Process for improving mechanical properties of epoxy resins by addition of cobalt ions

A resin product useful as an adhesive, composite or casting resin is described as well as the process used in its preparation to improve its flexural strength mechanical property characteristics. Improved flexural strength is attained with little or no change in density, thermal stability or moisture resistance by chemically incorporating 1.2% to 10.6% by weight Co(3) ions in an epoxidized resin system

Metal carbide-graphite composites

Carbon sources effects on niobium carbides, and determination of high temperature flexural strength, flexural creep, and thermal expansion up to 2550 deg C for various material

Flexural performance of textile fine grained mortar containing risk husk ash as a partial cement replacement in reinforced concrete beams

External strengthening of RC beam become a popular method to reduce deterioration. Due to highest demanding on external strengthening, a new innovation was introduced called as textile fine grained mortar (TFGM). TFGM is a composite material which is combined fine grained mortar (FGM) that utilized rice husk ash (RHA) as a partial cement replacement material of FGM and textile reinforcement made from glass fibre reinforcement called as alkali resistant (AR) glass. Characteristic of the binder were firstly performed by conducting X Ray Fluorescence, X Ray Diffraction, particle size distribution and surface morphology. From characterization of RHA, it is categorized as a pozzolanic material from chemical composition, amorphous form of RHA and fineness of RHA. FGM with different percentage of RHA replacement varies from 0 %, 10%, 20 %, 30 % and 40% was investigated under compressive and flexural strength. Optimum replacement of RHA in FGM also determined. 20 % of RHA replacement in cement consumption of FGM gave excellent of compressive and flexural strength. Utilization of 20 % RHA in FGM was continuing to use when FGM combined with AR glass as textile reinforcement and produced new composite material TFGM. Several layers of TFGM were selected in this study, namely 2 layers, 4 layers, 6 layers and 8 layers. Flexural strength was conducted to determine the prism increment in flexural when externally bonded with TFGM. After flexural prism were done, 4 layers and 8 layers of TFGM were selected as desired layer to be applied on RC beams. Flexural test was perform on RC beams and resulted 4 layers of TFGM shown highest in flexural compared to control RC beams. But, 8 layers of TFGM were resulted failed due to delamination at the end of TFGM. As a conclusion, TFGM were very excellent in strengthening of RC beams. RHA is a highly promising in increments of flexural strength and AR glass also reduced the deflection of RC beams

Recycled Glass Fiber Reinforced Polymer Composites Incorporated in Mortar for Improved Mechanical Performance

Glass fiber reinforced polymer (GFRP) recycled from retired wind turbines was implemented in mortar as a volumetric replacement of sand during the two phases of this study. In Phase I, the mechanically refined GFRP particle sizes were sieved for four size groups to find the optimum size. In Phase II, the select GFRP size group was incorporated at three different volumetric replacements of sand to identify the optimum replacement content. The mixtures were tested for compressive strength, flexural strength, toughness, and the potential for alkali-silicate reaction. Incorporation of GFRP in mortar proves promising in improving flexural strength and toughness in fiber-like shapes and 1–3% volumetric fractions

Lightweight, high-strength, reinforced plastic tube-franging die

Dies of a phenolic molding compound with chopped glass fibers as fill material possess a flexural strength of 20,000 psi and a compressive strength of 28,500 psi

Experimental analysis of manufacturing parameters’ effect on the flexural properties of wood-PLA composite parts built through FFF

This paper aims to determine the flexural stiffness and strength of a composite made of a polylactic acid reinforced with wood particles, named commercially as Timberfill, manufactured through fused filament fabrication (FFF). The influence of four factors (layer height, nozzle diameter, fill density, and printing velocity) is studied through an L27Taguchi orthogonal array. The response variables used as output results for an analysis of variance are obtained from a set of four-point bending tests. Results show that the layer height is the most influential parameter on flexural strength, followed by nozzle diameter and infill density, whereas the printing velocity has no significant influence. Ultimately, an optimal parameter set that maximizes the material’s flexural strength is found by combining a 0.2-mm layer height, 0.7-mm nozzle diameter, 75% fill density, and 35-mm/s velocity. The highest flexural resistance achieved experimentally is 47.26 MPa. The statistical results are supported with microscopic photographs of fracture sections, and validated by comparing them with previous studies performed on non-reinforced PLA material, proving that the introduction of wood fibers in PLA matrix reduces the resistance of raw PLA by hindering the cohesion between filaments and generating voids inside it. Lastly, five solid Timberfill specimens manufactured by injection molding were also tested to compare their strength with the additive manufactured samples. Results prove that treating the wood-PLA through additive manufacturing results in an improvement of its resistance and elastic properties, being the Young’s module almost 25% lower than the injected material.Preprin

Comparison of flexural properties of aramid-reinforced pultrusions having varied matrices, pretreatments and postcures

Aramid-reinforced composite materials of equal fiber volume and varied polymer thermoset matrices were pultruded and flexurally tested to failure. The objective was to improve the flexural properties of aramid-reinforced pultrusions. Pultrusions of both sized and unsized aramid fiber with four different resin systems were compared to determine the effects of sizing compounds and postcuring on flexural strength, fiber wettability, and fiber-to-resin interface bonding. Improvements in flexural strength resulting from pretreatments with the sizing solutions used were marginal. The most significant improvements in flexural properties resulted from postcuring. Flexural strengths ranged from a low of 39,647 psi (273MPa) to a high of 80,390 psi (554 MPa), an overall increase of 103 percent. The fact that postcuring improved the flexural properties of the pultrusions of the four resin systems indicates that a full cure did not occur in any of the resin systems during the pultrusion process. The increased flexural strengths of the polyester and vinyl ester pultrusions were the most surprising. The four resin systems examined were Interplastic Corporation VE 8300 vinyl ester, Ashland Chemical Company Aropol 7430 Polyester, and Shell Chemical Company Epon 9302 and Epon 9310 epoxides

Flexural behavior of two-span continuous prestressed concrete girders with highly eccentric external tendors

[Abstract]: It is generally known that the flexural strength of beams prestressed with external tendons is comparatively lower than that of members with internal bonded tendons. One possible method of enhancing the flexural strength of such beams is to place the tendons at high eccentricity. To obtain an insight into the flexural behavior of beams with highly eccentric tendons, an experimental investigation is conducted on single-span and two-span continuous beams. The test variables include external tendon profile, loading pattern on each span, casting method, and confinement reinforcements. It is found that continuous girders with linearly transformed tendon profiles exhibit the same flexural behavior irrespective of tendon layout. The presence of confinement reinforcement enhances the ductility behavior but does not increase the ultimate flexural strength. The degree of moment redistribution is affected by the tendon layout and the loading pattern on each span. The results of the experimental investigation are discussed in this paper

Mechanical and morphological properties of injection-molded rice husk polypropylene composites

In this work, the investigation of the physical, mechanical, and morphological properties of the rice husk flour/polypropylene composites was performed utilizing various filler loadings and coupling agent. Five levels of filler loading (35, 40, 45, 50, and 55 wt%) were designed. In addition, to help the interaction between fiber and polypropylene matrix, struktol coupling agent was added to the composites. All of tensile strength, Young's modulus, flexural strength, flexural modulus, and impact strength properties of the composites were carried out. Moreover, the 50 wt% filler-loaded composites had optimum tensile strength, flexural strength, and flexural modulus, whereas the 35 wt% of filler loading case was the best regarding Young's modulus, flexural strength, flexural modulus, and impact strength. Furthermore, the scanning electron microscope results demonstrate that as filler loading increases, more voids and fiber pullout occur