Fibers are used in many forms in engineering applications–one of the most common being used as reinforcement.Due to its renewable short natural growth cycle and abundance of bamboo resources,bamboo fiber has attracte...Fibers are used in many forms in engineering applications–one of the most common being used as reinforcement.Due to its renewable short natural growth cycle and abundance of bamboo resources,bamboo fiber has attracted attention over other natural fibers.Bamboo fiber has a complex natural structure but offers excellent mechanical properties,which are utilized in the textile,papermaking,construction,and composites industry.However,bam-boo fibers can easily absorb moisture and are prone to corrosion limiting their use in engineering applications.Therefore,a better understanding of bamboo fiber is particularly important.This paper reviews all existing research on the mechanical characterization of bamboo fiber with an emphasis on the extraction and treatment techniques,and their effect on relevant properties.The chemical composition of bamboo fibers has also been thoroughly investigated and presented herein.Current applications and future opportunities for bamboo fibers in various fields have been presented with a focus on research needs.This work can serve as a reference for future research on bamboo fiber.展开更多
Over the past decade,the physical and mechanical performances of laminated bamboo lumber(LBL)–a bamboo-based structural material,have been extensively studied using experimental,analytical,and numerical approaches.Th...Over the past decade,the physical and mechanical performances of laminated bamboo lumber(LBL)–a bamboo-based structural material,have been extensively studied using experimental,analytical,and numerical approaches.This paper presents a review of existing knowledge in the literature about the mechanical properties of LBL.The paper involved the review of the response of LBL to different types of loading such as tension,bending,compres-sion,and shear.Based on results of the literature reviewed,the strength of LBL parallel to grain was 90–124 MPa with MOE of 10700 MPa in tension,29.55–72.60 MPa,and MOE of 8396–11022 MPa in compression,63.87–128.4 MPa,and MOE of 8320–10912 MPa in bending,and 7.15–17.5 MPa in shear.The average strength of LBL was similar and in some cases exceeded the average values of bamboo-or wood-based materials,while the variability of its mechanical parameters was lower.The variability in strength values of LBL was affected by bamboo species,density and thickness of bamboo strips,growth portion,type of treatment,strips arrange-ments,and type of adhesive which in turn calls for classification of LBL by strength grades,degree of hardness,the capability of impregnation and penetration,as well as by areas of application in construction.The study pro-vided and discussed concluding observations,the current research gap,and future research directions on the mechanical properties of LBL.展开更多
This paper presents an experimental investigation to identify suitable indices to assess durability of glulam when subjected to freeze-thaw cycles in an exposed enviroenment.In this study,two types of glulam specimens...This paper presents an experimental investigation to identify suitable indices to assess durability of glulam when subjected to freeze-thaw cycles in an exposed enviroenment.In this study,two types of glulam specimens were tested for their performance when subjected to different levels of aging due to freezing and thawing.Effect of aging treatment on various parameters including thickness swelling rate,static bending strength,elastic modulus,shear strength,and peeling rate of adhesive layer were studied.Obtained results showed that freeze-thaw aging treatment did not affect the water-resistance of the specimens as measured by thickness swelling rate and had little effect on the dimensional stability of the material.However,the applied aging treatment weakened the bending resistance of the glulam specimens with more pronounced effects on on low-density wood.On the other hand,bond strength of high-density wood was relatively more affected due to the appliedfreeze-thaw cycles.For highdensity wood,it is suggested that the shear strength of the adhesive layer be taken as an important index to determine the durability of freeze-thaw cycles aging.For low-density wood,on the other hand,the static bending strength can be used as an index to determine the durability of glulam under freeze-thaw cycles aging.展开更多
Fiber reinforced polymer(FRP)has been used in the construction industry because of its advantages such as high strength,light weight,corrosion resistance,low density and high elasticity.This paper presents a review of...Fiber reinforced polymer(FRP)has been used in the construction industry because of its advantages such as high strength,light weight,corrosion resistance,low density and high elasticity.This paper presents a review of bonding techniques adopted to strengthen timber beams using FRP to achieve larger spans.Different methods of bonding between FRP and timber beams have been summarized with a focus on the influencing factors and their effects as well as relevant bond-slip models proposed for fundamental understanding.Experimental investigations to evaluate the flexural performance of timber beams strengthened by FRP bars,sheets and wraps have also been critically reviewed to identify key influencing parameters.Limited research available on the shear performance of FRP reinforced timber beams have been analyzed to determine the influencing factors of the shear performance in timber-FRP beams.The paper finally presents an overall summary of the current-state-of-the-art and proposes some future research directions in the field.展开更多
Cross laminated timber(CLT)is an innovative and environment friendly engineered timber product with superior structural performance.CLT offers strong resistance against both in-plane and out-of-plane loading.Hence,it ...Cross laminated timber(CLT)is an innovative and environment friendly engineered timber product with superior structural performance.CLT offers strong resistance against both in-plane and out-of-plane loading.Hence,it is widely used as floors,roofs or wall elements.Considerable experimental research on CLT under various loading conditions has been done in the recent past.This article presents a comprehensive review of various design methods to determine basic mechanical properties such as tension,compression and rolling shear strength of CLT with primary focus on Norway spruce.All relevant experimental data available from existing literature were collated and consequently been used to evaluate the performance of various methods to design CLT structures.The comparison revealed that different methods show considerable variance in predicting the capacity of CLT panels due to the variation in timber species,which affects the corresponding mechanical properties of the lamella.In addition to species,rolling shear properties can also vary considerably depending on the type of experimental technique used for testing.A predictive model has also been proposed to correlate rolling shear strength obtained from shear analogy method to that obtained using planar shear.展开更多
This article presents an experimental and numerical investigation on the strength and performance of intermediate length rack column sections with C-stitches under axial compression. The test program consisted of 10 a...This article presents an experimental and numerical investigation on the strength and performance of intermediate length rack column sections with C-stitches under axial compression. The test program consisted of 10 axial concentric compression tests on columns with and without C-stitches under pin end conditions for two different geometric lengths. Finite element (FE) models were developed using commercial FE package ABAQUS considering material and geometric nonlinearities as well as initial geometric imperfections. The elastic buckling properties of the section were calculated using readily available linear elastic buckling analysis tools based on Generalized Beam Theory (GBT) and Finite Strip Method (FSM). Obtained FE results were compared with those obtained experimentally, and once verified the developed FE modeling technique was used to carry out a parametric study to examine changes in structural response due to variations in length, depth and spacing of C-stitches. Observed influences of C-stitches on the behavior and resistance of the considered columns were carefully analyzed, and key design aspects are presented herein.展开更多
基金The research work presented in this paper is supported by the National Natural Science Foundation of China(Nos.51878354 and 51308301)the Natural Science Foundation of Jiangsu Province(Nos.BK20181402 and BK20130978)+1 种基金Six Talent Peak High-Level Projects of Jiangsu Province(No.JZ029)Qinglan Project of Jiangsu Higher Education Institutions.Any research results expressed in this paper are those of the writers and do not necessarily reflect the views of the foundations.
文摘Fibers are used in many forms in engineering applications–one of the most common being used as reinforcement.Due to its renewable short natural growth cycle and abundance of bamboo resources,bamboo fiber has attracted attention over other natural fibers.Bamboo fiber has a complex natural structure but offers excellent mechanical properties,which are utilized in the textile,papermaking,construction,and composites industry.However,bam-boo fibers can easily absorb moisture and are prone to corrosion limiting their use in engineering applications.Therefore,a better understanding of bamboo fiber is particularly important.This paper reviews all existing research on the mechanical characterization of bamboo fiber with an emphasis on the extraction and treatment techniques,and their effect on relevant properties.The chemical composition of bamboo fibers has also been thoroughly investigated and presented herein.Current applications and future opportunities for bamboo fibers in various fields have been presented with a focus on research needs.This work can serve as a reference for future research on bamboo fiber.
基金The research work presented in this paper is supported by the National Natural Science Foundation of China(Nos.51878354&51308301)the Natural Science Foundation of Jiangsu Province(Nos.BK20181402&BK20130978)+1 种基金Six Talent Peak High-Level Projects of Jiang su Province(No.JZ029)Qinglan Project of Jiangsu Higher Education Institutions.Any research results expressed in this paper are those of the writers and do not necessarily reflect the views of the foundations.
文摘Over the past decade,the physical and mechanical performances of laminated bamboo lumber(LBL)–a bamboo-based structural material,have been extensively studied using experimental,analytical,and numerical approaches.This paper presents a review of existing knowledge in the literature about the mechanical properties of LBL.The paper involved the review of the response of LBL to different types of loading such as tension,bending,compres-sion,and shear.Based on results of the literature reviewed,the strength of LBL parallel to grain was 90–124 MPa with MOE of 10700 MPa in tension,29.55–72.60 MPa,and MOE of 8396–11022 MPa in compression,63.87–128.4 MPa,and MOE of 8320–10912 MPa in bending,and 7.15–17.5 MPa in shear.The average strength of LBL was similar and in some cases exceeded the average values of bamboo-or wood-based materials,while the variability of its mechanical parameters was lower.The variability in strength values of LBL was affected by bamboo species,density and thickness of bamboo strips,growth portion,type of treatment,strips arrange-ments,and type of adhesive which in turn calls for classification of LBL by strength grades,degree of hardness,the capability of impregnation and penetration,as well as by areas of application in construction.The study pro-vided and discussed concluding observations,the current research gap,and future research directions on the mechanical properties of LBL.
基金the Natural Science Foundation of Jiang-su Province(Grant No.BK20181402)the National Natural Science Foundation of China(Grant No.51878354)+1 种基金a Project Funded by the National First-class Disciplines(PNFD),a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)a Project Funded by the Co-Innovation Center of Efficient Processing and Utilization of Forest Resources,Nanjing Forestry University(Nanjing,China).
文摘This paper presents an experimental investigation to identify suitable indices to assess durability of glulam when subjected to freeze-thaw cycles in an exposed enviroenment.In this study,two types of glulam specimens were tested for their performance when subjected to different levels of aging due to freezing and thawing.Effect of aging treatment on various parameters including thickness swelling rate,static bending strength,elastic modulus,shear strength,and peeling rate of adhesive layer were studied.Obtained results showed that freeze-thaw aging treatment did not affect the water-resistance of the specimens as measured by thickness swelling rate and had little effect on the dimensional stability of the material.However,the applied aging treatment weakened the bending resistance of the glulam specimens with more pronounced effects on on low-density wood.On the other hand,bond strength of high-density wood was relatively more affected due to the appliedfreeze-thaw cycles.For highdensity wood,it is suggested that the shear strength of the adhesive layer be taken as an important index to determine the durability of freeze-thaw cycles aging.For low-density wood,on the other hand,the static bending strength can be used as an index to determine the durability of glulam under freeze-thaw cycles aging.
基金the National Natural Science Foundation of China(Nos.51878354&51308301)the Natural Science Foundation of Jiangsu Province(Nos.BK20181402&BK20130978)+1 种基金Six Talent Peak High-Level Projects of Jiangsu Province(No.JZ029)Qinglan Project of Jiangsu Higher Education Institutions and the Ministry of Housing and Urban-Rural Science Project of Jiangsu Province under Grant No.JS2021ZD10。
文摘Fiber reinforced polymer(FRP)has been used in the construction industry because of its advantages such as high strength,light weight,corrosion resistance,low density and high elasticity.This paper presents a review of bonding techniques adopted to strengthen timber beams using FRP to achieve larger spans.Different methods of bonding between FRP and timber beams have been summarized with a focus on the influencing factors and their effects as well as relevant bond-slip models proposed for fundamental understanding.Experimental investigations to evaluate the flexural performance of timber beams strengthened by FRP bars,sheets and wraps have also been critically reviewed to identify key influencing parameters.Limited research available on the shear performance of FRP reinforced timber beams have been analyzed to determine the influencing factors of the shear performance in timber-FRP beams.The paper finally presents an overall summary of the current-state-of-the-art and proposes some future research directions in the field.
文摘Cross laminated timber(CLT)is an innovative and environment friendly engineered timber product with superior structural performance.CLT offers strong resistance against both in-plane and out-of-plane loading.Hence,it is widely used as floors,roofs or wall elements.Considerable experimental research on CLT under various loading conditions has been done in the recent past.This article presents a comprehensive review of various design methods to determine basic mechanical properties such as tension,compression and rolling shear strength of CLT with primary focus on Norway spruce.All relevant experimental data available from existing literature were collated and consequently been used to evaluate the performance of various methods to design CLT structures.The comparison revealed that different methods show considerable variance in predicting the capacity of CLT panels due to the variation in timber species,which affects the corresponding mechanical properties of the lamella.In addition to species,rolling shear properties can also vary considerably depending on the type of experimental technique used for testing.A predictive model has also been proposed to correlate rolling shear strength obtained from shear analogy method to that obtained using planar shear.
文摘This article presents an experimental and numerical investigation on the strength and performance of intermediate length rack column sections with C-stitches under axial compression. The test program consisted of 10 axial concentric compression tests on columns with and without C-stitches under pin end conditions for two different geometric lengths. Finite element (FE) models were developed using commercial FE package ABAQUS considering material and geometric nonlinearities as well as initial geometric imperfections. The elastic buckling properties of the section were calculated using readily available linear elastic buckling analysis tools based on Generalized Beam Theory (GBT) and Finite Strip Method (FSM). Obtained FE results were compared with those obtained experimentally, and once verified the developed FE modeling technique was used to carry out a parametric study to examine changes in structural response due to variations in length, depth and spacing of C-stitches. Observed influences of C-stitches on the behavior and resistance of the considered columns were carefully analyzed, and key design aspects are presented herein.
