Crane Load Research Articles

A Flexible Scheduling Mode of Gantry Cranes for Railway Container Terminal

This paper discusses problem about improving the utilization ratio of gantry cranes, accelerating the container circulating of railway container terminal, at the same time, reducing the waiting time of trains and trucks in the station. We mainly study at the mode named multi-line flexible range loading and unloading hybrid scheduling. In the case of two train lines and the truck line, the working area of gantry crane is unlimited. This mode is proposed for sequence optimization of gantry crane loading and unloading simultaneously, as well as shortening the accomplishing time of the most difficult task for the all gantry cranes.

An EKF for Lie Groups with Application to Crane Load Dynamics

An EKF for Lie Groups with Application to Crane Load Dynamics

Universal Mathematical Model of a Hydraulic Loader Crane

The paper presents the modeling technique of working processes of loader cranes installed on mobile machines using the developed universal mathematical model that considers complex interaction between the elements of a dynamic system ‘Working Body – Loader Crane – Basic Machine – Base Surface and Substructure – Control System – Environment’. The model considers the developed feedbacks between subsystems. The paper proposes the technique of imitating modeling of a loader crane loading during the entire operation period using the Monte-Carlo method and the universal mathematical model. The application of the developed approaches is shown on the example of a task concerning the general buckling of a mobile machine ACT-4-A equipped with a loader crane in the conditions of ground subsidence under a caterpillar.

A New Method for Analysis of Sliding Cable Structures in Bridge Engineering

The Sliding Cable Structure (SCS) is widely used in bridge construction by cable crane method. The SCS generally consists of cables and fixed pulleys and the cables will slide around the pulleys when the cables are loaded until the balanced state is achieved. In this paper, an efficient Angle Bisector Method (ABM) is proposed for the mechanical analysis of SCS. The constraint effect of pulley on the cable is simulated by fixed hinge and the constraint force perpendicular to the angle bisector of cable elements adjacent to the pulley is therefore zero at balanced state. By utilizing “Unit Length Influence Matrix” (ULIM), the adjustment of unstressed length of each sub-cable can be determined. As the angle bisector at each pulley will change when the unstressed lengths of cables are changed, iterative procedures are necessary to find the convergence solutions. The proposed method is firstly verified by two examples and then applied to the analysis of cable crane during construction of the world’s longest steel truss cable-stayed bridge, namely Yachihe Bridge. Satisfactory numerical solutions can be obtained only with several iterations and are in good agreement with field measurements from the cable crane load tests, which confirms the accuracy and validity of the proposed method.

Vision-based load sway monitoring to improve crane safety in blind lifts

ABSTRACTBlind lifts on congested offshore platform (OP) environments are inherently dangerous because of the substantial presence of spatial conflicts in the crane workspace and the operator’s limited visibility to the load. This research aims to improve operators’ spatial awareness in blind lifts in the OP environment through real-time crane states sensing and visualization. A technical framework is proposed that consists of two sensing modules (i.e., crane motion monitoring and load sway monitoring) and a visualization module. To augment the robustness of the inertial measurement unit (IMU)-based method, a computer vision (CV)-based approach was introduced to track load positions for load sway monitoring. A prototype system was built and tested in an offshore platform to validate the crane motion monitoring and visualization modules. A series of lab and field experiments were conducted to evaluate the accuracy and robustness of CV-based load sway monitoring in control and real-world scenarios. The results from the field and lab tests indicate the proposed framework and methods were able to accurately monitor and visualize the crane states in real-time and thus provide the operator with adequate assistance to identify and mitigate unsafe conditions during blind lifts.

Analysis of the fatigue cracks development in crane girders and assessment of their residual life

The results of analysis of the residual life of crane girders with operational defects based on numerical studies of the stress-strain state, equations of limiting states, and kinetic dependences of the fatigue crack development, based on the criteria of deformation and fracture mechanics are presented. High level of wear of the fixed capital assets of engineering constructions and metal structures as well as operation of the facilities in beyond-design-basis terms contribute to origination of the emergency situations caused by damage accumulation. Crane girders operated under emergency conditions due to the fatigue cracks of different lengths present in the most dangerous zones of the beam wall with an eccentric application of crane load are studied. The results of the numerical experiment revealed the lines of tension intensity impact at the crack tip appeared at the upper zone of the wall at different values of the loading eccentricity attributed to the rail shift from the vertical axis of the beam. The dependence of the length of the fatigue crack and stress intensity in the crack tip on the number of load cycles of the beam is determined. To assess the bearing capacity of crane girders operated in emergency conditions, it is suggested to use the effective values of the stress intensity factors calculated for the specific loading conditions, taking into account the structural features of the beams, size of the fatigue cracks and their location in the crane girders. Proceeding from the results of analysis the diagrams which provide of the remaining residual life of crane girders with a crack are constructed. Using traditional methods of structure calculation for cyclic fracture toughness we developed and implemented the calculation algorithm for individual lifetime of the crane girders which includes the obligatory analysis of the stress-strain state of the crane girders with a crack at the upper zone of the wall.

ПОСТРОЕНИЕ АЛГОРИТМА ОЦЕНКИ ПОКАЗАТЕЛЕЙ НАДЕЖНОСТИ ПРОМЫШЛЕННОГО ЗДАНИЯ

In terms of developing automated system of calculating and forecasting the residual life of industrial buildings the article compares the advantages and disadvantages of reliability models of industrial buildings. The scheme of examining mode of deformation of an industrial building has been created. Realization of successive actions helps to determine the terms of achievement of the limiting conditions of an industrial building, to estimate the reserve strength of its carcass, and to search for changes in the amplitude values of the displacements in the calculated points, according to the results of comparative analysis of corresponding values in different periods of industrial building operation at a constant value of the generalized load. There has been carried out comparative analysis of computer-aided design systems that revealed the need to develop the proper software product specialized in calculating the work of industrial structures equipped with electric bridge cranes, with a whole complex of disturbing effects. According to the results of calculation scheme there was developed a summary algorithm which implemented the possibility of solving direct, inverse and predictive problems, as well as realizing probabilistic approach as most appropriate for random nature of man-made and natural impact, and for the conditions of their perception. Summary algorithm generates the values of crane loads in the form of continuous random values in accordance with the distribution law for the given parameters of expectation and mean-square deviation. It enables to carry out comparative analysis of the obtained probabilistic values and results of the calculation of the normative values of loads under constant conditions of the system operation. This algorithm is the basis of the development of the settlement and software complex "ASR-2018".

Probability Analysis of Crane Load and Load Combination Actions

This study presents probability models of crane load and load combination actions for reliability analysis of the industry buildings. Crane load values are simplified here only varying in time, and load combination actions only vary in space. With the feasible survey program and K-S test, the Gumbel distribution is chosen as the probability distribution of the arbitrary point-in-time crane load values with the statistical investigation data. With the simple stationary binomial random process model hypothesis and the block maxima method, it determined that the maximum value of crane load during the design reference period also follows the Gumbel distribution, with the peaks-over-threshold method evaluation. For multiple crane load combination actions, the modified Turkstra rule is improved to determine the probability distribution of the actions as the Gumbel distribution by considering the occurrence probability, numbers, location, and values of each crane load acting on the influence line, evaluated by the Monte Carlo simulations. Design standard values for crane loads and load combination actions, as specified in building codes, are evaluated based on these distributions in probability significance. The calculation results illustrate that the design standard values for crane loads are relatively safe and conservative.

PROBABILISTIC NUMERICAL CHARACTERISTICS OF OVERHEAD CRANES LOADS ON INDUSTRIAL BUILDINGS FRAMEWORKS

The article is dedicated to the development of analytical model of loads four-wheels travelling cranes loads. The design values of mathematical expectation, variance and standard for vertical and horizontal component of crane load were received. Numerical example has shown that the values of analytical numerical characteristics are very close to the experimental values of loads, and can be applied in the reliability estimation. Analytical numerical characteristics are used in the of steel framework one-storey industrial building columns calculation reliability. The time factor and the stochastic nature of the loads and the strength of steel were considered. The effect of different parameters (cranes capacity and the mode of travelling cranes, columns step, type of connection the column and girder, the type of roofing and the values of wind and snow loads) on the reliability of steel frameworks was considered.

Failure analysis of the foundry crane to increase its working parameters

Abstract Foundry cranes have an important role in metallurgical processes. The final production depends on their performance and reliability. During their operation they are exposed to a whole range of loading that influences their wear and lifetime. Crane loading is a relevant indicator, which has to be well known especially when it is necessary to realize change of performance parameters during current operation. Change of the performance parameters represents a very important intervention into the crane performance with regard to production requirements and it also influences the crane damage process or it is able to cause even the crane destruction. This paper presents a complex method suitable for a possible analysis of foundry crane operation taking into consideration increasing of the crane operational parameters, failure analysis and prediction of the limit operational parameters.

Free vibration analysis of a DST-0285 truck crane considering changes in the system load configuration

A model of a truck crane, consisting of the fundamental units of the crane, is presented in this paper. The finite element method and a COSMOS/M package were applied to perform the modelling. Research into the influence of a change in the crane radius and load location on changes in the chosen free vibrations was carried out using the built models. Diagrams containing changes in the frequency of vibrations for chosen values of the crane radius and the load are presented and conclusions are drawn.

Оценка влияния крановых нагрузок на безопасную эксплуатацию промышленных зданий

Оценка влияния крановых нагрузок на безопасную эксплуатацию промышленных зданий

Уравнивание опорных нагрузок на ходовые колеса грузовой тележки крана мостового типа при применении универсальной компоновочной схемы

Уравнивание опорных нагрузок на ходовые колеса грузовой тележки крана мостового типа при применении универсальной компоновочной схемы

Dynamic rolling strategy for multi-vessel quay crane scheduling

This paper focuses on the container loading and unloading problem with dynamic ship arrival times. Using a determined berth plan, in combination with the reality of a container terminal production scheduling environment, this paper proposes a scheduling method for quay cranes that can be used for multiple vessels in a container terminal, based on a dynamic rolling-horizon strategy. The goal of this method is to minimize the operation time of all ships at port and obtain operation equilibrium of quay cranes by establishing a mathematical model and using a genetic algorithm to solve the model. Numerical simulations are applied to calculate the optimal loading and unloading order and the completion time of container tasks on a ship. By comparing this result with the traditional method of quay crane loading and unloading, the paper verifies that the quay crane scheduling method for multiple vessels based on a dynamic rolling-horizon strategy can provide a positive contribution to improve the efficiency of container terminal quay crane loading and unloading and reduce resource wastage.

Design of Pull Box Members on the Landing Pier Using Finite Element Analysis of a Steel Plate

In this study, pull box members were designed by finite element analysis of a steel plate covering a pull box to secure its safety on the landing pier dedicated to the large research survey ship. It was assumed that the maximum load is due to the 250 tonf class crane used for unloading work when the working environment in the upper part of the landing pier was considered. The safety of the pull box was evaluated by the comparison between the yield strength of the steel plate and the result of stress analysis on the steel plate due to the crane load. It was found that the stress at the plate from the crane load exceeded the yield strength of the steel(205MPa) when the upper part of the pull box was protected by a 1950×1950mm steel plate cover. In order to compensate for this, a concrete filled steel tube(CFT) column with a diameter of 150 mm and a steel thickness of 10 mm was reinforced at the center of the plate, and the finite element analysis was carried out. However, the maximum stress at the steel plate was higher than the yield strength of the steel in some load cases so that it was tried to find appropriate thickness of the steel plate and diameter of the CFT columns. Finally, the analysis results showed that the safety of the pull box was secured when the thickness of the steel plate and the diameter of the CFT column were increased to 30mm and 180mm, respectively.

The Application of ANSYS Contact Analysis in Cable Crane Load Conversion Device

This paper briefly introduces the development and the application of cable crane. And the composition of running gears and walking principle are introduced in details. At the same time, cable crane load conversion device as an important part of it, this article has carried on the detailed introduction and analysis to it. According to the contact analysis of ANSYS for load conversion device support frame, and compare the result of the analysis under different mesh size. We can definitely know the stress distribution of support frame structure, force transmission characteristics and the analysis results are influence by mesh size. Meanwhile, it proved that contact analysis can better response to the structure actual stress state.

CRANE LOAD STATISTICAL MODELLING AND DESIGN COMBINATIONS OF THE INTERNAL FORCES

Attention has been paid to the fact that design load case combinations and design combinations of the internal forces caused by these loads have got a different probability of implementation. This fact has been is illustrated by the example of the crane loads, where the traditional calculation does not take into account such random factors as position of the crane bridge and position of the trolley on the crane bridge. Analysis has been performed using statistical modelling. Results of the modelling has been also presented. It has been suggested that there is a specific way to include load combination factors into the calculation formulas by which inclusion of temporary load in a design load case combination should be performed with combinational value of the loadcombination factor decreased when including each new temporary load.

Crane girder fatigue life determination using SN and LEFM methods

Abstract This paper examines the fatigue life of a Melt Shop crane girder with over 30 years of operation. Research indicates that the most frequent failures in these structures is related to fatigue in welded joints, thus an initial approach was performed according to AASHTO standard for calculating the remaining fatigue life of the structure. The alternating stress at the most severe loading conditions was obtained by numerical simulation in ANSYS software. Based on history and production forecasts, each critical welded joint fatigue life was determined. To calibrate the model, a field test was performed with strain gages to determine the real stress variation during regular plant operation. At this stage, crane load was parameterized in the computational model and varied to simulate the real behavior of the structure under the measured stresses. The analysis pointed out the most critical points which guided a visual inspection that identified cracks that could lead to a structural collapse. Identified crack growth was simulated through FRANC2D software that applies the LEFM method to determine the stress intensity factor. The calculated values were used to reach fatigue life for crack growth from an initial to a critical value which is expected to lead to a brittle fracture. It was concluded that the S-N method associated with finite element analysis has proven to be an efficient technique for determining the most critical structure joints damage reducing inspection work significantly. The application of linear elastic fracture mechanics techniques reached more conservative results. This technique can assist the maintenance crew in determining inspection intervals and the best moment for intervention to repair existent cracks based on the calculated remaining life.

Универсальная компоновочная схема металлоконструкции грузовой тележки крана мостового типа

Универсальная компоновочная схема металлоконструкции грузовой тележки крана мостового типа

Capacity analysis, investigations and retrofitting of a long span steel grid hangar

Abstract In this study, a reticulated long space steel hangar that does not meet the allowable maximum deflection limits was investigated. The purpose was to assess, test and reinforce the structure so as to improve its capacity and prevent excessive deformation. Upon site investigations, some members had corroded, bolts are partially tightened onto node ball, mechanical air duct are suspended on the members rather than on joints. The support joint previously designed as a flexible joint translating in the y-dir is partially fixed, and some members experienced bending near support joint. The configuration of crane load path, assumptions of column stiffness effects and errors in designing and construction of joint support configuration contributed to an increment in deflection, internal member forces and bending/rotation on members near to support joints. The structure was incrementally loaded at specified points on the grid to test and evaluate deformation and its loading capacity, and an extensive analysis was carried out before and after retrofitting. Apart from servicing the hangar, other recommended strategies are retrofitting mechanism of welding new steel tubes to existing ones and reinforcing the bolt joints was agreed upon since the hangar was observed to be elastic. The hangar member loading capacity was observed to have improved significantly after the retrofitting. This study urges the stakeholders to be keen on discussed items and on roof erection process. A schedule for monitoring the behavior of the hangar is underway.