Lifting Gear Research Articles

A Code-to-Code Comparison for Dynamic Modeling and Response Analysis of Offshore Wind Turbine Blade Mating Process

Abstract Offshore wind turbine blade installation using jack-up crane vessel is a challenging task. Wave- and wind-induced loads on the installation system can cause large relative motion between the blade root and the hub during the mating process. Currently, several numerical tools are used to analyze such critical global motion responses; however, the industry suffers from lack of experiments and full-scale measurements to validate the accuracy of these results. Consequently, a code-to-code comparison exercise becomes critical as it allows comparing different numerical tools for reliable prediction and verification of results. In the present article, a numerical model of the offshore wind turbine blade mating process using a jack-up crane vessel is developed in orcaflex, and a code-to-code comparison is performed against sima; both these tools are immensely used in the industry for modeling marine operations. Different comparisons are made between both the tools such as: (1) modal analyses of the jack-up vessel and the blade lifting gear, (2) time-domain analysis of the fully coupled installation vessel-crane-blade system, and (3) a comprehensive sensitivity study based on different seed numbers and simulation periods. The results of the study show a good agreement between both the tools with a deviation of less than 3% in terms of modal analysis and less than 5% variation in time-domain results. Further, the article provides modeling guidelines for the industry practitioners that heavily rely on both the tools for modeling marine operations.

Density-based spatial clustering and discriminative modeling for automatic recognition and localization of cast-in hoist rings

Manual hooking the lifting gear of a crane onto the cast-in hoist rings (CHRs) of precast concrete components (PCCs) is the first step when loading PCCs for hoisting and transportation. However, the hooking process is dangerous and inefficient due to the complicated site environment and the falling risk workers may face when they need to work at height. This paper presents a method for automating the first step of the process: recognition and localization of CHRs of PCCs. We collect point clouds by placing laser radars on the surface of PCCs, and then the method follows three steps to implement the automation: denoising laser point clouds with a set of filtering rules, extracting rough recognition areas of CHRs using a spatial clustering algorithm, and determining the location of CHRs through pattern recognition. The experimental results indicate that the method achieves desired performance in terms of 0.864 precision and 0.822 recall.

The Development of the Automatic Lifting Gear for precision measurement

Precision measurement is an important method to evaluate the performance of spacecraft assembly. As flight missions become more complex, precision measurement has become an important link to ensure the reliability of spacecraft [1]. In order to solve the problems of precision measurement instruments required during the precise assembly of some components in the spacecraft assembly process, the installation height is high, the stability is sensitive, the ground measurement site is limited, the types of matching measurement instruments required are large, and the transportation needs are strong. An automatic lifting platform solution for longitude measurement is proposed, and the prototype is tested. The test results fully meet the requirements, which verifies the feasibility of the scheme.

The study of the lifting mechanism of the crane arm to a barge

During cargo loading and unloading, the vessels’ lifting gear, even if anchored or moored, is affected by the pitch and roll movements, in addition to the usual stresses, a similar shore crane is subjected to. This paper aims at presenting an analysis of the lifting operations of a boom crane pertaining to a self-propelled barge. The analysis starts with the meshing with triangle elements, the stresses and the embedding using the finite elements method. The crane and the pertaining boom were modeled using CAD design, NX 10.0 from Siemens. The lifting equipment of the ships boom crane may be subject to dangerous defects occurring during the loading and unloading process. Subsequently, the research emphasizes the stresses occurred in the piston rod and in the eye of the lifting equipment, using the finite element method (FEM). After the stress analysis, several fatigue matters are studied: fatigue safety factor, fatigue life, strength safety factor and crack. The damaging or breaking of the eye or of the piston rod from the lifting equipment of the ships boom crane is leading to the blocking of the cylinder with the result of unfavorable events, such as deformation of the boom crane, damaging the loads and even the danger of sinking the barge. The results of this analysis provide ship-owner and maintenance engineers a useful tool to take appropriate decision during inspection of the lifting gear of the ship, prior commencement of the loading and unloading operations.
 

DANSS: Detector of the reactor AntiNeutrino based on Solid Scintillator

The DANSS project is aimed at creating a relatively compact neutrino spectrometer which does not contain any flammable or other dangerous liquids and may therefore be located very close to the core of an industrial power reactor. As a result, it is expected that high neutrino flux would provide about 15,000 IBD interactions per day in the detector with a sensitive volume of 1 m3. High segmentation of the plastic scintillator will allow to suppress a background down to a ∼1% level. Numerous tests performed with a simplified pilot prototype DANSSino under a 3 GWth reactor of the Kalinin NPP have demonstrated operability of the chosen design. The DANSS detector surrounded with a composite shield is movable by means of a special lifting gear, varying the distance to the reactor core in a range from 10 m to 12 m. Due to this feature, it could be used not only for the reactor monitoring, but also for fundamental research including short-range neutrino oscillations to the sterile state. Supposing one-year measurement, the sensitivity to the oscillation parameters is expected to reach a level of sin2(2θnew) ∼ 5 × 10−3 with Δ m2 ⊂ (0.02–5.0) eV2.

Математическое моделирование рабочих процессов механизма подъема кабины грузового автомобиля

Математическое моделирование рабочих процессов механизма подъема кабины грузового автомобиля

Экспериментальные исследования систем регулирования усилий с различными электромеханическими преобразователями

The experimental researches with application of DC motor, induction motor and permanent-field synchronous motor have been performed at the stand of specialized lifting gear with a long rope-drive. At the same time different control methods of electromagnetic torque of the electric motors have been used. Experimental researches under determination of friction forces in the kinematic scheme of stand have been executed. Execution speed of control in used electric drives was determined. The efficiency of the oscillation damping in the kinematic transmission of stand has been researched by means of electric drive. In force-compensation systems with application of induction motors the frictional forces in mechanical part of the stand have the lower-range values. The highest control speed is being observed in AC drive with vector control with speed transducer. Application of force regulator allowed improving control precision and effectively limiting the oscillation in rope-drive.

Analysis and synthesis of the electric drive control system of a lifting gear which has distributive and elastic characteristics

Analysis and synthesis of the electric drive control system of a lifting gear which has distributive and elastic characteristics

A new move in energy recapture

The author explains how Urenco Power Technologies' kinetic energy storage system (UPT KESS) helps to smooth power fluctuations and maintain voltage levels in applications such as wind farms, uninterruptible power supplies, mining, heavy lifting gear and mass transit. At the heart of the system is a patented high-speed composite flywheel, which takes advantage of the basic physical laws whereby kinetic energy is proportional to the square of the speed. The modular KESS stores 14 MJ of energy, of which up to 11 MJ can be usefully used, depending upon the application.

449 歩行リハビリテーションにおける転倒防止制御

In this research, the walking support machine with a lifting up device used in the walking rehabilitation intended for elderly people was made for trial purposes. In this paper, the method of controlling the part of the lifting gear is proposed, examined, and the experimental results on confirming the operation is described. When walking, it was made to follow to patient's movement, and not to restrain by using the virtual compliance control. When falling, the fall was early detected by displacement and the reference acceleration, the motors of machine and lifting up device were stopped, posture was returned to roll up the ropes afterwards, and, the walking rehabilitation was restarted.

Design of lifting gear for a plastination laboratory.

Conventional lifting gear based on steel components can be safely used in a laboratory where acetone is used provided that: (a) the circumstances under which significant amounts of acetone vapour will be present are known and can be controlled and (b) operating practices are imposed to prevent the use of the lifting gear at times when acetone vapour may be present in explosive concentrations.

The lift‐form method

A building method has been developed by the Hungarian Institute for Building Science, where the author is the project manager, and the Kipszer industrial firm which allows flexibility in size, shape and internal layout of a building on a grid module of 1.2 m. Construction is essentially of in situ reinforced concrete. Foundations, staircase core and ground slab are first built in the normal way, but the floors are poured from the top floor downwards. The secret of this latter technique lies in a ‘space frame’ formwork support system and special hydraulic lifting gear.

Improvement of the mechanical equipment of high-head spillways

1. The wide range of computational, development, and experimental model investigations of the designs of high-pressure emergency-guard gates and main regulating gates, their movable parts and seals, hydraulic lifting gear of large capacity, gate chambers, and schemes of surplusing works performed in recent years showed the real possibility and economic expediency of manufacturing mechanical equipment for regulating large waste discharges at a head of 200 m. 2. Studies showed also the effectiveness of using the effect of swirling of the discharging flow in spillway systems. 3. Further perfection of the mechanical equipment of high-head spillways should improve the layouts, increase the precision and quality of manufacturing gates and drives, operating reliability of the seals, vibration resistance, and protection from cavitation.

The hazards of rope making.

10 ft. long. These fibres are used in the manufacture of strong heavy ropes and cables. The soft fibres of hemp and jute come mainly from Italy, India, and Chile, and are used in the main for the making of twines and cords. Some of these fibres average 8 to 9 feet in length. Flax is also used where strength and lightness of weight are required at the same time, and in recent years artificial fibres such as fibro and nylon have been increasingly used. The fibres come in bales weighing 250 to 300 lb., and these are stacked in bays up to 15 ft. high. Until modern lifting gear became available, accidents, often very severe, were common. Occasionally serious crushing accidents, or more rarely fractures of the legs, still occur, but these are being gradually eliminated. The bales are composed of bundles or heads which have to be separated by hand before the mechanical process begins. The separa tion of these heads stirs up an enormous quantity of dust. In the case of Indian hemp it was estimated some years ago that the loss of weight per bale was about 22 lb., almost 10%. Not

Cranes: their Construction, Mechanical Equipment, and Working

MODERN developments of means of transit, especially in the direction of the transhipment of heavy goods, have made it necessary that rapid and powerful lifting gear should be devised, and pari passu with the developments of heavy engines and wagons, heavy ordnance and large ocean liners, there has been an equally interesting and important advance in the construction of rapid and heavy cranes. Cranes: their Construction, Mechanical Equipment, and Working. Anton Böttcher. Translated and supplemented with English, American, and Continental Practice by A. Tolhausen. Pp. xvii + 510 (London: A. Constable and Co., Ltd., 1908.) Price 42s. net.