To extend the service life of the clinched joint,a reconditioning process conducted with an additional tubular rivet was proposed in this work.Different reconditioning forces were employed to produce dissimilar recond...To extend the service life of the clinched joint,a reconditioning process conducted with an additional tubular rivet was proposed in this work.Different reconditioning forces were employed to produce dissimilar reconditioned joints by experimental method.The experimental results indicated that the neck fracture was the common failure mode of both original clinched and reconditioned joints.Compared with the original clinched joint,the shearing strength of the reconditioned joint produced by a reconditioning force of 40 kN increased from 1810.5 to 1986.47 N,and the energy absorption increased from 2.34 to 3.46 J.The range of effective reconditioning force was from 35 to 40 kN and 40 kN was the best choice for reconditioning the AA5052 failed joints.The mechanical properties of the reconditioned joints are obviously better than those of the original clinched joints,which fully demonstrates that the reconditioning method proposed in this work has a broad prospect of industrial application.展开更多
In order to improve the safety of the battery of satellite side mounting,and prevent the screw from producing excess due to frequent assembly and disassembly,the YS-20 material replacement and structure optimization d...In order to improve the safety of the battery of satellite side mounting,and prevent the screw from producing excess due to frequent assembly and disassembly,the YS-20 material replacement and structure optimization design of the screw body are carried out under the premise of not changing the original tooling.The double⁃shear test of YS-20 bar is carried out,and the ANSYS optimization design module is used to design 7×7×6,a total of 294,calculation cases of D1,D2,T,the three important dimension parameters of screw structure.The actual bearing state of screw composite structure is accurately simulated by using asymmetric contact model.Three comprehensive evaluations are established,and the calculation examples satisfying the conditions are evaluated comprehensively.The final results are T=12.2 mm,D1=16 mm,D2=2 mm.The stress verification and contact analysis are carried out for the final scheme and the bearing state and contact state optimized screw structure are obtained.展开更多
Objective: To evaluate the efficacy of Cotrel-Dubeusset （CD） instrumentation combined with translaminar facet joint screw （TLS） in the treatment of thoracolumbar fracture.Methods: A total of six L2-L4 spines were ...Objective: To evaluate the efficacy of Cotrel-Dubeusset （CD） instrumentation combined with translaminar facet joint screw （TLS） in the treatment of thoracolumbar fracture.Methods: A total of six L2-L4 spines were used to establish unstable fracture model with three-dimensional range of motion （ROM） of the spines measured. Fixation with CD and fixation with CD combined with translaminar facet joint screw were achieved to compare their stability. Thirty cases of thoracolumbar fracture, in whom the anterior edge of vertebral body was compressed to 59% and the posterior edge compressed to 88%, were treated by pedicle screw fixation combined with TLS. Among them, 19 received posterolateral or anterior-posterior bone graftingResults: There was significant difference in ROM between the two techniques except that in extension. In Group CD+TLS, ROM was （5.38）% lower, lateral bending （4.91）% lower and axial rotation （11.85）% lower than those in Group CD respectively. In the clinical group, the average anterior edge restored to 97% and posterior edge to 98%. The duration of follow-up was 5-24 months （mean, 10 months）. The rate of correction loss on the anterior edge was （4.5）%. Among the 19 cases of bone grafting, all of them achieved bony fusion （mean fusion time, （4.3） month） with a correction loss rate of （3.4）%.Conclusions: In the treatment of thoracolumbar fracture, pedicle screw fixation combined with TLS can strengthen the stability of pedicle screws, especially anti-rotation stability and enhance fusion rate and reduce correction loss.展开更多
The impact of carbon emission and other pollution generated by the construction industry on the natural environment and ecosystems is immeasurable.Wood,as a renewable building material with excellent performance,is a ...The impact of carbon emission and other pollution generated by the construction industry on the natural environment and ecosystems is immeasurable.Wood,as a renewable building material with excellent performance,is a practical solution for future low-carbon buildings.Current screwed wood connections have good ductility,but the initial stiffness is relatively low.In this paper,composite wood connections with screw and adhesive were proposed and investigated.Static loading tests were conducted to screwed connections and composite connection specimens.The failure modes of different connection types,as well as the effects of adhesive type and adhesive connection area on the joint bearing capacity are discussed.The results show that the yield load and ultimate load of the composite joint made with the existing adhesive increased by up to 169%and 222%,respectively,compared with the screw connection.At the same time,the influence of curing time and bonding should also be taken into consideration.This study provides a foundation for wood joint design and promotes the sustainable development of the building industry.展开更多
基金financial supports from the National Natural Science Foundation of China (No. 51805416)the Young Elite Scientists Sponsorship Program by CAST, China (No. YESS20200279)+3 种基金the Natural Science Foundation of Hunan Province, China (No. 2020JJ5716)the Project of State Key Laboratory of High Performance Complex Manufacturing, Central South University, China (No. ZZYJKT2019-01)the Hunan Provincial Natural Science Foundation for Excellent Young Scholars, China (No. 2021JJ20059)the Huxiang High-Level Talent Gathering Project of Hunan Province, China (No. 2019RS1002)。
文摘To extend the service life of the clinched joint,a reconditioning process conducted with an additional tubular rivet was proposed in this work.Different reconditioning forces were employed to produce dissimilar reconditioned joints by experimental method.The experimental results indicated that the neck fracture was the common failure mode of both original clinched and reconditioned joints.Compared with the original clinched joint,the shearing strength of the reconditioned joint produced by a reconditioning force of 40 kN increased from 1810.5 to 1986.47 N,and the energy absorption increased from 2.34 to 3.46 J.The range of effective reconditioning force was from 35 to 40 kN and 40 kN was the best choice for reconditioning the AA5052 failed joints.The mechanical properties of the reconditioned joints are obviously better than those of the original clinched joints,which fully demonstrates that the reconditioning method proposed in this work has a broad prospect of industrial application.
文摘In order to improve the safety of the battery of satellite side mounting,and prevent the screw from producing excess due to frequent assembly and disassembly,the YS-20 material replacement and structure optimization design of the screw body are carried out under the premise of not changing the original tooling.The double⁃shear test of YS-20 bar is carried out,and the ANSYS optimization design module is used to design 7×7×6,a total of 294,calculation cases of D1,D2,T,the three important dimension parameters of screw structure.The actual bearing state of screw composite structure is accurately simulated by using asymmetric contact model.Three comprehensive evaluations are established,and the calculation examples satisfying the conditions are evaluated comprehensively.The final results are T=12.2 mm,D1=16 mm,D2=2 mm.The stress verification and contact analysis are carried out for the final scheme and the bearing state and contact state optimized screw structure are obtained.
文摘Objective: To evaluate the efficacy of Cotrel-Dubeusset （CD） instrumentation combined with translaminar facet joint screw （TLS） in the treatment of thoracolumbar fracture.Methods: A total of six L2-L4 spines were used to establish unstable fracture model with three-dimensional range of motion （ROM） of the spines measured. Fixation with CD and fixation with CD combined with translaminar facet joint screw were achieved to compare their stability. Thirty cases of thoracolumbar fracture, in whom the anterior edge of vertebral body was compressed to 59% and the posterior edge compressed to 88%, were treated by pedicle screw fixation combined with TLS. Among them, 19 received posterolateral or anterior-posterior bone graftingResults: There was significant difference in ROM between the two techniques except that in extension. In Group CD+TLS, ROM was （5.38）% lower, lateral bending （4.91）% lower and axial rotation （11.85）% lower than those in Group CD respectively. In the clinical group, the average anterior edge restored to 97% and posterior edge to 98%. The duration of follow-up was 5-24 months （mean, 10 months）. The rate of correction loss on the anterior edge was （4.5）%. Among the 19 cases of bone grafting, all of them achieved bony fusion （mean fusion time, （4.3） month） with a correction loss rate of （3.4）%.Conclusions: In the treatment of thoracolumbar fracture, pedicle screw fixation combined with TLS can strengthen the stability of pedicle screws, especially anti-rotation stability and enhance fusion rate and reduce correction loss.
基金the National Natural Science Foundation of China(Grant No.52208270)for supporting this research.
文摘The impact of carbon emission and other pollution generated by the construction industry on the natural environment and ecosystems is immeasurable.Wood,as a renewable building material with excellent performance,is a practical solution for future low-carbon buildings.Current screwed wood connections have good ductility,but the initial stiffness is relatively low.In this paper,composite wood connections with screw and adhesive were proposed and investigated.Static loading tests were conducted to screwed connections and composite connection specimens.The failure modes of different connection types,as well as the effects of adhesive type and adhesive connection area on the joint bearing capacity are discussed.The results show that the yield load and ultimate load of the composite joint made with the existing adhesive increased by up to 169%and 222%,respectively,compared with the screw connection.At the same time,the influence of curing time and bonding should also be taken into consideration.This study provides a foundation for wood joint design and promotes the sustainable development of the building industry.
