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The main objective of the study was to investigate the mechanical properties of Moso bamboo species (Phyllostachys pubescens) in wet and dry conditions and waste rubber engineered bamboo, according to climate for temporary shelter design during flood occurrence. For experiment, bamboo of diameter 5 cm and made four samples (length 25 mm, width 3 mm and thickness 1.5 mm) for testing tensile strength and flexure modulus (length 13 mm, width 2 mm and thickness 1 mm). The study finds that the tensile stress for dry sample (A) was 29.0 MPa; elongation break was 4.5% and these parameters for water soaked sample (A1) were 17.1 MPa and 10.6% respectively. Tensile stress for dry sample laminated with rubber tube (B) was 31.5 MPa; elongation break was 3.1% and these parameters for rubber tube laminated water soaked sample (B1) were 19.9 MPa and 5.6% respectively. Flexural strength for samples A, A1, B and B1 were 290.5, 283.1, 339.9 and 292.8 MPa respectively. Results indicate that the strength of rubber tube laminated samples increases. The study concludes that vehicles' waste rubber tubes can be utilized to enhance the strength of bamboo for making temporary shelter in flood affected areas.

As a natural graded material, bamboo has gradually increasing elastic modulus along the radial direction from the inner to the outer skin. Accurate measurement of the modulus distribution plays an important role in bamboo-based structural design. However, it is difficult to characterise this modulus distribution by using conventional testing approaches on bamboo slices. A more effective method was developed in this study for the inverse identification of gradually varying material properties. The method is based on the digital image correlation and finite element model updating techniques. The radial distribution of the elastic modulus of bamboo was obtained through only one four-point bending test. The inversely identified modulus distribution was verified through uniaxial tensile tests on sliced bamboo strips and microscopic observation of the volume fraction distribution of its vascular bundle. The results showed that the elastic modulus of the bamboo material decreased from the outer skin (20 GPa) to the inner skin (2 GPa), which is in good consistence with the tensile test results on sliced specimens.

Bamboo based composite materials are widely used for structural components in building and textile industries. The structural hierarchy across different scales could enhance the strength and toughness of bamboo for load-bearing applications. Firstly, chemical components of bamboo fibril are described, and bamboo fibril specimens are fabricated through chemical solution processing; Secondly, functionally graded mechanical properties of macroscopic bamboo fibers are studied with tensile experiments, and relations between graded mechanical properties and microstructures are explored; Afterwards, hierarchical microstructure characterization of bamboo across different scales are performed using scanning electron microscopy (SEM), and mechanical properties of bamboo fibrils are tested using homemade in-situ micro-tension setup. The results indicate that the elastic modulus, ultimate strain and strength of bamboo fibers are: 5.952 GPa, 0.0136 and 81.13 MPa respectively. The Young’s moduli, ultimate strains and fracture strengths of the five fibril samples located in (10.478, 12.285) GPa, (0.0172, 0.0217) and (181.87, 230.50) MPa, respectively. These experimental results suggest that the modulus and ultimate strength of bamboo fibril are higher than that of bamboo fibers which are attributed to several main factors including the ages of the bamboo, bamboo species, multi-lamella structures of the fibrils, geometry differences of fibrils, etc.

In this paper, mechanical properties of bamboo strip and bamboo strip-glass fiber reinforced hybrid composite were investigated. Composites were manufactured by using hand lay-up technique and bamboo strips were made from locally available bamboo. Four layers of bamboo strip composite were manufactured and in case of hybrid composite, two layers of glass fiber one at the top and the other at the bottom were used with the aim was to observe the effect of adding glass fiber layer on the mechanical properties of bamboo strip composite. Tensile and flexural properties were studied and it was found that adding the glass fiber layer doesn’t have any significant effect on tensile properties but flexural strength and modulus have increased by 22.49 % and 15.02 % respectively.

Inspired by the natural gradient structure of the moso bamboo wall, a hybrid moso bamboo（B)Wood(W) veneer Composite (BWC) was developed with a specific structure of [B0°/ W90°/ B0°]. The dynamic fracture behaviors and damage mechanism of the BWC were characterized using in situ scanning electron microscopy. X-ray micro- computed tomography imaging was employed to verify the off-axis tensile mechanical properties. The results showed that the maximum tensile strength and modulus of the BWC under off-axis loadings were 232.25 MPa and 17.47 GPa, respectively. Meanwhile, the maximum specific strength and specific modulus of the BWC were 290.31 MPa·cm3·g−1 and 23.84 GPa·cm3·g−1, respectively, which are higher than both natural wood (95.26 MPa·cm3·g−1, 10.82 GPa·cm3·g−1), bamboo (208.56 MPa·cm3·g−1, 15.74 GPa·cm3·g−1) and even steel alloy (237.86 MPa·cm3·g−1, 21.98 GPa·cm3·g−1). Compared to reorganized bamboo (RB), the porosity of the BWC was 61.1% lower. The BWC was strengthened via internal toughening mechanisms (i.e. fiber bridging) and external toughening mechanisms (i.e. multiregional distribution of micro-cracks). This work highlights methods to design high-performance bio composite from commonly used biomaterials through synergistic strengthening and toughening mechanisms, which has significant advantages in the ever-growing construction industry.

Currently, only two forms of laminated bamboo are commercially available as structural materials: unidirectional beams and boards, and cross-laminated boards. As a natural quasi-unidirectional composite, the lamination of bamboo into plies with specific orientations would allow the design and manufacture of a family of multi-axial composite laminates with unique properties. In this study, we test the tensile mechanical properties of single- and two-ply laminated bamboo at various off-axis loading angles and laminate configurations. The data is then compared to micro-mechanical models for predicting modulus and strength of composite laminates. On the basis of our analyses, we believe there is significant scope to extend the current range of laminated bamboo products to include angle-ply laminates. Moreover, we demonstrate that composite laminate theory is applicable to this natural composite and may be used for design of products and structures.

This study is to investigate the mechanical, hygral, and interfacial strength of continuous bamboo fiber reinforced epoxy composites. The untreated and alkali-treated continuous bamboo fibers were prepared from cutting the nature bamboo culm. The basic characteristics of the bamboo fibers, such as density, equivalent diameter, and tensile properties were experimentally measured. The bamboo fiber reinforced epoxy (BF/EP) composites were fabricated by the resin transfer molding (RTM) process with the resulting fiber volume fraction about 42%. The strength of bamboo fiber was found to decrease with the alkaline treatment. However, alkali-treated bamboo fiber reinforced epoxy composites acquired better tensile strength than those with untreated bamboo fibers. The untreated bamboo fiber was believed to have weak interface with the epoxy resin, which was verified by the subsequent interface strength tests. The size effect of bamboo fibers on the tensile properties of the BF/EP composites were also studied. The results showed that the tensile strength and Young's modulus of the composite increase with the decrease of the bamboo fiber diameter. For the hygrothermal aging test, BF/EP composites are highly sensitive to moisture absorption, and the moisture has a detrimental effect on the mechanical properties of the BF/EP composite.

The effects of bamboo flour (BF) content on the dynamic rheological properties of BF-filled HDPE composites were investigated. Our findings showed that the addition of BF caused an enhancement of the non-Newtonianism of wood-plastic composites (WPCs) melt as well as the appearance of some new relaxation processes. In addition, the viscosity and modulus of the BF-filled HDPE composites showed a remarkable increase at 170 °C and 190 °C when the BF content exceeded 30%, which could be associated with the solid-like property of the WPCs at high BF loading, we propose. The present study we suggest will be useful to the formula design as well as the optimization of processing parameters for WPCs in general.

A layer of woven E-glass fibre was embedded each at top and bottom layer of bamboo-filled epoxy, producing sandwich-structured hybrid composites. The incorporation of woven glass fibre was intended to slow down the crack propagation in composites. Different bamboo powder loading was applied to analyse its effect on the static and dynamic mechanical properties of composites. The composite with the lowest bamboo powder loading of 10% marked the highest tensile strength, where the strength decreased as the loading increased. Poor bamboo-epoxy adhesion, observed from the SEM, leads to more chances of pull out fibres when tensile load was applied. Opposite trend was observed in flexural strength, where the highest loading of 30% marked the highest value of flexural strength. The dynamic evaluation was carried out with respect to temperature, which ranged from 25°C to 150°C, and at a fixed frequency of 1 Hz. Effective stress transfer between the fibre and the matrix takes place in composites with 30% bamboo powder loading, shown by the lowest peak height of the Tanδ curves. The significant increase in the storage modulus values for the composites at low temperature compared to the rubbery plateau region at high temperature suggested the high utility of the composites at low temperature regardless of the effect of the percentage increment in bamboo powder loading. These results showed that the bamboo powder inclusion helps in bestowing stiffness to the composites with 30% as the optimum percentage in this dynamic mechanical evaluation. It can be suggested that the introduction of woven-typed fibre into short fibre composites in sandwich structure, as discussed in this study, can slow down the failure of composites, and thus notify users before the total failure.

This research studies the analysis of 2” x 4” glued bamboo laminated with Para-timber beam, comparing with 2” x 6” glued Para-timber laminated structure to study the deformation behavior of the two types of timber beams. The method used in testing is Finite Element Analysis: FEM, and in processing the result, Computational Aided Engineering: CAE was used by ANSYS 2020 R2 program to find out the distance of the pillar that affects to the structure of the wood, both in the compression force from the gravity and from the vertical displacement. The study found that 2” x 4” glued bamboo laminated with Para-timber beam can replace 2” x 6” glued laminated Para-timber beam. Although the deformation distance property of Para-timber is 0.33141 mm. (27.96%) less than the glued bamboo laminated with Para-timber, it has the difference in the modulus of elastic value at 84 megapascal, which results in that the undeformed behavior of glued bamboo laminated with Para- timber beam was less than Para-timber. In comparison, 2” x 4” glued bamboo laminated and Para-timber is cheaper, and it is able to reduce the size of the 2” x 6” glued Para-timber laminated to 2” x 4” glued bamboo laminated with Para-timber and still maintains the strength of the structure.

International audience; The objective of this research is to tailor composites with continuous bamboo fibers as reinforcement of a bio-based polyamide (RilsanXD). Using mild chemical and mechanical treatment, technical bamboo fibers were extracted from Phyllostachys viridiglaucescens. They have an average diameter of 397 µm. Their average tensile strength is 323 MPa, and their average Young modulus is 26 GPa. Single ply bamboo fibers/polyamide composites were processed. Gravimetric analyses show that polyamide allows mild processing conditions at 200 °C, therefore permitting to make composites without degrading the fibrous reinforcement. Composites composition was determined from peak analyses of the mass derivative curve associated with bamboo situated at 330 °C. Composites with 60 m % of bamboo fibers were prepared and analyzed. SEM images observation of cryo-cuts shows the absence of voids between technical fibers and polyamide matrix. The cohesion in shear was tested by dynamic mechanical analyses. Comparative data recorded on the bio-based polyamide and the 60/40 bamboo fibers/polyamide composite show a significant improvement of the shear glassy modulus which is multiplied by 1.6 at 20 °C. This result is consistent with the continuity of matter between bamboo fibers and polyamide observed by SEM. This effect may be due to a dense network of static hydrogen bonds.

Bamboo is a functionally graded and axially reinforced material displaying high longitudinal mechanical properties. However, it is prone to longitudinal splitting, mainly due to tensile and shear stress components. Therefore, this experimental study was focused at determining the transverse mechanical properties of five species of bamboo using digital image correlation (DIC). Thus, two tests with parts of rings were used to independently determine the inner and outer circumferential tensile strength as well as the variation of the circumferential Young's modulus through the culm wall. In the first set-up, a semi-ring (SR test) was radially loaded at the middle section and supported on rollers at both ends such that the inner surface of the specimen was under tensile stress. In the second protocol, a specimen bigger than a semi-ring (C test) was loaded by two radially applied compression loads to generate tensile circumferential stresses on the outer surface. A closed-form solution assuming a linear variation of the Young's modulus through the culm wall was developed to analyze the experimental results. The bamboo species Phyllostachys edulis (EDU), Phyllostachys bambusoides (BAM), Phyllostachys Iridescens (IRI), Phyllostachys Violascens (VIO) grown in North of Italy, and Guadua angustifolia (GA) grown in Colombia were tested. The inner tensile failure strain (range of means for all species: 0.014–0.035) was generally higher than the outer (range of means for all species: 0.008–0.0019). The effective modulus of GA (931 MPa–1148 MPa) was lower than those of the European species (range of means for all European species: 1209–2983 MPa). The inner Young's moduli for all species except EDU (796–1694 MPa) was lower than the outer (range of means for all species: 1976–4694 MPa). The trend was different for EDU that showed an outer Young's modulus about 30% lower than the inner modulus. The outer tensile strength of BAM, IRI and GA (range of means for the three species:16.5–30.5 MPa) was significantly higher than the inner (range of means for three species: 9.9–17.6 MPa), while no signficant differences were found for VIO. A different trend was obtained for EDU, for which the inner strength was about three times higher than the outer.

Fiber-reinforced thermosets composites are widely used in engineering fields, but it is difficult to be customized for objects with complex shapes. Photo-curing 3D printing technique can achieve high precision and customization for polymer composites preparation. Herein, we demonstrate a simple and convenient strategy to manufacture biocomposites from micro-scale bamboo fibers (MBFs) and a vinyl palm oil-based resins via photo-curing 3D printing. To improve the dispersion and stability of MBFs in the inks and the interfacial adhesion between fibers and matrix, the MBFs were modified with methacrylic anhydride to endow the fibers with C=C bonds. The modified MBFs could participate in the crosslinking of the bio-based matrix, thus greatly enhancing the mechanical strength and modulus as well as glass transition temperatures of the composites. More importantly, the matrix of the printed bio-based composites can be degraded in a mild condition, which is conducive to the recycle and utilization of fibers.

This research is focused on characterization, modelling and product designing from bamboo fiber reinforced polypropylene composite. Bamboo fiber of mesh size of − 80/+ 100 (180–225 μm) were blended with polypropylene in a twin screw extrusion system at different weight percentages of bamboo (10, 20, 30, 40, and 50%). In-house synthesized m-TMI-g-PP was used as the coupling agent. Mechanical characterization reveals a continuous increment in tensile strength, flexural strength and elastic modulus with increasing fiber content. At 50% bamboo content, tensile and flexural strengths increased by 36 and 64% respectively and elastic modulus increased by 300% with respect to virgin polypropylene. Scanning electron microscope images of the fractured surface of composite indicated effective wetting of bamboo fiber with polypropylene. Halpin–Tsai model was found to describe the relative modulus of the composites at different fiber content effectively. Macro mechanical approach in which the composite is assumed to be isotropic was used to simulate uniaxial tensile test. The simulation was performed using Hypermesh (a FEM preprocessor) and explicit solver LS-DYNA. The stress–strain behaviour predicted by material model MAT 24 was in close agreement with the experimental results. A portable toilet design is suggested from the developed composite material based on the simulation results.

Bamboo scrimbers (BCs) with an optimal resin dosage of 11% were fabricated from Bambusa rigida bamboos with different ages, and their physical–mechanical properties were investigated to determine the proper bamboo age for producing BCs with excellent properties. The anatomical characteristics and physical–mechanical properties of original bamboo were also investigated from bamboo age two to five. The physical–mechanical properties of BCs were highly correlated with the bamboo maturing process regarding the maturing of bamboo fibers. The compressive strength (CS) and horizontal shear strength (HSS) of BCs that were prepared with the 4-year-old bamboo samples were the highest, i.e. 88.3 and 16.2 MPa for the CS and HSS, respectively. The minimum thickness swelling and width swelling (WS) of BCs were found in BCs fabricated from 3-year-old bamboo samples; and the maximum modulus of rapture (MOR) and modulus of elasticity (MOE) of BCs were observed in BCs prepared from 5-year-old bamboo. Considering all factors comprehensively, especially high performance in mechanical strength and water resistant properties of BCs, combined with the lower moisture content of mature green bamboo, the 4-year-old bamboo culms are recommended to be used as raw materials for the preparation of BCs.

Three connection design properties (dowel embedment strength, slip modulus and screw withdrawal capacity) were determined for one species of bamboo (Guadua angustifolia Kunth) using experimental methods adopted from timber engineering. 151 embedment strength and slip modulus tests were undertaken using smooth dowels with diameters ranging from 3 to 16 mm, whilst 240 screw withdrawal tests were undertaken using 3.5–5 mm diameter self-tapping screws. Using regression analysis, predictive equations for the three connection design properties were derived, based on fastener diameter, density and bamboo wall thickness. Coefficients of determination (R2) ranged from 0.45 to 0.82. The predictive equations for embedment strength and screw withdrawal were adapted to output characteristic values and then compared to similar equations derived for timber contained in Eurocode 5, the latter would seem inappropriate for bamboo.

This research aimed to develop a set of practical and straightforward test methods to evaluate the rolling shear properties of cross-laminated bamboo and timber (CLBT) panels. Meanwhile, firsthand experimental data on the shear performance of panels laminated with unidirectional engineered bamboo panels and balsa wood lumbers were reported. The mechanical test results for balsa wood used in the hybrid CLBT panels were given. The bonding line's shear test between the out-layer bamboo panels and core wood was performed through the oblique compression shear test. The rolling shear tests of CLBT panels were performed with the two-plate planer shear test method and short-span bending shear test method. The full strain fields of specimens near ultimate loading conditions were given based on the two-dimensional Digital Image Correlation (DIC) method. This study showed that the rolling shear performance of core wood is determined by the annual ring geometrical parameters of wood products in the RT plane. The mean rolling shear moduli were 43 MPa and 48 MPa for two-plate specimens measured with dial gauges and strains, which is estimated through the Digital Image Correlation (DIC) method. The mean shear strength was 0.96 MPa obtained through two-plate shear tests and 2.50 MPa through the short-span bending shear test. The force corresponding to first-crack development instead of the maximum load is suggested to be adopted to calculate the shear strength of CLBT and other hybrid cross-laminated panels. Relatively small modulus and strength values were noticed for the hybrid panels due to the limited contribution of bamboo layers; thus, reinforcement at the stress-concentration regions was suggested for further researches on such lightweight hybrid cross-laminated panels.

To understand the stress-strain relationship and failure mechanism of bamboo scrimber at elevated temperatures, both parallel and perpendicular to grain properties in tension and compression at temperatures from 20 °C to 270 °C were experimentally studied. A total of 90 tensile coupon specimens and 60 compressive specimens were tested during heating at temperatures ranging from 20 °C to 270 °C. The experimental results indicated that tensile stress-strain relationships of a bamboo scrimber parallel to grain at elevated temperatures were linear from the beginning of loading to failure, and the tensile strength and modulus decreased with increasing the temperature from 20 °C to 270 °C, except at 200 °C. Perpendicular to grain direction, the tensile stress-strain relationships exhibited nonlinear behaviour, and the ultimate strengths were very small. Accordingly, it was observed that the modulus decreased to zero from 20 °C to 180 °C. The compressive stress-strain curves of bamboo scrimber exposed to elevated temperatures were divided into a linear branch and a nonlinear branch beyond proportional limit for both grain directions. The equations with reduction factors for strength and modulus of elasticity were established by regression analysis of the test data. Parallel to grain of a bamboo scrimber, the values from fitting formulas were mostly larger than those from Eurocode 5, and the maximum differences between reduction factors were 0.31, 0.04, 0.23, and 0.24. This study provides a valuable reference for potential application of bamboo scrimber in structural engineering.

This paper explored the effect of adding organic fibers from either bamboo or sugarcane on the mechanical properties of concrete. Cylindrical and prismatic specimens were made containing 2% and 5% v/w (volume to weight) of vegetable fibers to concrete. Following 28 days of curing period, the samples were evaluated for compressive strength, tensile strength using diametric compression, tensile strength during bending and static modulus. It was discovered that all concretes produced met the minimum strength of 20 MPa recommended by NBR 6118 for structural purposes, and it was observed an increase of the compressive strength on the specimens with addition of organic fibers. Moreover, an increase in the compressive strength was observed in the specimens with fiber addition, although no significant variation of water absorption was noticed when compared with the standard concrete. In conclusion, the concrete containing 2% v/w of bamboo fibers showed better mechanical strength and static modulus of elasticity when compared to both concrete with sugar cane fibers addition and the concrete without any additional fibers.

Bamboo is a unique unidirectional biocomposite, which consists of vascular bundles (VBs) as the reinforcement and parenchyma cells (PCs) as the matrix. The non-uniform distribution of VBs embedded in the matrix makes bamboo a functionally graded material. In order to investigate the compressive behavior of bamboo as a function of its components, compression tests were performed on specific bamboo samples with different VB volume fraction (V vb), collected from different positions in the culm wall. The results show that both compressive strength and modulus increased linearly with V vb, while the plastic deformation of samples in the compression decreased with increasing V vb. This indicates that VBs dominate the compressive strength and modulus of bamboo, while the ductile performance of the bamboo is determined by the foam-like PCs. Scanning electron microscope observation indicated that VBs buckling were the main cause of failure. The Euler theory was applied to investigate the buckling behavior of bamboo blocks, showing that theoretical buckling strength when only considering the effect of VBs was much lower than with the test results, with the theoretical buckling strength being closer to test results when considering both the effect of VBs and PCs. It is therefore necessary to consider the contribution of PCs to resist buckling in bamboo, as their foam-like structure can effectively prevent the large-scale buckling of VBs.

Bamboo is a sustainable material with high potential for structural applications. The aim of this study was to use edge bearing tests, digital image correlation analysis, and finite element simulations to research about the distribution of the circumferential elastic modulus through the wall and the associated failure strain and stress. Studied bamboo species were Phyllostachys edulis (Moso), Bambusa stenostachya (Tre Gai) and Guadua angustifolia (Guadua). Using the edge bearing tests, the effective circumferential moduli under compression were similar to those obtained under tension. Mean effective moduli were 1358.5 MPa, 662 MPa, and 862 MPa for bamboo Moso, Tre Gai, and Guadua, respectively. Linear, exponential and parabolic functions that were proposed to represent the circumferential modulus provided a relatively good fitting of the experimental results. Due to the radial gradation, the circumferential moduli at the outer position were 2.3, 1.9, and 2.6 higher than those at the inner location for Moso, Tre Gai, and Guadua, respectively. Mean circumferential failure strains and stresses in the inner culm surface were: 6693 μe and 7.6 MPa; 13137 μe and 12.1 MPa; and 5948 μe and 3.7 MPa for Moso, Tre Gai and Guadua respectively.

Bamboo fibers have excellent mechanical properties, and as such are a popular raw material in papermaking, textile, and various high-tech industries. In this study, the longitudinal mechanical properties of Moso bamboo ( Phyllostachys Heterocycla Var. Pubescens) fiber cell walls during development were systematically investigated via nano-indentation technique at the sub-cellular level. Several influencing factors were also analyzed, particularly the effects of different locations within the vascular bundle and age. The results showed that the longitudinal nano-indentationmodulus (NI modulus) of the 1-month-old bamboo fiber cell walls was relatively high and changed very little in different locations of the vascular bundle, only fluctuating near 22 GPa, while that at the interface between fibers and parenchyma cells (i.e., the edge of the vascular bundle) was smaller and less stable (15.61 GPa on average); nano-indentation hardness (NI hardness) decreased from the center of the vascular bundle to the outside, ranging between 0.4665 and 0.5603 GPa. Age had no significant effect on NI modulus from 1 month to 36 months, while NI hardness did increase with age ( p

The influence of moisture on the mechanical properties of bamboo fibre reinforced composites was assessed both for static and hygroscopic cyclic conditioning. Static conditioning revealed that bamboo fibre reinforced composites show a smaller decrease in Young’s modulus with moisture content than other natural fibre reinforced composites such as for example flax based composites. The behaviour is explained by the chemical composition of the fibre and demonstrated by dynamic mechanical analysis that illustrates how composites made with fibres of high lignin content retain their glass transition temperature in moist conditions. The influence of hygroscopic cycling was also assessed, with emphasis on the influence of the remaining parenchyma on the fibre surface. Clean fibres, are beneficial for the long term behaviour, with less deterioration in properties. Porosity analysis was performed via X-ray computed tomography to provide insight into the material structure of the composite and the effects of hygroscopic cycling. ispartof: Composites Part A - Applied Science and Manufacturing vol:119 pages:48-60 status: published

Four Phyllostachys species grown in Europe were analysed with the aim of extracting long bamboo fibres for composite applications. The morphological characteristics of the plant were determined and compared to the species grown in their native region. Though the species tend to grow smaller, the Phyllostachys vivax showed similar Young’s modulus as the tropical Guadua angustifolia Kunth, i.e. 49 GPa versus 52 GPa. But the strength of all species was 16–44% lower. A chemical analysis of the fibres and an interface study of their composites was performed by analysing the wetting behaviour of the fibres and the chemical composition of their surface. All fibres showed a lignin rich surface, with minor differences in wetting behaviour; therefore difference in the fibre mechanical properties cannot be explained by interface differences. The chemical bulk composition of the fibres was determined as well, and the cellulose content of the fibres showed a linear correlation with the Young’s modulus and strength of the fibres. Seasonal investigation, performed on one selected species, revealed that harvest in autumn or winter lead to higher fibre extraction yields with higher mechanical properties. ispartof: Industrial Crops And Products vol:133 pages:304-316 status: published

This study aims to investigate the void content, tensile, vibration and acoustic properties of kenaf/bamboo fiber reinforced epoxy hybrid composites. The composites were made using the hand lay-up method. The weight ratios of kenaf/bamboo were 30:70, 50:50 and 70:30. Further, kenaf and bamboo composites were fabricated for the purpose of comparison. The hybridization of woven kenaf/bamboo reduced the void content. The void contents of hybrid composites were almost similar. An enhancement in elongation at break, tensile strength and modulus of hybrid composites was observed until a kenaf/bamboo ratio of 50:50. Kenaf/bamboo (50:50) hybrid composite displays the highest elongation at break, tensile strength and modulus compared to the other hybrid composites which are 2.42 mm, 55.18 MPa and 5.15 GPa, respectively. On the other hand, the highest natural frequency and damping factors were observed for Bamboo/Kenaf (30:70) hybrid composites. The sound absorption coefficient of composites were measured in two conditions: without air gap and with air gap (10, 20, 30 mm). The sound absorption coefficient for testing without air gap was less than 0.5. Introducing an air gap improved the sound absorption coefficient of all composites. Hence, hybrid kenaf/bamboo composites exhibited less void content, as well as improved tensile, vibration and acoustic properties.

Bamboo scrimbers (BCs) with excellent performances were made from Bambusa rigida (2 to 5 years old). It was found that BCs made from 3-year-old bamboo have the smallest thickness swelling (TS) and width swelling (WS). BCs prepared from 4-year-old bamboo has the maximum compressive strength (CS) and horizontal shear strength (HSS). The maximum modulus of rapture (MOR) and modulus of elastic (MOE) of BCs were observed in BCs made from bamboo with age of 5 years. Overall, the resin dosage of 11% was optimized to fabricate BCs with different maturing bamboo culms; 4-year-old bamboos were recommended to be used as the raw material for the production of BCs.

Engineered bamboo scrimber has processed from the raw bamboo culm into a compressed or laminated product with thermosetting resin in the density range of 800–1200 kg/m3. The present work investigates the mechanical properties of commercially available engineered bamboo scrimber and compares the results of present work with the existing results in the literature. The main aim of this work is to investigate the influence of bamboo scrimber densities on the mechanical properties. The strength and modulus properties in tensile, compression, shear and flexural were evaluated using the specimens of three different densities. The dynamic modulus of elasticity of bamboo scrimber beams were evaluated using ultra-sonic pulse method. According to the present results it can be concluded that the density have significant influence on the mechanical properties of bamboo scrimber. The long term water absorption was also conducted to analysis the weight gained by the bamboo scrimber having different densities and the results revealed that density of specimen’s influences the water absorption.

Despite the potential of bamboo products for use in construction, they are not yet widely developed owing to a lack of high-quality composites. In the present study, outdoor bamboo-fiber-reinforced composites (OBFRC) were prepared with four different phenol formaldehyde resin concentrations (10, 15, 20, and 25 wt%) using a novel technique, and their water resistance and mechanical properties were evaluated. Resin content significantly affected OBFRC performance. When resin content increased, water resistance increased gradually, shear strength increased initially before decreasing, while compressive strength decreased. There was no significant change in water resistance when resin concentration increased from 20 to 25%, but mechanical properties decreased significantly. Thus, the optimum resin concentration for the prepared OBFRC was 20%. This OBFRC is stronger and has better modulus and water resistance than other similar products, implying that it could be developed as an improved outdoor flooring and building material.

International audience; This work describes the bending and shear mechanical properties of a novel concept of sustainable sandwich panel made from unidirectional prepreg flaxtape skins and bamboo rings as a circular core material. A Design of Experiment (DoE) is used to determine the influence of the bamboo diameter and the type of adhesive bonding between core and skins on the equivalent density, flexural and shear properties of these panels. Numerical analysis are also performed using cohesive surface contacts between skins and bamboo rings to investigate thestructural behaviour and failure mechanisms of the sandwich panels. The equivalent density is affected by both factors, with an overall decrease when larger bamboo rings and lower density adhesive are used. Although sandwich panels with the larger bamboo rings as core showsuperior flexural properties and skin stress, smaller bamboo rings cores shows an increase in the core transverse shear modulus. The physical and mechanical characteristics of the adhesives directly affect the failure mode and the overall structural integrity of the panels.

The objective of this study was to investigate the effect of specimen size on the mechanical properties of bamboo. Single bamboo fibers and bamboo fiber bundles obtained from both chemical retting and mechanical retting were tested. The tensile strength of chemically retted single bamboo fiber was 47.6 % higher than that of the mechanically retted fibers. The tensile strength of the chemically retted fiber bundles was over 2.1 times higher than that of the mechanically retted one, while the tensile modulus was almost 1.4 times higher. For the chemical retting, the fiber bundles were 65.7 % less in tensile strength compared to the single fiber, 12.3 % less for the tensile modulus, and 9.7 % less for the elongation. For the mechanical retting, the tensile strength, tensile modulus and elongation of fiber bundles were 68.8, 52.3 and 60.9 % lower than that of the single fibers, respectively. Compared with single bamboo fibers and bamboo fiber bundles, the tensile strength of bamboo strips was reduced by 67.7 and 3.3 %, respectively. The modulus of bamboo fiber bundles was 42.7 % less compared to the single bamboo fibers, and 16.9 % higher compared to the bamboo fiber bundles. The mechanical properties of bamboo strips were lower than that of samples made from outer portion of the bamboo, but higher than that of samples made from inner portion of the bamboo.

Bending and shear stiffness, which are used as deformation resistance indexes, are very important mechanical properties of bamboo-wood sandwich composites. Thus, a new methodology to calculate the elastic constants of this type of material was proposed in this paper. First, the elastic constants of the composites were derived based on composite mechanics. In particular, the equivalent shear stiffness and modulus were determined by the energy method. Then, the three-point bending test and a revised three-point bending test were used to verify the accuracy of the theoretical model, which uses the properties of the skin and core layers as its input parameters. The model was subsequently evaluated. The results show that, generally, the predicted values were slightly smaller than the test results for the same bamboo-wood composite because of the strengthening of the wood veneer after hot-pressing.

The history of carbon composites dates back to the late 1800s. Thomas Edison used carbon composite filament in light bulbs. A carbon composite is composed of two or more materials to create a superior and unique material. Edison’s carbon composite filaments were made out of cellulose-based materials, such as cotton or bamboo, unlike the petroleum-based precursors used today. It was not until late 1950s that high tensile strength carbon fibers were discovered [1–3]. However, the first truly modulus commercial grade carbon fibers were invented in 1964. The benefits of these high-strength carbon-based composites are that they weighed a fraction of the weight of steel, yet contained much greater tensile strength than steel [4].

This paper was undertaken to evaluate Giant bamboo (Dendrocalamus Asper) which is abundant natural resource that can be considered as an alternative for construction materials for reinforcement to compensate the low tensile property of the concrete. Considering the cost, even though steel reinforcement is a very suitable material for complementing concrete’s low tensile strength, bamboo products as it enter the diverse worldwide markets, the value of these natural resource stands to grow. Bamboo and steel are structural materials with different engineering qualities used for the construction of buildings and other engineering construction related purposes. To overcome these problems, full socio-economic potential of bamboo is yet to be realized as alternative materials to substitute the reinforcing bar in concrete for less important structures by investigating the tensile properties of this type of natural reinforcement. To evaluate these properties, 5 for each bamboo were tested in natural preservation submerged in fresh-water and salt-water for 7 days and 28 days cycles for internode and node section in which tension test was conducted on bamboo specimen following the ASTM standards. From this test, average ultimate tensile strength is approximately 211.18 MPa in the specimens without node for 7 days soaked in salt-water and 138.97 MPa in the specimens with node soaked in fresh water for 28 days. Finally, 7 cycles of wetting and drying in solution of salt-water treated did not increase the bamboo tensile strength neither the Young’s Modulus, therefore, the study concludes that due to the minimal breaking force (FB) of bamboo, it cannot be employed as a main structural member in buildings and other heavy engineering works but can be used for partition walls, ceilings, roofs and other areas of lightweight engineering construction that is not heavy loadbearing capacity.

The bamboo fiber and PVC foam sheet composites were developed via hot compression molding process. Different percentages (0%, 5%, 8%, 12% and 15%) of bamboo fibers were introduced into the PVC foam sheets. Various physical and mechanical properties of the composites have been investigated. Bulk density decreases with the increase of percentage of fibers introduction to the PVC sheets. Percentage of water absorption was found to increases with the soaking time for all the samples. Mechanical properties e.g., tensile strength, flexural stress, flexural strain and tangent modulus of the composites are observed to be increases while the tensile strain decreases with the subsequent fiber addition to the PVC sheets. At the same time, the Young's modulus found to be increased up to 10% of the bamboo fibers introduction and then decreases with the further enhance of the fiber content. The maximum Young's modulus (1250 MPa) was found for 8 % of bamboo fiber to the PVC composite sheets. Thermal analysis confirmed the better thermal stability of bamboo fiber PVC composites.

In this paper, the bamboo-poplar composite oriented strand board (OSB) with different hybrid ratios were aged under the standard of ASTM D1037 to evaluate its weathering performances. The thickness swelling (TS), water absorption, modulus of rapture in perpendicular direction (MOR⊥), modulus of elasticity in perpendicular direction (MOE⊥) and internal bonding (IB) of specimens were tested. The results showed that the reduction rate of TS ranged from 21% to 69%, which increased with the poplar ratio increasing; the growth multiple of 24h water absorption of bamboo-poplar composite OSB were at the similar level, the values of which were much smaller than that of the pure bamboo or poplar OSB; the maximum and minimum retention rate of MOR⊥ and MOE⊥ belonged to pure bamboo and poplar OSB respectively, retention rate of MOR⊥ of the bamboo-poplar composite OSB rose with the increment of poplar ratio, while retention rate of MOE⊥ and IB of bamboo-poplar composite OSB were similar and the hybrid ratio 2.5:7.5(bamboo: poplar) obtained the maximum IB retention rate of 16%. Through detailed comparison, the bamboo-poplar composite OSB with the hybrid ratio 2.5:7.5 performed the best after aging.

Bamboo fibers are very promising reinforcements for polymer composites production due to its high aspect ratio and strong mechanical performances. In order to better understand their reinforcing potential, the mechanical properties of single bamboo fibers extracted from eleven commercial bamboo species in China were measured with a newly developed microtensile technique. For comparison, the mechanical properties of mature single Chinese Fir and Masson Pine wood fibers were measured. The results show that the average longitudinal tensile modulus of the eleven kinds of bamboo fibers ranges from 25.5 to 46.3 GPa with an average value of 36.7 GPa. For tensile strength, the value ranges from 1.20 to 1.93 GPa with an average value of 1.55 GPa. The tensile strength and modulus of bamboo fibers are nearly two times of that of single Chinese Fir and Masson Pine fibers, and significantly higher than most of the published data for other softwood fibers. The average elongation at break of bamboo fibers is about 4.84 %, only a little lower than the value 5.15 % of the tested mature softwood fibers. Additionally, bamboo fibers were found to have smaller diameters and larger aspect ratio than most documented wood fibers, which favored an improved reinforcing effect. These combined mechanical and morphological advantages highlight the potential of bamboo fibers as the reinforcing phase in polymer composites for structural purpose.

The biomaterials with excellent properties such as high strength-weights ratio and so on will inspire inspirations about bionic composite materials to satisfy the scalding hypercriticisms for aerial materials. The investigations of biomaterial mechanical performances are of great advantages in bionic designs and bionic manufactures. The mechanical performances of Bamboo BeetlesOtidognathus Davidis Fairs abdominal shells were tested with a nanoindenter in this paper. The experiments results demonstrated that the harnesses and modulus are different at different test areas. The mechanical performances resemble much at the same latitude but decrease along longitude from the forehead to the rearward, indicating that the mechanical performances of the abdominal shells distribute topologically. Whats more, the topological distributions of mechanical performances illustrate a kind of unlearned structure optimizations of insects which will provide edifications to designs of light and strong materials.

A systematic study has been carried out to investigate the mechanical and physical properties of jute, bamboo and coir (brown and white) single fibers. The tensile properties (tensile strength, Young’s modulus and strain to failure) were determined by varying span length. Scanning electron microscopic analysis was also carried out to determine the physical properties of fibers in order to correlate with its strength, Young’s modulus and strain to failure. The Young’s modulus and strain to failure were corrected using newly developed equations. The study revealed that with increasing test span length the Young’s modulus increased and tensile strength as well as strain to failure decreased. This is because no extensometer could be used in this test set-up and machine displacement (denoted by α) was used for the modulus determination. It is also attributed that larger span length helps to minimize the machine displacement compared to smaller ones due to the reduced relative effect of slippage in the clamps. Among all fibers, the Young’s modulus of bamboo fiber was the highest. Jute fiber had smoother surface compared to other three examined fibers.

Different species of bamboo are extensively used to build houses and temporary structures in developing countries. Few studies have been carried out to establish the elastic constants along the transverse axes which are the weakest directions, making them prone to failure. This is mainly due to the difficulty to cut specimens long enough to accomplish correct circumferential or radial uniaxial tests. A simple test protocol is proposed in this study to determine the radial-circumferential Poisson’s ratio, the circumferential Young’s modulus and the circumferential-axial shear modulus of bamboo using ring specimens. The proposed protocol was used to determine the elastic properties of Guadua angustifolia , which is a species frequently used in structural applications in South America. The radial-circumferential Poisson’s ratios were equal to 0.43, 0.14 and 0.12 for the bottom, middle and top portions of the culm, respectively; the circumferential Young’s modulus was equal to 398 MPa; and the circumferential-axial shear modulus was equal to 581 MPa. These values are within the range reported for different species of bamboo and structural timber. These values could be used to accomplish reliable finite element analyses of joints of bamboo structures. The proposed protocol may be used to determine the anisotropic elastic constants of other species of bamboo.

Fine bamboo strips (BSs) have been laid on polypropylene (PP) web, stacked, and compression molded to prepare unconsolidated light-weight (0.312 g/cm 3 ) composites. Composite properties are superior compared with jute-based composites and bamboo strips show potential to replace fiberglass or polyurethane in composites. Flexural strength, modulus, offset yield load, and Noise Reduction Coefficient (NR) of the BS–PP composites are 5.8×, 2.9×, 6.5×, and 1.4× higher, respectively, compared to jute–PP composites. Bamboo-based non-consolidated composites with excellent mechanical and sound absorption properties utilizing the methods described in this research provide an opportunity to manufacture functional composites with bio-based materials leading to reduction of environmental pollution and sustainable manufacturing.

In this article, three bio-composites, i.e. flax, linen and bamboo fabric reinforced epoxy resin, were manufactured using a vacuum bagging technique. The influence of alkali treatment (with 5 wt% NaOH solution for 30 min) on tensile properties of flax, linen and bamboo single-strand yarns, surface morphology and mechanical properties (with respect to tensile and flexural properties) of the composites were investigated. It was found that the failure mechanism of single-strand fibres under tension consists of fibre breakage and slippage simultaneously. The alkali treatment had a negative effect on the tensile strength and modulus of the flax, linen and bamboo single-strand yarns. However, after the treatment, the tensile and flexural properties of all the composites increased, e.g. the tensile and flexural strength of the treated flax/epoxy composite increased 21.9% and 16.1%, compared to the untreated one. After the treatment in all the composites, the tensile fractured surfaces exhibited an improvement of fibre/epoxy interfacial adhesion.

Bamboo is a typical natural fiber-reinforced composite material with superior mechanical properties. As the reinforce phase in bamboo composite, the vascular bundles were extracted from different height locations of a Moso bamboo with an alkali treatment method, and the mechanical properties were investigated via the tensile test. It is found that both the longitudinal Young’s modulus and strength of the vascular bundles are linearly increased from the inner to outer side. To study the variation of mechanical properties of bamboo culm along the radial direction, thin bamboo slices were also tested. Using a modified rule of mixtures, the longitudinal Young’s modulus of bamboo slices are analyzed and excellent agreement can be found between experimental and theoretical results, which indicates that the longitudinal Young’s modulus of bamboo culm is cubically increased in the radial direction.

In order to understand the basic performances of bamboo yarns, the tensile strength, abrasion resistance and hairiness of yarns are analyzed through the comparison of bamboo yarns, cotton yarns and ramie yarns. Bamboo yarns show a higher strength, a lower breaking elongation, a better abrasive resistance and an obvious hairiness. Because of the existence of uneven fineness, the strength of bamboo yarns display a higher level of unevenness than cotton yarns and ramie yarns. After moisture absorption, the strength, initial modulus and work to break will increase remarkably.

Natural fibers are widely used as “reinforcing agents” in polymer composites. The aim of the current study is to evaluate the effect of span length on the tensile properties of several natural fibers (Vietnamese coir and bamboo and Bangladeshi jute). Tensile testing of jute, bamboo and coir fibers was carried out by varying span length (5, 10, 15, 25 and 35 mm). The Young’s modulus and strain to failure were corrected by using newly developed analytical equations in order to correlate the Young’s modulus and strain to failure of natural fibers. Scanning electron microscopy of the fibers was also carried out. It is clearly observed that the Young’s modulus increased with an increase in span length. Whereas tensile strength and strain to failure decreased with an increase in the span length of single fibers. The correction method resulted in a high Young’s modulus for larger span, while strain to failure found was lower compared to smaller span. This is because larger span length helps to minimize the machine displacement compared to smaller ones. Among all fibers, the Young’s modulus of bamboo fiber was highest, followed by jute and coir respectively. Jute fiber had smoother surface and compact structure compared to other two fibers.

Bamboo is a typical natural fiber reinforced composite material with superior mechanical strength and toughness. As a typical hierarchical material, the macroscopic properties of bamboo are determined by its microscopic structure. The vascular bundles are the reinforce phase in bamboo composite. There was little research on the variation of mechanical properties of bamboo vascular bundles. In this work, the mechanical properties of Moso vascular bundles along the axial direction were investigated by tensile test. It is shown that the longitudinal Young’s modulus and strength of the Moso vascular bundles are linearly increased from inner zone to outer surface.

Woodceramics is made from bamboo powder and epoxy resin. Analysis with X-ray diffraction (XRD) shows that with an increase in sintering temperature, the degree of graphitization increases. Scanning electron microscopic (SEM) analysis also indicates that bamboo powder exists in the composite as natural plant template. The study suggests that both sintering temperature and epoxy resin content have significant effects on its basic properties. Compressive strengths of woodceramics increase as sintering temperature rises but decrease as temperature rises to 1,000°C, and Young’s modulus rises along with higher resin content. Its density increases as sintering temperature rises but decreases as temperature rises further to 1,300°C. The apparent porosity tends to increase with increasing sintering temperature. In addition, elevation of resin content and sintering temperature can reduce electrical resistance, and sintering temperature has greater impact.

In this work, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/bamboo pulp fiber composites were melt-compounded and injection-molded. Tensile, impact and dynamic mechanical properties of the composites were studied. In contrast to many other short natural fiber reinforced biocomposites which demonstrate decreased strain-at-break, impact toughness and tensile strength, the PHBV/bamboo pulp fiber composites displayed increased tensile strength and impact toughness, and maintained/increased strain-at-break. Microscopic study of the fracture surfaces revealed extensive fiber pullout in both tensile and impact tests. The fiber pullout suggests insufficient interfacial adhesion between the fiber and the matrix. The pullout process in the impact testing dissipated a significant amount of energy and hence substantially improved the impact toughness of the composites. With the improved interfacial adhesion provided by coupling agent polymeric diphenylmethane diisocyanate (pMDI), the strength and modulus of the...