The Optimum Stepped-Pipe String With Vibration Absorbers for Mining Manganese Nodules, to Reduce Its Maximum Axial Stress

1998 ◽  
Vol 120 (4) ◽  
pp. 917-921 ◽  
Author(s):  
Gang Cui ◽  
Kazuo Aso
Keyword(s):  
Deep Sea ◽  
Longitudinal Vibration ◽  
Axial Stress ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Manganese Nodules ◽  
The One ◽  
Heave Motion ◽  
Maximum Axial Stress

In order to reduce the maximum axial stress produced in the pipe string for mining manganese nodules from deep-sea floors by a pump-lift system, the string is assumed to be a two-stepped pipe string with larger diameter in the upper part. Moreover, a buffer and two pump-modules attached to the string are assumed to be equipped with a vibration absorber. Then, the longitudinal vibration and axial stress caused in the string by the heave-motion of the mining ship are analyzed theoretically for practical cases. The result shows that the maximum axial stress in the optimum stepped pipe-string with the buffer having the optimum vibration absorber is found to be smaller by about 42 percent than the one produced in the uniform pipe string with the same mass and no vibration absorbers.

scholarly journals Vibration Characteristics and Reduction Analysis of Lifting Pipe under Ocean Current

2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Qinghui Song ◽  
Haiyan Jiang ◽  
Qingjun Song ◽  
Linjing Xiao ◽  
PeiSi Zhong
Keyword(s):  
Mathematical Model ◽  
Deep Sea ◽  
Longitudinal Vibration ◽  
Axial Stress ◽  
Element Model ◽  
Ocean Current ◽  
Vibration Absorbers ◽  
Dynamic Vibration Absorber ◽  
Mining System ◽  
Model And Simulation

Effects of vibration absorbers on the lifting pipe in deep-sea mining have been attracting more and more attention in the recent three decades; however, there are very few reports about the influence of ocean current on the pipe vibration in the literature. Considering the geometrical features of the prototype, this paper establishes the physical model, mathematical model, and simulation model of the lifting subsystem. A comprehensive finite element model for the deep-sea mining system by the OrcaFlex is developed to explore the influences of buffer mass and sailing velocity on the deflection angle and the axial load and stress of the lifting pipe. Analytical and numerical simulations have been formulated to illustrate variation rule of longitudinal vibration and axial stress at the position of pump and buffer for the lifting subsystem to determine the dynamic vibration absorber parameters. In this paper, MATLAB and Orcaflex software are used to verify the mathematical model. The simulation results show that the attaching DVAs can effectively reduce the axial stress, and longitudinal displacement at certain positions of the lifting pipe.

Effects of nonlinear interactions of flexural modes on the performance of a beam autoparametric vibration absorber

2019 ◽  
Vol 26 (7-8) ◽  
pp. 459-474
Author(s):  
Saeed Mahmoudkhani ◽  
Hodjat Soleymani Meymand
Keyword(s):  
Frequency Response ◽  
Internal Resonance ◽  
Continuation Method ◽  
Harmonic Balance Method ◽  
Vibration Absorber ◽  
Primary System ◽  
Lumped Mass ◽  
Response Curves ◽  
Internal Resonances ◽  
The One

The performance of the cantilever beam autoparametric vibration absorber with a lumped mass attached at an arbitrary point on the beam span is investigated. The absorber would have a distinct feature that in addition to the two-to-one internal resonance, the one-to-three and one-to-five internal resonances would also occur between flexural modes of the beam by tuning the mass and position of the lumped mass. Special attention is paid on studying the effect of these resonances on increasing the effectiveness and extending the range of excitation amplitudes at which the autoparametric vibration absorber remains effective. The problem is formulated based on the third-order nonlinear Euler–Bernoulli beam theory, where the assumed-mode method is used for deriving the discretized equations of motion. The numerical continuation method is then applied to obtain the frequency response curves and detect the bifurcation points. The harmonic balance method is also employed for detecting the type of internal resonances between flexural modes by inspecting the frequency response curves corresponding to different harmonics of the response. Parametric studies on the performance of the absorber are conducted by varying the position and mass of the lumped mass, while the frequency ratio of the primary system to the first mode of the beam is kept equal to two. Results indicated that the one-to-five internal resonance is especially responsible for the considerable enhancement of the performance.

Dynamic Vibration Absorber Optimal Design With Emphasis on Complete Machine Dynamics Modelling

2008 ◽  
Author(s):  
Bohdan M. Diveyev ◽  
Zinovij A. Stotsko
Keyword(s):  
Optimal Design ◽  
Vibration Absorber ◽  
Vibration Absorbers ◽  
Rotating Machines ◽  
Dynamic Vibration Absorber ◽  
New Methods ◽  
Dynamic Vibration ◽  
Methods Development ◽  
Dynamic Vibration Absorbers ◽  
Dynamics Modelling

The main aim of this paper is improved dynamic vibration absorbers design with taking into account complex rotating machines dynamic The is considered for the complex vibroexitated constructions. Methods of decomposition and the numerical schemes synthesis are considered on the basis of new methods of modal methods. Development of of complicated machines and buildings in view of their interaction with system of dynamic vibration absorbers is under discussion.

V.—Manganese in the Sea

1876 ◽  
Vol 1 (2) ◽  
pp. 50-53 ◽  
Author(s):  
A. H. Church
Keyword(s):  
Chemical Analysis ◽  
Deep Sea ◽  
The Other ◽  
Manganese Nodules ◽  
Red Clay ◽  
Chemical Examination ◽  
Sea Bottom ◽  
Ample Supply

To the geologist, the mineralogist and the chemist, two of the observations made during the voyage of the Challenger are of especial interest. One of these observations is the occurrence over vast areas of the deep sea bottom of a peculiar red clay, containing silica, peroxide of iron, and alumina. The other discovery to which I refer has been described by Sir Wyville Thomson as the occurrence throughout this red clay of nodules of “nearly pure peroxide of manganese.” To these nodules, as well us to the red clay, an organic origin has been assigned. But the immediate source of so much manganese is hard to find, for this element is by no means an abundant constituent of animal or vegetable organisms. The difficulty is, however, somewhat lessened when the manganese nodules are submitted to a more minute chemical examination. From two correspondents I have received an ample supply of these curious concretions, accompanied by a suggestion that they should be submitted to chemical analysis.

scholarly journals Sponge and coral communities of potential mineral resources in the deep-sea: An overview

2018 ◽  
Author(s):  
Tina Molodtsova ◽  
Christopher Kelley ◽  
Lénaick Menot ◽  
Les Watling
Keyword(s):  
Deep Sea ◽  
Slow Growth ◽  
Mineral Resources ◽  
Ore Deposits ◽  
Manganese Nodules ◽  
Cumulative Impact ◽  
Mining Sites ◽  
Intensive Exploitation ◽  
Coral Communities ◽  
Hard Substrata

Depletion of commercially valuable minerals on land and increased need of such resources for modern electronics and manufacturing is attracting more and more attention to deep-sea mineral deposits such as cobalt crusts, manganese nodules, phosphorites, polymetallic sulfides and even deep-sea ooze. In a few years we expect intensive exploitation in the deep-sea. Being suspension feeders, corals and sponges associated with hard substrata in potential mining sites would be adversely impacted by deep-sea mining. Deep-sea corals and sponges are characterized by extremely slow growth rates and, as can be seen from fishery impacts, they may take decades to centuries to restore. At the same time, they serve as a substrate, shelter and food for a number of associated deep-sea organisms, thus increasing the cumulative impact of their loss. We summarize here the available data on coral and sponge communities of solid deep-sea ore deposits and possible mechanisms driving their diversity.

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