Three processing techniques, split-squaring(SS),V-grooving(VG), and split-edging(SE), were evaluated and compared in terms of their processing time and recovery. Semantan bamboo(Gigantochloa scortechinii Gamble) was u...Three processing techniques, split-squaring(SS),V-grooving(VG), and split-edging(SE), were evaluated and compared in terms of their processing time and recovery. Semantan bamboo(Gigantochloa scortechinii Gamble) was used as a raw material and the results showed that the VG-method required the longest processing time(32.1 min), followed by the SS-method(18.2 min), and the SE-method(17.9 min). However, the VG-method showed the highest recovery(82.0%) compared to the SS-method and SE-method, 31.0 and 49.4%, respectively. When both processing time and recovery factors were combined with the same weighing factor, the highest value was recorded with the VG-method(49.1), while the SE-method had values of 31.1 and the SS-method 12.8. The results suggest that the VG-method is the best option. However, the V-grooving machine is still a prototype and therefore the SE-method could be an alternative option until the improved V-grooving machine is available.展开更多
Cross laminated timber(CLT)panels,which are used as load bearing plates and shear panels in timber structures,can serve as roofs,walls and floors.Since timber is construction material with relatively less stiffness,th...Cross laminated timber(CLT)panels,which are used as load bearing plates and shear panels in timber structures,can serve as roofs,walls and floors.Since timber is construction material with relatively less stiffness,the design of such structures is often driven by serviceability criteria,such as deflection and vibration.Therefore,accurate vibration and elastic properties are vital for engineered CLT products.The objective of this research is to explore a method to determine the natural frequencies of orthotropic wood plates efficiently and fast.The method was developed based on vibration signal processing by wavelet to acquire the effective sample data,and a model developed by artificial neural network(ANN)to achieve the prediction of nature frequencies.First,experiments were performed to obtain vibration signals of single-layer plates.The vibration signals were then processed by wavelet packet transform to extract the eigenvectors,which served as the samples to train the ANN model.The trained model was employed to predict three nature frequencies of other test specimens.The results showed that the proposed method can produce predicted frequencies fast and efficiently within 10%of the measured values.展开更多
Stress laminated timber(SLT)deck is assembled using timber(umber or glulam)components placed side by side and stressed together,which has the advantages of easy prefabrication and good cost performance.This work pre-s...Stress laminated timber(SLT)deck is assembled using timber(umber or glulam)components placed side by side and stressed together,which has the advantages of easy prefabrication and good cost performance.This work pre-sented an experimental investigation of bending tests per formed on SLT slabs.Several parameters,including pre-stress levels,distance of pre-stressing bars,and the existence of self tapping screw(STS)reinforcement,were taken into consideration.To reinforce the compressive property of timber perpendicular to the grain,the STSs were placed under the anchor plate of the pre-stressed bars.The experimental results were analyzed and discussed in terms of failure modes,ultimate bearing capacity,ultimate strain,and bending sifness.It was found that the SLT slab showed satisfactory composite action as well as resid ual bearing capacity.The pre stress levels showed an obvious effect on the load bearing capacity and relatively slight effect on the bending stiffness.展开更多
The timber-concrete composite(TCC)slabs have become a preferred choice of floor systems in modern multi story timber buildings.This TCC slab consisted of timber and a concrete slab which were commonly connected togeth...The timber-concrete composite(TCC)slabs have become a preferred choice of floor systems in modern multi story timber buildings.This TCC slab consisted of timber and a concrete slab which were commonly connected together with inclined self-tapping screws(STSs).To more accurately predict the fire performance of TCC slabs,the mechanical behavior of TCC connections under high temperature was investigated by numerical simulation in this study.The interface slip of TCC connections was simulated by a proposed Finite Element(FE)model at room temperature,and different diameter and penetration length screws were considered.The effectiveness of this FE model was validated by comparing with the existing experimental results.Furthermore,the sequentially coupling thermal stress analyses of this model were conducted,and the relationship between the reduction coefficient of connection performance and the effective penetration length of screws was summarized.This study gave the fit-ting expressions for the reduction coefficient of slip modulus and joint strength.Finally,the numerical investiga-tions of the fire performance of TCC slabs considering the char fall-off of Cross Laminated Timber(CLT)were performed to verify the effectiveness of the proposed reduction law.Comparing the fire-resistance time with experimental results showed deviation of the proposed model was−14.02%.展开更多
基金supported by Fundamental Research Grant Scheme(FRGS)Ministry of Higher Education,Malaysia and Higher Institutions’ Centre of Excellence(HICoE)
文摘Three processing techniques, split-squaring(SS),V-grooving(VG), and split-edging(SE), were evaluated and compared in terms of their processing time and recovery. Semantan bamboo(Gigantochloa scortechinii Gamble) was used as a raw material and the results showed that the VG-method required the longest processing time(32.1 min), followed by the SS-method(18.2 min), and the SE-method(17.9 min). However, the VG-method showed the highest recovery(82.0%) compared to the SS-method and SE-method, 31.0 and 49.4%, respectively. When both processing time and recovery factors were combined with the same weighing factor, the highest value was recorded with the VG-method(49.1), while the SE-method had values of 31.1 and the SS-method 12.8. The results suggest that the VG-method is the best option. However, the V-grooving machine is still a prototype and therefore the SE-method could be an alternative option until the improved V-grooving machine is available.
基金supported by National Natural Science Foundation of China(Project No.31660174)Guangxi Innovation-Driven Development Special Fund Project of China(Project No.AA17204087-16)through funding to NSERC Strategic Network on Innovative Wood Products and Building System,by the Natural Sciences and Engineering Research Council of Canada.
文摘Cross laminated timber(CLT)panels,which are used as load bearing plates and shear panels in timber structures,can serve as roofs,walls and floors.Since timber is construction material with relatively less stiffness,the design of such structures is often driven by serviceability criteria,such as deflection and vibration.Therefore,accurate vibration and elastic properties are vital for engineered CLT products.The objective of this research is to explore a method to determine the natural frequencies of orthotropic wood plates efficiently and fast.The method was developed based on vibration signal processing by wavelet to acquire the effective sample data,and a model developed by artificial neural network(ANN)to achieve the prediction of nature frequencies.First,experiments were performed to obtain vibration signals of single-layer plates.The vibration signals were then processed by wavelet packet transform to extract the eigenvectors,which served as the samples to train the ANN model.The trained model was employed to predict three nature frequencies of other test specimens.The results showed that the proposed method can produce predicted frequencies fast and efficiently within 10%of the measured values.
基金This research was sponsored by the National Natural Science Foundation of China(Grant Nos.51878344 and 51578284).
文摘Stress laminated timber(SLT)deck is assembled using timber(umber or glulam)components placed side by side and stressed together,which has the advantages of easy prefabrication and good cost performance.This work pre-sented an experimental investigation of bending tests per formed on SLT slabs.Several parameters,including pre-stress levels,distance of pre-stressing bars,and the existence of self tapping screw(STS)reinforcement,were taken into consideration.To reinforce the compressive property of timber perpendicular to the grain,the STSs were placed under the anchor plate of the pre-stressed bars.The experimental results were analyzed and discussed in terms of failure modes,ultimate bearing capacity,ultimate strain,and bending sifness.It was found that the SLT slab showed satisfactory composite action as well as resid ual bearing capacity.The pre stress levels showed an obvious effect on the load bearing capacity and relatively slight effect on the bending stiffness.
基金This study was funded by National Natural Science Foundation of China(Grant No.5187082769).
文摘The timber-concrete composite(TCC)slabs have become a preferred choice of floor systems in modern multi story timber buildings.This TCC slab consisted of timber and a concrete slab which were commonly connected together with inclined self-tapping screws(STSs).To more accurately predict the fire performance of TCC slabs,the mechanical behavior of TCC connections under high temperature was investigated by numerical simulation in this study.The interface slip of TCC connections was simulated by a proposed Finite Element(FE)model at room temperature,and different diameter and penetration length screws were considered.The effectiveness of this FE model was validated by comparing with the existing experimental results.Furthermore,the sequentially coupling thermal stress analyses of this model were conducted,and the relationship between the reduction coefficient of connection performance and the effective penetration length of screws was summarized.This study gave the fit-ting expressions for the reduction coefficient of slip modulus and joint strength.Finally,the numerical investiga-tions of the fire performance of TCC slabs considering the char fall-off of Cross Laminated Timber(CLT)were performed to verify the effectiveness of the proposed reduction law.Comparing the fire-resistance time with experimental results showed deviation of the proposed model was−14.02%.
