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,...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 LVL.We investigated stress mechanisms,failure modes,and fracture toughness values of the different fracture types.The 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 broke.The mode-I cross-grain interlaminar fracture specimen had cracks in the vertical direction near the prefabricated crack.In the mode-II interlaminar fracture specimen,cracks appeared along the initial prefabricated crack direction.The load–displacement curves of these three specimens were linear in the early stage of loading.With the increase in the load,a nonlinear segment appeared before crack propagation and a descending segment appeared after crack propagation.The 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 fracture.The nonlinear segment of the mode-I cross-grain interlaminar fracture was long,resulting in plastic failure.The 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.展开更多
The stress-strain relation of laminated veneer lumber (LVL) was established by the method of regression, and its constitutive equation at large deformation and constant loading conditions was given to predict the stat...The stress-strain relation of laminated veneer lumber (LVL) was established by the method of regression, and its constitutive equation at large deformation and constant loading conditions was given to predict the static mechanical behaviors of LVL.展开更多
基金the National Natural Science Foundation of China(Grant No.51878590)the Jiangsu Provincial Department of Housing and Construction(Grant Nos.2019ZD092,2020ZD40,2020ZD42)the Sixth Phase of“333 Project”Training Objects in Jiangsu Province and Jiangsu Province High-Level Talent Selection Training(Grant No.JNHB-127)for their financial support.
文摘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 LVL.We investigated stress mechanisms,failure modes,and fracture toughness values of the different fracture types.The 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 broke.The mode-I cross-grain interlaminar fracture specimen had cracks in the vertical direction near the prefabricated crack.In the mode-II interlaminar fracture specimen,cracks appeared along the initial prefabricated crack direction.The load–displacement curves of these three specimens were linear in the early stage of loading.With the increase in the load,a nonlinear segment appeared before crack propagation and a descending segment appeared after crack propagation.The 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 fracture.The nonlinear segment of the mode-I cross-grain interlaminar fracture was long,resulting in plastic failure.The 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.
文摘The stress-strain relation of laminated veneer lumber (LVL) was established by the method of regression, and its constitutive equation at large deformation and constant loading conditions was given to predict the static mechanical behaviors of LVL.
