• MACHINES

    Influence of trolley motion in the dynamic behavior of semi-portal cranes

    Machines. Technologies. Materials., Vol. 15 (2021), Issue 5, pg(s) 170-175

    The paper presents dynamic analysis of the Semi-Portal Cranes for the case of Trolley motion travelling on Crane’s Girders. Semi-portal cranes are mainly mounted in the industrial facilities, and they consist of metallic structures with big dimensions and many mechanisms that carry heavy loads. We will analyze the influence of the Trolley motion in the dynamic behavior of Semi-Portal Crane while carrying maximum Load, in particular the influence of Load swinging and oscillations. The method of analysis is acquiring experimental measurements and comparing those results with the results gained through modeling of crane, and carrying simulations. Designing the Crane’s 3D model with software and motion simulations is the method applied in the paper to analyze dynamics and is important to explain the form and intensity of oscillations that can cause accidents, failures of parts, and other concerns about the safety. Analysis will be done for maximal and minimal speed of the Trolley. Conclusions from this paper will be useful about the design, dynamic response and safety of Semi-Portal Cranes. The analysis will be focused to find main kinematic and dynamic parameters influencing the crane dynamics, like forces, moments, speed (velocity), and Load swinging magnitude. The Crane is modeled based on the Data from standard manufacturer of Semi-Portal Cranes.

  • TRANSPORT TECHNICS. INVESTIGATION OF ELEMENTS. RELIABILITY

    Scissor lift dynamic analysis and motion regulation for the case of lifting with maximum load

    Trans Motauto World, Vol. 6 (2021), Issue 2, pg(s) 38-42

    This paper deals with Dynamic analysis of Scissor Lifts during the Load Lifting to determine their dynamic behavior, find the nature of oscillations, and the regulation of lifting to minimize these oscillations and optimize the work process. During the motion processes, the lift and its main parts undergo heavy forces, moments, and oscillations. The method of research is acquiring results through design, modeling, and simulations, comparing them with analytic calculations, and looking for the optimal motion regulation of the Load Lifting. The analysis will be acquired when the Scissor lift is carrying maximum Load. The study will be concentrated in the finding the nature of dynamic forces and stresses that acts on the main parts of the lift and the extent and the form of oscillations. Results will be shown in the form of diagrams and contour views as the solution results of the tested system. Modeling and simulations will be carried using software SimWise 4D, based on the type of the Scissor Lift taken from Standard Manufacturer. Conclusions of these analyses are useful for design considerations, dynamic behavior, and safety of these types of lifts.

  • TRANSPORT. SAFETY AND ECOLOGY. LOGISTICS AND MANAGEMENT

    Improving the Performance of a DTN with Transportation System in Tirana City

    Trans Motauto World, Vol. 6 (2021), Issue 1, pg(s) 20-23

    Delay Tolerant Networks (DTNs) enable communication in networks with low density, low connectivity and high mobility. DTNs are suitable in areas where an infrastructure does not exist. DTNs use store-carry-forward approach. The performance of such networks is strongly connected with nodes mobility. Vehicles can be part of DTNs. In this paper we will investigate the role of buffer size and vehicles of transportation system as message forwarders in a DTN in Tirana city. The performance metrics for evaluation are delivery probability, average latency and overhead ratio. The simulation results show that transportation system can be used as a backbone for DTNs in urban areas.

  • MATHEMATICAL MODELLING OF TECHNOLOGICAL PROCESSES AND SYSTEMS

    MODELING AND SIMULATIONS OF AN UPPER LIMB EXOSKELETON DESIGNED FOR REHABILITATION AND TRAINING

    Mathematical Modeling, Vol. 3 (2019), Issue 2, pg(s) 59-62

    The work presents a study of an upper limb exoskeleton designed for rehabilitation and training. While in the first stages of rehabilitation, when the patient is unable to move alone, the exoskeleton must be rigid, in the next stages it should be able to respond to any movement made by the patient. The key feature here is transparency: the robot must be able to “hide” if the patient is able to make the movement without assistance. The aim of the work is to identify and evaluate an appropriate solution of the upper limb exoskeleton that provides transparency and natural safety on the one hand, and force impact and performance on the other. In the paper, the mechanical model of the exoskeleton was shown. The mechanical structure is similar to the structure of the human arm. Through the kinematic model, the direct and inverse tasks of kinematics are solved using the Octave matrix software. The upper limb exoskeleton is designed as a haptic device that can perform tasks in virtual reality. Simulations of the interaction force between the patient and the exoskeleton were conducted also using the Octave software. Here, an assessment of the interaction force was made as a result of the exoskeleton passive impedance and the active control of the exoskeleton. Finally, conclusions and development recommendations are given.

  • DYNAMIC ANALYSIS OF BRIDGE CRANE WITH ONE MAIN GIRDER DURING TELPHER MOTION WITH FULL LOADING

    Machines. Technologies. Materials., Vol. 12 (2018), Issue 8, pg(s) 305-308

    This paper deals with dynamic analysis of bridge crane with one main girder during telpher motion in order to determine dynamic behavior and oscillations while carrying full load. During the telpher motion the main girders and side girders are heavy loaded parts while they undergo forces, moments and oscillations from lifting mechanism that carries workload. The method of analysis is the comparison of results gained through modeling and simulation and experimental measurements. The analysis will be concentrated in finding the nature of dynamic forces, moments and stresses that acts on main crane’s parts and finding the extent and form of oscillations that can cause damage and failures. Also the interest is to study the effects of load swinging in crane’s stability. Results will be shown in the form of diagrams as the solution results of the tested system. Crane is modeled from standard manufacturer, as a special type of Bridge Crane with one main girder and telpher. Conclusions of these analyses are useful for design considerations, dynamic behavior and safety.

  • MATHEMATICAL MODELLING OF TECHNOLOGICAL PROCESSES AND SYSTEMS

    ROTATIONAL MOTION OF TOWER CRANE – DYNAMIC ANALYSIS AND REGULATION USING SCHEMATIC MODELING

    Mathematical Modeling, Vol. 2 (2018), Issue 1, pg(s) 21-25

    This paper deals with dynamic analysis of particular type Construction Cranes known as tower crane during rotational motion of its jib. Methodology of analysis consists of Schematic Design of model, which implements schemes with block diagrams to analyze cranes and their parts during particular work cycle. This procedure consists of crane model development of interconnected elements that represents crane parts, 3-D visualization and simulation of motion. Analysis will be carried out through simulations, and solution of Euler differential equations of second order gained from schematic model. Dynamic parameters investigated are: acceleration, angular velocity, forces and torques in main parts of crane, and influence of load swinging. Diagrams will be presented for main parts of crane as the solution results of the analyzed system. Results gained will be used to get conclusions about dynamic behavior of crane, present graphs of main parameters and search for regulation of optimal jib rotation. Analysis will be done using modeling and simulations with computer application MapleSim. Also, results gained from simulations will be compared with those from experimental measurements.

  • MACHINES

    MATERIAL DEFORMATION ANALYSIS IN BRIDGE CRANE DURING TRAVEL MOTION WITH FULL LOADING

    Machines. Technologies. Materials., Vol. 11 (2017), Issue 8, pg(s) 389-392

    This paper deals with dynamic analysis of bridge crane with single girder in order to determine material deformations in their main parts – cables and girder’s, while moving and carrying load. It is known that these are mostly loaded parts in crane, while they accept forces, moments and oscillations from lifting mechanism and load. Analysis will be accomplished using computer modeling and simulations. Work process of crane in the study is forward travel motion. It is assumed that this motion process makes major impact in the deformations of lifting cables and girders due to stress, oscillations, and negative effect of load swinging. The analysis will be concentrated in finding the nature of oscillations that acts on crane and finding the extent and form of materials stress and deformations that can cause fatigue, failures and accidents. Question is whether acting loads exceed elasticity limits, or there are plasticity deformations which lead to permanent damages. Results will be shown in the form of diagrams, contour stress and strain in cables and girders. They will be compared with experimental measurements. Conclusions of these analyses can be useful for design considerations and safety.

  • MACHINES

    DEVELOPMENT OF SCHEMATIC DESIGN MODEL OF GANTRY CRANE FOR DYNAMIC ANALYSIS AND REGULATION OF TRAVEL MOTION

    Machines. Technologies. Materials., Vol. 11 (2017), Issue 6, pg(s) 268-271

    This paper deals with Dynamic analysis of Gantry Crane using Method of Schematic Design which implements schemes with block diagrams to analyze machines and their parts during work process. This procedure is new to analysis of Gantry crane dynamics and consists of crane model development of interconnected elements that represents crane parts, 3-D visualization and motion of crane. Dynamic analysis will be carried through simulations and solution of Euler differential equations of second order gained from schematic design. Simulations will be planned and applied for regulation of travel motion with hanging load. Diagrams with results of main dynamic and kinematic parameters will be presented for main parts of crane as the solution results of the analyzed system. Results gained will be used to get conclusions about dynamic behavior, optimal motion regulation and safety during work. Analysis will be done using modeling and simulations with computer application MapleSim.

  • MACHINES

    TRUCK MOUNTED CRANES DURING LOAD LIFTING – DYNAMIC ANALYSIS AND REGULATION USING MODELLING AND SIMULATIONS

    Machines. Technologies. Materials., Vol. 10 (2016), Issue 8, pg(s) 12-15

    Truck Mounted Cranes are used for load lifting and lowering, mainly in construction industry for materials handling. These cranes have complex structure with many parts and mechanisms with bars, linkages, actuators, cables, outriggers, etc. Using modeling and simulations with software we will analyze dynamics and oscillations in crane while lifting the maximal load, and methods of control of these oscillations in order to optimize the work process of truck crane. Dynamic parameters analyzed are: velocity, acceleration, angular velocity, forces and torques that act in main parts of crane, including load swinging. The study will be accomplished with design of block diagrams that represents crane model and motion, and gain results in form of diagrams containing main kinematic and dynamic parameters. Results of the tested system will be used to get conclusions about dynamic behavior of crane, and look for optimal motion control. Analysis will be done using modeling and simulations with software MapleSim, based on truck crane from standard manufacturer.

  • STUDYING ROTATIONAL MOTION OF LUFFING BOOM CRANES WITH MAXIMUM LOAD USING SIMULATIONS

    Machines. Technologies. Materials., Vol. 9 (2015), Issue 12, pg(s) 20-23

    Luffing Boom Cranes are type of cranes used for load carrying in building sites. They have complex structure with big dimensions and mechanisms. Their working usage is high. Main cycles of the work of Luffing Boom cranes are: lifting and lowering the working load, Boom luffing – upwards and downwards, rotation around vertical axes, and (if mobile type) translational movement forward and backwards. In this work, we are going to study the work of this crane while rotating with full loading. Study will be done using simulations with computer applications. The aim is to see the effects of dynamic forces and moments in the crane’s main parts – metal construction, cables, and constraints during rotational work cycle, particularly at the start and end of the rotation. Also interest is to study the effects of load swinging in crane’s stability. For this purpose, we modeled with software entire luffing boom crane. Crane is modeled from standard manufacturer, as a common model of luffing boom Crane.

  • INFLUENCE OF LOAD SWINGING ON DYNAMIC BEHAVIOR OF L-TYPE PORTAL CRANES DURING FORWARD TRAVELLING

    Machines. Technologies. Materials., Vol. 9 (2015), Issue 7, pg(s) 69-72

    Portal Cranes are used for load carrying in industrial and transportation sites. They have complex structure with big dimensions and many mechanisms with high security requests. In this work, we will study the influence of load swinging in dynamic behavior of Single girder L- type portal crane, in case of forward motion- travelling with full loading using computer modelling and simulations. Studying the behavior of portal cranes proves to be difficult using physical experimentation and measurement devices. Creating the crane’s computer model and applying simulations is useful method to study dynamic occurrences, which helps explaining the reasons of oscillations, failures and accidents of cranes, and gives conclusions that can be useful for design considerations and safety. The analysis will be concentrated in finding the nature of forces, moments and stresses that acts on crane’s construction and effects the stability, particularly at the start and end of travelling motion. Also, the study will look to find main parameters that contributes on the negative effects of load swinging. For this purpose, we designed “virtual portal crane” using model design and simulation applications. Crane is modeled from standard manufacturer, as a common model of L type portal cranes.

  • ANALYSIS OF THE VEHICLE UNDERCARRIAGE

    Machines. Technologies. Materials., Vol. 9 (2015), Issue 7, pg(s) 25-28

    Parameters of the vehicle undercarriage affect the vehicle movement and its behaviour on the road or on the terrain. Basic geometry of the vehicle undercarriage can be expressed by mathematical methods, yet undercarriage analysis of the moving vehicle on the terrain is very complex procedure. We have to take into account wheels vertical movement and deflection (which influences the suspension system). Utilization of the simulating technologies can be very beneficial for solution of this issue. The paper is focus on mathematic model of the vehicle undercarriage and its application for analysis of the vehicle undercarriage.