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Fiber reinforced polymer (FRP) bars have been widely used as a replacement for steel bars in civil engineering due to their high strength and superior durability. However, compared to steel reinforced concrete (RC) beams, FRP RC beams have insufficient ductility and are more expensive. Therefore, a hybrid beam reinforced with steel and FRP bars has been proposed recently. In this study, the flexural properties of steel bar RC beam, basalt FRP (BFRP) bar RC beam, and BFRP steel bars hybrid RC beams were studied based on numerical simulation. The effect of As/Af on the stress of longitudinal reinforcements, load–midspan curves, ductility, and overall performance of the hybrid RC beams is analyzed. Results indicated that the hybrid RC beams exhibited a second‐order stiffness after the steel bars yielded owing to the contribution of the BFRP bars. As As/Af increases, the ductility of the hybrid RC beam and the strength utilization of BFRP bars increase, and a preferable ductility and overall performance can be achieved when As/Af was close to 1.0. The theoretical calculation results of hybrid RC beams based on ACI, CSA, and GB codes are compared with the simulation results, and the accuracy of the ultimate flexural strength of the prediction results is verified. In addition, equations for predicting the deflection of hybrid RC beams are proposed, and they exhibit higher prediction accuracy compared to the prediction models based on the ACI code. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Glass ionomer cement (GIC) releases fluorides and has good biocompatibility, carbonated drinks, sometimes known as fizzy drinks, are carbonated liquids that contain dissolved carbon dioxide, sweeteners, and natural or artificial flavoring. The aim of our study is to determine the flexural strength of GIC after immersing in carbonated beverages. Twelve samples of GIC filling material were used among which six samples prepared were from the Dtech brand and six were prepared from the Shofu brand for the in vitro study. Bar-shaped specimens were prepared from each group with the dimension of 2 mm × 2 mm × 25 mm. They were immersed in Sprite, fizz drinks, and in distilled water as a control group. The immersion period was 7 days. Then, the determination of maximum force and displacement was done using INSTRON E3000 (ElectroPuls) universal testing machine, then the collected data were used to determine flexural strength. The mean flexural strength of Dtech GIC was 24.84 ± 6.523 Mpa. The mean flexural strength of Dtech GIC was 18.57 ± 11.60 Mpa. The independent sample t-test showed that P = 0.247 (>0.05) which was statistically not significant. The flexural strength of GIC material decreased after being immersed in Sprite and fizz drinks. [ABSTRACT FROM AUTHOR]

The long cycle of manufacturing continuous carbon fiber-reinforced composite has significantly limited its application in mass vehicle production. High-pressure resin transfer molding (HP-RTM) is the process with the ability to manufacture composites in a relatively short forming cycle (<5 min) using fast reactive resin. The present study aims to investigate the influence of HP-RTM process variables including fiber volume fraction and resin injection flow rate on void characteristics, and flexural properties of manufactured CFRP components based on experiments and numerical simulations. An ultrasonic scanning system and optical microscope were selected to analyze defects, especially void characteristics. Quasi-static bending experiments were implemented for the CFRP specimens with different void contents to find their correlation with material's flexural properties. The results showed that there was also a close correlation between void content and the flexural strength of manufactured laminates, as the flexural strength decreased by around 8% when the void content increased by ~0.5%. In most cases, the void size was smaller than 50 μm. The number of voids substantially increased with the increase in resin injection flow rate, while the potential effect of resin injection flow rate was far greater than the effect of fiber volume fraction on void contents. To form complicated CFRP components with better mechanical performance, resin injection flow rate should be carefully decided through simulations or preliminary experiments. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Four kinds of sandwich-structured C/C-SiC and C/C-SiC-ZrC composites with or without a SiC interphase deposited by isothermal chemical vapor infiltration (ICVI), were designed and fabricated by a joint process of electromagnetic coupling chemical vapor infiltration (ECVI) and precursor infiltration and pyrolysis (PIP). The fabricated composites are macroscopically nonhomogeneous materials with low density, high strength and low ablation rate. The interphase and matrix constituents had remarkable effects on the mechanical and ablation properties of these composites. The C/C-SiC composites with an ICVI-SiC interphase exhibited the highest flexural strength of 306.5 MPa. While the C/C-SiC-ZrC composites with the interphase showed the best anti-ablation performance with low linear and mass ablation rates of 0.37 μm/s and 0.04 mg/cm2·s, respectively, after the ablation for 500 s under an oxyacetylene flame test at around 2000 °C. [ABSTRACT FROM AUTHOR]

Ta 0.78 Hf 0.22 C solid solution ceramic was synthesized and introduced into carbon/carbon (C/C) composites by polymer infiltration and pyrolysis (PIP). Effect of the introduction of Ta 0.78 Hf 0.22 C on the microstructure, ablation resistance, and flexural performance of C/C composites were investigated. Results showed that the flexural strength and modulus of the composites were increased by 108 % and 117 %, respectively, after adding Ta 0.78 Hf 0.22 C solid solution into C/C composites. In addition, the introduction of Ta 0.78 Hf 0.22 C improved the ablation resistance of C/C composites under oxyacetylene ablation environment, over 2200 °C. The linear and mass ablation rates were decreased 73 % and 70 %, respectively. The oxide with low melting point, Ta 2 O 5 , exhibited good sealing and oxygen-barrier capacity, and the formation of new solid solution oxide particles, Hf 6 Ta 2 O 17 , could pin cracks during ablation, both of them were contributed to better ablation resistance of modified C/C composites. [ABSTRACT FROM AUTHOR]

Flaxseed plants are widely grown globally due to the beneficial seed oil derivatives for human and animal consumption and other industrial uses. However, plentiful flaxseed straws are annually burnt after the harvesting of seeds, lacking utilization of the abundant flaxseed fibers, resulting in wastage of a valuable fiber resource and drastic increase in environmental pollution. In this study, initially the chemical composition and mechanical property of flaxseed fiber bundle were investigated, which resulted as 40.11% cellulose, 28.27% hemi-cellulose, 15.08% lignin, 6.3% pectin, 3.1% wax, and the tensile strength of 1.14 cN/dTex. The surface modification treatment was carried out with concentrations of 10 g/L and 20 g/L sodium hydroxide (NaOH). Later, flaxseed fiber bundles reinforced Polybutylene Succinate (PBS) resin composites were fabricated by thermal compression method. The tensile strength of untreated flaxseed fiber bundle/PBS composites was 78.2 MPa, while the flexural strength of 20 g/L NaOH treated flaxseed fiber bundle/PBS composites showed 84% increment from 26.70 MPa to 49.16 MPa. The scanning electron microscopy (SEM) images revealed significantly rougher surface morphology and stronger interfacial bonding of the alkali treated fiber bundles with matrix. The good mechanical properties observed demonstrated the absolute potential of resultant composites reinforced by flaxseed fiber bundles for utilization in the civil and industrial applications. [ABSTRACT FROM AUTHOR]

This study investigates the interply hybridization of carbon fibre reinforced polymer (CFRP) composite laminate to improve the flexural performance and cost efficiency. Carbon layers were replaced partially by basalt and/or glass fibres to explore the effects of hybrid ratio and stacking sequence on the flexural behavior and material usage. Hybrid laminates were manufactured by vacuum assisted resin transfer molding (VARTM) process. Three-point bending tests were carried out to characterize the flexural properties and failure mechanisms of the hybrid composite laminates. The fracture surfaces were examined by scanning electron microscopy (SEM). The results showed that flexural strength and modulus of the hybrid laminates decreased with the increase in the hybrid ratio of basalt fibres ranging from 0 to 50%; however negligible effects on flexural properties were observed when hybrid ratio increased further up to 75%. For the hybrid samples, a higher flexural modulus can be obtained by placing carbon layers on the both tensile and compressive sides symmetrically; and a higher flexural strength can be achieved by placing basalt or glass fibre through a sandwich-like stacking sequence with a hybrid ratio of 50%. The finite element modeling and classic laminate theory (CLT) analysis were also conducted through validation against the experimental results, which enabled to reveal the details of strain, damage and fracture under bending. The study exhibited a better material efficiency for glass/carbon hybrid laminates in terms of strength/cost and modulus/cost ratio; and the benefits of such cost efficiency of hybridization were discussed in depth for potential engineering applications. • Conducted three-point bending tests to characterize the flexural properties and failure mechanisms of the hybrid composite laminates. • Flexural modulus/strength for hybrid laminates varied with different stacking sequence. • Established the finite element modeling to predict damage onset of hybrid carbon/basalt composite laminates. • Adopted classic laminate theory (CLT) to calculate the flexural modulus and stress distribution across each hybrid laminate. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Widely reported anisotropy in 3D printed cementitious structures has been a primary concern to structural integrity, especially for fiber-reinforced cementitious material, e.g., engineered cementitious composites (ECC). To alleviate the anisotropy present in 3D printed ECC (3DP-ECC), two innovative printing patterns, "knitting" and "tilting" filaments, were proposed, mimicking the natural crossed-lamellar structure of conch shells. 3D spatial paths were designed to allocate tensile/flexural resistance to multiple directions and to create an interwoven interface system to strengthen the structure. Four-point bending tests loading from three different directions were conducted. It was found that knitted and tilted filaments revealed superior or comparable bending performance to cast ECC in two favorable orientations. Furthermore, flexural performance in the weakest orientation was notably improved by knitting and tilting, with up-to-179% increases in flexural strength compared with that of parallel filaments. This novel approach holds great promise in alleviating anisotropy of 3DP-ECC without introducing additional reinforcement. • Two innovative 3D spatial printing patterns were proposed: knitting and tilting filaments. • Flexural performances of 3DP-ECC in preferred orientations generally surpass or are comparable to cast ECC. • Anisotropy of 3DP-ECC was notably alleviated by knitting and tilting. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) fabric composite is a newly developed sandwich structure, consisting of two identical parallel fabric decks woven integrally and mechanically together by means of vertical woven fabrics. In this paper, six types of 3D fabric sandwich composites were developed in terms of compressive and flexural properties as a function of pile height (10, 20 and 30 mm) and pile distance (16, 24 and 32 mm) in pile structures. The mechanical characteristics and the damage modes of the 3D fabric sandwich composites under compressive and flexural load conditions were investigated. Besides, the influence of pile height and pile distance on the 3D fabric sandwich composites mechanical properties was analyzed. The results showed that the compressive properties decreased with the increase of the pile height and the pile distance. Flexural properties increased with the increase of pile height, while decreased with the increase of pile distance. [ABSTRACT FROM AUTHOR]

Tendon or ligament reconstructions often use autologous or allogenic tendons from either extrasynovial or intrasynovial sources. Allograft tendons must be lyophilized for preservation before transplantation, a process which can impact mechanical properties of the graft. Reconstituted graft properties that are similar to native tendon are desirable. Although tensile and compressive properties of tendons have been investigated, there is a paucity of information describing flexural properties of tendon, which can impact the gliding resistance. This study aims to design a testing method to quantify tendon flexural modulus, and investigate the effects of lyophilization/rehydration procedures on tendon flexibility. A total of 20 peroneus longus tendons (extrasynovial) and 20 flexor digitorum profundus tendons (intrasynovial) were collected. Ten of each tendon were processed with 5 freeze–thaw cycles followed by lyophilization and rehydration with saline solution (0.9%). Bend testing was conducted on tendons to quantify the flexural modulus with and without processing. As canine FDP tendons contain fibrous and fibrocartilaginous tissue regions, the flexural moduli were measured in both regions. Flexural modulus of rehydrated, lyophilized extrasynovial PL tendon was significantly lower than that of similarly processed intrasynovial FDP tendon ( p  < 0.001). Flexural moduli of both the fibrocartilaginous and non-fibrocartilaginous regions of intrasynovial tendon significantly increased after lyophilization ( p  < 0.001). The flexural modulus of the fibrocartilaginous region was significantly higher than that of the non-fibrocartilaginous region in intrasynovial tendon ( p  < 0.001). Lyophilization significantly increases the flexural modulus of extrasynovial and intrasynovial tendons, and flexural modulus differs significantly between these two tendon types. Increases in stiffness caused by lyophilization may impact the mechanical performance of the allograft in vivo. [ABSTRACT FROM AUTHOR]

The steady increase in production of corn based ethanol fuel has dramatically increased the supply of its major co-product known as distiller’s dried grain with solubles (DDGS). Large amount of DDGS and corn flour are used as an animal feed. The elusieve process can separate DDGS or corn flour into two fractions: DDGS fraction with enhanced protein and oil content or corn flour fraction with high starch content, and hull fiber. This study investigated the feasibility of using fiber from DDGS and corn grain as alternative fillers to wood fiber in high density polyethylene (HDPE) composites made with two different sources of polymers. Two fiber loading rates of 30 and 50% were evaluated for fiber from DDGS, corn, and oak wood (control) to assess changes in various physical and mechanical properties of the composite materials. Two HDPE polymers, a bio-based HDPE made from sugarcane (Braskem), and a petroleum based HDPE (Marlex) were also compared as substrates. The biobased polymer composites with DDGS and corn fibers showed significantly lower water absorption than the Marlex composite samples. The Braskem composite with 30% DDGS fiber loading showed the highest impact resistance (80 J/m) among all the samples. The flexural properties showed no significant difference between the two HDPE composites. [ABSTRACT FROM AUTHOR]

As a promising structural material, three dimensional woven fabric reinforced composites are subjected to machining or drilling during manufacturing processes for components assembly. In-plane tensile and flexural properties of a three dimensional orthogonal woven E-glass/epoxy composites (3DOWC) with 4 and 6 mm drilled holes (DH) and moulded-in holes (MH) are investigated. 2D woven E-glass/epoxy laminated composites (2DWC) with the same drilled hole sizes are also tested for comparison. Two different calculation methods based on gross and net sectional area are adopted to evaluate the effects of the holes on mechanical performance of the composites. The 3DOWC-MH possesses the highest tensile and flexural strength, followed by 3DOWC-DH and 2DWC-DH. As the hole diameter increases, the mechanical properties of all the composites degrade, while those of the 3DOWC-MH increases when the net sectional areas are used for calculation. X-ray 3D microscopy and scanning electron microscopy are employed to analyze damages at submicron level resulted from the tests. Various failure modes such as fiber fracture, matrix cracking and tow debonding are observed, while serious delamination occurs in 2DWC but not in 3DOWC. [ABSTRACT FROM AUTHOR]

The glass fiber reinforced poly cyclic butylene terephthalate (GF/pCBT) composite laminates and their fusion-bonded joints were prepared at appropriate polymerization temperature. The connection types of joints were designed and optimized. A series of bending tests were conducted to research their mechanical behaviors at different temperatures. Experimental results showed that flexural properties of laminates and joints decreased as temperature increased. The temperature sensitivity of specimens changes in the temperature range from 50 °C to 75 °C due to the glass transition of the pCBT matrix. Furthermore, the failure modes of GF/pCBT composite joints were investigated at room and high temperature. In addition, the specimens suffered by different high temperatures ranging from 25 °C to 200 °C were cooled and then tested at room temperature. The results indicated the flexural strength of laminates was nearly constant after experience of high temperature, and increased slightly when the temperature is above 175 °C. The flexural strength of fusion-bonded joints was not affected by high temperature. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effect of long-term water immersion or thermal shock on the mechanical properties of high-impact acrylic denture base resins. Two high-impact acrylic denture base resins were selected for the study. Specimens of each denture base material tested were fabricated according to the manufacturers' instructions (n=10). The flexural strength at the proportional limit, the elastic modulus and the impact strength of the specimens were evaluated. The flexural strength at the proportional limit of the high-impact acrylic denture base resins did not change after six months' water immersion or thermocycling 50,000 times. The elastic moduli of the high-impact acrylic denture base resins significantly increased after six months' water immersion or thermocycling 50,000 times. The impact strengths of the high-impact acrylic denture base resins significantly decreased after water immersion or thermocycling as described above. [ABSTRACT FROM AUTHOR]

In this study, the flexural properties of fully integrated honeycomb plates (FIHPs) were analyzed using experimental methods and finite element analyses. The effects of the perforated surface on the flexural properties of FIHPs were investigated by analyzing the flexural failure patterns and load-deformation curves of the FIHPs. The direction of the perforated surface has a significant influence on the flexural strength, and the structure exhibits different destruction patterns depending on the orientation. The experimental results indicate that although destruction occurs in the lower skin regardless of whether the perforated surface is up or down, the strength of the material of FIHPs can be optimized if the perforated surface faces upward because the chopped basalt fiber-reinforced epoxy resin composite material is strong in compression and weak in tension. A sub-model of a thin honeycomb plate containing holes was developed to discuss these issues in detail. The analysis results suggest that the stress concentration around the hole is distinct and that cracks initially appear in this high-stress area. This paper provides some conclusions to support the better use of biological structures, and it offers some important theoretical support for the application of FIHPs in natural disaster emergency projects. [ABSTRACT FROM AUTHOR]

The growing ethanol production around the world demands more value-added applications for its main byproduct, distillers grains. The present work reports the study of using corn based distillers dried grains (DDG) as biofillers for biobased epoxy resin and the mechanical, physical and thermal properties of the composites. The biobased epoxy resin is the blend of diglycidylether of bisphenol-A based resin and epoxidized soybean oil. The incorporation of DDG into the biobased resin accelerated the curing process as evident from the differential scanning calorimetry and temperature-modulated Fourier transform infrared spectroscopy. The 40 wt% DDG filled composite showed an excellent retention of flexural strength of up to 94 % of that of the neat epoxy. Furthermore, the composite filled with the DDG treated with epoxy functionalized oligomeric silsesquioxane showed even better flexural properties thanks to the improved wettability of the biobased resin with the filler. Dynamic mechanical analysis showed a 12 % increment in storage modulus for the surface-treated DDG composites over the biobased resin. The improved interfacial adhesion between the DDG and matrix through the surface modification was also observed in the morphological characterization with electron microscope. The study demonstrates the viability of combining DDG biofiller with the epoxy bioresin to produce novel biomaterials at low cost. [ABSTRACT FROM AUTHOR]

Objective. High flexural properties are needed for fixed partial denture or implant prosthesis to resist susceptibility to failures caused by occlusal overload. The aim of this investigation was to clarify the effects of four different kinds of fibers on the flexural properties of fiber-reinforced composites. Materials and methods. Polyethylene fiber, glass fiber and two types of carbon fibers were used for reinforcement. Seven groups of specimens, 2 × 2 × 25 mm, were prepared ( n = 10 per group). Four groups of resin composite specimens were reinforced with polyethylene, glass or one type of carbon fiber. The remaining three groups served as controls, with each group comprising one brand of resin composite without any fiber. After 24-h water storage in 37°C distilled water, the flexural properties of each specimen were examined with static three-point flexural test at a crosshead speed of 0.5 mm/min. Results. Compared to the control without any fiber, glass and carbon fibers significantly increased the flexural strength ( p < 0.05). On the contrary, the polyethylene fiber decreased the flexural strength ( p < 0.05). Among the fibers, carbon fiber exhibited higher flexural strength than glass fiber ( p < 0.05). Similar trends were observed for flexural modulus and fracture energy. However, there was no significant difference in fracture energy between carbon and glass fibers ( p > 0.05). Conclusion. Fibers could, therefore, improve the flexural properties of resin composite and carbon fibers in longitudinal form yielded the better effects for reinforcement. [ABSTRACT FROM AUTHOR]

In this paper, acrylonitrile-butadiene-styrene (ABS) nanocomposite foams are produced using carbon dioxide through the solid-state batch process. Microcellular closed-cell foams are produced with the relative density ranging from 0.38 to 0.97. The effects of the processing conditions on the density, morphology, and flexural properties of ABS and its nanocomposite foams are studied. It is found that nano-clay particles, as nucleating sites, play an important role in reducing the size of cells and increasing their number in the unit volume of foamed polymer, as well as increasing the flexural modulus of foam through reinforcing its matrix. [ABSTRACT FROM AUTHOR]

Highlights: [•] Organic vermiculite (O-VMT) was prepared by intercalation reaction. [•] O-VMT was used as reinforcing filler of wood–plastic composites (WPC). [•] O-VMT have homogeneous dispersion and strong interfacial interaction in WPC. [•] The WPC/O-VMT composites displayed lower water absorption properties. [•] The WPC/O-VMT composites displayed higher flexural and tensile properties. [Copyright &y& Elsevier]

Pre-tensioned construction material is utilized in engineering applications of high strength demands. The purpose of this study was to evaluate the effect of the pre-tensioning fibers of fiber-reinforced composite (FRC) using three-dimensional finite element (FE) analysis. The 3D FE models of particulate composite resin (CR), FRC and composite resin reinforced with pre-tensioned fibers (PRE-T-FRC) were constructed. The uniaxial three-point bending test was simulated using FE analysis to calculate the principal stress distribution. In the FRC and PRE-T-FRC, stresses were higher than CR, and they were located in the fiber. However, the maximum principal stress value at the composite of PRE-T-FRC was lower than the FRC and CR. Composite resin reinforced with pre-tensioned fibers was advantageous for stress distribution and lowering the stress at the composite itself. Experimental studies on physical properties of pre-tensioned FRC are encouraged to be conducted. [ABSTRACT FROM AUTHOR]

In order to study the flexural performance of steel fiber reinforced high strength concrete (SFHSC) four-pile caps, the experiments of 17 specimens, which have various steel fiber volume ratio, effective thickness, reinforcement ratio and concrete strength, were conducted to observe and analyze the crack distribution, load-deflection curve, concrete strain and longitudinal reinforcement strain, and failure mechanism. The results indicate the failure mode of the SFHSC four-pile caps with the moderate reinforcement is the flexural failure. The flexural tensile stress is resisted by reinforcement and steel fiber reinforced concrete. The ultimate moment capacity of the pile cap is improved evidently with the increase of the effective thickness and the steel fiber volume ratio. The calculation model and formula of ultimate moment capacity for the SFHSC four-pile caps is put forward, which serves as a reference for the CECS 38:2004 'Technical specification for fiber reinforced concrete structure' in China. [ABSTRACT FROM AUTHOR]

Fused deposition modeling possesses great advantages in fabricating high performance composites with controllable structural designs. As such, it has attracted attention from medical, automatic, and aerospace fields. In this paper, the influence of short carbon fibers (SCFs) and the orthogonal building orientation on the flexural properties of printed polyether ether ketone (PEEK) composites are systematically studied. The results show that the addition of SCFs raises the uniform nucleation process of PEEK during 3D printing, decreases the layer-to-layer bonding strength, and greatly changes the fracture mode. The flexural strength of vertically printed PEEK and its CF-reinforced composites show strengths that are as high as molded composites. X-ray micro-computed tomography reveals the microstructure of the printed composites and the transformation of pores during bending tests, which provides evidence for the good mechanical properties of the vertically printed composites. The effect of multi-scale factors on the mechanical properties of the composites, such as crystallization in different positions, layer-by-layer bonding, and porosity, provide a successful interpretation of their fracture modes. This work provides a promising and cost-effective method to fabricate 3D printed composites with tailored, orientation-dependent properties. [ABSTRACT FROM AUTHOR]