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Experimental Study of Mode-I and Mode-II Interlaminar Fracture Characteristics of Poplar LVL

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Journal of Renewable Materials 2023年第1期11卷 245-255页

作者： Zhongping Xiao Chen Li biqing shu shukai Tang Xinghuan Yang Yan Liu College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China College of Civil Science and Engineering Yangzhou UniversityYangzhou225127China

Fracture is a common failure form of poplar laminated veneer lumber(LVL).In the present work,we performed an experimental study on the mode-I along-grain interlaminar fracture,mode-I cross-grain interlaminar fracture,and mode-II interlaminar fracture of poplar *** investigated stress mechanisms,failure modes,and fracture toughness values of the different fracture *** experimental results revealed that the crack in the mode-I along-grain interlaminar fracture specimen propagated along the prefabricated crack direction,and the crack tip *** mode-I cross-grain interlaminar fracture specimen had cracks in the vertical direction near the prefabricated *** the mode-II interlaminar fracture specimen,cracks appeared along the initial prefabricated crack *** load–displacement curves of these three specimens were linear in the early stage of *** the increase in the load,a nonlinear segment appeared before crack propagation and a descending segment appeared after crack *** nonlinear segments of the mode-I along-grain interlaminar fracture and mode-II interlaminar fracture were very short,and cracks expanded quickly after their initiation,resulting in brit-tle *** nonlinear segment of the mode-I cross-grain interlaminar fracture was long,resulting in plastic *** average toughness values of the mode-I along-grain interlaminar fracture,mode-I cross-grain inter-laminar fracture,and mode-II interlaminar fracture were 15.43,270.15,and 39.72 MPa·mm^(1/2),respectively.

关键词： Poplar LVL crack propagation fracture toughness

Study on the Bonding Performance of the Moso Bamboo Dowel Welded to a Poplar Substrate Joint by High-Speed Rotation

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Journal of Renewable Materials 2021年第7期9卷 1225-1237页

作者： Suxia Li Haiyang Zhang biqing shu Liangsong Cheng Zehui Ju Xiaoning Lu College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Furniture and Art Design Central South University of Forestry and TechnologyChangsha410004China College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China

The wood friction welding technique with its high bonding strength,low cost,high efficiency,and without any adhesive has been increasing concern in *** bamboo(Phyllostachys pubescens)and poplar(Populus sp.)are widely planted and used in the furniture industry,interior decoration,and wood structure construction in *** aim of this work was to investigate the bonding performance of moso bamboo dowel rotation welded joints with different dowel/receiving hole diameter *** results indicated that the ratio of dowel/receiving hole diameter was an important parameter that influenced the welding *** bonding strength of the bamboo-to-poplar welded joints at the optimal ratio of 10/7 was as high as 7.50 MPa,which was higher than that of the beech(Fagus sylvatica,L.),schima(Schima superba)dowels and PVAc glued *** temperature measurement results showed a peak temperature of bamboo dowel welding as high as 350–360°*** differences in the temperature curves between each dowel/hole diameter ratio group were observed at the three different hole depths,such as the friction time,peak temperatures,and stabilization time at the maximum temperature,which could explain the differences in welding strengths between different *** SEM results showed the temperature-induced softening,melting and flowing of cell-interconnected polymer material in the wood and bamboo struc*** addition,the bamboo fibers(mainly vascular bundles)were wrapped to form a dense continuous bonding layer,similar to the reinforced concrete,thus producing a good bonding *** Fourier transform-infrared spectroscopy(FT-IR)analyses showed that the high temperature resulted in the increase of the lignin relative content due to the degradation reaction of cellulose in the welding zone,which improved the bonding properties.

关键词： Moso bamboo rotation welding tensile strength optimal ratio poplar

Improving the Properties of Fast-Growing Chinese Fir by Vacuum Hot Pressing Treatment

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Journal of Renewable Materials 2021年第1期9卷 49-59页

作者： Lu Hong biqing shu Qian He Zehui Ju Haiyang Zhang Xiaoning Lu College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China

Chinese fir was compressed by vacuum hot pressing and conventional hot pressing at different temperatures(180℃,200℃ and 220℃),*** color parameters of the heat-compressed sample were measured,the relative mechanical properties of the material were tested and changes in the chemistry of fir were investigated using Fourier transform infrared spectroscopy(FTIR)and Xray photoelectron spectroscopy(XPS).The results indicated that the color difference between compressed and untreated wood increased gradually with the increase of *** with the conventional hot pressing treatment,the color difference(ΔE*)of the Chinese fir treated by vacuum hot pressing decreased by 43.73%,69.91%,and 77.17%,*** mechanical properties(bending elastic modulus and bending strength)of Chinese fir treated by vacuum hot pressing were significantly *** 24-hour water absorption thickness expansion rate of fir treated by vacuum hot pressing is smaller than that of conventional hot *** is implied that vacuum hot pressing treatment is an effective method to produce compressed wood,which can improve the mechanical properties and dimensional stability of wood,and reduce the influence of carbonization on wood color.

关键词： Chinese fir vacuum hot pressing color mechanical properties dimensional stability

Review on the Application of Bamboo-Based Materials in Construction Engineering

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Journal of Renewable Materials 2020年第10期8卷 1215-1242页

作者： biqing shu Zhongping Xiao Lu Hong Sujun Zhang Chen Li Naiqiang Fu Xiaoning Lu The College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China

Due to the continuously increasing demand for building materials across the world,it is necessary to use renewable materials in place of the existing nonrenewable materials in construction *** is a fast-growing flowering plant that may be used as a renewable material in *** use of bamboo in the construction of buildings can improve its long-term carbon fixation capacity and economic *** bamboo has the advantages of superior performance,low carbon content,high energy-saving and emission-reducing capacity,bamboo is an anisotropic material,which has many factors affecting its material performance,large variability of material performance,lack of systematic research,and the use of bamboo as the main building material is not always *** paper systematically summarizes the research status of bamboo as a building material from the aspects of bamboo composition,gradation,material properties,bamboo building components,connection nodes,and use of artificial *** this basis,some constructive suggestions are put forward for the further study of bamboo in the field of architecture.

关键词： Bamboo building element connection node glue-laminated bamboo bamboo scrimber binderless plywood

Structure Design and Properties of Three-Layer Particleboard Based on High Voltage Electrostatic Field(HVEF)

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Journal of Renewable Materials 2021年第8期9卷 1433-1445页

作者： Man Yuan Lu Hong Zehui Ju Wenli Gu biqing shu Jianxin Cui Xiaoning Lu Zhiqiang Wang College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China

In this study,the effects of three different particle sizes of wood wastes(A=–8+12 mesh;B=–12+20 mesh;C=–20+30 mesh)and factory shavings(D)on the properties of particleboard were *** to the test results,three-layer particleboard was *** face layers made with mixture of A,B,and *** core layer made with *** ratio of core layer to face layers is 50:***-layer particleboard were fabricated with 12%urea-formaldehyde(UF)resins and three different high voltage electrostatic field intensities(0 kv,30 kv,60 kv).The internal bond(IB)strength,modulus of rupture(MOR),modulus of elasticity(MOE),thickness swelling(TS),and water absorption(WA)of particleboard were *** density distribution of the three-layer particleboard were examined by vertical density profiles(VDP),and the bonding mechanism and functional groups changes in the particles were analyzed by FTIR *** results showed that HVEF treatment intensity play a remarkable role in properties of *** particleboard with higher electrostatic field intensities treatment has higher MOE,MOR,IB,and *** HVEF treatment(60 kv),the MOR,modulus of MOE,and IB of three-layer particleboard were 23.61 N/mm^(2),2787.09 N/mm^(2),and 0.86 N/mm^(2),*** indicated that the surface activity of wood particles was increased electric field treatment.

关键词： High voltage electric field three-layer particleboard physical property mechanical property

Study on the Tangential Tensile Mechanical Properties of Moso Bamboo

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Journal of Renewable Materials 2022年第8期10卷 2203-2216页

作者： biqing shu Lu Hong Suxia Li Yupeng Tao Jianxin Cui Naiqiang Fu Junbao Yu Chen Li Xiaoning Lu The College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China School of Forestry and Landscape Anhui Agricultural UniversityHefei230036China College of Furniture and Art Design Central South University of Forestry and TechnologyChangsha410004China

In this work,we used tensile tests to analyze the tangential failure forms of raw bamboo and determine a relationship between tangential tensile strength,elastic modulus,position,density,and moisture *** found that the tangential mechanical properties of the culm wall were mainly dependent on the mechanical properties of the basic structure of the thin *** for calculating the tangential tensile strength of moso bamboo and adjusting the moisture content were also *** tangential tensile strength and the tangential tensile modulus of elasticity(TTMOE)followed:outer>middle>inner,and diaphragm>bamboo node>culm *** the fiber saturation point,the tangential tensile strength and TTMOE values of the bamboo gradually decreased with increasing moisture *** the moisture content was 15%,the tangential tensile strengths of the inner,middle,outer,culm wall,bamboo node,and diaphragm samples of the five-year-old moso bamboo were 3.17,3.29,3.31,3.24,3.67,and 8.85 MPa,***,their TTMOE values were 215.09,227.98,238.45,224.04,267.21,and 559.27 MPa,***,this study provides a theoretical basis for future research on bamboo cracking.

关键词： Engineering raw bamboo moso bamboo tangential tensile strength tangential tensile modulus of elasticity bamboo cracking

Effect of Steam Explosion Technology Main Parameters on Moso Bamboo and Poplar Fiber

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Journal of Renewable Materials 2021年第3期9卷 585-597页

作者： biqing shu Qin Ren Lu Hong Zhongping Xiao Xiaoning Lu Wenya Wang Junbao Yu Naiqiang Fu Yiming Gu Jinjun Zheng The College of Materials Science and Engineering Nanjing Forestry UniversityNanjing210037China College of Civil Engineering Yangzhou Polytechnic InstituteYangzhou225127China

One of the large-scale industrial applications of Moso bamboo and poplar in China is the production of standardized *** making fiberboard,a steam blasting pretreatment without the addition of traditional adhesives has become increasingly popular because of its environmental friendliness and wide *** this study,the steam explosion pretreatment of Moso bamboo and poplar was *** steam explosion pressure and holding time were varied to determine the influence of these factors on fiber quality by investigating the morphology of the fiber,the mass ratio of the unexploded specimen at the end face,the chemical composition,and the tensile *** following conclusions were drawn:As the steam burst pressure and holding time increased,more cellulose and hemicellulose degradation occurred(the degradation of hemicellulose was greater than that of cellulose),the lignin content rose,and the fiber bundle strength *** degradation of bamboo cellulose was slightly higher than that of poplar,and the degradation of poplar hemicellulose was significantly faster than that of ***,increasing the steam explosion pressure and pressure holding time could not effectively increase the lignin *** is recommended to use a steam blasting pressure of 2.5 MPa or 3.0 MPa and a holding time of 180 s to perform steam blasting on bamboo and poplar specimens.

关键词： Fiber binderless fiberboard steam explosion moso bamboo poplar

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某排架结构厂房的检测鉴定及加固

工业建筑 2014年第6期44卷 139-142页

作者：束必清郑娟扬州工业职业技术学院江苏扬州225127 扬州市职业大学江苏扬州225009

通过对某单层单跨双坡排架结构厂房进行现场检测、结构计算和分析研究,发现其主要问题为钢筋混凝土柱的承载能力不满足规范要求,确定其可靠性为四级,已不能正常使用,须立即采取加固措施。经多方案比较,最终采用外包钢加固技术对混凝土... 详细信息

通过对某单层单跨双坡排架结构厂房进行现场检测、结构计算和分析研究,发现其主要问题为钢筋混凝土柱的承载能力不满足规范要求,确定其可靠性为四级,已不能正常使用,须立即采取加固措施。经多方案比较,最终采用外包钢加固技术对混凝土柱进行了加固,并对现场一些缺陷进行了修复处理,取得了良好的效果。经过处理,厂房的可靠性被鉴定为一级,满足了正常使用要求,避免了厂房的拆除重建,节省了大量的社会资源。

关键词：排架结构检测鉴定加固

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热处理工艺对微合金建筑用钢力学性能的影响

热加工工艺 2016年第16期45卷 186-189页

作者：郑娟葛文杰束必清扬州市职业大学土木工程学院江苏扬州225000 扬州大学建筑科学与工程学院江苏扬州225127 扬州工业职业技术学院建筑工程学院江苏扬州225127

设计了微合金建筑用钢的成分,研究了热处理工艺对微合金建筑用钢力学性能和组织的影响。结果表明:1035℃开轧、805℃终轧且在800℃进行正火处理,此时力学性能最佳,其抗拉强度为562 MPa、屈服强度为470 MPa、伸长率为22.6%,屈强比为0.84... 详细信息

设计了微合金建筑用钢的成分,研究了热处理工艺对微合金建筑用钢力学性能和组织的影响。结果表明:1035℃开轧、805℃终轧且在800℃进行正火处理,此时力学性能最佳,其抗拉强度为562 MPa、屈服强度为470 MPa、伸长率为22.6%,屈强比为0.84。600℃回火前后的显微硬度分别为175 HV0.1和189 HV0.1。

关键词：热处理工艺合金建筑钢力学性能显微结构