Effect Of Fiber Reinforcement Research Articles

Experimental and numerical studies of the effects of micro/nano carbon fibers in the dynamic behavior of cement-based grouting materials for reinforcement of sand layers

Geological hazards of sand layers pose a serious threat to engineering safety. Grouting reinforcement technology is widely used in such conditions due to its convenience, economy, and effectiveness. To explore the reinforcement effect of carbon fiber (CF) modified cement-based grouting materials on sand layers, grouting solidified bodies (GSB) with CF contents of 0.0%, 0.5%, 1.0%, and 1.5% are selected for Split Hopkinson Pressure Bar (SHPB) impact tests, scanning electron microscope (SEM) scanning, and numerical simulation experiments. The mechanical properties of specimens under dynamic impact conditions and the reinforcement mechanism of CF are studied. Results show that GSB is a strain-rate-dependent material. With the increase of impact rate, peak stress, incident energy, transmitted energy, and dissipated energy of specimens gradually increase, while the integrity of specimens decreases. The CF content remarkably affects the mechanical properties of specimens. When the impact rate is constant, with the increase of CF content, the peak stress and transmitted energy of specimens show a decreasing–increasing– decreasing trend, and the performance of CF-1.0% specimens is optimal. The cement matrix is the main energy storage and release medium, accounting for 97.66% of the energy. When damaged, the cement matrix is mainly fractured. At the microcrack tip, CF influences the direction of crack propagation, reducing the radius of crack propagation, and the main failure mode of CF is debonding. CF can substantially improve the mechanical properties of specimens and reduce the number of cracks. Compared with CF-0.0%-cementitious material (CM) specimens, the peak stress of CF-1.0%-CM specimens is increased by 19.98%. The magnitude of CF force is related to the angle between crack and CF. As the angle increases from 0° to 90°, the CF force gradually increases, reaching the maximum at 90°, with an increase of 133.82%. At this angle, the anti-cracking effect of CF is most substantial. The research results can provide technical support for sand layer grouting reinforcement technology.

MECHANICAL PROPERTIES OF DIFFERENT TYPES OF FIBER-REINFORCED CONCRETE: BENEFITS AND LIMITATIONS

Fibers are widely used in the concrete industry to enhance the mechanical properties of concrete, especially tensile strength and post-cracking behavior. This study evaluates the mechanical performance of steel, glass, polypropylene fibers, and hybrid fiber-reinforced concrete through a detailed literature review. It was found that fiber addition significantly enhances the tensile strength, flexural strength, and ductility of concrete, with variations attributed to the type and volume of fibers used. The impact on compressive strength was minimal. Fibers with high elastic modulus notably improved concrete strength, whereas fibers with lower modulus enhanced concrete’s ductility and toughness. Each fiber type presents unique benefits and limitations concerning mechanical properties, environmental resistance, and cost. Hybrid fiber reinforcement emerged as particularly effective, offering substantial improvements over single-fiber systems, and mitigating some of their inherent limitations. This research aims to provide comprehensive insights into the effects of fiber reinforcement on concrete's mechanical properties, highlighting the distinct benefits and drawbacks of different fiber types.

Frost Resistance and Damage Evolution Model of Basalt Fiber-Reinforced Recycled Concrete Based on Recycled Coarse Aggregate Strengthening and Vibration Mixing Processes

A self-created grinder machine was utilized to clear the wrapped mortar from recycled coarse aggregate (RCA) in order to enhance the performance of basalt fiber-reinforced recycled aggregate concrete (BFRAC). In combination with the RCA strengthening and vibration mixing processes, the mechanical properties and freeze-thaw frost of BFRAC were tested to clarify the mechanism for improving the frost resistance under the synergistic effect of basalt fiber (BF) reinforcement and vibration mixing. Meanwhile, the impact of the production process and BF strengthening technique on RAC performance was explained from a microscopic standpoint using a scanning electron microscope (SEM) test, and aggregate-old mortar interface transition zones were significantly reduced. BF is beneficial in improving the mechanical properties and frost resistance of recycled aggregate concrete (RAC). Among them, the performance improvement effect of RAC is the most significant when using vibration mixing processes, adding BF with a length of 18 mm and a content of 0.2%. It can increase the compressive strength of RAC by 19% compared to ordinary mixing, the splitting tensile strength by 37.6%, and the flexural strength by 34.4%. A polynomial damage deterioration model was established with relative dynamic elastic modulus and compressive strength as damage variables. The results show that the model can accurately predict the degree of freeze-thaw damage of BFRAC. The research results have significant theoretical value for enhancing the frost resistance performance of RAC.

Bioinspired helical fiber/elastomer composites with high strength

For general composites, fiber can improve the strength of rubber matrix, but it will damage the original high deformation that affect the toughness. Therefore, to solve this problem, we propose a strategy of constructing rubber-helical fiber composite, which can not only improve the strength of rubber, but also maintain the original high deformation of rubber. Inspired by helical structure in nature, we convert straight fibers into helical fibers by winding. The helical fibers with spring characteristic have high strength and large deformation matching with rubber. The tensile strength and fracture toughness of the composite are 3.51 and 3.41 times those of the rubber matrix, respectively. When the aramid fiber was used instead of nylon fiber, the strength of the composite is 12.81 MPa, which is 17.8 times that of pure rubber matrix, and the mass fraction of the fiber is only about 1.60 %. Furthermore, by analyzing the reinforcement and toughening effect of helical fiber, we have determined that helical fiber plays the role of bearing stress and dispersing stress into three-dimensional space in composites.

Study on interaction of Viscoelastic and Mechano-sorptive creep and effect of Fibre Reinforcement on creep of Timber beams

Timber is a sustainable material widely used in structural elements. Its viscoelastic nature, in which the stress-strain relation varies with time, poses significant challenge to the durability of timber structures. Creep of timber under constant loading depends on various factors like stress level, moisture content, load-to-grain angle, temperature, relative humidity etc. Among these, relative humidity and moisture content in timber are the most crucial. Drastically varying moisture content causes mechano-sorptive creep. However, the interaction and contribution of various factors causing creep is still a matter of research. Various codes provide generalized creep coefficient for long term deflection and load reduction factors. A detailed rheological model was proposed by Toratti which addresses mechano-sorptive creep explicitly, incorporating both recoverable and irrecoverable part in creep. This paper aims to review the study on interaction between viscoelastic creep and Mechano-sorptive creep in various environmental conditions. Effect of reinforcing timber beams, on the long term deflection due to creep is also made a subject of study to identify a possible solution to the accelerated deflection by Mechano-sorptive creep, which will be unavoidable in tropical areas with extreme climactic changes. A comparative study between the various standard codes with Indian Standard Codes for timber with respect to creep, is also made, to identify the gaps in IS codes.

Enhanced high-temperature dimensional accuracy by fibers in silica ceramic cores prepared through vat photopolymerization 3D printing

3D printing technology provides new ways to complex-shaped ceramic cores forming inner structures in aero-engine blades, but its high-temperature dimensional accuracy is highly impacted by their volume shrinkage and creep deformation. Silica ceramic cores reinforced by mullite fibers were fabricated by 3D printing in terms of vat photopolymerization in this work. Due to the scraper paving the ceramic slurry in 3D printing, majority of the mullite fibers displayed orientation distribution inside the printing layers and decreased the bending strength as the fiber content was below 5 wt%. With 12.5 wt% of mullite fibers, some fibers showed disorder distribution and arranged to connect the interlayer cracks, therefore improving the strength by fiber pull-out. Even though the reinforcement effect of mullite fibers was inadequate, the porosity and leaching rate were significantly improved. Furthermore, the mullite fibers were beneficial to lower shrinkage during sintering and casting, and enhanced the creep resistance due to the high softening temperature, which resulted in enhanced dimensional accuracy.

Effect of Nylon Fiber Reinforcement on Mechanical Behavior of Expanded Perlite/Sodium Silicate Composites

In this research, expanded perlite/sodium silicate composites reinforced with nylon fibers were manufactured with varying percentages of nylon fibers without changing the quantity of expanded perlite and sodium silicate solution. The composites were made by compression molding and cured at a temperature of 120 degrees Celsius for 48 hours. The flexural and compression tests were conducted according to the ASTM standards in the universal testing machine. The maximum flexural and compressive properties are found for 1.62 percent nylon fiber reinforcement. The addition of a higher quantity of nylon fiber in the composites deteriorates the compressive and flexural properties. The energy absorption during flexural and compression tests is improved significantly due to nylon fiber reinforcement. The fiber-reinforced composites show the ability to carry a significant amount of load even after crack initiation.

Increasing Strength of Clay Soils with the Use of Basalt Fiber: An Experimental Study

Due to the increase in population, the demand for buildings increases. The engineering properties of the soils on which these structures will be built may not always meet the desired conditions. In such cases, soil improvement methods are used. One of these methods is additive used stabilization, in which additives such as lime, fly ash, volcanic ash and tuff, silica fume, and blast furnace slag are used. This method has been used successfully for years. However, in recent years, interest in the use of different types of fibers has increased. Some of these fibers are glass, basalt, polypropylene, and carbon. Basalt fibers have begun to attract attention in soil reinforcement applications due to the properties of their raw material, basalt rock, which is widely distributed in nature, natural, and has high strength. In this study, the effect of basalt fiber reinforcement on the unconfined compressive strength of high plasticity bentonite clay was revealed. For this purpose, 12 mm long basalt fiber in different proportions (1%, 2%, 3%, 4%, and 5%) was used as reinforcement in bentonite clay, and the optimum fiber ratio that provided the maximum increase in strength was determined. According to the results of the study, when 12 mm long basalt fiber was used as reinforcement in bentonite clay, the maximum strength value was obtained at a 4% basalt fiber ratio. However, the strength value decreased in the sample where 5% BF was used. It has been determined that basalt fiber reinforcement improves the strength properties of bentonite clay.

Sandwich structures of aluminium skins and egg-box-shaped cores made with biobased foam and composites

Sandwich panels composed of aluminium skins and egg-box-shaped cores made with natural fibre composites are tested in three-point bending and evaluated statistically and through failure analysis. The corrugated cores are assessed with filled bio-based foam. In order to produce these sandwich panels, preliminary investigations on natural fibre composites, and their use as egg-box-shaped structures are conducted. A full factorial design is performed to assess the effects of fibre reinforcement (sisal or coir) and polymer matrix types (epoxy or castor oil) on the physical-mechanical properties of flat composite laminates. These composites are also used to manufacture the egg-box shaped structures in different sizes, which are characterized under compression testing. A new analytical approach called RJS Method is used to determine the flexural and shear modulus of the proposed sandwich panels and estimate the shear contribution. The results reveal that flat laminated composites and their corresponding egg-box shaped cores, composed of sisal fibres and epoxy polymer, achieve higher absolute and specific mechanical properties. The corrugated core also leads to sandwich panels with higher mechanical properties, increasing the skin and core shear stresses by up to 60 and 76%, respectively, compared to the coir fibre castor-oil cores. The failure modes of the sandwich panels are limited to the core and are chronologically established through foam tearing, foam-egg-box shaped composite debonding, and final egg-box cell-wall flattening. The findings demonstrate that the sandwich panel based on egg-box shaped core made from natural resources is feasible for scaling up in different structural applications.

Characterization of mechanical properties, efficiency, and design considerations for the additive manufacturing of hybrid composites with continuous fibers

The integration of continuous fibers into additively manufactured plastic components greatly enhances their mechanical properties. Nonetheless, a challenge lies in the limited adaptability of these properties to specific loading scenarios. To address this issue, present research aims to exploit the hybridization of additively manufactured composites, combining diverse fiber materials within a single component. Specifically, fabricating continuous fiber-reinforced hybrid composites through material extrusion enables high flexibility in adapting local fiber materials. To further the understanding of the effects of hybrid fiber reinforcement in additively manufactured plastic parts, this study investigates how distinct stacking sequences in hybrid and non-hybrid PA6-based composite components, reinforced with carbon and glass fibers, affect deformation and failure behavior. Mechanical properties are assessed using tensile, flexural, and impact tests, in conjunction with an analysis of cost and weight efficiency. The results unveil a distinct correlation between stacking sequences and the mechanical properties of additively manufactured composites. While the hybrid samples predominantly exhibit slight negative hybrid effects, a positive hybrid effect of 96.4 % is achieved in terms of impact toughness with an optimized stacking sequence. With the exception of impact strength, specimens reinforced solely with carbon fibers frequently demonstrate a remarkable ratio between mechanical properties, weight, and cost, whereas hybrid composites exhibit a balanced compromise across all tested mechanical properties. Building upon the obtained results, three comprehensive design approaches are introduced and applied, demonstrating the new design possibilities arising from the combination of hybrid composites and additive manufacturing. The developed design approaches and material combinations can be used for a wide range of lightweight construction applications.

Exceptional mechanical performance by spatial printing with continuous fiber: Curved slicing, toolpath generation and physical verification

This work explores a spatial printing method to fabricate continuous fiber-reinforced thermoplastic composites (CFRTPCs), which can achieve exceptional mechanical performance. For models giving complex 3D stress distribution under loads, typical planar-layer based fiber placement usually fails to provide sufficient reinforcement due to their orientations being constrained to planes. The effectiveness of fiber reinforcement could be maximized by using multi-axis additive manufacturing (MAAM) to better control the orientation of continuous fibers in 3D-printed composites. Here, we propose a computational approach to generate 3D toolpaths that satisfy two major reinforcement objectives: (1) following the maximal stress directions in critical regions and (2) connecting multiple load-bearing regions by continuous fibers. Principal stress lines are first extracted in an input solid model to identify critical regions. Curved layers aligned with maximal stresses in these critical regions are generated by computing an optimized scalar field and extracting its iso-surfaces. Then, topological analysis and operations are applied to each curved layer to generate a computational domain that preserves fiber continuity between load-bearing regions. Lastly, continuous fiber toolpaths aligned with maximal stresses are generated on each surface layer by computing an optimized scalar field and extracting its iso-curves. A hardware system with dual robotic arms is employed to conduct the physical MAAM tasks depositing polymer or fiber reinforced polymer composite materials by applying a force normal to the extrusion plane to aid consolidation. When comparing to planar-layer based printing results in tension, up to 644% failure load and 240% stiffness are observed on shapes fabricated by our spatial printing method. We demonstrate the versatility of our approach through various complex load cases which demonstrate their successful implementation of continuous fiber printing in 3D.

Optimization design of fiber rubber asphalt gravel sealing layer based on fatigue crack resistance test.

Crack is one of the main diseases of pavement structure. In order to improve the anti-reflective crack ability of pavement, fiber rubber gravel sealing layer is proposed as the stress absorbing layer. In view of the shortcoming that Mcleod design method can not be associated with road performance, a sealing layer optimization design method based on fatigue crack test is proposed. Firstly, the reinforcement effect of fiber on rubber asphalt was studied through force ductility testing. Secondly, the optimum dosage of fiber, asphalt and gravel was optimized through fatigue cracking resistance test. Finally, the cracking resistance of fiber rubber gravel seal was verified through fracture energy test. The results show that fibers can significantly increase the maximum tensile force and strain yield energy of rubber asphalt, and basalt fiber has the best reinforcement effect. The most obvious effect on cracking resistance performance in the sealing layer is the amount of fiber, followed by the amount of asphalt, and finally the amount of gravel. The optimized material combination with the best crack resistance is 120g/m2 fiber, 14kg/m2 gravel and 2.4kg/m2 rubber asphalt, and the fatigue resistance times can reach 19532 times. The fracture energy of the composite pavement treated by the optimized sealing layer is nearly double that of the non-treated pavement structure, and it has a good anti-crack effect.

Epoxy‐hemp and epoxy‐flax composites filled with glass dust for enhanced thermal insulation: An analytical and experimental study

AbstractThis article reports on an analytical and experimental investigation on the effects of fiber and filler reinforcement on the effective thermal conductivity (keff) of epoxy‐based composites. This research aims at enhancing the thermal insulation capability of fiber reinforced composites by adding an industrial waste, WGD (waste glass dust) as particulate filler. For this, an analytical model is proposed to estimate the keff values of particle filled polymer composites with and without fiber reinforcement. The results computed from the proposed correlations are then validated with some previously reported investigations. For an experimental validation, hemp and flax fiber reinforced epoxy based hybrid composites are fabricated with WGD as the fillers in varying weight fractions of 0 to 0.2. Effects of filler content on keff of fiber‐polymer systems are studied. Their keff are measured by a Unitherm Model 2022 instrument. It is found that the predicted and measured values are in good agreement. It is observed that the keff of the epoxy composites reduced from 0.359 to 0.297 W/m K with increase in the WGD weight fraction from 0 to 0.2. The keff of hybrid composites are also reduced by 27% and 15.53%, respectively, with 20 wt% addition of WGD.Highlights Hybridization of natural fiber based polymer composites. Utilization of waste glass dust as functional filler. Model development for heat conduction across hybrid composite system. Insulation capability enhancement of epoxy using fiber/filler reinforcements. Low cost thermal insulation materials using green materials and industry waste.

An Overview on the Dispersion of Steel Fiber in Ultra-High-Performance Concrete

Abstract Ultra-high-performance concrete (UHPC) is widely recognized for its high toughness, which is directly affected by the dispersion of steel fiber and its loading mode. To investigate the reinforcement effect of steel fiber, this paper summarizes the influencing factors, evaluation methods, and theoretical models of steel fiber dispersion in UHPC. First, the results reveal that a scientifically designed mixture can reduce the cost of steel fiber dosage in UHPC and improve fiber dispersion by adjusting matrix rheological properties. The optimum plastic viscosity of the slurry should range from 30 to 80 Pa·s for achieving the best fiber dispersion effect. Second, during slurry placement, the orientation of fibers in UHPC can be improved by up to 80 % through flow induction and the wall effect, which increases the bending strength, tensile strength, and toughness of UHPC matrix by 5–67 %, 30–90 %, and 13–200 %, respectively. Moreover, although the dispersion of fiber in two-dimensional space has been extensively studied, further characterization in three-dimensional space is required. Lastly, some theoretical simulation results have been achieved on fiber orientation, but factors such as aggregate or reinforcement must be considered.

Effect of Glass Fiber Reinforcement on the Mechanical Properties of Polyester Composites

Introduction. Glass fibers significantly improve the quality of composite materials, make them lighter, stronger, more corrosion resistant and thermally stable. Strengths and weaknesses of specific composites are actively discussed in the scientific and applied literature. At the same time, the effect of the ratio of fibers and matrix material on the mechanical characteristics of composites has not been sufficiently investigated. The presented study is intended to fill this gap. The work is aimed at manufacturing a composite material on a polymer basis reinforced with glass fiber, and investigating the influence of weight ratios of elements on the mechanical characteristics of the composite. For the first time, a report on the comparison of the characteristics of composites (with different fiber content) to each other and to steel is published.Materials and Methods. Fiberglass and polyester were used as starting materials with the addition of a mediator to speed up the molding process. The samples were made manually and tested for tensile strength, hardness, and impact strength using standard equipment. The results were summarized in the form of tables, visualized in the form of graphs, and processed by comparative analysis.Results. The technique of creating samples and methods of their testing were described. The research showed that hardness, tensile strength and impact resistance increased with a growth in the percentage of randomly distributed fiberglass to 50% with 50% unsaturated polyester. In this case, the maximum values of tensile strength — 175.4 MPa, hardness — 38 HV and impact resistance — 1.56 J/mm2 were obtained. The inexpediency of exceeding the proportion of fiberglass by more than 50% was experimentally proven, since mechanical properties deteriorated. This was due, in particular, to the fragility of the glass, which, if the proportions were violated, was transmitted to the entire composite. In addition, with an excessively high volume of reinforcing fibers, the resin was not enough for high-quality bonding of the elements, which significantly reduced the strength of the material. Most of the mechanical characteristics of a composite made of 50% polyester and 50% fiberglass are better than those of steel.Discussion and Conclusion. It has been proved that the properties of the composite material depend significantly on the glass fiber content. The resulting composite was compared to steel. It turned out that it had better mechanical characteristics and less weight. This allows us to recommend the material for boat hulls.

Dynamic characterization and damage analysis for the thermoplastic fiber-reinforced epoxy composites exposed to repeated low velocity impact

In the current study, contrary to conventional fiber-reinforced composites, polyamide fiber was used as reinforcement material, and the effects of thermoplastic fiber reinforcement on repeated low velocity impact (LVI) responses of composites were examined. In this regard, polyamide fiber-reinforced composites were fabricated using the vacuum-assisted hand lay-up method (VAHLM) and then exposed to repeated LVI loadings. Experimental tests were performed on the specimens for 100 impacts with a constant velocity of 3 m/s, which is equivalent to 25.2 J, and the impacts of repeated LVI loadings on the dynamic responses such as peak force, energy absorbing/rebounding, total impulse, bending stiffness and contact stiffness were examined. Moreover, the damage mechanisms resulting from the relative damage accumulation depending on the impact numbers were examined. According to the findings, the thermoplastic polyamide fibers absorbed more than 60% of the applied energy, and the absorbed energy increased with ascending impact number. Furthermore, the thermoplastic fiber-reinforced epoxy composites gained stiffness with increasing impact, which was linked to the thermoplastic chain structure. Despite quite a number of impact loadings, no serious damage mechanisms such as fiber breakage, perforation, or penetration were observed, and the specimens maintained their structural integrity. Due to the higher energy absorption of thermoplastics, the utilization of polyamide fibers in composites has been found to be well suited for applications subjected to repeated impacts.

Behavior of ultra-high performance concrete under true tri-axial compression

Confinements have been adopted to alleviate the brittleness of ultra-high performance concrete (UHPC). However, as the foundation of confinement mechanism, the research on behavior of UHPC under tri-axial compression is rather limited. Furthermore, the confinement mechanism of PE fiber-strengthened UHPC (PE-UHPC) has not been reported yet. To this end, conventional and true tri-axial compression tests were performed for 22 UHPC cubes with different PE fiber lengths and various lateral confining stresses. The typical axial stress-strain curve has a long elastic ascending stage, a relatively short plastic ascending stage and a steep post-peak decline stage. Increasing the lateral confining stresses could extend the elastic ascending stage, and make the plastic ascending stage longer and clearer. Furthermore, the reinforcement effect of longer PE fibers became more pronounced with increasing lateral confining stresses. However, only increasing intermediate principal stresses with minor principal stresses unchanged had minor effect on the axial strain-volumetric strain behavior.

Enhancing geotechnical reinforcement: Exploring molybdenum tailings and basalt fibre-modified composites for sustainable construction

Excessive tailings accumulation leads to secondary disasters and environmental pollution. Although the tailings used in this experiment have been filtered by beneficiation, the tailings soil itself has low strength and is not suitable for direct use as engineering materials. In order to make better secondary use of molybdenum tailings and improve the mechanical properties of tailings soil, the basalt fibre reinforcement method was used to improve the strength of tailings soil. We assessed the reinforcement embedding effect of fibre reinforcement in molybdenum tailings from macro and micro perspectives. Triaxial shear tests and numerical simulations of rigid fibre-modified tailings were performed and compared with indoor tests. We obtained the stress–strain curve, inter-particle displacement field, and soil particle friction cloud map. Tailings had fine- and medium-grained embedded particles with strong roughness and minimal agglomeration. Fibres exhibited good support and shear resistance. Microscopic analysis confirmed excellent tailings particle embedding. Under different confining pressures, the optimal combination of triaxial shear strength was as follows: water-cement ratio was 0.17, fibre content was 0.8% and fibre length was 9 mm. The results of laboratory triaxial test show that the peak strength of basalt modified tailings is increased by 21.70% compared with that of unmodified molybdenum tailings. By exploring the mechanical properties of fibre modified molybdenum tailings, it is found that basalt fibre can improve the strength of molybdenum tailings sand, and provide a reference for the application of fibre modified sand in civil engineering.

Effect of glass fiber and nylon fiber reinforcement on the mechanical and thermal properties of styrene butadiene rubber mixed PMMA denture base material

ObjectivesThe present investigation is aimed at evaluating the effect of styrene butadiene rubber, glass fibre, nylon fibre and hybrid reinforcement of glass and nylon fibre with 0.5 and 1.0 wt% on the impact, flexural, and compressive properties. MethodsA total of 19 groups were formed, including one control group and 18 study groups. All specimens were fabricated according to the standards and tests were performed. The enhancement of strengths were characterised by using scanning electron micrographs, FTIR results, XRD, and DMA tests. The degradability was studied using TGA/DTA analysis. The results were analysed using one-way ANOVA and Dunnett’s post hoc multiple comparison test at p ≤ 0.05. ResultsThe maximum impact, flexural, and compressive strength were found to be 3.234 ± 0.202 kJ/m2, 70.07 ± 0.7 MPa, and 84.929 ± 0.85 MPa for hybrid reinforcement of 0.5 wt% nylon fiber and 0.5 wt% glass fiber with 1.0 wt% of styrene butadiene rubber (SBR) mixed PMMA denture base material. Statistical analysis shows that the maximum mean impact strength, flexural strength, and compressive strength are about 84%, 58%, and 67% higher than the pure PMMA (control group). The maximum flexural modulus and compressive modulus are 914.4 MPa and 407.847 MPa for denture base material made of 1.0 wt% SBR, 1.0 wt% nylon fiber, 0.5 wt% glass fiber, and 0.5 wt% SBR, 0.5 wt% nylon fiber, respectively. The storage moduli of 1.0 wt% SBR, 1.0 wt% nylon fiber, and 0.5 wt% glass fiber-reinforced denture base material and pure PMMA are 0.096 and 0.422 at 79 °C, respectively, which indicates significant crosslinking of fiber and PMMA. The failure surfaces are characterized by a homogeneous distribution of fiber with increased surface roughness and fiber pullout, strong bonding, and well-dispersed SBR.

Sound absorption and transmission loss of 3D printed wood fibre reinforced poly lactic acid with functionally graded perforations

ABSTRACT The effect of wood fibre reinforcement on acoustic properties of 3D printed poly lactic acid samples having varying cross-section perforation and functionally graded spherical perforations is presented. Acoustic characteristics like sound absorption as well as transmission loss are obtained using an impedance tube setup. Results revealed the benefits due to the addition of wood fibres in PLA improved samples’ sound transmission loss characteristics significantly. The sound absorption curve peaks shifted to low-frequency regions which are favourable to living beings. The material can be used in acoustic insulation for structural and transportation applications, especially where eco-friendliness and aesthetics are of major concern.