A novel forming method of nickel based super-alloy thin-walled part with variable diameter sections was proposed by using inner and outer pressure with the visco-elasto-plastic pressure-carrying medium at room tempera...A novel forming method of nickel based super-alloy thin-walled part with variable diameter sections was proposed by using inner and outer pressure with the visco-elasto-plastic pressure-carrying medium at room temperature,and the principle of the method was provided.Experiments and FE simulations were carried out to analyze the deformation characteristics for the part with larger variable diameter ratio(35%).The results show that visco-elasto-plastic pressure-carrying medium can meet the requirements of the room-temperature deformation condition for nickel based super-alloy sheet.The inner and outer pressure forming with the visco-elasto-plastic pressure-carrying medium can meet the requirements of dimensional accuracy for the thin-walled part with variable diameter sections.The thinning of wall-thickness is less than 4%.This method provides a new approach for near-net shape forming of nickel based super-alloy thin-walled parts with variable diameter sections.展开更多
Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large de...Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large deformation of the part into inner and outer pressure forming deformations, the limit deformation of tube part can be increased by several times. Meanwhile, the principle of viscous inner and outer pressure forming was provided, and key problems during the forming process such as reduction of the wall-thickness and instability wrinkling were analyzed. Thereby, the complex curved surface super-alloy GH3044 thin-walled tube with varying diameter ratio of 1.35（the ratio between the maximum and minimum diameters of the part） can be integrally formed by this method. The experimental surface of the formed part is superior in quality and the wall-thickness distribution is uniform. The results show that the viscous inner and outer pressure forming can provide a new approach for integral forming of thin-walled tubes with complex shapes.展开更多
Taking a section of the Ming Dynasty Outer City Wall from Xianhe Gate to Qilin Gate for example, this paper proposed the landscape design from the perspective of experience tourism, highlighted the wal, and took the b...Taking a section of the Ming Dynasty Outer City Wall from Xianhe Gate to Qilin Gate for example, this paper proposed the landscape design from the perspective of experience tourism, highlighted the wal, and took the beautiful environment and rich history and cultures of the Ming Dynasty Outer City Wall as the essential experience elements, to build cultural recreational corridors with the theme of "experiencing the Ming Dynasty culture", so that visitors will get unforgettable experience, tourism quality, popularity of the Ming Dynasty Outer City Wall as well as its cultural and educational significance will be further promoted.展开更多
The pre-multiplied spanwise energy spectra of streamwise velocity fluctuations are investigated in this paper. Two distinct spectral peaks in the spanwise spectra are observed in low-Reynolds-number wall-bounded turbu...The pre-multiplied spanwise energy spectra of streamwise velocity fluctuations are investigated in this paper. Two distinct spectral peaks in the spanwise spectra are observed in low-Reynolds-number wall-bounded turbulence. The spectra are calculated from direct numerical simulation （DNS） of turbulent channel flows and zero-pressure-gradient boundary layer flows. These two peaks locate in the nearwall and outer regions and are referred to as the inner peak and the outer peak, respectively. This result implies that the streamwise velocity fluctuations can be separated into large and small scales in the spanwise direction even though the friction Reynolds number Rer can be as low as 1000. The properties of the inner and outer peaks in the spanwise spec- tra are analyzed. The locations of the inner peak are invariant over a range of Reynolds numbers. However, the locations of the outer peak are associated with the Reynolds number, which are much higher than those of the outer peak of the pre-multiplied streamwise energy spectra of the streamwise velocity.展开更多
目的:研究微创股骨近端防旋髓内钉(proximal femoral nail antirotation,PFNA)对外侧壁完整型和危险型股骨转子间骨折的预后。方法:回顾性分析92例股骨转子间骨折患者资料,根据术前股骨X线片及CT扫描结果分为外侧壁完整型(52例)和外侧...目的:研究微创股骨近端防旋髓内钉(proximal femoral nail antirotation,PFNA)对外侧壁完整型和危险型股骨转子间骨折的预后。方法:回顾性分析92例股骨转子间骨折患者资料,根据术前股骨X线片及CT扫描结果分为外侧壁完整型(52例)和外侧壁危险型(40例),2组均经过PFNA手术治疗。结果:外侧壁完整型组的术中出血量、术后首次下床活动时间、住院时间、骨折愈合时间、末次随访时髋关节屈伸活动度及Harris评分均显著优于外侧壁危险型(P<0.05)。结论:微创PFNA用于外侧壁完整型股骨转子间骨折的治疗,具有Harris评分优良率高、骨折愈合和负重所需时间短等优点。展开更多
文摘A novel forming method of nickel based super-alloy thin-walled part with variable diameter sections was proposed by using inner and outer pressure with the visco-elasto-plastic pressure-carrying medium at room temperature,and the principle of the method was provided.Experiments and FE simulations were carried out to analyze the deformation characteristics for the part with larger variable diameter ratio(35%).The results show that visco-elasto-plastic pressure-carrying medium can meet the requirements of the room-temperature deformation condition for nickel based super-alloy sheet.The inner and outer pressure forming with the visco-elasto-plastic pressure-carrying medium can meet the requirements of dimensional accuracy for the thin-walled part with variable diameter sections.The thinning of wall-thickness is less than 4%.This method provides a new approach for near-net shape forming of nickel based super-alloy thin-walled parts with variable diameter sections.
基金Funded by the National Natural Science Foundation of China(No.51205260)
文摘Aiming at overcoming the difficulties in integral forming of thin-walled tubes with complex shapes, a novel forming method by inner and outer pressure through viscous was proposed. In this method, by dividing large deformation of the part into inner and outer pressure forming deformations, the limit deformation of tube part can be increased by several times. Meanwhile, the principle of viscous inner and outer pressure forming was provided, and key problems during the forming process such as reduction of the wall-thickness and instability wrinkling were analyzed. Thereby, the complex curved surface super-alloy GH3044 thin-walled tube with varying diameter ratio of 1.35（the ratio between the maximum and minimum diameters of the part） can be integrally formed by this method. The experimental surface of the formed part is superior in quality and the wall-thickness distribution is uniform. The results show that the viscous inner and outer pressure forming can provide a new approach for integral forming of thin-walled tubes with complex shapes.
基金Sponsored by Youth Program of National Natural Science Foundation of China(41601131)Youth Program of Humanistic and Social Science Research,Ministry of Education(15YJC790092)Nanjing Scientific and Technological Innovation Team Program“Tourism Geography(Wel ness Tourism)”
文摘Taking a section of the Ming Dynasty Outer City Wall from Xianhe Gate to Qilin Gate for example, this paper proposed the landscape design from the perspective of experience tourism, highlighted the wal, and took the beautiful environment and rich history and cultures of the Ming Dynasty Outer City Wall as the essential experience elements, to build cultural recreational corridors with the theme of "experiencing the Ming Dynasty culture", so that visitors will get unforgettable experience, tourism quality, popularity of the Ming Dynasty Outer City Wall as well as its cultural and educational significance will be further promoted.
基金supported by the National Natural Science Foundation of China (Grants 11302238, 11232011, 11572331, and 11490551)the support from the Strategic Priority Research Program (Grant XDB22040104)+1 种基金the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences (Grant QYZDJ-SSW-SYS002)the National Basic Research Program of China (973 Program 2013CB834100 : Nonlinear Science)
文摘The pre-multiplied spanwise energy spectra of streamwise velocity fluctuations are investigated in this paper. Two distinct spectral peaks in the spanwise spectra are observed in low-Reynolds-number wall-bounded turbulence. The spectra are calculated from direct numerical simulation （DNS） of turbulent channel flows and zero-pressure-gradient boundary layer flows. These two peaks locate in the nearwall and outer regions and are referred to as the inner peak and the outer peak, respectively. This result implies that the streamwise velocity fluctuations can be separated into large and small scales in the spanwise direction even though the friction Reynolds number Rer can be as low as 1000. The properties of the inner and outer peaks in the spanwise spec- tra are analyzed. The locations of the inner peak are invariant over a range of Reynolds numbers. However, the locations of the outer peak are associated with the Reynolds number, which are much higher than those of the outer peak of the pre-multiplied streamwise energy spectra of the streamwise velocity.
文摘目的:研究微创股骨近端防旋髓内钉(proximal femoral nail antirotation,PFNA)对外侧壁完整型和危险型股骨转子间骨折的预后。方法:回顾性分析92例股骨转子间骨折患者资料,根据术前股骨X线片及CT扫描结果分为外侧壁完整型(52例)和外侧壁危险型(40例),2组均经过PFNA手术治疗。结果:外侧壁完整型组的术中出血量、术后首次下床活动时间、住院时间、骨折愈合时间、末次随访时髋关节屈伸活动度及Harris评分均显著优于外侧壁危险型(P<0.05)。结论:微创PFNA用于外侧壁完整型股骨转子间骨折的治疗,具有Harris评分优良率高、骨折愈合和负重所需时间短等优点。
