Bending Modulus Of Elasticity Research Articles

Influence of the content of recycled artificial leather waste particles in particleboards on their selected properties

Influence of the content of recycled artificial leather waste particles in particleboards on their selected properties. Artificial leather is a layered fabric-plastic composite that resembles natural leather in appearance. Due to its wide range of advantages, artificial leather is widely used as an upholstery material in the renovation and production of furniture or even car upholstery. The aim of the research was to manage upholstery leather waste by adding previously shredded particles of artificial leather of different contents (5, 10, 25 and 50% by weight) to particleboard. Tests of selected mechanical properties (bending strength and modulus of elasticity and resistance to screw withdrawal) and physical properties (density profile, thickness swelling after immersion in water) were completed. It can be concluded that, depending on the further use of the board, there is a possibility of using the recovered artificial leather particles as a reasonable addition to wood fibres in the production of particleboard.

Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum

: Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum. The popularity of composites reinforced with natural fibers is constantly growing and therefore, they are a subject of many scientific works as well. An example of interesting concept is the use of hemp fibers to reinforce a gypsum matrix and therefore, presented study was aimed to determine the effect of their content on the properties of resultant composites. Moreover, the influence of setting temperature was also investigated. The scope of the research included determination of properties such as: density, setting time, bending strength, modulus of elasticity and thermal conductivity coefficient. Studies have shown that as the amount introduced fibers increases, the density of manufactured composites decreases. Furthermore, increase in the content of hemp causes a significant extension in setting time of the gypsum matrix. Based on the outcomes of mechanical properties, it was found that the optimal content of fibers is 4% and further increase in their share results in a deterioration of flexural strength characteristics. The increase in a setting temperature leads to thereduction in their bending strength and modulus of elasticity. Composites reinforced with hemp fibers demonstrate significantly improved thermal insulation properties

Microscopic Study of Shale Anisotropy with SEM In Situ Compression and Three-Point Bending Experiments

The microscopic anisotropy of shale has an important impact on its mechanical properties and crack behavior, so it is essential to understand the microscopic origin of anisotropic growth with a more effective laboratory work scheme. Uniaxial compression test and three-point bending test are considered to be efficient means to study the elastic properties and crack behavior of rocks. In this paper, uniaxial compression experiments and three-point bending experiments were conducted on shale outcrops in the Changqing area using field emission scanning electron microscopy (SEM) and in situ tensile testing, and the microscopic deformation and crack processes were quantitatively characterized by the digital image correlation (DIC) method. For the compression experiments, the observation of the first principal strain fields indicated that the microscopic anisotropy of shale was related to the bedding planes, and the microscopic deformations were mainly concentrated in the clay mineral accumulation area and at the microcracks. Elastic moduli and compressive strengths of specimens with different bedding angles were affected by the strong shear stress effects. The specimens with a bedding angle of 30° showed lower peak loads and compressive strengths, and the specimens with a bedding angle of 60° had lower elastic moduli. Three-point bending experiments were conducted for studying the effects of crack-bedding orientation relationships on cracking processes, and four critical fracturing mechanical properties were calculated. The short transverse-type cases were prone to break and had a lower peak load, tensile strength, fracture toughness and elastic-bending modulus. The divider-type cases were more difficult to break, formed a more tortuous crack and had a higher tensile strength, fracture toughness and elastic-bending modulus. The arrester-type cases had a middle range of mechanical parameters but developed the longest cracks. This study provides a feasible experimental and analysis method for understanding the microscopic anisotropy of shale samples. The small specimen size also makes the requirements of core samples easier to be satisfied considering the field application. Furthermore, the anisotropy of cracking processes can be understood better by building the connections between microstructural characteristics and mechanical performances.

Research on Mechanical Properties of Winding Axial Bending Under Unbalance of Transformer Pad

To improve the study on the influence of transformer windings and pad support on transformer short-circuit resistance, the calculation method of wire bending elastic modulus is analyzed, and the sample test is carried out: The influences of the unbalance of the two ends of the wire between the number of wires wound and the span of adjacent pads on the force-deflection curve, the bending force at the selected deflection, and the elastic modulus of bending were analyzed. The results showed that: Increasing the number of wires and decreasing the height difference of adjacent pads can improve the bending force and bending elastic modulus of wires, the axial stability, and short-circuit resistance of transformer windings. When the height of the adjacent pad is not balanced, the axial force can increase the compression degree between the pad and the wire, and reduce the span of the wire. Under the action of force, the wire yields twice, which further reduces the bending force and elastic modulus of the wire. This research can provide test data support for improving the installation of transformer winding pads and theoretical evaluation of short-circuit tolerance.

Effect of Carbon Nanofibers on the Viscoelastic Response of Epoxy Resins.

Two epoxy resins with different viscosities were enhanced up to 1 wt.%, applying a simple method with carbon nanofibers (CNFs). These were characterized in terms of static bending stress, stress relaxation, and creep tests. In bending, the contents of 0.5 wt.% and 0.75 wt.% of CNFs on Ebalta and Sicomin epoxies, respectively, promote higher relative bending stress (above 11.5% for both) and elastic modulus (13.1% for Sicomin and 16.2% for Ebalta). This highest bending stress and modulus occurs for the lower viscosity resin (Ebalta) due to its interfacial strength and dispersibility of the fillers. Creep behaviour and stress relaxation for three stress levels (20, 50, and 80 MPa) show the benefits obtained with the addition of CNFs, which act as a network that contributes to the immobility of the polymer chains. A long-term experiment of up to 100 h was successfully applied to fit the Kohlrausch-Williams-Watts (KWW) and Findley models to stress relaxation and creep behaviour with very good accuracy.

Spatial Variation in Young Ovine Cortical Bone Properties.

Significant effort continues to be made to understand whether differences exist in the structural, compositional, and mechanical properties of cortical bone subjected to different strain modes or magnitudes. We evaluated juvenile sheep femora (age = 4 months) from the anterior and posterior quadrants at three points along the diaphysis as a model system for variability in loading. Micro-CT scans (50 micron) were used to measure cortical thickness and mineral density. Three point bending tests were performed to measure the flexural modulus, strength, and post-yield displacement. There was no difference in cortical thickness or density between anterior or posterior quadrants; however, density was consistently higher in the middle diaphysis. Interestingly, bending modulus and strength were higher in anterior quadrants compared to posterior quadrants. Together, our results suggest that there is a differential spatial response of bone in terms of elastic bending modulus and mechanical strength. The origins of this difference may lie within the variation in ongoing mineralization, in combination with the collagen-rich plexiform structure, and whether this is related to strain mode remains to be explored. These data suggest that in young ovine cortical bone, modulation of strength occurs via potentially complex interactions of both mineral and collagen-components that may be different in regions of bone exposed to variable amounts of strain. Further work is needed to confirm the physiological load state of bone during growth to better elucidate the degree to which these variations are a function of the local mechanical environment.

Additively-Manufactured High-Concentration Nanocellulose Composites: Structure and Mechanical Properties.

Additive manufacturing technology (AMT) has transformed polymer composites' manufacturing process with its exceptional ability to construct complex products with unique materials, functions, and structures. Besides limiting studies of manufacturing arbitrarily shaped composites using AMT, printed structures with a high concentration of nanocellulose face adhesion issues upon drying, resulting in shape fidelity issues and low mechanical strength. This research demonstrates an economical approach to printing a high-concentration (25.46 wt%) nanocellulose (NC) layer-wise pattern to fabricate structures. Two different composites are fabricated: (1) 3D-printed pure and high-concentration (10, 15, and 20 wt%) polyvinyl-alcohol (PVA)-blended NC structures followed by freeze-drying and impregnation of Epofix resin by varying hardener contents; (2) 3D-printed PVA-blended NC green composites dried at cleanroom conditions (Relative humidity 45%; Temperature 25 °C). Different contents (10, 15, and 20 wt%) of PVA as a crosslinker were blended with NC to assist the printed layers' adhesions. An optimum PVA content of 15 wt% and an Epofix resin with 4 wt% hardener cases showed the highest bending strength of 55.41 ± 3.63 MPa and elastic modulus of 4.25 ± 0.37 GPa. In contrast, the 15 wt% PVA-blended NC cleanroom-dried green composites without resin infusion showed bending strength and elastic modulus of 94.78 ± 3.18 MPa and 9.00 ± 0.27 GPa, reflecting high interface adhesions as confirmed by scanning electron microscope. This study demonstrated that AMT-based nanocellulose composites could be scaled up for commercial use.

Towards circular economy by valorization of waste upholstery textile fibers in fibrous wood-based composites production

The aim of the research was to utilize textile waste by adding upholstery fabric fibers with different content (0, 5, 10, and 20% by weight referred to dry wood fibers) to high density fiberboards (HDF) and analyze selected physical and mechanical properties of the obtained boards. Tests of mechanical (modulus of elasticity in bending and bending strength, surface soundness, internal bond, screw withdrawal resistance) and physical (density profile, swelling in thickness after immersion in water, water absorption) properties were performed. The results show that the increasing content of textile fibers in HDF panels has the strongest negative influence on mechanical properties, especially internal bond, and screw withdrawal resistance. Modulus of elasticity and modulus of rupture also decreased, but still fulfilled the requirements of European standards. No significant influence of rising content of textile fibers on HDF thickness swelling and water absorption has been found. It can be concluded that, depending on further application of HDF, it is possible to utilize the recovered upholstery textile fibers as a reasonable addition to wood fibers when producing HDF panels. It is also a step toward carbon storage extension, which is fixed in textile fibers.

Assessing 2 by 6 Southern Pine Lumber Flexural and Tensile Properties with Nondestructive Techniques

Abstract The objective of this study was to assess the flexural and tensile properties of 702 pieces of No. 2 grade 2 by 6 southern pine lumber using nondestructive testing (NDT) techniques. Longitudinal and transverse vibration techniques were used to test each specimen. The mean dynamic modulus of elasticity in the longitudinal direction was 11,246 MPa, and the mean transverse vibration dynamic modulus of elasticity was 11,491 MPa. Proof-loading bending tests were conducted on each specimen. The mean bending modulus of elasticity (MOE) was 10,615 MPa. Each specimen was then destructively tested in tension parallel to the grain to determine tension MOE (Et) and ultimate tensile stress (UTS). The overall mean for Et was 11,339 MPa and the UTS mean was 28.54 MPa. Correlations between growth characteristics, and physical and mechanical properties were analyzed. From the linear regression analysis, a strong relationship between Et and dynamic MOE was found using both NDT tools. Multivariable regression models were developed to improve UTS estimation. NDT techniques are recommended for the estimation of mechanical properties of No. 2 grade 2 by 6 southern pine lumber.

Determination of physical and mechanical properties of plywood produced using beech, okoume and ozigo species

Wood and wood-based materials are widely used in the construction industry in the world. The sustainable and renewable nature of wood is seen as an important advantage in contrast to non-renewable resources such as aluminum, steel, concrete, and plastic. In order to protect the advantages of wood and eliminate / reduce its disadvantages, plywood, particle board, fiber board, LVL, CLT, wood plastic composites etc. such as new wood-based engineering products are produced. Plywoods are widely used in automotive, construction, furniture, and many industries. In our country, plywoods are produced using tropical species as well as native tree species. In this study, density, water absorption, thickness swelling, bending resistance, elasticity of modulus in bending and shear strength values of plywood made of beech, okoume and ozigo wood species are investigated. Comparison of plywood produced from tropical species with beech has been made. It has been determined that beech plywood has higher density than okoume and ozigo plywood. It has been determined that beech plywood has higher density than okoume and ozigo plywood. It has been observed that there is a linear relationship between the bending strength, elasticity modulus and shear strength values of beech plywood and their full dry density.

Effects of surface lamination process parameters on medium density fiberboard (MDF) properties

Medium density fiberboard (MDF) is widely utilized in furniture production. Most MDF in such applications has a surface laminate layer. The lamination process improves the physical and mechanical properties of the boards. The temperature, press time, and pressure values applied during the lamination process affect such properties. In this work, the lamination process was carried out using a constant temperature (180 °C), four different press times (18, 20, 22, and 24 s), and three different pressures (25, 30, and 35 kg/cm2). The raw weight of the decor paper was 90 g/m2 and UF and MF glues were used in its production. The properties of the laminated panels were then determined for each variation. In general, the water absorption and thickness swelling properties were improved at the lower pressure and higher press times. The internal bonding strength exhibited a linear change at different press times depending on increasing pressure values, whereas the changes in the bending strength and modulus of elasticity in bending were not statistically significant. It was concluded that the BS increased with rising pressure in the short-term lamination process and that the effect of the pressure on the BS declined with increasing press time.

Effects of joint stiffness degradation on vertical stability of CRTSII slab ballastless track

Joint damage of the China Railway Track System (CRTS)II slab track leads to typically non-uniformity of the longitudinal stiffness of the track slab, which tends to produce different degrees of arching at the joint. The objective of the present study was to investigate the arching mechanism of the non-uniform track slab. The buckling eigenvalues and arch curves of the non-uniform track slab were obtained using the Newton iterative eigenvalue algorithm. An analytical expression for the equilibrium path of the slab with an initial arch was obtained using the energy method. Then, the arching law and stability of the non-uniform track slab were analysed. The following results were obtained. 1) The reduction of the joint bending stiffness significantly affects the arching deformation and buckling mode of track slab, thus, it is necessary to consider the non-uniform characteristics of the track slab when analysing its stability. 2) The most unfavorable wavelength of track slabs is between 6 m, and 7.5 m considering the different joint bending stiffnesses and elastic moduli, and the reduction of the bending stiffness of the joint is the main factor for reducing the most unfavorable wavelength. 3) The reduction of the joint bending stiffness is the most important factor for causing the instability of the track slab, the maximum allowable temperature rise decreased from 83.97 to 49.12 ℃ when the bending stiffness of the joint was reduced by a factor of 100. 4) For improving the stability of the track slab, releasing part of the temperature force in the track slab by reducing the elastic modulus of the joints is a feasible method, the maximum temperature rise of track slabs can be rapidly increased when the elastic modulus of the joints is < 5000 MPa.

Physical, Mechanical and Acoustic Characteristics of Anogeissus leiocarpus, Manilkara multinervis and Cylicodiscus gabunen-sis Woods Marketed in Benin in West Africa

Wood is a material used in construction, in instrument making, etc. In Benin, for heavy construction and construction on wetland, species with high technological characteristics are imported. But the performance of these imported species compared to local indigenous or exotic species remains to be verified. Thus, it is necessary to determine the basic technological properties of these species. It is within this framework that we have, on 500mm×20mm×20mm prismatic wood specimens of Anogeissus leiocarpus, Manilkara multinervis and Cylicodiscus gabunensis, used the acoustic method BING (Beam Identification by Non-destructive Grading) of CIRAD-Forest to determine the density ρ, the moduli of Young's modulus E, shear modulus G and the internal friction tan𝛿 and then evaluated the modulus of specific stiffness E/ρ. On other 20 mm edge cubic specimens, we evaluated the reference physical properties of density, infradensity, total shrinkage, radial shrinkage, tangential shrinkage and shrinkage anisotropy. It appears that the wood of Anogeissus leiocarpus and Manilkara multinervis present better physico-mechanical characteristics than those of Cylicodiscus gabunensis. Anogeissus leiocarpus and Manilkara multinervis are very dense woods with physico-mechanical characteristics better than those of most Benin's popular species. The average modulus of elasticity in bending of these two species is higher than 12000 MPa while that of Cylicodiscus gabunensis is 10713 MPa. In compression all these species have an average modulus of elasticity above 14100 MPa. Cylicodiscus gabunensis wood tested is light with a lower shrinkage anisotropy than the other two species studied and have excellent acoustic properties. Its average specific stiffness (14 GPa) is higher than that of the other two species studied (12 GPa). The good physical-mechanical and acoustic properties of these species show that they are good structural timbers with also good potential for instrument making and acoustic insulation.Keywords: BING; Construction; Infradensity; Modulus of elasticity; Shrinkage anisotropy; Timber.

Flexural and Tensile Properties of f2x6 and 2x10 Southern Pine Lumber

Bending modulus of elasticity (MOE) and tensile properties parallel to the grain were studied on 702 pieces of 2 X 6 and 285 pieces of 2 X 10 No. 2 visually graded southern pine lumber. The overall rings per inch (RPI) in 2 X 6 pieces was 4.82, whereas 2 X 10 had an RPI average of 3.82. For latewood percentage (LW), 2 X 6 pieces found 45.88% of LW and 45.02% for 2 X 10 pieces. Bending MOE (Eb) mean for 2 X 6 was 10,615 MPa, whereas for 2 X 10 lumber, the mean was 13,665 MPa. The tension MOE (Et) mean for 2 X 6 lumber was 11,339 MPa, whereas for 2 X 10 the mean was 9735 MPa. The ultimate tensile stress (UTS) mean for 2 X 6 lumber was 28.42 MPa and the overall mean UTS for 2 X 10 lumber was 24.51 MPa. Linear regression models were useful to explain the relationship between Eb and Et. Strong coefficients of determination (r250.70 and r250.74) were found for both lumber sizes between these two properties. Moderate relationships (r250.43 up to r250.51) between Eb and UTS were also found for both lumber sizes. However, weaker relationships were found between Et and UTS (r250.32 up to r250.40). Three distributions were fit to the Eb, Et, and UTS data and evaluated for goodness of fit. The results suggest that Eb of 2 X 6 lumber might be adequately modeled by a normal distribution, and tensile properties of 2 X 10 lumber might be adequately modeled by a lognormal distribution.

Interfacial treatment-induced high-strength plant fiber/phenolic resin composite

Plant straw fibers have been used widely in composite materials as reinforcement due to their advantages of low density, easy degradation, low cost, and abundance. However, the mechanical properties and water resistance of the as-prepared composites are limited due to the poor compatibility between plant straw fibers and polymer matrix. In this work, the rice straw fibers were pretreated with the silane coupling agent, lipase, and hydrothermal, and then blended with phenolic resin to prepare composites. The results showed that the pretreatment of the fibers can improve their compatibility with the resin matrix and improve the comprehensive mechanical properties and the thickness swelling of composites. When the mass ratio of fiber to resin is 1:1 and the hot-pressing condition is 160°C and 11 min, the static bending strength, elastic modulus, and thickness swelling of the phenolic resin/lipase-treatment rice straw fibers (PF/L-SF) composite reached 23.03 MPa and 2588.39 MPa, which increased by 32.9% and 30.5% compared with the unmodified fiber/phenolic resin composite (PF/SF).

Upcycling Different Particle Sizes and Contents of Pine Branches into Particleboard.

A growing world population means that demand for wood-based materials such as particleboard is constantly increasing. In recent years, wood prices have reached record highs, so a good alternative can be the utilization of branches, which can reduce the cost of raw materials for particleboard production. The goal of the study was to confirm the feasibility of using an alternative raw material in the form of Pinus sylvestris L. pine branches for the production of three-layer particleboard. Characterization of the alternative raw material was also carried out, and the bulk density was determined. As part of the research, six variants of particleboard, 0%, 5%, 10%, 25%, and 50%, w/w, and two variants where the first one had the face layer made of branch particles and the core layer made of industrial particles, and the reverse variant (all produced panels were three-layer) were produced and then their physical and mechanical properties were studied. The results show that even if the bulk density of branch particles is significantly higher than industrial material, the internal bond and water absorption rises as branch particle content increases. In the case of bending strength and modulus of elasticity, these were decreased with a branch particle content increase. The conducted tests confirmed the possibility of using the raw material, which was usually used as fuel or mulch, to produce particleboards even in 50% content. The present solution also contributes to the positive phenomenon of carbon storage, due to incorporating the branches' biomass into panels rather than burning it. Further research should be focused on the modification of particle production from branches to obtain lower bulk density and to reach fraction shares closer to industrial particles. Furthermore, the chemical characterization of the pine branch particles (cellulose and lignin content, extractives content, pH value) would provide valuable data about this potential alternative raw material.

COMPARATIVE STUDY OF PARTICLEBOARDS WITH HEVEA BRASILIENSIS WASTE FROM DIFFERENT PRODUCTION AND MOISTURE CONFIGURATIONS

After the production cycle of latex, Hevea brasiliensistrees becomeresidual living plants for this activity, although their woody trunks are still potentially subject to industrial utilization. Bio-composites derived from rubberwood particles were manufactured using two different configurations as a strategy to examine the potential of this species with respect to mechanical behavior. Homogeneous panels were developed from particles at the saturation condition, and heterogeneous panels were obtained from dry particles conditioned at 12% moisture content. Both examples were heat-pressed and glued with castor oil-based polyurethane resin. Density, short-term water absorption and thickness swelling, modulus of rupture and modulus of elasticity in the static bending and perpendicular tensile were evaluated. Panels derived fromrubberwood particles proved to be viable according to the technical standards.

Influence of face grain angle, size, and moisture content on the edgewise bending strength and stiffness of birch plywood

Birch plywood exhibits outstanding mechanical properties with regards to tensile, compressive, and shear behaviors, making this engineered wood product promising in timber connection applications. However, the edgewise bending strength and stiffness, which are often critical for the design of gusset plates, have not been investigated thoroughly. Moreover, in engineering applications, the size and moisture content of the plywood plate are in general very different from those adopted in laboratory testing according to current standards. This paper aims to investigate the influence of face grain angle, size, and moisture content on the edgewise bending strength and stiffness of birch plywood. In total, 288 birch plywood specimens were tested in three-point bending at five different face grain angles to the beam longitudinal axis (from 0° (parallel) to 90° (perpendicular), with an angle step of 22.5°), with four different sizes (with the nominal depth of 20 mm, 30 mm, 40 mm, and 50 mm) and three different moisture contents (7.2 %, 11.9 %, and 21.8 %). Analytical and numerical models, both taking non-linear elasto-plastic compressive behaviors into account, were developed for the prediction of the ultimate moment capacity based on different failure definitions. Lastly, the relationships between the bending strength and elastic modulus were analyzed.

Support compliance: A non-ignorable factor for cantilever sensors for MEMS application

Support compliance at the fixed end of cantilever beams has significant effects on the measured modulus of elasticity in bending (Eb) and accurate deflection response. Additional deflection caused by support compliance is an easily neglected but an inevitable factor, which results in the large errors of the measured Eb. An effective strategy to design cantilever sensors was proposed by enhancing the loading distance, which not only improve the sensitivity, but also weaken the support compliance effect. In a nutshell, the support compliance effect must be taken into accounted by engineers carefully to improve the accuracy of the measured Eb and deflection response for cantilever sensors which used in MEMS.

Hybrid composite board produced from wood and mineral stone wool fibers

Wood fiberboards are used extensively, mainly in the fields of furniture production, interior fittings, construction, etc. Mineral stone wool materials are used for heat and sound insulation in the construction industry. This study aimed to produce a new hybrid-based composite material by mixing fibers obtained from wood and mineral stone wool. For this purpose, hybrid fiberboards with 50, 40, 30, and 20% stone wool addition and a fiberboard group consisting of 100% pine and beech fibers (control sample) were produced in a hot press using thermoset-based urea formaldehyde and phenol formaldehyde resins. Statistical comparisons of the results were made for values of density, thickness swelling, and water absorption extents after 24 h immersion, bending strength and modulus of elasticity in bending, tensile strength perpendicular to the board surface (internal bond strength), and time to ignition (TTI) analysis. Additionally, percentage of mass loss (PML), average heat release rate (A-HRR), average effective heat of combustion (A-EHC), and mass loss rate (MLR) were studied. The results showed that as the stone wool content in the produced boards increased, the mechanical properties and thickness swelling decreased. The combustion results showed that the combustion resistance of the boards increased with increasing stone wool ratio.