Study on Vertical Bearing Capacity of the Riser Composite Pile in Clay

2018 ◽  
Author(s):  
Liang Chao ◽  
Liu Run ◽  
Wan Jun ◽  
Guan Pei ◽  
Li Xiangyun
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Variable Cross Section ◽  
Small Scale ◽  
Variable Cross ◽  
Pile Diameter ◽  
Composite Pile ◽  
Calculation Results ◽  
S Curve ◽  
Vertical Bearing

In order to meet the development need of small-scale marginal oilfield, it is proposed to use the riser and surface casing to bear the loads replacing or partially replacing the steel pipe pile foundation. In this paper, the vertical bearing behavior of variable cross-section composite pile with the diameter of upper part larger than that of lower part (composed of riser and surface casing) is analyzed by finite element method. Then, the influences of different length combinations and diameter combinations of the composite pile on vertical bearing mechanism are studied, and the characteristics of stress concentration at the variable cross-section are revealed. The calculation results show that the increase in pile diameter, pile length and diameter ratio can effectively improve the bearing capacity of riser composite piles. The vertical ultimate bearing capacity of riser composite piles is greatly affected by upper part and less affected by lower part. The bearing capacity of lower part is gradually exerted, as the plastic zone appears at the end of the upper part, meanwhile, the Q-s curve shows as a broken line, which means that a larger pile top settlement is needed in order to effectively activate the bearing capacity of lower part.

Field Test of DX Pile Group

2011 ◽  
Vol 243-249 ◽  
pp. 2451-2455
Author(s):  
Song Tao Tang ◽  
Li Hong Chen
Keyword(s):  
Bearing Capacity ◽  
Cross Section ◽  
Pile Group ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Test Results ◽  
The Mean ◽  
Engineering Practices ◽  
Pile Length

DX pile is a newly developed variable cross-section pile. Compared to conventional straight pile, it has distinct advantages on bearing capacity and settlement control. However, the bearing mechanism and characteristics of settlement, especially on group DX piles, are not clear. This paper illustrated and analyzed the bearing capacity and settlement characteristics of single DX pile and group DX piles according to the test results of in-situ model test. Special attention was paid on single and group DX pile comparison under same circumstances, at the mean while, compared the single DX pile and conventional pile with the same pile length and diameter, and with the same bearing capacity. The conclusions from the test results provided theoretical references for the design of the DX piles in engineering practices.

Study on Flexible Spin-Up Maneuver with Variable Cross-Section Based on Positional FEM

2014 ◽  
Vol 670-671 ◽  
pp. 834-837
Author(s):  
Lv Zhou Ma ◽  
Yu Qin Yan ◽  
Xun Lin Diao ◽  
Jian Liu
Keyword(s):  
Cross Section ◽  
Mass Matrix ◽  
Variable Cross Section ◽  
Beam Element ◽  
Variable Cross ◽  
Lumped Mass ◽  
Nonlinear Fem ◽  
Calculation Results ◽  
Properties Of Materials ◽  
Consistent Mass Matrix

Based on positional finite element method (FEM) and MATLAB platform, program VBEP (Variable cross-section Beam Element based on Positional FEM) is compiled. Flexible spin-up maneuver is calculated. The calculation results show that positional FEM uses fewer elements and gains higher calculation precision and efficiency when compared with traditional nonlinear FEM, and that calculated quantity using lumped mass matrix is less than using consistent mass matrix about properties of materials under the same calculation precision.

Mechanical Calculation Model for L-Shape Traffic Signs Bar with Variable Cross-Section

2013 ◽  
Vol 444-445 ◽  
pp. 1001-1006
Author(s):  
Ben Ning Qu ◽  
Bang Cheng Yang ◽  
Ran Guo
Keyword(s):  
Cross Section ◽  
Variable Cross Section ◽  
Calculation Model ◽  
Thin Wall ◽  
Variable Cross ◽  
Axial Line ◽  
Traffic Sign ◽  
Cross Sectional ◽  
Bolted Connection ◽  
Calculation Results

L shape traffic sign bar is composed of a stand column and a cantilever bar using bolted connection. The cross-section of stand column and a cantilever bar is closed thin wall with regular octagon and their cross sectional area is variable along axial line. The calculation formulas of stress for cantilever bar, stand column and flange bolts and calculation formulas of deformation for L rod are derived under gravities and wind loads, which provide theoretical basis for the design and use of L-shape bar. Calculation results using these formulas by comparison with finite element calculation results verify the correctness.

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.

Sign in / Sign up

Export Citation Format

Share Document