A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first- and second-stage cable with tensile ...A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first- and second-stage cable with tensile or bending strain. The contact and friction forces between the strands are presented by two-dimensional contact model. Several theoretical models have been proposed to verify the results when the triplet subjected to the tensile strain, including contact force, contact stresses, and mechanical loss. It is found that loadings will affect the friction force and the mechanical loss of the triplet. The results show that the contact force and mechanical loss are dependent on the twist pitch. A shorter twist pitch can lead to higher contact force, while the trend of mechanical loss with twist pitch is complicated. The mechanical loss may be reduced by adjusting the twist pitch reasonably. The present model provides a simple analysis method to investigate the mechanical behaviors in multistage-structures under different loads.展开更多
The load compensation equipment for anchor cable named low retraction prestressed anchorage system with twice-tension(referred to as twice-tension anchorage system) is proposed in the paper. Calculation results of loo...The load compensation equipment for anchor cable named low retraction prestressed anchorage system with twice-tension(referred to as twice-tension anchorage system) is proposed in the paper. Calculation results of loop anchorage prestressing loss(PL) values of inner lining(IL)in Yellow River-crossing tunnel under two anchorage systems,including twice- tension anchorage system and HM(Chinese transliteration is huanmao)anchorage system,are introduced. The software ANSYS is selected to realize the three-dimensional(3D) finite element modeling to accomplish simulation and calculation works under the two anchorage systems,respectively. Stress processes of IL under the two working conditions,of which one is completed cable tensioning(CCT) and the other is water in the tunnel with the designed water pressure(DWP),are contrasted and analyzed. Impacts of prestressing forces of anchor cables on structural safety under the two anchorage systems are contrasted. The calculation results show that the twice-tension anchorage system can reduce PL effectively and then increase prestresses of wall concrete(WC). Meanwhile,the anchorage system has the advantages of improving security and stability of tunnel structure,reducing project costs and saving steel consumption. The research work is available to related design and construction of anchor cable,and is worthy of promotion and application.展开更多
目的:探讨腹腔镜经腹膜前腹股沟疝修补术(TAPP)对腹股沟疝患者疼痛程度及皮质醇(Cor)、组织金属蛋白酶抑制物-2(TIMP-2)的影响。方法:选取2017年1月—2022年12月常熟市第五人民医院收治的102例腹股沟疝患者。根据随机数表法将其分为观...目的:探讨腹腔镜经腹膜前腹股沟疝修补术(TAPP)对腹股沟疝患者疼痛程度及皮质醇(Cor)、组织金属蛋白酶抑制物-2(TIMP-2)的影响。方法:选取2017年1月—2022年12月常熟市第五人民医院收治的102例腹股沟疝患者。根据随机数表法将其分为观察组和对照组,各51例。对照组给予传统腹股沟疝无张力修补术,观察组给予TAPP。比较两组围手术期指标,术后1 h、6 h、12 h、24 h疼痛程度,术前、术后24 h相关指标及并发症。结果:观察组术中出血量少于对照组,住院时间短于对照组,差异有统计学意义(P<0.05)。两组视觉模拟评分法(VAS)评分组间、时间、交互比较,差异有统计学意义(P<0.05)。与术后1 h比较,两组术后6 h、12 h VAS评分升高,对照组术后24 h VAS评分升高;与术后6 h比较,两组术后12 h、24 h VAS评分降低,与术后12 h比较,两组术后24 h VAS评分降低,观察组术后6 h、12 h、24 h VAS评分低于对照组,差异有统计学意义(P<0.05)。术后24 h,两组Cor水平升高,TIMP-2水平降低,观察组TIMP-2、Cor水平均低于对照组,差异有统计学意义(P<0.05)。观察组并发症发生率低于对照组,差异有统计学意义(P<0.05)。结论:与传统腹股沟疝无张力修补术比较,TAPP治疗腹股沟疝可减少术中出血量,缩短住院时间,缓解患者的疼痛感,调节Cor、TIMP-2水平,并且降低患者术后并发症发生率。展开更多
基金supported by National Natural Science Foundation of China (Grants 11202087, 11472120, 11421062)the National Key Project of Scientific Instrument and Equipment Development (Grant 11327802)+1 种基金the National Key Project of Magneto-Constrained Fusion Energy Development Program (Grant 2013GB110002)New Century Excellent Talents in University of Ministry of Education of China (Grant NCET-13-0266)
文摘A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first- and second-stage cable with tensile or bending strain. The contact and friction forces between the strands are presented by two-dimensional contact model. Several theoretical models have been proposed to verify the results when the triplet subjected to the tensile strain, including contact force, contact stresses, and mechanical loss. It is found that loadings will affect the friction force and the mechanical loss of the triplet. The results show that the contact force and mechanical loss are dependent on the twist pitch. A shorter twist pitch can lead to higher contact force, while the trend of mechanical loss with twist pitch is complicated. The mechanical loss may be reduced by adjusting the twist pitch reasonably. The present model provides a simple analysis method to investigate the mechanical behaviors in multistage-structures under different loads.
基金National Natural Science Foundation of China(No.51079107)Fundamental Research Funds for the Central Universities(No.5082022)
文摘The load compensation equipment for anchor cable named low retraction prestressed anchorage system with twice-tension(referred to as twice-tension anchorage system) is proposed in the paper. Calculation results of loop anchorage prestressing loss(PL) values of inner lining(IL)in Yellow River-crossing tunnel under two anchorage systems,including twice- tension anchorage system and HM(Chinese transliteration is huanmao)anchorage system,are introduced. The software ANSYS is selected to realize the three-dimensional(3D) finite element modeling to accomplish simulation and calculation works under the two anchorage systems,respectively. Stress processes of IL under the two working conditions,of which one is completed cable tensioning(CCT) and the other is water in the tunnel with the designed water pressure(DWP),are contrasted and analyzed. Impacts of prestressing forces of anchor cables on structural safety under the two anchorage systems are contrasted. The calculation results show that the twice-tension anchorage system can reduce PL effectively and then increase prestresses of wall concrete(WC). Meanwhile,the anchorage system has the advantages of improving security and stability of tunnel structure,reducing project costs and saving steel consumption. The research work is available to related design and construction of anchor cable,and is worthy of promotion and application.
文摘目的:探讨腹腔镜经腹膜前腹股沟疝修补术(TAPP)对腹股沟疝患者疼痛程度及皮质醇(Cor)、组织金属蛋白酶抑制物-2(TIMP-2)的影响。方法:选取2017年1月—2022年12月常熟市第五人民医院收治的102例腹股沟疝患者。根据随机数表法将其分为观察组和对照组,各51例。对照组给予传统腹股沟疝无张力修补术,观察组给予TAPP。比较两组围手术期指标,术后1 h、6 h、12 h、24 h疼痛程度,术前、术后24 h相关指标及并发症。结果:观察组术中出血量少于对照组,住院时间短于对照组,差异有统计学意义(P<0.05)。两组视觉模拟评分法(VAS)评分组间、时间、交互比较,差异有统计学意义(P<0.05)。与术后1 h比较,两组术后6 h、12 h VAS评分升高,对照组术后24 h VAS评分升高;与术后6 h比较,两组术后12 h、24 h VAS评分降低,与术后12 h比较,两组术后24 h VAS评分降低,观察组术后6 h、12 h、24 h VAS评分低于对照组,差异有统计学意义(P<0.05)。术后24 h,两组Cor水平升高,TIMP-2水平降低,观察组TIMP-2、Cor水平均低于对照组,差异有统计学意义(P<0.05)。观察组并发症发生率低于对照组,差异有统计学意义(P<0.05)。结论:与传统腹股沟疝无张力修补术比较,TAPP治疗腹股沟疝可减少术中出血量,缩短住院时间,缓解患者的疼痛感,调节Cor、TIMP-2水平,并且降低患者术后并发症发生率。
