http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Yiqun Zhou (검색결과 4 건)
- 무료
- 기관 내 무료
- 유료
-
A novel numerical approach for workspace determination of parallel mechanisms
Yiqun Zhou,Junchuan Niu,Zhihui Liu,Fuliang Zhang 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.6
In this paper, a novel numerical approach is proposed for workspace determination of parallel mechanisms. Compared with the classicalnumerical approaches, this presented approach discretizes both location and orientation of the mechanism simultaneously, not onlyone of the two. This technique makes the presented numerical approach applicable in determining almost all types of workspaces, whiletraditional numerical approaches are only applicable in determining the constant orientation workspace and orientation workspace. Thepresented approach and its steps to determine the inclusive orientation workspace and total orientation workspace are described in detail. A lower-mobility parallel mechanism and a six-degrees-of-freedom Stewart platform are set as examples, the workspaces of thesemechanisms are estimated and visualized by the proposed numerical approach. Furthermore, the efficiency of the presented approach isdiscussed. The examples show that the presented approach is applicable in determining the inclusive orientation workspace and totalorientation workspace of parallel mechanisms with high efficiency.
-
Yiqun Tang,Siqi Xiao,Jie Zhou 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.3
Artificial ground freezing method, is a popular technique applied in coastal soft soil area for underground engineering construction. This method can bring some side effects, like frost heave and thaw settlement, due to the water migration in soil during freezing-thawing process. A self-designed one-dimensional freezing apparatus is used to study the deformation performance of the reconstituted soft clay from Shanghai 4th layer during freezing-thawing process. Test results show that total frost heave amount increases with decreasing boundary freezing temperature while it remains with the variation of initial water content in the test. The deformation of multilayers during freezing process reveals compression phenomenon due to the water migration in the soil samples. The compression area is the main part contributed to thaw settlement. Besides, a prediction model is established with void ratio as a variable to connectfrost-heave model with thaw-settlement model. FDM (Finite Difference Method) method is used for computation through compiling code in MATLAB software. Comparison shows that compression phenomenon is necessary to be considered when calculating thaw settlement. This study provides valuable reference to the deformation control of soil in the construction of artificial ground freezing.
-
Seepage Effects of Sequence Strata on Artificial Ground Freezing and Surrounding Environment
( Jie Zhou ),( Yiqun Tang ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2
Almost all cross passages of subway tunnels, underground pumping houses, in and out tunnels in shield tunneling, cross-river or ocean tunnels in soft soil area, and even engineering accident fast repairs involve Artificial Ground Freezing (AGF) in China. Nowadays, the coastal extreme hydro-geological environment brings new problems and challenges to AGF. This paper uses scale model experiments to study the seepage effects on artificial ground freezing and surrounding environment by a typical sequence strata design of large seepage boundary of underlying sands and overlying frost sensitive soft clay. Freezing temperatures, frost heave forces, residual water contents, surface settlements under different seepage velocities within model soils are measured. Results show that when the seepage velocity is within 3m/d, the seepage increases the influence of heat convection on the heat transfer of the soil, but the heat transfer is still the main heat transfer mode of the soil. This provides a theoretical implication reference for multi-field coupled numerical simulation analysis of AGF involved seepage environment. The seepage weakens the effect of latent heat influence, that is, the phase transition equilibrium time is shortened, and linearly decreases with the increase of the seepage velocity. In addition, seepage has adverse effects of prolonging the freezing time and causing uneven settlement; even though it also reduces frost heave force, minish surface settlement and the amount of latent heat of soils, at the same time it slows the rate of thaw, and increases the time of the settlement process, which is also disadvantageous in practical engineering.
-
Wenbo Sun,Yiqun Luo,Weijian Zhou,Wei Huang 국제구조공학회 2012 Steel and Composite Structures, An International J Vol.13 No.3
Concrete filled steel tubular (CFST) member has been widely used in the construction of highrise buildings for its high axial bearing capacity. It can also be applied on long-span structures such as spatial structures or bridges not only for its high bearing capacity but also for its construction convenience. Concrete casting effect of CFST member is considered in the study of its bearing capacity in this paper. Firstly, in order to authenticate the applicability of constitutive relationship and yield criterion of steel and concrete based on FEM, two ANSYS models are built to simulate and compared with other’s test. Secondly, in order to find the huge difference in bearing capacity due to different construction processes, two full-size CFST models are studied when they are horizontally cast and axially compressed. Finally, the effects of slenderness ratio (L/D) and confining parameter (D/t) of CFST members are studied to reveal the intrinsic links between bearing capacity and slenderness ratio or confining parameter.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
