The Transmission Tower with Angles Composed by the Variable Cross-Section is Studied Modal Analysis and Secondary Stress

2014 ◽  
Vol 680 ◽  
pp. 391-394
Author(s):  
Li Qin ◽  
Guo Rong Yu
Keyword(s):  
Modal Analysis ◽  
Cross Section ◽  
Element Model ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Transmission Tower ◽  
Regulatory Requirements ◽  
Internal Forces ◽  
Node Variable ◽  
Main Material

In order to study the mechanical properties of the angle variable cross-section transmission tower against the corner of a 500kV transmission line tower, it becomes a node by node plate tower slope at a single angle and dual angle connected to a total of ten bars, dozens of bolts. The entire tower was built finite element model, the model is modal analysis, the results of the analysis of compliance with regulatory requirements. In the most unfavorable conditions, the tower each node variable slope rod internal forces are extracted, come times of stress accounted main material angle of principal stress ratio is large, need to be considered in the design.

Structural Analysis and Internal Force Calculation of Variable Cross-Section Silo

2012 ◽  
Vol 446-449 ◽  
pp. 429-434
Author(s):  
Rui Ting Ma
Keyword(s):  
Cross Section ◽  
Variable Cross Section ◽  
Internal Force ◽  
Variable Cross ◽  
Axially Symmetric ◽  
Internal Forces ◽  
Differential Element ◽  
Symmetric Load ◽  
Force Calculation ◽  
Constant Section

In this paper, the differential element of constant-section silo wall suffering from axially symmetric load is analyzed. From the results of constant-section silo, the author derives the displacements and internal forces of variable cross-section silo. Through a specific example, this paper compares the displacements , internal forces and concrete consumption of variable cross-section silo with those of constant-section silo, and discusses the merits of variable cross-section silo.

Transmission Loss of Variable Cross Section Apertures

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
J. Li ◽  
L. Zhou ◽  
X. Hua ◽  
D. W. Herrin
Keyword(s):  
Finite Element ◽  
Cross Section ◽  
Sound Propagation ◽  
Transmission Loss ◽  
Element Model ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Cross Sectional ◽  
Radiation Impedance ◽  
The Cross

Openings in enclosures or walls are frequently the dominant path for sound propagation. In the current work, a transfer matrix method is used to predict the transmission loss of apertures assuming that the cross-sectional dimensions are small compared with an acoustic wavelength. Results are compared with good agreement to an acoustic finite element approach in which the loading on the source side of the finite element model (FEM) is a diffuse acoustic field applied by determining the cross-spectral force matrix of the excitation. The radiation impedance for both the source and termination is determined using a wavelet algorithm. Both approaches can be applied to leaks of any shape and special consideration is given to apertures with varying cross section. Specifically, cones and abrupt area changes are considered, and it is shown that the transmission loss can be increased by greater than 10 dB at many frequencies.

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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