In order to establish the design method for T-shaped tensile connector with high strength bolt,the theoretical analysis is carried out. Firstly,it analyzes the performance of the connector and establishes prying force...In order to establish the design method for T-shaped tensile connector with high strength bolt,the theoretical analysis is carried out. Firstly,it analyzes the performance of the connector and establishes prying force calculation model. Based on the model,prying force equation and function between bolt prying force and flange thickness is derived,and the min and max thickness requirement of flange plate under a certain tension load is then obtained. Finally,two simplified design methods of the connector are proposed,which are bolt pulling capacity method and flange plate bending capacity method.展开更多
Steel connection design using pre-tensioned bolts depends significantly on the value of the Prying forces exerted from the end plate. The Egyptian Code ECP （205） suggested a formula that can determine the Prying for...Steel connection design using pre-tensioned bolts depends significantly on the value of the Prying forces exerted from the end plate. The Egyptian Code ECP （205） suggested a formula that can determine the Prying force value. In this research, the Prying force is numerically computed in a T-Stub connection using nonlinear finite element techniques. The model uses plane stress four node elements with two degrees of freedom per node to simulate the flange of the T-Stub. The bolts are simulated using a truss element with large deformation capability to allow modeling of the pretension force. Surface to surface gap elements are used in order to simulate the contact between the T-Stub and the supporting element. Parametric study on the end plate thickness, bolt size, bolt arrangement and pretension forces is performed in order to calibrate the Code formula. The parametric study covers all the practical ranges of the variables. The study revealed that the Code formula, inaccurately, determines the Prying force in a certain range. Moreover, a new equation for the prying force is developed using regression analysis on the finite element results.展开更多
目的:探讨弯钳撬拔术在股骨近端髓内钉(proximal femoral nail antirotation,PFNA)内固定治疗难复性股骨粗隆间骨折中的应用效果。方法:选择2021年6月—2023年5月在罗定市中医院接受手术治疗的难复性股骨粗隆间骨折患者144例,用随机数...目的:探讨弯钳撬拔术在股骨近端髓内钉(proximal femoral nail antirotation,PFNA)内固定治疗难复性股骨粗隆间骨折中的应用效果。方法:选择2021年6月—2023年5月在罗定市中医院接受手术治疗的难复性股骨粗隆间骨折患者144例,用随机数字表法将患者分为对照组(n=72,接受切开复位PFNA内固定治疗)、观察组(n=72,接受弯钳撬拔PFNA内固定治疗)。对比两组手术基本情况、骨折愈合情况、髋关节功能评分、并发症发生情况。结果:两组手术时间比较,差异无统计学意义(P>0.05);观察组术中出血量较对照组少,差异有统计学意义(P<0.05)。观察组术后住院时间、负重开始时间、骨折愈合时间均较对照组短,差异均有统计学意义(P<0.05)。术后6个月,观察组髋关节功能评分较对照组高,差异有统计学意义(P<0.05)。两组术后6个月的髋关节功能优良率比较,差异无统计学意义(P>0.05)。两组并发症发生率比较,差异无统计学意义(P>0.05)。结论:弯钳撬拔PFNA内固定治疗难复性股骨粗隆间骨折较切开复位PFNA内固定治疗更具优势,在促进术后骨折愈合、恢复患侧髋关节功能方面的作用均较理想,且不会增加并发症,是一种优质的手术模式。展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.51408620)the Major Science and Technology Project during the Third Five-Year Plan Period of China MCC(Grant No.0012013010)
文摘In order to establish the design method for T-shaped tensile connector with high strength bolt,the theoretical analysis is carried out. Firstly,it analyzes the performance of the connector and establishes prying force calculation model. Based on the model,prying force equation and function between bolt prying force and flange thickness is derived,and the min and max thickness requirement of flange plate under a certain tension load is then obtained. Finally,two simplified design methods of the connector are proposed,which are bolt pulling capacity method and flange plate bending capacity method.
文摘Steel connection design using pre-tensioned bolts depends significantly on the value of the Prying forces exerted from the end plate. The Egyptian Code ECP （205） suggested a formula that can determine the Prying force value. In this research, the Prying force is numerically computed in a T-Stub connection using nonlinear finite element techniques. The model uses plane stress four node elements with two degrees of freedom per node to simulate the flange of the T-Stub. The bolts are simulated using a truss element with large deformation capability to allow modeling of the pretension force. Surface to surface gap elements are used in order to simulate the contact between the T-Stub and the supporting element. Parametric study on the end plate thickness, bolt size, bolt arrangement and pretension forces is performed in order to calibrate the Code formula. The parametric study covers all the practical ranges of the variables. The study revealed that the Code formula, inaccurately, determines the Prying force in a certain range. Moreover, a new equation for the prying force is developed using regression analysis on the finite element results.
文摘目的:探讨弯钳撬拔术在股骨近端髓内钉(proximal femoral nail antirotation,PFNA)内固定治疗难复性股骨粗隆间骨折中的应用效果。方法:选择2021年6月—2023年5月在罗定市中医院接受手术治疗的难复性股骨粗隆间骨折患者144例,用随机数字表法将患者分为对照组(n=72,接受切开复位PFNA内固定治疗)、观察组(n=72,接受弯钳撬拔PFNA内固定治疗)。对比两组手术基本情况、骨折愈合情况、髋关节功能评分、并发症发生情况。结果:两组手术时间比较,差异无统计学意义(P>0.05);观察组术中出血量较对照组少,差异有统计学意义(P<0.05)。观察组术后住院时间、负重开始时间、骨折愈合时间均较对照组短,差异均有统计学意义(P<0.05)。术后6个月,观察组髋关节功能评分较对照组高,差异有统计学意义(P<0.05)。两组术后6个月的髋关节功能优良率比较,差异无统计学意义(P>0.05)。两组并发症发生率比较,差异无统计学意义(P>0.05)。结论:弯钳撬拔PFNA内固定治疗难复性股骨粗隆间骨折较切开复位PFNA内固定治疗更具优势,在促进术后骨折愈合、恢复患侧髋关节功能方面的作用均较理想,且不会增加并发症,是一种优质的手术模式。
