The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the typ...The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.展开更多
A systematic, accurate and robust evaluating method for fine pitch printed circuit board （PCB） positioning assessment in testing fixture is developed. Targeting reliability of bed-of-nails tester is successfully eva...A systematic, accurate and robust evaluating method for fine pitch printed circuit board （PCB） positioning assessment in testing fixture is developed. Targeting reliability of bed-of-nails tester is successfully evaluated by the 2D pattern transform. Probe offset vector with its Weibull and Gaussian distribution estimates are obtained for further investigation about the causes of misalignment on the basis of a batch tests for same kind of PCBs.展开更多
Fractures of long bones are commonly treated with intramedullary (IM) nails and they have been shown to have a very high success rate. Recently we have concerns with the use of the newer IM nailing systems, that uses ...Fractures of long bones are commonly treated with intramedullary (IM) nails and they have been shown to have a very high success rate. Recently we have concerns with the use of the newer IM nailing systems, that uses longer cross screws, which have been developed with variation in implant designs. We believe that the newer implants provide less fracture stability, due to decreased stiffness of the IM nailing system. The aim of this study was to biomechanically determine the influence of the length of cross screw on the stiffness of the IM nailing system, using a composite model. Our test results confirmed our suspicion that the newer IM nailing system using longer cross screw-length is less stiff than traditional nailing systems using shorter cross screw length, during axial loading.展开更多
研发了一种装配式外伸钢管土钉,对黏性土中外伸爪片长度为20 cm, 25 cm, 30 cm的装配式外伸钢管土钉与普通钢管土钉进行抗拉性能对比试验,分析了其受力性能的差异以及外伸爪片长度对土钉受力性能的影响。通过有限元建模模拟对基坑开挖...研发了一种装配式外伸钢管土钉,对黏性土中外伸爪片长度为20 cm, 25 cm, 30 cm的装配式外伸钢管土钉与普通钢管土钉进行抗拉性能对比试验,分析了其受力性能的差异以及外伸爪片长度对土钉受力性能的影响。通过有限元建模模拟对基坑开挖后土钉的轴力分布特点进行了分析。分析结果表明,在该次试验外伸爪片长度的范围内,装配式外伸钢管土钉极限抗拔承载力均高于相同尺寸的普通钢管土钉,且土钉抗拔力随外伸爪片长度的增加而增大。随着外伸爪片长度的增加,装配式外伸钢管土钉的最大轴应力值也有所提高,土钉支护的整体稳定安全系数也随之增大。展开更多
文摘The pull-out capacities for soil nailing systems comprising of one single 29 mm diameter(type A) and four 16 mm diameter(type B) rebars with grouted cement were examined.A field test and numerical analysis for the type A and type B systems were carried out to investigate the pull-out capacities and the slope stability reinforcement efficiency in soil and rock slopes.The results of the pull-out tests show the mobilized shear force and load transfer characteristics with respect to soil depth.The load-displacement relationship was examined for both type A and type B systems.Slope stability analyses were carried out to study the relationships between soil and nail reinforcement and bending stiffness as well as combined axial tension and shear forces.Factors of safety were calculated in relation to the number of nails and their outside diameters.Both soil and rock slopes were included in this evaluation.
基金This project is supported by US Pennsylvania Dept. of Community & Economic Development(No.20-906-0015)National Natural Science Foundation of China(No.50390064, No.50575230)National Basic Research Program of China(973 Program, No.2003CB716202).
文摘A systematic, accurate and robust evaluating method for fine pitch printed circuit board （PCB） positioning assessment in testing fixture is developed. Targeting reliability of bed-of-nails tester is successfully evaluated by the 2D pattern transform. Probe offset vector with its Weibull and Gaussian distribution estimates are obtained for further investigation about the causes of misalignment on the basis of a batch tests for same kind of PCBs.
文摘Fractures of long bones are commonly treated with intramedullary (IM) nails and they have been shown to have a very high success rate. Recently we have concerns with the use of the newer IM nailing systems, that uses longer cross screws, which have been developed with variation in implant designs. We believe that the newer implants provide less fracture stability, due to decreased stiffness of the IM nailing system. The aim of this study was to biomechanically determine the influence of the length of cross screw on the stiffness of the IM nailing system, using a composite model. Our test results confirmed our suspicion that the newer IM nailing system using longer cross screw-length is less stiff than traditional nailing systems using shorter cross screw length, during axial loading.
文摘研发了一种装配式外伸钢管土钉,对黏性土中外伸爪片长度为20 cm, 25 cm, 30 cm的装配式外伸钢管土钉与普通钢管土钉进行抗拉性能对比试验,分析了其受力性能的差异以及外伸爪片长度对土钉受力性能的影响。通过有限元建模模拟对基坑开挖后土钉的轴力分布特点进行了分析。分析结果表明,在该次试验外伸爪片长度的范围内,装配式外伸钢管土钉极限抗拔承载力均高于相同尺寸的普通钢管土钉,且土钉抗拔力随外伸爪片长度的增加而增大。随着外伸爪片长度的增加,装配式外伸钢管土钉的最大轴应力值也有所提高,土钉支护的整体稳定安全系数也随之增大。
