Motion and Whiplash Effect of a Floating Crane Model und er Wave Load: Experiment

2020 ◽  
Vol 99 (sp1) ◽  
pp. 346
Author(s):  
Jiannan Zhou ◽  
Haiyuan Wang ◽  
Zhaobing Jiang
Keyword(s):  
Wave Load ◽  
Floating Crane ◽  
Whiplash Effect

A Method of Dynamic Modeling of a Large Floating Crane and its External Excitations

2010 ◽  
Vol 139-141 ◽  
pp. 2440-2445
Author(s):  
Qing Zhang ◽  
Jian Jie Zhang ◽  
Ji He ◽  
Yong Feng Li ◽  
Xian Rong Qin
Keyword(s):  
Wind Wave ◽  
Linear Method ◽  
Dominant Frequency ◽  
Global Coordinate System ◽  
Wave Loads ◽  
Wave Load ◽  
External Excitation ◽  
Lagrange’S Equation ◽  
Local Coordinates ◽  
Floating Crane

According to the characteristics of floating cranes, an affordable numerical method to model the floating cranes and the external excitations such as wind, wave and shimmy loads was proposed. Local coordinates modifying wind, wave and shimmy loads which are determined separately were combined in the global coordinate system according to the geometric positions. The spectra of wind loads and wave loads were converted into time domain separately according to the linear method, while a shimmy load is determined according to the Lagrange’s Equation. As an example, the external excitation caused by random wind, wave and shimmy loads on a 7500-ton giant floating crane were simulated, and the transient dynamic response was predicted and discussed. Focusing on the characteristics of structure of floating cranes, the research indicates that the dominant frequency of the wave load is low, as compared to wind and shimmy loads, and that the shimmy load is closely related to the environmental excitations such as wind and wave loads. The results also suggest that the transient response of the crane is mainly related to the shimmy load.

scholarly journals Fluctuation of magnitude of wave loads for a long array of bottom-mounted cylinders

2019 ◽  
Vol 868 ◽  
pp. 244-285 ◽  
Author(s):  
Xiaohui Zeng ◽  
Fajun Yu ◽  
Min Shi ◽  
Qi Wang
Keyword(s):  
Incidence Angle ◽  
Local Maximum ◽  
Destructive Interference ◽  
Horizontal Distance ◽  
Wave Loads ◽  
Wave Load ◽  
Intrinsic Mechanism ◽  
Fluctuation Phenomenon ◽  
Analytical Formulae ◽  
Incident Waves

For wave loads on cylinders constituting a long but finite array in the presence of incident waves, variations in the magnitude of the load with the non-dimensional wavenumber exhibit interesting features. Towering spikes and nearby secondary peaks (troughs) associated with trapped modes have been studied extensively. Larger non-trapped regions other than these two are termed Region III in this study. Studies of Region III are rare. We find that fluctuations in Region III are regular; the horizontal distance between two adjacent local maximum/minimum points, termed fluctuation spacing, is constant and does not change with non-dimensional wavenumbers. Fluctuation spacing is related only to the total number of cylinders in the array, identification serial number of the cylinder concerned and wave incidence angle. Based on the interaction theory and constructive/destructive interference, we demonstrate that the fluctuation characteristics can be predicted using simple analytical formulae. The formulae for predicting fluctuation spacing and the abscissae of every peak and trough in Region III are proposed. We reveal the intrinsic mechanism of the fluctuation phenomenon. When the diffraction waves emitted from the cylinders at the ends of the array and the cylinder concerned interfere constructively/destructively, peaks/troughs are formed. The fluctuation phenomenon in Region III is related to solutions of inhomogeneous equations. By contrast, spikes and secondary peaks are associated with solutions of the eigenvalue problem. This study of Region III complements existing understanding of the characteristics of the magnitude of wave load. The engineering significances of the results are discussed as well.

Experimental investigation on the shock-wave load attenuation by geometrical means

Shock Waves ◽  
2009 ◽  
Vol 20 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Shachar Berger ◽  
Oren Sadot ◽  
Gabi Ben-Dor
Keyword(s):  
Shock Wave ◽  
Experimental Investigation ◽  
Wave Load

Tubarão Martelo Field Riser System: Shallow Water Challenging

2015 ◽  
Author(s):  
Elton J. B. Ribeiro ◽  
Zhimin Tan ◽  
Yucheng Hou ◽  
Yanqiu Zhang ◽  
Andre Iwane
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Oil And Gas ◽  
Vertical Motion ◽  
Oil And Gas Industry ◽  
System Configuration ◽  
Wave Load ◽  
Gas Industry ◽  
Campos Basin ◽  
Water Problem

Currently the oil and gas industry is focusing on challenging deep water projects, particularly in Campos Basin located coast off Brazil. However, there are a lot of prolific reservoirs located in shallow water, which need to be developed and they are located in area very far from the coast, where there aren’t pipelines facilities to export oil production, in this case is necessary to use a floating production unit able to storage produced oil, such as a FPSO. So, the riser system configuration should be able to absorb FPSO’s dynamic response due to wave load and avoid damage at touch down zone, in this case is recommended to use compliant riser configuration, such as Lazy Wave, Tethered Wave or Lazy S. In addition to, the proposed FPSO for Tubarão Martelo development is a type VLCC (Very Large Crude Carrier) using external turret moored system, which cause large vertical motion at riser connection and it presents large static offset. Also are expected to install 26 risers and umbilicals hanging off on the turret, this large number of risers and umbilicals has driven the main concerns to clashing and clearance requirement since Lazy-S configuration was adopted. In this paper, some numerical model details and recommendations will be presented, which became a feasible challenging risers system in shallow water. For instance, to solve clashing problem it is strictly recommended for modeling MWA (Mid Water Arch) gutter and bend stiffener at top I-tube interface, this recommendation doesn’t matter in deep water, but for shallow water problem is very important. Also is important to use ballast modules in order to solve clashing problems.

Dynamic Responses Analysis of Permeable Breakwater Subjected to Random Waves

2014 ◽  
Vol 1061-1062 ◽  
pp. 809-812
Author(s):  
Hu Ping
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Responses ◽  
Exceedance Probability ◽  
Random Waves ◽  
The Finite Element Method ◽  
Wave Load ◽  
Power Spectral ◽  
Density Analysis ◽  
Element Method

In this paper, based on the finite element method and ANSYS software, the dynamic responses of permeable breakwater under wave load response is analyzed and studied. Taking the method of combining modal analysis and power spectrum analysis research on dynamic response of breakwater in the frequency domain and the principal stress and displacement distribution of the structure in the exceedance probability of 0.7%. The results prove that the finite element method of power spectral density analysis can provide effective guidance for the actual engineering.

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