios, for which a fully instrumented drop tower testing rig has been designed and utilised. The numerical results are compared with the experimentally observed impact response. The predictive capability of the proposed multidisciplinary evaluation approach for composites subjected to impact loading conditions is finally discussed.

Evaluation of a Life Prediction Model and Environmental Effects of Fatigue for Glass Fiber Composite Materials

Fiber-reinforced polymer (FRP) composites are being utilized in an increasing number of applications in structural industries. Establishing values for longterm fatigue response is essential for widespread use of FRP composites. The variety of available fibers, matrix materials, and manufacturing processes makes the fatigue response difficult to predict without extensive empirical testing. A proposed fatigue life prediction model uses the internal strain energy release rate as the metric for predicting fatigue life from a minimum of data points. The objective of this research was to apply the above model to fatigue data for various composite coupons and components in order to evaluate its applicability in predicting fatigue life. The model was found to be able to regularly fit and predict fatigue data within 5% log error at both coupon and component levels. The effects of environmental conditions, including 12 MPa pressurized absorption and fatiguing in salt water and elevated temperatures, were also explored for a glass/vinyl ester FRP. The results of this research can be used to aid in the design of numerous structural FRP applications, such as windmill blades, bridge decks, or deep sea piping.

Ultimate Strength Analysis of Ship Hulls of Continuous Basalt Fiber Composite Materials

Based on effective composite material failure criteria and property limited degradation model, axial compressive ultimate strength of composite laminated stiffened panels are analyzed by nonlinear laminated degenerated 3D finite element analysis, which is based on incremental continuum-based updated Lagrangian formulation. Comparison between analytical solutions and test results in this article indicates that this article provides an effective and practical method to evaluate the axial compressive ultimate strength of composite laminated stiffened panels. Using this method, ultimate strength of hull girders made of continuous basalt fiber composite materials are analyzed . Comparing the results，it can be seen that the ship hull in basalt fiber composite materials has equivalent longitudinal ultimate strength to S-2 glass fiber composite materials, basalt fiber composite material could replace the S-2 glass fiber composite materials used in shipbuilding engineering. The gist for building ship with basalt fiber composite materials was provided by this paper.

Deposition of metallic coatings on polymer surfaces using cold spray

Current coating technologies such as plasma spray, High Velocity Oxygen Fuel (HVOF) or laser cladding involve the delivery of molten materials during the deposition process. However, such techniques are not well suited to the deposition of metallic coatings on polymers and composites. Cold spray (CS) has attracted much industrial interest over the past two decades. In this method, a material in powder form is accelerated on passage through a converging–diverging nozzle to high speeds via a high pressure coaxial carrier gas jet. The high impact kinetic energy deforms the particles, which creates effective bonding to the substrate.This paper presents the results of an initial study on the potential of the CS process to produce metallic coatings on non-metallic surfaces such as polymers and composites for engineering applications. Experimental and Computational Fluid Dynamics (CFD) results when spraying copper, aluminium and tin powder on a range of substrates such as PC/ABS, polyamide-6, polypropylene, polystyrene and a glass-fibre composite material are presented and analyzed.

Multicriteria optimization of cutting parameters in turning of UD-GFRP materials considering sensitivity

In this paper, a new multicriteria optimization approach is proposed for the selection of the optimal values of cutting conditions in machining. This approach aims to handle the possible manufacturing errors in design stage. These errors are taken into consideration as change in design parameters and the design most robust to change is selected as the optimum design. Machining of a glass fiber composite material is chosen in case studies. Experiments on the unidirectional glass fiber reinforced composite material are performed to investigate the effect of cutting speed, feed, and cutting depth on the cutting forces. Also, material removal rate values are obtained. Minimizing cutting forces and maximizing the material removal are considered as objectives. It is believed that the used method provides a robust way of looking at the optimum parameter selection problems.

Uncertainty analysis of a neural network used for fatigue lifetime prediction

The application of interval set techniques to the quantification of uncertainty in a neural network regression model of fatigue lifetime is considered. Bayesian evidence training was implemented to train a series of multi-layer perceptron networks on experimental fatigue life measurements in glass fibre composite sandwich materials. A set of independent measurements conducted 2 months after the training session, and at intermediate fatigue loading levels, was used to provide a rigorous test of the generalisation capacity of the networks. The robustness of the networks to uncertainty in the input data was investigated using an interval-based technique. It is demonstrated that the interval approach allowed for an alternative to probabilistic-based confidence bounds of prediction accuracy. In addition, the technique provided an alternative network selection tool, and also allowed for an alternative to estimating the lifetime prediction error that was found to be a significant improvement over the Bayesian-derived estimate of confidence bound.

Sea water effect on pinned-joint glass fibre composite materials

The effect of sea water on the bearing strength behavior of the woven glass fibre composite has been investigated experimentally. The ratio of the edge distance to the pin diameter (E/D), and the ratio of the specimen width to the pin diameter (W/D) were systematically varied during experiments. In order to provide the real environmental conditions, specimens were tied to a ship, making voyage in the Sea of Marmara having 2.2% of salt and 22–26 °C of surface temperature, with a stainless wire to keep the specimens into sea. The specimens were kept into sea 1, 2 and 4 months. The experiments were carried out according to the ASTM D953 [ASTM D 953-D, Standard test method for bearing strength of plastics. ASTM Designation. p. 342–6]. The results show that while the bearing values obtained from the specimens kept into sea for four months decrease considerably with respect to 1 and 2 months. But, the failure modes for all configurations are the same mode. Failure distance of the pin displacement increases with the increasing of immersing period owing to softening of the specimen.

Statistical Analysis of Bearing Strength of Glass—Fiber Composite Materials

In this study, bearing strength of woven glass—fiber composite plates has been statistically analyzed by Weibull distribution. The ratio of the edge distance to the pin diameter (E/D), and the ratio of the specimen width to the pin diameter (W/D) were systematically varied during analyses. Eight specimens were tested for each specimen configuration. The results show that the 99% reliability values of each bearing strength configuration is approximately equivalent to the 0.7 average value of the bearing strength. In addition, the bearing strengths obtained from Weibull distribution and from average value reach their upper limit when (E/D) and (W/D) ratios are equal or greater than 4.