Strength Of Composite Materials Research Articles

Exploding wire method for the characterization of dynamic tensile strength of composite materials

In the presented study a wire electric explosion method is adopted for the shock loading test of wound T700/LY113 carbon/epoxy composite. The advantage of the proposed test method is a possibility to reach strain rate ∼104 s−1, exceeding upper limit of split Hopkinson pressure bar, but matching lower limits of plate impact test. Compared to the latter test method, a promising feature is a capability to measure in-plane tensile strength of the laminated composite. To implement the proposed method, test samples were fabricated by winding of carbon fiber layers over a polymethyl methacrylate (PMMA) cylinder. Electric explosion of wire inserted in the channel inside the cylinder generates a shock wave, which propagates towards the outer composite shell, and free surface velocity history is recorded using a laser interferometer. It allows estimation of failure strain and tensile strength of the composite in circumferential direction. However, incident shock wave and reverberations are also critical for out-of-plane strength, including delamination, so finite element analysis is used to elaborate what type of failure mode is critical.

Preparation and Performance Improvement Mechanism Investigation of High-Performance Cementitious Grout Material for Semi-Flexible Pavement.

Semi-flexible pavement material (SFPM) combines the advantages and avoids the disadvantages of asphalt concrete flexible pavement and cement concrete rigid pavement. However, due to the problem of interfacial strength of composite materials, SFPM is prone to cracking diseases, which limits the further application of SFPM. Hence, it is necessary to optimize the composition design of SFPM and improve its road performance. In this study, the effects of cationic emulsified asphalt, silane coupling agent and styrene-butadiene latex on the improvement of SFPM performance were compared and analyzed. The influence of modifier dosage and preparation parameters on the road performance of SFPM was investigated by an orthogonal experimental design combined with principal component analysis (PCA). The best modifier and the corresponding preparation process were selected. On this basis, the mechanism of SFPM road performance improvement was further analyzed by scanning electron microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) spectral analysis. The results show that adding modifiers can significantly enhance the road performance of SFPM. Compared to silane coupling agents and styrene-butadiene latex, cationic emulsified asphalt changes the internal structure of cement-based grouting material and increases the interfacial modulus of SFPM by 242%, allowing cationic emulsified asphalt-SFPM (C-SFPM) to exhibit better road performance. According to the results of the principal component analysis, C-SFPM has the best overall performance compared to other SFPMs. Therefore, cationic emulsified asphalt is the most effective modifier for SFPM. The optimal amount of cationic emulsified asphalt is 5%, and the best preparation process involves vibration at a frequency of 60 Hz for 10 min and 28 days of maintenance. The study provides a method and basis for improving the road performance of SFPM and a reference for designing the material composition of SFPM mixes.

Mechanical and thermal properties of recycled polyethylene/surface treated hemp fiber bio‐composites

AbstractHemp is a good option for polyethylene additives because of its high cellulose and fibrous content. This study aims to modify natural hemp fibers with the maleic anhydride/ionic liquid method, manufacture the composites, and compare the thermal and mechanical properties of natural hemp fiber and hemp cellulose. In this study recycled polyethylene as a binder, and filling ratios between 0 and 50 (wt/wt)% are investigated as a parameter. Differential scanning calorimeter and thermomechanical analysis were performed, and it was determined that the coefficient of thermal expansion from 973 to 147 ppm/K. It was determined that the strength of composite materials obtained from cellulose fibers with maleic anhydride/liquid ionic modification improved by around 20% from 19.5 to 24.4 MPa. In addition, as a result of scanning electron microscope analyses performed on the fractured surfaces, it was determined that the pressure, temperature, and time were suitable for producing composite materials. This work shows the potential of recycled polyethylene/hemp composites as a sustainable green material with simple fabrication procedure and useful mechanical and thermal properties.

Optimization of Composite Grouting Material Proportioning Based on Regression Analysis Method

In order to improve the impermeability of ordinary “cement–water glass” double-liquid grouting material, this study prepares a composite grouting material with sodium bentonite, cement, and water glass as the main materials, water-reducing agent, and early strength agent as activators. In this study, orthogonal tests were conducted using an L16(45) orthogonal table and the test results were analyzed using regression analysis. Using bentonite instead of partial cement, the experimental factors of the bentonite ratio, glass slurry ratio, water-reducing agent admixture, and early strength agent admixture were used to study the laws of single-factor and two-factor interactions on the initial apparent viscosity, setting time, and compressive strength of composite grouting materials. After obtaining the optimal ratio of composite grouting materials, the mechanism of formation of material strength and seepage resistance properties was revealed. The results show that the mass ratio of bentonite to cement and the mass ratio of water glass to slurry have a large effect on the material properties, and there is an interactive effect of several factors at the same time. The optimal ratio of the material is 28.42% water, 36.58% cement, 6.20% bentonite, 0.04% water-reducing agent, 0.9% early strength agent, and 27.85% water glass. The microstructural analysis shows that the denseness of the stone body structure is enhanced, and thus the strength and impermeability of the material are improved. This composite grouting material improves injectability and seepage resistance and is more suitable for underpinning grouting of weakly cemented soft rocks, but the ratio optimization method and model used in this study can be applied to other materials.

Research on Properties of Ash and Slag Composite Cementitious Materials for Biomass Power Plants

The effects of ash and slag from a biomass power plant on the compressive strength, setting time and fluidity of the pastes of Portland cement (P.O) and sulfoaluminate cement (SAC) were studied, and the hydration products and microstructure at the age of 7 days were analyzed via XRD, SEM and other test methods. The results show that the compressive strength of the composite cementitious material decreases, the setting time prolongs and the fluidity increases with the increase in the ash and slag content in the power plant. The microscopic analysis shows that the ash and slag of the biomass power plant can promote the hydration of Portland cement and sulfoaluminate cement paste, and increase the generation of hydration products. The results showed that replacing SAC clinker with 20–30% biomass power plant ash (BPPA) decreased the cement strength, and that an appropriate amount of BPPA (10–15%) could significantly improve the mechanical strength of SAC blended cement. The compressive strength of blended BPPA composite cementitious material in 28 days could reach 60 MPa. This study provided solutions to utilizing the BPPA as a building material admixture to minimize the consumption of energy-intensive cement and to meet the growing needs of the construction industry.

Application And Improvement of Composite Materials in Truss Bridge Structure

Composite materials are new materials with the features of light weight, high strength, high specific modulus, strong corrosion resistance, and aging resistance. The truss structure is subject to unidirectional force, which gives full play to the advantages of high strength of composite materials along the fiber direction. Therefore, composite truss structure is gradually attracted attention in engineering fields, i.e., aerospace, bridges, and construction. By analyzing the application status of composite truss bridge at home and abroad, it can be concluded that compared with traditional steel truss, composite truss bridge has advantages in flexural performance, tensile performance, stability and other mechanical properties. However, due to the stiffness control design, the strength of composite material is not fully utilized, and the structural reliability of composite truss bridge is low due to the low efficiency of structural joints. The improvement methods of these two problems are reducing the allowable deflection-span ratio of composite truss bridge design and using composite materials with greater stiffness and changing the laying Angle and laying proportion of composite materials, respectively.

Investigating the Influence of Hydroperoxide Treatment on the Bagasse Fiber Reinforced Composite Properties

This study has investigated the effect of hydroperoxide treatment on the properties of bagasse fibers in order to get the value added material using by-products from sugar production such as reinforcement for composite materials. The results of processing bagasse fibers with hydroperoxide at different concentration, temperature and treatement time showed that treatment condition had a great influence on the properties of the obtained fibers. With the suitable treatement conditions of 10% peroxide concentration, treatment time of 40 minutes, treatment temperature at 60 0C, the treated fiber has a more homogeneous surface than the untreated. The composite using hybrid bagasse/glass fiber has higher flexural and impact resistance than when using glass fiber and reaches 162.6 MPa and 38.9 KJ/m2 (16.7% and 213% respectively compared to composite using glass fiber only). This can be explained that the treated bagasse fiber has better wetting ability with the matrix resin and together with the energy absorption capacity of the fiber bundle, it leads to an increase in flexural strength and impact strength of composite material.

Single-filament-wide tensile-testing specimens reveal material-independent fibre-induced anisotropy for fibre-reinforced material extrusion additive manufacturing

PurposeThis study/paper aims to develop fundamental understanding of mechanical properties for multiple fibre-reinforced materials by using a single-filament-wide tensile-testing approach.Design/methodology/approachIn this study, recently validated single-filament-wide tensile-testing specimens were used for four polymers with and without short-fibre reinforcement. Critically, this specimen construct facilitates filament orientation control, for representative longitudinal and transverse composite directions, and enables measurement of interlayer bonded area, which is impossible with “slicing” software but essential in effective property measurement. Tensile properties were studied along the direction of extruded filaments (F) and normal to the interlayer bond (Z) both experimentally and theoretically via the Kelly–Tyson model, bridging model and Halpin–Tsai model.FindingsEven though the four matrix-material properties varied hugely (1,440% difference in ductility), consistent material-independent trends were identified when adding fibres: ductility reduced in both F- and Z-directions; stiffness and strength increased in F but decreased or remained similar in Z; Z:F strength anisotropy and stiffness anisotropy ratios increased. Z:F strain-at-break anisotropy ratio decreased; stiffness and strain-at-break anisotropy were most affected by changes to F properties, whereas strength anisotropy was most affected by changes to Z properties.Originality/valueTo the best of the authors’ knowledge, this is the first study to assess interlayer bond strength of composite materials based on measured interlayer bond areas, and consistent fibre-induced properties and anisotropy were found. The results demonstrate the critical influence of mesostructure and microstructure for three-dimensional printed composites. The authors encourage future studies to use specimens with a similar level of control to eliminate structural defects (inter-filament voids and non-uniform filament orientation).

Modelling the residual strength degradation in composite materials without using residual strength tests

Residual strength models are widely used to predict the fatigue life of composite laminates under highly variable loads. However, they often require considerable experimental effort to accurately determine model parameters. This paper introduces a new approach for predicting the residual strength of composite materials with less experimental data. The method is based on two common strength-based wearout models, the Sendeckyj model and Schaff and Davidson model. The Sendeckyj model consists of an equation with two model parameters, which describes the shape of the S-N curve by fitting fatigue test data. The Schaff and Davidson model is a single-parameter function which calculates the residual strength based on the number of fatigue cycles. Using a novel mathematical algorithm, the residual strength model parameter in the Schaff and Davidson model is estimated directly from the S–N curve without running any residual strength tests. Five data sets from the literature are used to validate the new methodology. The results show that the residual strength model parameter is dependent on both the stress level and the number of loading cycles experienced at this stress level, both of which are considered in the new strategy. In addition, if the fatigue data are well distributed, the residual strength model parameter estimated by the new strategy is close to the experimental data.

Super-Resolution Processing of Synchrotron CT Images for Automated Fibre Break Analysis of Unidirectional Composites.

Fibre breaks govern the strength of unidirectional composite materials under tension. The progressive development of fibre breaks is studied using in situ X-ray computed tomography, especially with synchrotron radiation. However, even with synchrotron radiation, the resolution of the time-resolved in situ images is not sufficient for a fully automated analysis of continuous mechanical deformations. We therefore investigate the possibility of increasing the quality of low-resolution in situ scans by means of super-resolution (SR) using 3D deep learning techniques, thus facilitating the subsequent fibre break identification. We trained generative neural networks (GAN) on datasets of high-(0.3 μm) and low-resolution (1.6 μm) statically acquired images. These networks were then applied to a low-resolution (1.1 μm) noisy image of a continuously loaded specimen. The statistical parameters of the fibre breaks used for the comparison are the number of individual breaks and the number of 2-plets and 3-plets per specimen volume. The fully automated process achieves an average accuracy of 82% of manually identified fibre breaks, while the semi-automated one reaches 92%. The developed approach allows the use of faster, low-resolution in situ tomography without losing the quality of the identified physical parameters.

Study on Dispersion Characteristics of HwBKP Hydrophobized by Repeated Gas Grafting in Polypropylene

This study investigated the fiber dispersion characteristics and physical property changes of HwBKP-PP composites through repeated hydrophobization and recycling of cellulose fiber. The gas-grafted paper was disintegrated and then gas-grafted again to achieve uniform dispersion of the cellulose fibers with PP. With each gas grafting repetition, the interfacial affinity between the hydrophobized fibers and PP improved, leading to enhanced tensile strength and melt flow index of the HwBKP-PP composite material due to the improved fiber dispersibility. However, recycling of hydrophobic paper resulted in the loss of fines in the recycled paper, so that increase in average fiber length caused fiber agglomeration, resulting in poor dispersibility, and subsequently decreasing the tensile strength and melt flow index of the composite.

Strength of Onyx-based composite 3D printing materials according to fiber reinforcement

This study evaluates the mechanical strength of 3D-printed objects of composite material. The composite material considered in this study comprises onyx as the base material with glass fiber and carbon fiber as the internal reinforcements. 3D printing using composite materials generally involves laminating fiber reinforcements in the form of layers within the printed part. To analyze the effect of such reinforcements on the printed parts, specimens were prepared by varying the number of layers and arrangement conditions of the reinforcement. The analysis shows that the tensile strength of the composite increases with the number of reinforcement layers due to the effect of the fibers on the longitudinal direction and a larger bonding area between the internal Onyx and the fibers. Furthermore, higher tensile strength is observed when the reinforcements are laminated at regular intervals than when they are arranged in the center. This study serves as a database for 3D printing fiber-reinforced composites aiding future research in comparing and optimizing their strength according to the 3D printing conditions.

COMPOSITE MIXTURES BASED ON SYNTHETIC POLYMERS AND FILLERS AND EQUIPMENT FOR 3D PRINTING WITH THEM

The article states that the use of composite materials instead of traditional materials allows you to significantly reduce the weight of the product, while not changing the strength characteristics of this material. It was determined that polymer composite materials based on metal powders, high-strength organic (aramid) and carbon fiber fillers with a polymer matrix are promising for use as structural materials. Fillers are used to improve the operational properties of the composite material (strength, stiffness, heat resistance), give them various specific properties and reduce the cost. The classification of polymer composite materials by matrix and filler is presented. It is noted that the greatest variety of properties can be obtained using solid fillers of different nature (metals, ceramics, polymers) and structures. It has been established that both the type of filler and the shape and size of the particles are important when forming certain properties of polymer composite materials. It was determined that composite materials are used in additive technologies, in particular in 3D printing. Examples of the production of composite filaments by various companies, including various types of fillers, are given. The developed technology of printing with a mixture of polymer connector and filler using a 3D printer, which includes certain stages, is presented. Polymer materials and solid fillers of various nature were selected as the matrix for experimental research and their properties were described. The classification of equipment for forced mixing of materials is described. The developed extruder that prints with granules or composite mixtures of polymer materials and the 3D printer on which it is installed are presented. Composite mixtures for conducting experimental studies are given. The parameters of the printed samples to be examined are specified.

Optimization of Uniaxial Tensile Stress-Strain Response of 3D Angle Interlock Woven Fabric Composite using Weft Density and Draw-In Plan Variables

Currently, 2D woven composites are extensively incorporated into a variety of technical automotive body parts and protective body armor owing to their excellent fabric strength performance. However, there is still a lack of attempts to utilize 3D woven fabrics for the same technical application. Hence, it is vital to examine the fundamental tensile strength of woven fabric composite materials when determining their suitability for end-use applications. This study aimed to investigate the novel effects of two parameters on the uniaxial tensile strength of a high-tenacity polyester three-layer 3D angle interlock (3DAI) woven fabric composite, namely, weave drafting draw-in insertion and weave density. Four different drafting patterns were considered: pointed (DRW 1), broken (DRW 2), broken mirror (DRW 3), and straight (DRW 4), for weft density at 14 and 25 pick.cm-1. Samples of the 3DAI woven fabric reinforced with epoxy composite at different drafting patterns and weft density combinations were produced and tested. Consequently, the maximum tensile stress and strain were recorded in the woven fabric composite sample with DRW 4 and 25 pick.cm-1 at 113 MPa and 11%, respectively. The study shows that different weft densities and draw-in plan settings play a significant role in the tensile strength performance of the 3DAI woven composite.

Evaluation of Micro-Tensile Bond Strength of A New Resin Composite Restorative Material at Two Different Dentin Depth After Aging (An In-Vitro Study)

Evaluation of Micro-Tensile Bond Strength of A New Resin Composite Restorative Material at Two Different Dentin Depth After Aging (An In-Vitro Study)

Influence of Rigid and Flexible Matrices on Ultimate Strength and Fracture Mechanisms of Polymer Composite Materials upon Impact and in Static Loading Conditions

Influence of Rigid and Flexible Matrices on Ultimate Strength and Fracture Mechanisms of Polymer Composite Materials upon Impact and in Static Loading Conditions

Relationship between fractal feature and compressive strength of fly ash-cement composite cementitious materials

Microscopic pore structure and compressive strength of fly ash-cement composite cementitious materials at 20 °C and 60 °C measured by mercury intrusion porosimetry and compressive strength test. Microscopic pore structure was analyzed from porosity, pore volume, total pore surface area, average pore diameter, median pore diameter, most probable diameter, threshold diameter and fractal feature. The fractal dimensions of each specimen were calculated by Menger Sponge. The regression analysis between fractal dimension and pore structure parameters were fitted by linear function, quadratic polynomial function, power function and exponential function, respectively. Eventually, the relationship between pores structure and compressive strength was characterize by the mathematical model between the optimal comprehensive parameter of pores structure and compressive strength. And the T-test and F-test were used to reveal the significance of the regression parameter and function. Research results showed that the fractal curves of all specimens consist of four segments. The pores have obvious fractal features in Region I and Region IV, while presented no-fractal feature in Region II and Region III. In Region I and Region IV, fractal dimension followed the exponential function with average pore diameter, median pore diameter, most probable diameter and threshold diameter, consistent with quadratic polynomial function with porosity, pore area and pore volume, and accords with the positive power exponential function with compressive strength. Thus, the morphology of hierarchical aggregates expressed by fractal dimension can reflect the relationship compressive strength and pore structure in fly ash-cement composite cementitious materials more directly.

Analisis Kekuatan Mekanik Komposit Polimer Diperkuat Serbuk Kulit Kerang

In recent decades, the development of composite material technology has continued to increase rapidly and has been used for various applications as an alternative material to replace metal. In line with growing environmental issues, the utilization of natural materials which are abundant in nature and easy to find is the main priority for composite building materials. In this study, shell powder was used as a reinforcing material for epoxy polymer composites. The aims of this study were to obtain the average compressive, tensile, and flexural strength of shell powder-reinforced polymer composite materials, to calculate the distribution of test results using the PDF method, and to calculate the contribution of shell powder to the mechanical properties mentioned using the ANOVA method. The tensile, compressive, and flexural test specimens follow the test specimen standards of ASTM D638, ASTM D7264, and ASTM D695 respectively. The composition of shell powder consists of 10%, 30%, and 50%. Testing of these mechanical properties using a UTM-type hydraulic test equipment model WEW-300D with a capacity of 300 kN. The test results show an increase in the mechanical properties of the material. The increase occurred in compressive and flexural strength where the composition was given up to 30% and 50%, namely between 120 – 125 MPa. However, increasing the composition of shell powder at 30% and 50% actually resulted in a decrease in tensile strength between 12 – 9 MPa. Finally, based on the results of ANOVA analysis, it was shown that the addition of shell powder as a reinforcement for polymer composites significantly improved their mechanical properties.

The properties of fibre-reinforced calcium phosphate cement composites under prolonged increasing cyclic thermal loads

This work is focused on thermo-mechanical behaviour of fibre-reinforced calcium phosphate cement (CPC) under thermal load. Macro-polypropylene, amorphous metallic and recycled carbon fibres at a dosage of 1.5% by volume were individually incorporated into a molten premixed plain CPC to improve its fracture behaviour. The tested specimens with dimensions 40x40x160 mm3 were first autogenously cured at room temperature for 14 days before being exposed to a temperature of 50 °C-1000 °C in an oven. The thermal resistance of the cement composites was then investigated. The residual properties observed in non-destructive and destructive experiments showed that the strength of CPC composite material is affected by extreme heat. Nevertheless, this material holds great potential for refractory applications.

Influence of the milling conditions on the compressive strength of Ti/TiC composite materials sintered at atmospheric pressure

High compressive strength composite materials based on commercially pure titanium were synthesized from Ti Cp grade 2 powders processed by high-energy ball milling using n-hexane as PCA and subsequent sintering in a tubular furnace under argon atmosphere at 1100 °C for 2 h, at atmospheric pressure. The study focused on two main aspects: (i) The effect of speed and milling time on the microstructure and (ii) the relationship between the microstructure and the mechanical resistance of the obtained material. It was found that the presence of TiC was related to the mechanochemical process during milling that occurs under specific conditions of speed and time when enough energy was transferred to the powder coupled with the thermal process at elevated temperature. According to the DSC peaks, the activation energy for the transformations is close to 171 kJ/mol. The microstructure of the sintered samples was characterized by SEM EDS, XRD, and TEM, and the mechanical properties by compression and hardness tests. The high compressive strength of the specimens was attributed to three aspects: (i) the distribution of particles in the sintered samples, (ii) the fine grain size derived from the milling process and (iii) the formation of titanium carbide. A maximum compressive strength of 2.8 GPa makes this material sintered by a simple and low-cost route, very competitive with other advanced Ti composites.