Reinforcement Material Research Articles

Mechanical Properties and Flammability Analysis of Wood Fiber Filled Polylactic Acid (PLA) Composites Using Additive Manufacturing

ABSTRACT Natural fibers, such as wood fibers, can substitute for synthetic fibers in various applications due to their low environmental impact, cost-effectiveness, and outstanding mechanical properties as rapid-growing materials and renewable resources. This paper aims to investigate the mechanical properties of 20% wood fiber as a reinforcement material in polylactic acid (PLA) using an additive manufacturing approach. The samples were fabricated using 3D printing techniques. The relevant parameters included the orientation of printing in X, Y, and Z directions, with the percentage of infill set to be 100%. The findings indicated that bio-composites and their adopted printing orientations confirmed the significant effects on the mechanical properties. Pure PLA possessed superior properties in all directions compared to wood/PLA. The highest values were 50.33 MPa for tensile strength and 94.36 MPa for flexural strength, both achieved in Y orientations. However, composites showed an improvement in tensile and flexural moduli in X orientation with 1395.40 MPa, and 2937.72 MPa for Young and flexural modulus, respectively. In the flammability test, wood/PLA bio-composites were ignited easily with reduced smoke production compared to the neat PLA. Wood/PLA bio-composites exhibited high stiffness, and their mechanical properties were influenced by many factors, such as percentage of weight fraction, wood type, and printing orientations.

Physico-Thermal and Mechanical Characterization of Alfa Fiber/Polypropylene Composites: Effects of Fiber Treatment and MAPP Compatibilization

ABSTRACT This study investigates the enhancement of compatibility between natural reinforcement materials and polymer matrices, with a focus on Alfa fibers polypropylene (PP) composites. Composites Alfa fibers/PP are prepared using untreated and treated alfa fibers and with or without the addition of a MAPP compatibilizing agent. Firstly, Alfa fibers extracted from the plant are categorized into two groups: untreated and treated with a 3% (wt/v) alkaline solution followed by bleaching. This chemical treatment significantly increases the cellulose content and crystallinity index of the fibers, with improvements of 39.7% and 13.6%, respectively. Secondly, the study incorporates 5 wt% MAPP in the PP matrix as a compatibilizer. The composites produced with 30 wt% of alfa fibers are processed using a single screw extruder, followed by injection molding. Composites samples obtained are characterized using various methods. Thermal analysis reveals that the incorporation of chemically treated alfa fibers along with MAPP significantly accelerates the crystallization rate of the PP matrix, indicating the fibers’ role as effective nucleating agents. Mechanical testing shows marked improvements in the Young’s modulus and tensile strength of the composites obtained with treated alfa fibers reinforcing the MAPP-PP matrix, with increases of 1.67% and 4.61% over their untreated counterparts, respectively.

Development of anti-corrosion, structural, and optoelectronic potential of Capsicum annuum-Doped AA6063 alloy for marine applications

The study explores the potential of incorporating pepper waste as a reinforcement material in aluminium AA6063 composites, with focussing on the morphological, mechanical, electrochemical, and optoelectric properties. Pepper wastes, including stalks and seeds, were carbonised, pulverized, and sieved to yield 75 μm particulates. These were mixed with molten AA6063 alloy via stir casting, with the pepper content ranging from 0% to 25% by weight. The composites were characterised using hardness testing, electrochemical evaluation, optoelectrical analysis, and morphological analysis. Hardness tests revealed that the 25% pepper-reinforced sample exhibited the highest hardness value of 37 HRB, a 31.7% increase over the control sample. Electrochemical evaluations showed significant improvements in corrosion resistance, with the corrosion potential (Ecorr) of the 25% pepper-reinforced sample reducing to −0.59 V and the corrosion rate decreasing to 7.69 mm/yr. Optoelectrical testing indicated enhanced conductivity in samples with higher pepper content, with the 25% reinforcement achieving a conductivity of 0.1979 (Ωm)⁻1. Morphological tests, such as SEM and XRD, revealed the uniform distribution of pepper particles and the occurrence of several phases that contribute to the composite's improved properties.

Behavior of corroded HSC beams repaired by sprayed UHTCC and textile: Experimental study and theoretical analysis

Behaviors of twelve high strength concrete (HSC) beams were studied, including one control specimen, five corroded but non-repaired beams, and six corroded beams repaired by sprayed ultra-high toughness cementitious composites (UHTCC) with or without textile reinforcement. Galvanostatic accelerated corrosion technique was adopted, and three targeted corrosion levels (5 %, 10 %, and 15 %) were selected for each tensile steel bar. Corrosion-induced results, such as voltage change, crack initiation, concrete spalling, corrosion crack length and width, and non-uniform corrosion of steel bars were studied and compared with the results observed in normal strength concrete (NSC) beams. Structural behaviors, including failure modes and load-displacement responses were investigated through four-point bending tests. Results revealed that compared to NSC beams, HSC beams sustained more severe damages under a comparable corrosion level. Spalling was observed at a relatively lower corrosion ratio of 4.43 % and the maximum non-uniform corrosion coefficient, which was defined as the ratio of the maximum corrosion ratio to the average corrosion ratio, was 4.28. Corrosion-induced bonding degradation can alter the failure mode of corroded specimens in bending tests from bending to debonding. For repaired beams, however, the bonding degradation effect was reduced and bending failure was observed for all specimens. The bearing capacity of the beams repaired with sprayed UHTCC cannot be restored with a 12.42 % corrosion ratio, while the beams repaired with sprayed UHTCC/textile can recover their capacity even at a 13.6 % corrosion ratio. Furthermore, an improved theoretical model based on the fiber section analysis and virtual work method was developed to predict structural bending responses. The comparison of the experimental and theoretical results indicated the average corrosion ratio-based method may overestimate the loading capacity, especially for the beams with severe corrosion.

Influence of Temperature-Strain Parameters of Shelters Reinforcing Materials on Increasing Properties in the Z-Direction

Influence of Temperature-Strain Parameters of Shelters Reinforcing Materials on Increasing Properties in the Z-Direction

Study on the Flexural Deformation Behavior of High-Titanium Heavy-Slag Concrete Composite Beams: Material Application, Experimental Investigation, and Theoretical Refinement.

To investigate the flexural performance of high-titanium heavy-slag concrete composite beams under loading, this study examined the impact of various factors on deflection development and crack propagation as well as the applicability of empirical formulas for monolithic concrete beams. Seven concrete beams were fabricated with variables such as the reinforcement ratio, prefabrication height, and material composition, and were subjected to two-point concentrated loading. By comparing deflection values and crack widths during loading and analyzing the correlations with empirical formulas from standards, theoretical formulas with significant deviations were modified and compared. The study indicated that the cracking moment and deflection correlated with the reinforcement ratio, material structure combination, and composite height. The empirical formulas for the maximum crack width and deflection of flexural members were applicable to high-titanium heavy-slag concrete composite beams, although some discrepancies existed compared with the experimental values. After modifications, these discrepancies were reduced. This research provides a comprehensive analysis of the deformation characteristics and fracture behavior of high-titanium heavy-slag concrete composite beams.

Increasing the Interlayer Fracture Toughness of Polymer Fabric Composites Using Local 3D-Reinforcement (Felting)

Introduction. One of the reasons for undesirable delamination of polymer composites with fabric reinforcement is low transverse shear properties. It is known that the reinforcement of polymer fabric composites in the Z direction reduces the sensitivity to delamination and increases the viscosity of interlayer fracture. Various methods of three-dimensional reinforcement of polymer fabric composites are proposed in the literature. However, they complicate the manufacturing process of the structure. The problem is solved by the method of three-dimensional reinforcement proposed in this article — felting. This is a local reinforcement of the composite in the Z direction with minimal production changes. The degree of Z-reinforcement is determined by the felting density, i.e., the number of needle punches per 1 cm2 of the fabric package. The work is aimed at evaluating the effect of felting on the interlayer crack resistance of a composite material.Materials and Methods. The interlayer fracture toughness GIIc was determined on a cross-woven fiberglass with felting of 10 cm-2. The material was impregnated with Etal-370 resin and Etal-45 hardener. Experiments according to ASTM D7905M–14 and GOST 33685–2015 standards were carried out on an Instron 5900R test machine. The stress state at the crack tip was analyzed with regard to the nonlocal strength theory in the ANSYS Workbench program (option “static strength analysis”). The finite element method (FEM) was used.Results. The “load — displacement” curves were considered for the samples. Values GIIc were calculated. The results of ENF tests for felting density of 0 cm–2 and 10 cm–2 were summarized. Control samples and felting samples were compared. In the latter case, GIIс turned out to be ~33% higher. The stress state at the crack tip was calculated under DCB and ENF loading. The dependences of maximum normal and shear stresses, as well as displacements, were visualized in the form of graphs and color charts. To get the calculated “load — displacement” dependences using FEM, the reverse method of obtaining transverse shear constants was used. DCB loading showed that felting provided increasing the rupture strength in the Z direction to ~18%, by 39 to 46 MPa, and in the planes XZ— to ~16%, by 77 to 89 MPa.Discussion and Conclusion. Felting as a method of local three-dimensional reinforcement enhances the interlayer crack resistance of polymer fabric composites. It provides reducing the area of stratifications after local impacts during the operation of structures. Flexible felting technology makes it possible to create zones with an arbitrary impact density, increasing fracture toughness only in the required places of structures. The FEM analysis of the stress state at the crack tip within the framework of the nonlocal strength theory has shown that in strength calculations, the stratification crack can be considered as a stress concentrator.

Interaction of reinforcement, process, and form in Digital Fabrication with Concrete

Material, manufacturing process, and form are mutually dependent. In formwork-based concrete construction, the reinforcement must be positioned and fixed in the formwork, limiting material efficiency and freedom of form. In Digital Fabrication with Concrete (DFC), the formwork no longer limits the concrete forming process. Furthermore, the reinforcement no longer must be installed in advance, but can be placed before, during or after the concrete application. Therefore, the role of reinforcement and its interaction with processing must be fundamentally rethought in DFC. Furthermore, with reinforcement integration a concrete component expands from a contour-based shape into a structural form.The current paper proposes a new so-called RPF-framework expressing the interaction of reinforcement, process and form in DFC. The application of this framework is illustrated using current examples of DFC, whose structural forms are critically discussed. Finally, the need for a holistic approach to material, process and form in DFC is emphasised.

Triaxial drained behaviour of disposable face mask fibre reinforced sand

ABSTRACT The widespread usage of disposable face masks (DFM) during the COVID-19 pandemic has exacerbated waste management challenges, prompting an investigation into their potential reuse as a soil reinforcement material. Previous researchers have investigated the effect of mask fibres on pavement subbases and the environmental problems caused by these fibres. This study examines the mechanical properties of sandy soil enhanced with shredded and layered DFM under triaxial testing conditions, focusing on key parameters like shear resistance, elastic modulus, stress-strain characteristics, axial resistance, failure envelope, and brittleness index. Results show that adding DFM significantly improves soil cohesion, friction angle, shear strength, and peak deviatoric stress, especially at higher fibre contents and relative densities. However, increased DFM fibre content was associated with reduced elastic modulus, which stabilised in specimens with layered DFM, suggesting complex interactions between DFM content and soil mechanics. Concerns include potential void formation leading to asymmetric settlement and environmental issues on non-biodegradable fibre integration in soil. These findings highlight the need for meticulous mixture preparation, large-scale studies, and environmental assessments to evaluate the impact of using DFM in soil reinforcement, particularly for road construction and slope stabilisation. This research provides crucial insights into the potential of DFM for soil reinforcement.

Wear behaviour of titanium diboride and zirconium carbide reinforced LM13 hybrid composite for automotive applications

Abstract This study investigates the wear behaviour of a hybrid composite material reinforced with titanium diboride and zirconium carbide in LM13. The ASTM standard is followed for conducting wear tests, utilizing a pin-on-disc setup to assess the wear rate. An empirical relationship is established to predict the wear rate using statistical tool analysis of variance, and the model’s adequacy is checked. Low wear is observed at a sliding distance of 110 mm, sliding speed of 2.5 m s−1, and sliding load of 12.5 N. The observed low wear is attributed to the optimal level of reinforcement provided by titanium diboride and zirconium carbide. From the analysis of variance, sliding speed is identified as the major contributing factor to wear rate, followed by sliding distance and load. The reinforcement materials enhance the wear resistance of the hybrid composite and their effectiveness is particularly evident under the specified sliding conditions.

Mechanical characteristics of kenaf-glass fiber reinforced hybrid composites by varying the stacking sequences

Fiber composite materials are preferred for their lightweight, low-cost, and commercial uses. As part of this study, laminate materials consisting of two different fiber materials as their reinforcement materials are produced using the hand layup method. This study investigates the mechanical properties of hybrid composite laminates fabricated using kenaf and glass fibers. Six stacking arrangements of the fibers are examined, alongside two reference laminates with individual reinforcements. Epoxy resins HY951 and LY556 serve as matrix materials. ASTM standards guide the mechanical testing of the composites. Results indicate varied tensile strengths based on stacking sequence, with laminate L2 (KKGKK) featuring a single glass fiber core at 75 MPa, and increasing strengths in laminates with additional glass layers: L1 (GKKKG) at 123 MPa, L5 (KGKGK) at 110 MPa, L3 (GKGKG) at 150 MPa, L6 (KGGGK) at 118 MPa, and L4 (GGKGG) at 159 MPa, the highest among all. It was observed that adding one layer of glass fiber with kenaf fiber boosts strength and modulus by 9.52% and 12.19% respectively, compared to pure kenaf fiber composites. Morphological analysis via Scanning Electron Microscopy (SEM) confirms failure due to initial crack propagation in the matrix and fibers. This study offers insights into hybrid composite laminate behavior, pertinent for various industrial applications.

Residual Strengths of RC Beams Strengthened with Basalt and Carbon Textile Reinforced Mortars After Exposure to Elevated Temperatures

Residual Strengths of RC Beams Strengthened with Basalt and Carbon Textile Reinforced Mortars After Exposure to Elevated Temperatures

Powder Metallurgical Processing of Al–5 wt% Cu Matrix Composites Reinforced with MoSi2 and WSi2 Particulates

Herein, investigations on the microstructural, physical, and mechanical properties of molybdenum disilicide (MoSi2)‐ and tungsten disilicide (WSi2)‐reinforced aluminum (Al)–copper (Cu) matrix composites are reported. Powder metallurgy methods such as mechanochemical synthesis (MCS), mechanical alloying (MA), cold pressing, and pressureless sintering are combined to produce composites. First of all, MoSi2 and WSi2 nanoparticles are synthesized by MCS and selective acid leaching, yielding reinforcement materials for Al–Cu matrix. Powder blends consisting of 95 wt% Al and 5 wt% Cu are mixed with metal disilicides at different weight percentages (1, 2, and 5 wt%). MA for 4 h is conducted on these overall blends using a high‐energy ball mill. Microstructural and thermal properties of the as‐blended and mechanically alloyed powders are determined, and then they are compacted under 450 MPa and sintered at 550 °C for 2 h. Mechanical characterization of the composites reveals an increase in hardness and wear resistance with an increasing amount of reinforcement content. Among bulk samples, 5 wt% WSi2‐reinforced composites have the highest microhardness (165 ± 15 HV) and lowest wear rate (1.69 × 106 μm3 Nm−1) values. However, under the compression forces, the highest toughness and strength are obtained from 2 wt%‐reinforced composites.

Enhancing bio-composite performance: mechanical properties of Diss fibre-reinforced epoxy

As industries increasingly adopt composites for their superior stress resistance, the high cost and environmental challenges associated with their disposal remain significant concerns. Bio-composites offer a sustainable alternative by addressing these issues with better recyclability and lower environmental impact. This study explores the mechanical performance of a bio-composite featuring Diss fibres embedded in an epoxy matrix. We conducted tensile and Charpy impact tests to measure Young's modulus and impact energy, respectively. Different weight percentages of Diss fibres (wtD%) were used to prepare the specimens. The findings indicate that the Young's modulus of the bio-composite peaked at 1.30GPa with 20wtD%, after which it declined. The incorporation of Diss fibres notably enhanced the tensile strength of the samples compared to the pure epoxy matrix. Additionally, impact energy increased with higher wtD%, reaching a maximum of 3.5J at 30wtD%. These results suggest that Diss fibres are a viable reinforcement material for developing greener composites.

Evaluation of the Flexural Behavior of One-Way Slabs by the Amount of Carbon Grid Manufactured by Adhesive Bonding

Fiber-reinforced polymers (FRPs), which are resistant to corrosion, are used as reinforcement material for concrete. However, the flexural behavior of concrete members reinforced with FRPs can vary depending on the properties of FRPs. In this study, the flexural behavior of one-way concrete slab specimens reinforced with a new grid-type carbon-fiber-reinforced polymer (CFRP) (carbon grid) manufactured by bonding pultruded CFRP strands to an adhesive was investigated. The experimental results indicated differences in the load–deflection relationships of the specimens depending on the carbon grid reinforcement amount. Specimens in which the carbon grids were over-reinforced or reinforced close to the balanced reinforcement ratio reached the maximum load due to concrete crushing and exhibited ductile failure. The specimen under-reinforced with the carbon grid exhibited brittle failure. Specimens with carbon grid reinforcement close to a balanced reinforcement ratio exhibited maximum loads ranging from 0.43 to 0.61 times the calculated flexural strength, which resulted in becoming 0.86–1.00 lower in the specimens with a wider width of the CFRP strands. This study proposes coefficients to estimate the stiffness of carbon-grid-reinforced concrete flexural members after cracking. Applying these coefficients resulted in stiffness calculations that reasonably simulated the behavior of the specimens reinforced with carbon grids after crack formation.

Flexural behavior of textile reinforced concrete using waste fishing net as continuous reinforcement

The present study investigated the flexural properties of Textile Reinforced Concrete (TRC) incorporated with waste fishing nets as reinforcement with a view to providing a potential solution to the environmental impact caused by these nets. Locally available waste fishing nets having two different mesh sizes and thicknesses were used as textile reinforcement for investigation. The fishing nets composed of nylon fibres were selected due to their potential as a sustainable and cost-effective reinforcement material. TRC composite with A.R. Glass textile was used as a reference specimen and that with A.R. Glass textile and waste fishing net were considered for the flexural tests. The influence of different layers of textiles was also investigated. The epoxy coating was used to coat the waste fishing nets along with A.R. glass textile to develop a hybrid textile. Properties of TRC composites incorporated with uncoated nets were compared with the composites using coated nets in order to understand the effect of coating on the reinforcement. The efficiency of textiles as reinforcement was also analyzed in detail by determining the strength and ductility ratio. Investigating the flexural behaviour of TRC with epoxy-coated waste fishing nets aims to understand this innovative composite material’s mechanical properties and performance.

Preparation and study on electrical/thermal properties of epoxy/polyacrylate rubber composite dielectric

AbstractWith the development of power systems and electronic devices, epoxy resin (EP) is facing increasingly severe operating environments, and its performance may not meet expectations. In order to broaden the application of EP, the DE/EP composite films were prepared with EP as matrix, polyacrylic rubber dielectric elastomer (DE) as reinforcement materials. The structure of DE/EP composite films was characterized by XRD, SEM, and other methods, and the electrical and thermal properties of the materials were tested and studied. The study found that with appropriate dissolution and stirring treatment, DE can be evenly dispersed in the EP matrix, and the introduction of DE does not significantly affect the structure of the EP molecular chain, also found the introduction of DE improve the electrical and thermal properties of EP. The breakdown strength of the 4% DE/EP composite film surpasses that of the pure EP film by 15.58%. Additionally, the thermal conductivity of the 8% DE/EP composite film is elevated by 41.6% compared to the pure EP film, while its dielectric constant is also enhanced by 8.2%. This work may provide a theoretical basis for studying the application of EP modified system in electrical engineering, integrated circuit packaging and other fields.

Experimental and Analytical Study of Tensile and Bond Performances of Glass Fabric Reinforced Cementitious Matrix for Retrofit Applications on Concrete Surfaces

Experimental and Analytical Study of Tensile and Bond Performances of Glass Fabric Reinforced Cementitious Matrix for Retrofit Applications on Concrete Surfaces

Investigation on corrosion behaviour of metal oxide nanoparticles reinforced magnesium composites by salt spray and immersion corrosion test methods

ABSTRACT This study explores the increasing utilisation of lightweight materials, particularly magnesium (Mg) alloy, in sectors such as automobile, aerospace, and marine due to its notable advantages such as high strength-to-weight ratio, good castability, and excellent damping capacity. Despite these merits, Mg alloy faces challenges, notably in wear and corrosion resistance. The research focuses on enhancing the corrosion resistance of Mg alloy by incorporating Zinc Oxide (ZnO), Manganese Oxide (MnO), and Titanium Oxide (TiO2) nanoparticles. The alloy AZ91D and three nanocomposites, namely AZ91D + 1% ZnO, AZ91D + 1% MnO, and AZ91D + 1% TiO2, were manufactured using a stir squeeze casting technique combined with an ultrasonication process. To confirm the even distribution of reinforcement particles, Optical Microscope (OM), Scanning Electron Microscope (SEM) and High-Resolution Scanning Electron Microscope (HR-SEM) were employed. X-ray Diffraction (XRD) analysis revealed the presence of matrix and reinforcement material with intermetallic precipitates around the grain boundaries. Corrosion properties were assessed following ASTM standards and utilising a 3.5% NaCl concentration. The study found that AZ91D + 1% TiO2 nanocomposites exhibited superior corrosion resistance compared to the AZ91D alloy, showing a remarkable 77.78% and 69.89% improvement in corrosion behaviour under salt spray and immersion environments, respectively, after 48 hours.

Progressive failure analysis of woven and non‐woven CFRP composite/steel bolted joints

AbstractDue to recent advancements in textile fabrication, woven fabric reinforcements are used in composite structures as an alternative to traditional unidirectional fiber reinforcing layups. In this paper, experimental work was performed to study the behavior of multiple bolt‐lapped joints under uniaxial tension. Different bolt numbers, composite layups, and fabric configurations were studied. Single‐ and double‐lap configurations were used to investigate the effect of secondary stresses. It was found that the P‐δ curves of lapped joints exhibit four primary stages: a linear elastic stage, followed by a nonlinear hardening stage, then linear hardening leading up to the peak, and finally a softening stage. For double‐lapped non‐woven joints, the curves encompass only the first three stages; however, for woven composites, the last stage is very small. In addition, among the laminates, the non‐woven laminate sustains the highest normalized failure load, except in the staggered case, where the quasi‐isotropic woven laminate exhibits higher strength. Conversely, the bidirectional woven laminate demonstrates the lowest loads and the highest deformation.Highlights A study compared bolted joint performance of woven and uni‐based composites. Lapped joints with different bolt arrangements were experimentally studied. P‐δ curves showed elastic, nonlinear, linear hardening, and softening stages. Woven laminates showed higher displacements compared to non‐woven laminates. Secondary bending induced additional stress with less impact on woven samples. Bearing failure predominated, with variations in extent of bearing damage.