Starling with the L- and D,L-lactide copolymer (L:DL = 9:1) [P(L-DL)LA] of M-W = 32.1 x 10(4), rods were obtained through a two stage process: (1) melt-extrusion at 155 degreesC, and (2) hot-drawing at 90 degreesC to ...Starling with the L- and D,L-lactide copolymer (L:DL = 9:1) [P(L-DL)LA] of M-W = 32.1 x 10(4), rods were obtained through a two stage process: (1) melt-extrusion at 155 degreesC, and (2) hot-drawing at 90 degreesC to various drawing ratios. The molecular weight of P(L-DL)LA fell to 9.3 x 10(4) as a consequence of the production process. The crystallization and molecular orientation of P(L-DL)LA developed as a result of the hot-drawing. The mechanical strengths of the rods increase with the drawing ratio; The maximum for tensile strength, bending strength, bending modulus, and shear strength are 329 MPa, 237 MPa, 8.8 GPa, and 157 MPa, respectively.展开更多
The woody structural elements represent a significant portion of old works and historical buildings,and the need for retrofit and strengthening them increases.Glued-in rods are an efficient way of providing stiff,high...The woody structural elements represent a significant portion of old works and historical buildings,and the need for retrofit and strengthening them increases.Glued-in rods are an efficient way of providing stiff,high-capacity connections in timber structures.Those flexible joint systems have the advantages of high load transition,appropriate behavior in case of fire,easy application combined with a high level of prefabrication for fast installation.Besides,the aesthetic appearance of the finished joint also plays an important role.Many experiments were undertaken on this subject in Europe,but a common database about the designing instructions of glued-in rods was never encouraged.This paper aims at summarizing the different factors that can affect repairs made with glued-in rods and their influence on said repairs.展开更多
文摘Starling with the L- and D,L-lactide copolymer (L:DL = 9:1) [P(L-DL)LA] of M-W = 32.1 x 10(4), rods were obtained through a two stage process: (1) melt-extrusion at 155 degreesC, and (2) hot-drawing at 90 degreesC to various drawing ratios. The molecular weight of P(L-DL)LA fell to 9.3 x 10(4) as a consequence of the production process. The crystallization and molecular orientation of P(L-DL)LA developed as a result of the hot-drawing. The mechanical strengths of the rods increase with the drawing ratio; The maximum for tensile strength, bending strength, bending modulus, and shear strength are 329 MPa, 237 MPa, 8.8 GPa, and 157 MPa, respectively.
文摘The woody structural elements represent a significant portion of old works and historical buildings,and the need for retrofit and strengthening them increases.Glued-in rods are an efficient way of providing stiff,high-capacity connections in timber structures.Those flexible joint systems have the advantages of high load transition,appropriate behavior in case of fire,easy application combined with a high level of prefabrication for fast installation.Besides,the aesthetic appearance of the finished joint also plays an important role.Many experiments were undertaken on this subject in Europe,but a common database about the designing instructions of glued-in rods was never encouraged.This paper aims at summarizing the different factors that can affect repairs made with glued-in rods and their influence on said repairs.
