Experimental Study of Strucural Responses of a Ship With Multi-Segments and Variable Cross-Section Beams

2014 ◽  
Author(s):  
Jun Ding ◽  
Chao Tian ◽  
Xueliang Wang ◽  
Xiaoming Cheng ◽  
Peng Yang
Keyword(s):  
Cross Section ◽  
Wave Height ◽  
Cross Sections ◽  
Design Method ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Segmented Model ◽  
Segment Number ◽  
Large Ship ◽  
Vessel Speed

The motion and structural response to wave loading are studied experimentally for a large ship modeled with multiple segments and beams of variable cross-sections. As opposed to the traditional method with small number of segments and beams of uniform cross-section, the multi-segmented model with beams of variable cross-sections can more accurately simulate some of the hull properties that will otherwise be neglected. In this paper, the design method for the multi-segmented model is presented, and the model test results for the multi-segmented model with variable cross-section beams are compared with the traditional uniform beams and less segmented model for calm water, regular and irregular wave conditions. The influences of the segment number, variable cross-section, vessel speed and wave height are investigated using the load forecasting methods based on the rigid body and hydroelastic theories. It has been found that using variable cross-section beams can simulate hull stiffness of each section more accurately, and with the increase of the segment number in the ship model, the high frequency characteristics of the bending response are better reflected. Furthermore, the calculation results agree well with the experimental data, and the hydroelastic theory is found to be able to predict the higher frequencies of the hull structural responses. At the same time, with the increase of the vessel speed and wave height, the bending moment and wave height show an obvious nonlinear relationship. The methods and results presented in this paper have a certain guiding significance for the tank model tests and design of large ship structures.

scholarly journals Failure Analysis of Intersections of Large-Scale Variable Cross-Section Roadways in Deep Soft Rock and Study of Integrated Control Technology of Bolting and Grouting

2021 ◽  
Author(s):  
Shengrong Xie ◽  
Yiyi Wu ◽  
Dongdong Chen ◽  
Ruipeng Liu ◽  
Xintao Han ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Large Scale ◽  
Integrated Control ◽  
Soft Rock ◽  
Variable Cross Section ◽  
Surrounding Rock ◽  
Variable Cross ◽  
Geological Environment ◽  
Cable Bolt

Abstract In deep underground mining, achieving stable support for roadways along with long service life is critical and the complex geological environment at such depths frequently presents a major challenge. Owing to the coupling action of multiple factors such as deep high stress, adjacent faults, cross-layer design, weak lithology, broken surrounding rock, variable cross-sections, wide sections up to 9.9 m, and clusters of nearby chambers, there was severe deformation and breakdown in the No. 10 intersection of the roadway of large-scale variable cross-section at the − 760 m level in the Nanfeng working area of the Wuyang Coal Mine. As there are insufficient examples in engineering methods pertaining to the geological environment described above, the numerical calculation model was oversimplified and support theory underdeveloped; therefore, it is imperative to develop an effective support system for the stability and sustenance of deep roadways. In this study, a quantitative analysis of the geological environment of the roadway through field observations, borehole peeking, and ground stress testing is carried out to establish the FLAC 3D variable cross-section crossing roadway model. This model is combined with the strain softening constitutive (surrounding rock) and Mohr-Coulomb constitutive (other deep rock formations) models to construct a compression arch mechanical model for deep soft rock, based on the quadratic parabolic Mohr criterion. An integrated control technology of bolting and grouting that is mainly composed of a high-strength hollow grouting cable bolt equipped with modified cement grouting materials and a high-elongation cable bolt is developed by analyzing the strengthening properties of the surrounding rock before and after bolting, based on the Heok-Brown criterion. As a result of on-site practice, the following conclusions are drawn: (1) The plastic zone of the roof of the cross roadway is approximately 6 m deep in this environment, the tectonic stress is nearly 30 MPa, and the surrounding rock is severely fractured. (2) The deformation of the roadway progressively increases from small to large cross-sections, almost doubling at the largest cross-section. The plastic zone is concentrated at the top plate and shoulder and decreases progressively from the two sides to the bottom corner. The range of stress concentration at the sides of the intersection roadway close to the passageway is wider and higher. (3) The 7 m-thick reinforced compression arch constructed under the strengthening support scheme has a bearing capacity enhanced by 1.8 to 2.3 times and increase in thickness of the bearing structure by 1.76 times as compared to the original scheme. (4) The increase in the mechanical parameters c and φ of the surrounding rock after anchoring causes a significant increase in σc and σt; the pulling force of the cable bolt beneath the new grouting material is more than twice that of ordinary cement grout, and according to the test, the supporting stress field shows that the 7.24 m surrounding rock is compacted and strengthened in addition to providing a strong foundation for the bolt (cable). On-site monitoring shows that the 60-day convergence is less than 30 mm, indicating that the stability control of the roadway is successful.

scholarly journals Characterization of Soft Tooling Photopolymers and Processes for Micromixing Devices with Variable Cross-Section

Micromachines ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 970
Author(s):  
J. Israel Martínez-López ◽  
Héctor Andrés Betancourt Cervantes ◽  
Luis Donaldo Cuevas Iturbe ◽  
Elisa Vázquez ◽  
Edisson A. Naula ◽  
...  
Keyword(s):  
Flow Regime ◽  
Cross Section ◽  
Cross Sections ◽  
Microfluidic Devices ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Multiple Cross ◽  
3D Printed

In this paper, we characterized an assortment of photopolymers and stereolithography processes to produce 3D-printed molds and polydimethylsiloxane (PDMS) castings of micromixing devices. Once materials and processes were screened, the validation of the soft tooling approach in microfluidic devices was carried out through a case study. An asymmetric split-and-recombine device with different cross-sections was manufactured and tested under different regime conditions (10 < Re < 70). Mixing performances between 3% and 96% were obtained depending on the flow regime and the pitch-to-depth ratio. The study shows that 3D-printed soft tooling can provide other benefits such as multiple cross-sections and other potential layouts on a single mold.

A unified procedure for the vibration analysis of elastically restrained Timoshenko beams with variable cross sections

2020 ◽  
Vol 68 (1) ◽  
pp. 38-47
Author(s):  
Gang Wang ◽  
Wen L. Li ◽  
Wanyou Li ◽  
Zhihua Feng ◽  
Junfang Ni
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Vibration Analysis ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Timoshenko Beams ◽  
Unified Approach ◽  
Cross Section Area ◽  
Section Area ◽  
Elastically Restrained

A generalized analytical method is developed for the vibration analysis of Timoshenko beams with elastically restrained ends. For a beam with any variable cross section along the lengthwise direction, the finite element method is the only unified approach to handle those kinds of problems, since the analytical solutions could not be obtained by the governing equations when the cross section area and the second moment of area changing variably lengthwise. In this article, a unified approach is proposed to study the Timoshenko beam with any variable cross sections. The cross section area and second moment of area of the beam are both expanded into cosine series, which are mathematically capable of representing any variable cross section. The translational displacement and rotation of cross section are expressed in the Fourier series by adding some admissible functions which are used to handle the elastic boundary conditions with more accuracy and high convergence rate. By using Hamilton's principle, the eigenvalues and the coefficients of the Fourier series are both obtained. Some examples are presented to illustrate the excellent accuracy of this method. Analytical solutions of the vibration of the beam are achieved for different combinations of boundary conditions including classical and elastically restrained ones. The derived results can be used as benchmark solutions for testing approximate or numerical methods used for the vibration analysis of Timoshenko beams with any variable cross section.

Reliability Analysis and Sensitivity Design of the Uniform Strength Component

2012 ◽  
Vol 446-449 ◽  
pp. 1203-1206
Author(s):  
Qiao Ling Liu ◽  
Hai Feng Xing ◽  
Tian Xiao Zhang
Keyword(s):  
Normal Distribution ◽  
Reliability Analysis ◽  
Cross Section ◽  
Design Method ◽  
Random Variable ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Uniform Strength ◽  
Reliability Sensitivity ◽  
Variable Probability

In this study, the reliability sensitivity of the uniform strength Variable Cross-section Component is analyzed, which is the normal distribution. We propose a method for the reliability and sensitivity of the Uniform Strength Components. We may accurately obtain the uniform strength component's reliable sensitivity information on basic of random variable probability characteristic for certain situation. Through the value examples, we have studied the random variable reliable sensitivity for dangerous sections. We propose a design method with practicality for the uniform strength components.

Mathematical Model Of Liquid Flow Through The Pipe Of Curcular Cross-Section

2016 ◽  
Vol 11 (4) ◽  
pp. 61-67
Author(s):  
Eduard Arinstein ◽  
Denis Tokarev
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Liquid Flow ◽  
Analytical Approach ◽  
Variable Cross Section ◽  
Cylindrical Symmetry ◽  
Variable Cross ◽  
Current Line ◽  
Flow Velocity Profile ◽  
Flow Through

This article analyses the properties of homogeneous viscous liquid flow in the pipe with variable cross-section characterized by cylindrical symmetry. The analytical approach is proposed in order to determine the flow velocity profile in the pipe’s extremium cross-sections. The conditions when dead spaces emerge in neighborhood of the maximum cross-section are identified. The particular case of problem-solving allowing prime presentation is examined for the set of current line allowing prime presentation.

Optimization Design of Section for Bisymmetric Built-Up Steel H-Shaped Beams

2013 ◽  
Vol 405-408 ◽  
pp. 948-951
Author(s):  
Su Juan Dai ◽  
Yan Chun Meng
Keyword(s):  
Cross Section ◽  
Optimization Design ◽  
Theoretical Foundation ◽  
Design Method ◽  
Variable Cross Section ◽  
Steel Beam ◽  
Variable Cross ◽  
Concentrated Load ◽  
Design Procedures ◽  
Section Design

Built-up steel H-shaped beam with variable cross-section design can save steel and realize the economy requirements of structure.The existing design method of variable width of flange of steel beam is only applicable to beam under uniformly distributed load.This paper presents optimization design procedures of the Variable cross-section.The related formulas used to optimization design of section for bisymmetric built-up steel H-shaped beams under concentrated load were derived,and the position of varying cross section of beams under concentrated load was calculated ,it is convenient to be used in engineering design,and provides theoretical foundation for variable cross-section design .

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.

COMBINED FIRMWARE OF DEEP CHANNELS OF VARIABLE CROSS-SECTION

2020 ◽  
pp. 10-13
Author(s):  
V. P. Smolentsev ◽  
A. A. Shirokozhukhova ◽  
N. S. Potashnikova
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Economic Effect ◽  
Variable Cross Section ◽  
Combined Processes ◽  
Variable Cross ◽  
Chemical Production ◽  
Small Cross Section ◽  
Engineering Information ◽  
Traditional Processing

Variants of manufacturing deep channels of different cross-sections in typical details of modern equipment are considered. Most of the methods were created with the participation of the authors of the article and are protected by Russian patents. The results of the research are implemented in production at enterprises of various branches of mechanical engineering. Information is given about the original methods of piercing deep holes with a depth-to-diameter ratio of more than 25:1 by using combined processes with the imposition of high-frequency vibrations and the possibility of obtaining holes of variable cross-section in pressed ceramic and metal workpieces. The production of mating surfaces from small cross-section channels and narrow grooves is considered,which allowed us to offer an original technological process for the erosive chemical production of precision parts. This technology has been used in the manufacture of parts whose traditional processing methods are poorly understood or not feasible.In particular, a new application of combined firmware for obtaining deep holes of small cross-section in metal workpieces obtained by pressing is shown.Typical parts containing deep channels are given, the combined processing of which is the most technologically advanced and allows for a high economic effect.

scholarly journals SOLUTION OF PROBLEMS OF CURVED SURFACE APPROXIMATION BY LAYERS WITH CONSTANT AND VARIABLE CROSS-SECTIONS AT SHAPING WITH ADDITIVE METHODS

2019 ◽  
Vol 2019 (3) ◽  
pp. 38-40 ◽  
Author(s):  
Александр Гречухин ◽  
Aleksandr Grechuhin ◽  
Вадим Куц ◽  
Vadim Kuc ◽  
Михаил Разумов ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Single Layer ◽  
Variable Cross Section ◽  
Comparative Assessment ◽  
Curved Surface ◽  
Parameter Control ◽  
Variable Cross ◽  
Surface Approximation ◽  
Additive Methods

The problems of parameter control in a single layer cross-section at additive shaping are considered. The problem of curved surface approximation in parts by layers with a constant and variable cross-section is solved. The results of geometric and computer modeling are shown. The comparative assessment of the results of problems mentioned above is given.

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.

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