Study on Drifting Drilling Assembly and Casing String’s Stiffness Ratio

2011 ◽  
Vol 339 ◽  
pp. 583-589
Author(s):  
Xiao Dong Zhang ◽  
Ru Yi Gou ◽  
Hong Jun Liang ◽  
Yan Gong ◽  
Ping Xiao
Keyword(s):  
Computer Program ◽  
Calculation Method ◽  
Focal Point ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Stiffness Ratio ◽  
Conservation Of Energy ◽  
Assembly Design ◽  
Ratio Calculation ◽  
Deep Well

Drilling technology of ultra-deep well is still the focal point of drilling research, there are many difficulties in ultra-deep well drilling, such as bottom hole with high temperature and high pressure, complex geology, borehole with sharp dogleg, etc. These technical difficulties put forward higher request in casing running, well quality must be controlled strictly in order to run larger diameter combination casing string successfully. Well quality is closely linked with the drifting drilling assembly design. The accurate stiffness ratio calculation is the key prerequisite of drifting drilling assembly design. In this paper, a new mechanical model is applied to simulate deflection of the drifting drilling assembly. The solution of variable cross-section beam’s equivalent stiffness is applied to solve the stiffness of the drifting drilling assembly. Modified stiffness ratio calculation method for drifting drilling assembly and casing string is proposed. In the process of calculation formula derivation, the conservation of energy law has been used multiple times. At last, the VB computer program is compiled, which contains the modified calculation method. The computer program calculation value is larger than the conventional method’s calculation value. Modified calculation method is more reasonable, which has important significance for drifting drilling assembly optimal design.

The Calculation Method of Axial Force in the Calculation of the Boom Tower Crane Stability

2013 ◽  
Vol 372 ◽  
pp. 305-308
Author(s):  
Bin Li ◽  
Li Ze Xu ◽  
Xin Tao ◽  
Jiu Fu Jin ◽  
Yan Zhang
Keyword(s):  
Cross Section ◽  
Axial Force ◽  
Calculation Method ◽  
Variable Cross Section ◽  
Negative Stiffness ◽  
Variable Cross ◽  
Constant Cross Section ◽  
Equivalent Stiffness ◽  
Tower Crane ◽  
Stiffness Method

The concept of equivalent stiffness and equivalent negative stiffness is introduced in this paper, established the equivalent relationship between the force acting on the middle of variable cross-section column and the force acting on the top of constant cross-section column on boom tower crane lifting plane and slewing plane by the equivalent stiffness law and the equivalent negative stiffness method, The force on the middle of column is converted into the force on the top of column by the equivalent relationship.

scholarly journals Torsional vibration of suspension bridge with a variable cross section

1981 ◽  
Vol 3 (2) ◽  
pp. 22-26
Author(s):  
Nguyen Van Tinh
Keyword(s):  
Computer Program ◽  
Transfer Matrix ◽  
Cross Section ◽  
Cross Sections ◽  
Torsional Vibration ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Suspension Bridge ◽  
Variable Cross Section ◽  
Variable Cross

The transfer matrix method to torsion’ al vibrations of a suspension bridge with variable cross sections is reported. The method described above is particularly suitable for implementing an efficient computer program. A numerical example is also givens.

Boundary element method in numerical study of three-dimensional Stokes flows in channels of arbitrary shape

2012 ◽  
Vol 9 (1) ◽  
pp. 94-97
Author(s):  
Yu.A. Itkulova
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Cross Section ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cylindrical Tube ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Periodic Flows ◽  
Element Method

In the present work creeping three-dimensional flows of a viscous liquid in a cylindrical tube and a channel of variable cross-section are studied. A qualitative triangulation of the surface of a cylindrical tube, a smoothed and experimental channel of a variable cross section is constructed. The problem is solved numerically using boundary element method in several modifications for a periodic and non-periodic flows. The obtained numerical results are compared with the analytical solution for the Poiseuille flow.

Longitudinal oscillation of a rod with a variable cross section

2019 ◽  
Vol 14 (2) ◽  
pp. 138-141
Author(s):  
I.M. Utyashev
Keyword(s):  
Cross Section ◽  
Natural Frequencies ◽  
Liouville Problem ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Independent Functions ◽  
The Cross ◽  
The Right

Variable cross-section rods are used in many parts and mechanisms. For example, conical rods are widely used in percussion mechanisms. The strength of such parts directly depends on the natural frequencies of longitudinal vibrations. The paper presents a method that allows numerically finding the natural frequencies of longitudinal vibrations of an elastic rod with a variable cross section. This method is based on representing the cross-sectional area as an exponential function of a polynomial of degree n. Based on this idea, it was possible to formulate the Sturm-Liouville problem with boundary conditions of the third kind. The linearly independent functions of the general solution have the form of a power series in the variables x and λ, as a result of which the order of the characteristic equation depends on the choice of the number of terms in the series. The presented approach differs from the works of other authors both in the formulation and in the solution method. In the work, a rod with a rigidly fixed left end is considered, fixing on the right end can be either free, or elastic or rigid. The first three natural frequencies for various cross-sectional profiles are given. From the analysis of the numerical results it follows that in a rigidly fixed rod with thinning in the middle part, the first natural frequency is noticeably higher than that of a conical rod. It is shown that with an increase in the rigidity of fixation at the right end, the natural frequencies increase for all cross section profiles. The results of the study can be used to solve inverse problems of restoring the cross-sectional profile from a finite set of natural frequencies.

scholarly journals Theoretical and Experimental Studies on MEMS Variable Cross-Section Cantilever Beam Based Piezoelectric Vibration Energy Harvester

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 772
Author(s):  
Xianming He ◽  
Dongxiao Li ◽  
Hong Zhou ◽  
Xindan Hui ◽  
Xiaojing Mu
Keyword(s):  
Power Density ◽  
Cantilever Beam ◽  
Cross Section ◽  
Energy Harvester ◽  
Variable Cross Section ◽  
Vibration Energy ◽  
Variable Cross ◽  
Vibration Energy Harvester ◽  
Piezoelectric Vibration Energy Harvester ◽  
Piezoelectric Vibration

The piezoelectric vibration energy harvester (PVEH) based on the variable cross-section cantilever beam (VCSCB) structure has the advantages of uniform axial strain distribution and high output power density, so it has become a research hotspot of the PVEH. However, its electromechanical model needs to be further studied. In this paper, the bidirectional coupled distributed parameter electromechanical model of the MEMS VCSCB based PVEH is constructed, analytically solved, and verified, which laid an important theoretical foundation for structural design and optimization, performance improvement, and output prediction of the PVEH. Based on the constructed model, the output performances of five kinds of VCSCB based PVEHs with different cross-sectional shapes were compared and analyzed. The results show that the PVEH with the concave quadratic beam shape has the best output due to the uniform surface stress distribution. Additionally, the influence of the main structural parameters of the MEMS trapezoidal cantilever beam (TCB) based PVEH on the output performance of the device is theoretically analyzed. Finally, a prototype of the Aluminum Nitride (AlN) TCB based PVEH is designed and developed. The peak open-circuit voltage and normalized power density of the device can reach 5.64 V and 742 μW/cm3/g2, which is in good agreement with the theoretical model value. The prototype has wide application prospects in the power supply of the wireless sensor network node such as the structural health monitoring system and the Internet of Things.

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