Behavior Of Cranes Research Articles

Proposal of Rocking Type of Vibration Isolation System for Container Crane.

The 1995 Hanshin Awaji Earthquake caused enormous damage to Container Cranes at Kobe Harbor. It was reported that a behavior of container crane under strong earthquakes involved uplifting and slipping of their legs. However, such behavior is not taken into consideration in the seismic design of crane, because of the difficulty due to its nonlinearly. The purpose of this study is to present a new method of the seismic isolation system for the container crane by comparing the horizontal isolation system. This paper presents the rocking type of vibration, its performance is investigated by the nonlinear transient analysis of 3-D FEM. The results show the availability of the rocking type of isolation system as well as horizontal isolation system.

1204 コンテナクレーンの地震時脱輪現象の解析と実験

The 1995 Hyogoken Nanbu Earthquake caused enormous damage to Container Crane of Kobe Harbor. It was reported that a behavior of container crane under strong earthquakes involved uplifting and slipping of their legs. However, such behavior is not taken into consideration in the seismic design of crane, because of difficulty due to its nonlinearly. The purpose of this study is to establish the method of the seismic design of container crane by verifying the analysis method which are compared the result of vibration test of 1/15 scale model. This report describe the seismic isolation method to make verification by the nonlinear transient analysis of 3-D FEM model and vibration test.

Experiment on Behavior of Container Cranes during Strong Earthquakes.

Currently, the seismic design method of a container crane is adopted the 'seismic coefficient method'(pseudo static method). In case of extremely high intensity input seismic motion such as Level 2, the dynamic behavior of a container crane is expressed in terms of lift off of the legs from the rails and locking motion. The current design method can not treat the behaviors mentioned above. To evaluate and develop the design method for the Level 2 input motion, 1/15 scale model shake tsets, simple mass-spring numerical analyses and 3-D dynamic FEM analyses were conducted. From the model shake test results, a threshold acceleration level of the lift off of the legs from the rails showed good agreement with a pseudo static horizontal acceleration of lift off the legs predicted in the design method. Proposed 3-D FEM model of container crane can simulate the dynamic behavior of a crane model during a shake table test even when the legs lifted off from the rails. The simple mass-spring model is also a useful numerical method for the case of smaller acceleration level when the legs do not lift off.

Dynamic Behavior of Rubber Tire-mounted Gantry Cranes. 2nd Report. Body Behavior and Travelling Performances.

Rubber Tire-mounted Gantry crane (RTG) is designed in a big gantry structure, and features some degree of flexibility and high position of its center of gravity. This results in a large influence against the travelling performaoces. The main factors affecting on the crane behavior (pitching romng and yawing) are the torque variation of the gantry-travel motors due to the road roughnes and inclination and the dynamic interactive forces between the tires and runway surface during the travelling motion. Based on both the experiments by actual RTG and simulation analysis, this paper clarifies the influence of the crane behavior on the travelling traiectory during straight travelling.

Patch use in cranes: a field test of optimal foraging predictions

The marginal value theorem states that foragers should leave patches when the instantaneous capture rate has fallen to the average capture rate for the habitat. This predicts that patch residence time should increase with increasing patch quality and decrease with increasing habitat quality. These and other predictions from prescient, Bayesian and fixed-time models were tested using observations on 14 radio-tagged free-living common cranes,Grus grus, foraging in cereal farmland. Cranes behaved as Bayesian foragers. Their intake rates on leaving patches changed with patch and habitat quality. The behaviour of cranes was consistent with marginal value theorem predictions only in patches where energy return was lower than required to meet daily food requirements. In contrast, birds left richer patches earlier than expected and at higher intake rates than poor patches. In addition, cranes stayed longer in larger flocks. These results suggest that cranes changed their foraging rules according to their expected energy balance.

発達障害児の「クレーン行動」に関する一考察 : 文献の展望と行動の観察例から

発達障害児の「クレーン行動」に関する一考察 : 文献の展望と行動の観察例から

Modelling of Dynamic Behavior and Control of Truck Cranes. (Modelling of Dynamic Behavior of Truck Cranes with Hydraulic System in Swing Operation).

This paper is concerned with the modelling of dynamic behavior of hydraulic truck cranes in swing operation. A crane model with a hydraulic system is proposed to study control of swaying motion of a suspended load. The booms of the truck crane and a suspended load are approximately expressed by lumped-mass models, and the mechanical system of the truck crane is combined with a hydraulic system containing a swing moter, a hydraulic pump, an operated valve, and pipe lines. The dynamic behavior of the crane model in swing operation is simulated and compared with experimental results.

Age-related differences in time budgets and parental care in wintering common cranes

ABsTRcT.-We compared the behavior and food intake rate of parent, nonparent and juvenile wintering Common Cranes (Grus grus) to evaluate possible costs and benefits resulting from parental care. Time devoted to feeding and food intake rates were highest in autumn after arrival from the breeding areas, and decreased throughout the winter in all birds. This decrease was in part determined by a decrease in food availability, but also by satiation, as suggested by the increasing time devoted to resting and other nonforaging activities. Juveniles spent more time feeding and less time alert and preening than birds of both adult classes until February, but had achieved the same time budget as nonparent adults in March, when most juveniles were already independent from their parents. Increased feeding time allowed juveniles to obtain the same daily food intake as nonparent adults during the winter. Juveniles did not change their time budget when the family was in a flock, but the net intake rate of juveniles decreased due to interference from other birds. Parents spent less time feeding and resting, and more time scanning than nonparents. Parental vigilance effort was higher in isolated families than in flocks. However, parents seemed not to suffer from parental care, since their net and absolute intake rates were higher than those of nonparent adults. Received 3 October 1991, accepted 14 June 1992.

Electromechanical modelling of overhead cranes

A non-linear electromechanical model describing the dynamical behaviour of overhead cranes is presented. The model takes into consideration the non-linear dependence of the load sway on transients of driving motors during voltage disturbances and start-ups. This is extremely useful in practice since load sway control schemes normally utilize input voltages as control variables. The mechanical subsystem within the model is that of the load sway and has the swing angles and their derivatives as state variables. Each of the two driving motors, namely, the girder motor and the trolley motor, is represented by the classical fifth-order model of induction machines where electrical transients as well as mechanical transients are considered. The model is linearized using Taylor series expansion around a normal operating point. A numerical example is presented to illustrate the usefulness of the results.

Dynamic Behaviors of Gantry Cranes. 5th Report. Natural Frequency.

For the design of material-handling equipment like gantry cranes, for which large size and high performance have been demanded, it is important to evaluate their dynamic behaviors. In this paper, the dynamic behaviors of gantry cranes with loads are analyzed by the method of modal analysis, and the main factors having effects on the natural frequency are investigated. On analysis, the coupling of deformation behaviors in the horizontal and vertical directions is considered. The importance has been clarified from a series of studies. Moreover, simple equations for calculating the fundamental natural frequency in structural parts of a crane with a load are proposed. The results from these equations are in good agreement with those from the experiment using an actual crane, and the equations are useful for the design of gantry cranes.

Ressources en maïs et stationnement hivernal des grues cendrées (Grus grus) dans le sud-ouest de la France

The influence of distribution and abundance of food (maize) on Common Crane behaviour and distribution patterns in time and space was analysed in the farmlands of south-western France. The maize stock most likely to be exploited by cranes gradually decreases from November to March because of autumnal germination, seed mass loss during winter, and burial during tilling of the soil. The variation of crane numbers over time does not depend on seed stock changes. The feeding behaviour of these birds does not change with decreasing seed availability, whereas gregariousness increases. The plots most likely to be selected by cranes offer accessibility to seeds and the best food supplies: crushed maize, in the first instance, and when this is not available, pulverized maize. Feeding behaviour and gregariousness do not vary with plot quality.

Dynamic behavior of gantry cranes. 4th Report, The hoisting dynamic coefficient.

This paper is the fourth part in a series of research reports on the dynamic behavior of gantry cranes. The hoisting dynamic coefficient is an important parameter in crane design. In this paper, the limitation of the formulas in current use calculating the hoisting dynamic coefficient is proved by both theoretical result and experimental result. A new simplified formula which will be useful in practical design is proposed. It will be helpful to the engineers engaged in the crane design and research.

Dynamic behavior of truck cranes in pile pulling out motion.

The behaviores of a truck crane during pile pulling out, tipping and load hoisting are numerically analyzed, using FEM model with nonlinear elements. To verify the analysis, experimental tests are carried out using a scale model. The numerical results are in good agreement with the experimental data. The differences between the dynamic stress and rope tension for each motion are clarified.

Dynamic behavior of gantry cranes. 3rd Report. The hoisting-traversing combined motion.

This paper analyzed the dynamic behavior and stresses of gantry crane structures during the hoisting-traversing combined motion using a simulation model. Equations of motion for the hoisting-traversing combined motion are obtained on the basis of the theory established in the 1st and 2nd papers. The theoretical results are in good agreement with the experimental data. In addition, the dynamic effects of variations of operator's operation timing in the hoisting-traversing combined motion have been measured using a testing machine. The following conclusions are obtained. (1) To reduce the dynamic effect of changes of rope tension, it is more effective to perform hoisting motion prior to traversing motion. (2) To decrease horizontal vibration, good timing operation is necessary. These conclusions are considered to be useful for the forthcoming dynamic design of gantry cranes.

Dynamic behavior of gantry cranes. 2nd report. The study on traversing motion.

This paper analyzes the dynamic behavior and stresses in a gantry crane structure during traversing motion using a simulation model. Mathematical equations for the deflection curve of a crane structure are given, and the equivalent masses and spring constants are obtained through the static condensation method. The theoreticant analysis is in good agreement with the experimental results. Non-dimensional coefficients with regard to vertical and horizontal deflections and a method of describing vertical and horizontal deflections in the static state by using those coefficients will be useful in the design of gantry cranes. In addition, the result shows that the maximum stress in a structure is sensitive to the swing angle of its load, which be a significal point of discussion in the future national and international design standards for gantry-type cranes.

Dynamic behavior of gantry cranes. (1st report The study on load hoist motion)

Dynamic behavior of gantry cranes. (1st report The study on load hoist motion)

Dynamic Behavior of Truck Cranes Equipped with the Box Jib : 1st Report, The Study on Load Hoist Motion and Jib Hoist Motion

The behavior of a truck crane equipped with a telescopic box jib during load hoisting and fib hoisting is numerically analyzed on the basis of a simulation model. To verify the analysis, experimental tests are carried out using a real crane. The theoretical results are in good agreement with the experimental data. Thus, the dynamic behavior of truck cranes with a box jib can be predicted, Effects of jib rigidity, jib inertial forces, and braking time on the behavior of such cranes are also revealed in the analysis.

Some observations on mating behaviour of several cranes in captivity

Responding to the actions of the mate and taking somewhat fixed patterns,Grus japonensis, G. vipio, G. antigone, Anthropoides paradisea andBalearica regulorum pairs are finally led to copulation by a sequence of mating behaviours. There are slight differences in pre-copulatory behaviour patterns between the species and the female's ‘wing-spreading’, being the soliciting and key posture for copulation, differs between the genera; The female's wings are spread wide inGrus, fairly wide inAnthropoides, and are almost folded inBalearica. Post-copulatory behaviours, however, have definite species-specific characters. They usually consist of ‘head-down’ (bowing) or ‘warping’, ‘arching’, etc. immediately following the dismounting of the male inGrus. But a pair ofBalearica first keep their heads high, or gaze at each other for a while, and then show remarkable ‘ruffle-bowing’. These characteristic post-copulatory behaviours are obviously correlated with the threat displays, evolved under agonistic situations, typical to each species.