scholarly journals Analysis of heavy floating cranes and features of their operation

2021 ◽  
pp. 68-80
Author(s):  
Vladilen S. Ignatovich Ignatovich ◽  
Anna V. Kuzmina ◽  
Konstantin V. Perepadya Perepadya
Keyword(s):  
Optimal Design ◽  
Maximum Load ◽  
Structural Type ◽  
Full Scale ◽  
Operating Conditions ◽  
Lifting Capacity ◽  
Floating Crane ◽  
Full Scale Tests ◽  
Production Conditions ◽  
Design And Construction

The main characteristics of offshore heavy floating cranes, which are independent navigation without tugs and the performance of cargo operations in open waters with wind and waves, are considered. The safety of navigation in these conditions can be ensured with high seaworthiness and maneuverability by giving the appropriate shape of the bow end of the hull, the minimum windage of the structure, as well as the optimal design of the topside (crane). The requirements for the design and construction of universal heavy sea floating cranes, built after 1966, are analyzed, the operating conditions, depending on the purpose, and the architectural and structural type of floating cranes with a lifting capacity of 100–900 tons are considered. When calculating the strength of the topside, the possibility of the floating crane operating with the maximum load was taken into account when the sea is rough up to three points and the wind is up to five points, taking into account the dynamic and inertial loads arising from rolling in waves, when picking up and breaking the load. In the event of an emergency breakage of the load, the structure of the topside and the boom system must exclude or minimize vibrations caused by the breakage of the load. The results of the calculation of the forces at the breakage of the load must be verified by full-scale tests of floating head cranes, for which the corresponding methods have been developed. The possibility of using the developed structure of the hull and the topside (crane) in the design and construction of modern floating cranes in the production conditions of shipyards is shown.

Full-Scale Wrinkling Tests and Analyses of Large Diameter Corroded Pipes

1998 ◽  
Author(s):  
Marina Q. Smith ◽  
Daniel P. Nicolella ◽  
Christopher J. Waldhart
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Axial Compression ◽  
Wall Thickness ◽  
Full Scale ◽  
Operating Conditions ◽  
Material Behavior ◽  
Combined Loading ◽  
Longitudinal Bending ◽  
Full Scale Tests

The aging of pipeline infrastructures has increased concern for the integrity of pipelines exhibiting non-perforating wall loss and settlement induced bending. While pressure based guidelines exist which allow pipeline operators to define operational margins of safety against rupture (e.g.; ANSI/ASME B31-G and RSTRENG (Battelle, 1989)), reliable procedures for the prediction of wrinkling in degraded pipes subjected to combined loading are virtually non-existent. This paper describes full-scale testing and finite element investigations performed in support of the development of accurate wrinkling prediction procedures for the Alyeska Pipeline Service Company. The procedures are applicable to corroded pipes subjected to combined loading such as longitudinal bending, internal pressure, and axial compression. During the test program, full-scale 48-inch diameter sections of the trans-Alaska pipeline were subjected to internal pressure and loads designed to simulate longitudinal bending from settlement, axial compression from the transport of hot oil, and the axial restraint present in buried pipe. Load magnitudes were designed based on normal and maximum operating conditions. Corrosion in the pipe section is simulated by mechanically reducing the wall thickness of the pipe. The size and depth of the thinned region is defined prior to each test, and attempts to bound the dimensions of depth, axial length, and hoop length for the general corrosion observed in-service. The analytical program utilizes finite element analyses that include the nonlinear anisotropic material behavior of the pipe steel through use of a multilinear kinematic hardening plasticity model. As in the tests, corrosion is simulated in the analyses by a section of reduced wall thickness, and loads and boundary constraints applied to the numerical model exactly emulate those applied in the full-scale tests. Verification of the model accuracy is established through a critical comparison of the simulated pipe structural behavior and the full-scale tests. Results of the comparisons show good correlation with measurements of the pipe curvature, deflections, and moment capacity at wrinkling. The validated analysis procedure is subsequently used to conduct parameter studies, the results of which complete a database of wrinkling conditions for a variety of corrosion sizes and loading conditions.

Design, Testing and Operation of Grit Chambers with Hydraulic Roll

1988 ◽  
Vol 20 (4-5) ◽  
pp. 237-248
Author(s):  
Y. Gruber ◽  
D. Farchill ◽  
M. Goldstein
Keyword(s):  
Treatment Plant ◽  
Optimal Operation ◽  
Hydraulic Model ◽  
Full Scale ◽  
Operating Conditions ◽  
Prototype System ◽  
Preliminary Treatment ◽  
Clear Water ◽  
Start Up ◽  
Full Scale Tests

The Soreq biological treatment plant has been recently brought into operation, after a comprehensive start-up and testing program. The plant's preliminary treatment facilities include four grit chambers 40 m long, equipped for both grit removal and scum skimming. The variable energy input required to control the deposition of the grit and the floating of the scum, is provided by a hydraulic jet system, using pumped recycled wastewater to generate the necessary motive power. The basic concept in designing grit chambers equipped with a hydraulic jet system, instead of a bubble aeration system, is to avoid the release of noxious odours and corrosive gases which are often associated with the conventional aerated grit chambers. Experiments were conducted on a hydraulic model of the grit chamber to develop the necessary design criteria for the full scale jet system. During the initial start-up program of the Soreq plant, the grit chambers and the related equipment were tested with clear water, and the actual transversal velocities were measured through a range of simulated operating conditions. This paper summarizes the hydraulic model test results, the upscaling approach used for design of the prototype system, and the on-site full-scale tests with clear water. A follow-up program under actual operating conditions is now in progress to establish the variable parameters for optimal operation of the hydraulically powered grit chambers with wastewater.

Wastewater Lagoons in a Cold Climate

1987 ◽  
Vol 19 (12) ◽  
pp. 47-53 ◽  
Author(s):  
J. A. Oleszkiewicz ◽  
A. B. Sparling
Keyword(s):  
Control Mechanism ◽  
Maximum Load ◽  
Domestic Sewage ◽  
Full Scale ◽  
Cold Climate ◽  
Odor Control ◽  
Intermittent Rivers ◽  
In Series ◽  
Break Up ◽  
Lagoon Systems

Severe climate, intermittent rivers and availability of land make facultative lagoon systems the method of choice in treating primarily domestic sewage from smaller municipalities. The lagoons are designed on a recommended maximum load of 55 kgBOD5/ha d to first cell, while the second cell provides storage. The discharge is twice annually and the occurrence of the spring ice break-up odor period is one of the primary criteria limiting this load. Based on full scale performance data, it is demonstrated that, from the standpoint of odor nuisance, the load to the first cell should be kept equal to or less than 35 kg/ha d. Full scale studies of an overloaded lagoon system show the futility of under-ice aeration for odor control. Mechanism of natural odor control during ice break up is elucidated. Upgrading of the overloaded systems or lagoons receiving significant industrial contribution is best achieved by construction of a 3–5 m deep aerated lagoon preceding the two or more facultative cells in series.

A Critical Look into the Deviation of Full Scale Performance from Design Expectations

1989 ◽  
Vol 21 (10-11) ◽  
pp. 1389-1402 ◽  
Author(s):  
R. Zaloum
Keyword(s):  
Expert Systems ◽  
Waste Treatment ◽  
Full Scale ◽  
Operating Conditions ◽  
Organic Load ◽  
Computer Assisted ◽  
Uniform Load ◽  
Effluent Quality ◽  
Simulation Techniques ◽  
Steady Level

Deviations from design expectations appear to stem from views which assume that a unique response should result from a given set of operating conditions. The results of this study showed that two systems operating at equal organic loads or F/M ratios and at the same SRT do not necessarily give equal responses. This deviation was linked to the manner in which the HRT and influent COD are manipulated to obtain a constant or uniform load, and to subtle interactions between influent COD, HRT and SRT on the biomass and effluent responses. Increases of up to 200% in influent COD from one steady level to the next did not significantly influence the effluent VSS concentration while an effect on filtered COD was observed for increases as low as 20%. Effluent TKN and filtered COD correlated strongly with the operating MLVSS while phosphorus residual depended on the operating SRT and the organic load removed. These results point to the inadequacy of traditional models to predict effluent quality and point to the need to consider these effects when developing simulation techniques or computer assisted expert systems for the control of waste treatment plants.

Investigation of planing craft maneuverability using full-scale tests

2021 ◽  
pp. 147509022110303
Author(s):  
Kazem Sadati ◽  
Hamid Zeraatgar ◽  
Aliasghar Moghaddas
Keyword(s):  
Full Scale ◽  
Performance Characteristics ◽  
Forward Speed ◽  
Speed Reduction ◽  
Planing Craft ◽  
Full Scale Tests ◽  
Turning Maneuver

Maneuverability of planing craft is a complicated hydrodynamic subject that needs more studies to comprehend its characteristics. Planing craft drivers follow a common practice for maneuver of the craft that is fundamentally different from ship’s standards. In situ full-scale tests are normally necessary to understand the maneuverability characteristics of planing craft. In this paper, a study has been conducted to illustrate maneuverability characteristics of planing craft by full-scale tests. Accelerating and turning maneuver tests are conducted on two cases at different forward speeds and rudder angles. In each test, dynamic trim, trajectory, speed, roll of the craft are recorded. The tests are performed in planing mode, semi-planing mode, and transition between planing mode to semi-planing mode to study the effects of the craft forward speed and consequently running attitude on the maneuverability. Analysis of the data reveals that the Steady Turning Diameter (STD) of the planing craft may be as large as 40 L, while it rarely goes beyond 5 L for ships. Results also show that a turning maneuver starting at planing mode might end in semi-planing mode. This transition can remarkably improve the performance characteristics of the planing craft’s maneuverability. Therefore, an alternative practice is proposed instead of the classic turning maneuver. In this practice, the craft traveling in the planing mode is transitioned to the semi-planing mode by forward speed reduction first, and then the turning maneuver is executed.

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