scholarly journals Application of computer systems for modeling dynamic processes of lifting machines

2021 ◽  
pp. 69-77
Author(s):  
Volodimir Mikolayovich Grischenko ◽  
Kateryna Serhiivna Leonova
Keyword(s):  
Vertical Plane ◽  
Operating Mode ◽  
Hydraulic Cylinder ◽  
Operating Conditions ◽  
Main Task ◽  
Relative Movement ◽  
Machinery Construction ◽  
Modeling And Analysis ◽  
Successful Design ◽  
Kinetostatic Model

The main task of mechanical engineering is to organize the production of a range of machines to meet the needs of all industries. These are power, transport, lifting and transport units, agricultural machinery, construction industry, etc. Among them, one can single out devices in which the relative movement of their parts is assigned, that is, kinematic pairs are included in the calculation models. The real operating conditions of machines are varied, but most often they are associated with periodic starts-stops, which determines the relevance of the study of unsteady modes. The analysis of the operation of such models becomes more complicated. For successful design results, mathematical modeling of individual processes in mechanisms is carried out. One of the first calculations is dynamic. Modern, available CAD / CAE systems for modeling and analysis provide automation capabilities, building more realistic design models. The paper discusses the approbation of the use of CAD for modeling the dynamics of a jib crane with a set of four units: platform, boom, sleeve and rod. The developed model is combined: the platform and the sleeve correspond to the kinetostatic model, and the boom and rod are elastic. The crane is designed to perform lifting operations in a vertical plane, with the possibility of relative movement in 3 rotational and one translational kinematic pairs. The performed calculations of the static, modal and dynamic analyzes of the links of the mechanism confirm the adequacy of their models. Among them is the task of instantaneous load application, which is typical for the "lifting and picking" operating mode of crane lifting mechanisms. The deformation of the entire structure in one of the boom positions is also considered. The determination of the reaction forces in the hydraulic cylinder provides important information for the selection of the power unit.

Experimental Study on the Behavior of a Swimming Pool Onboard a Large Passenger Ship

2009 ◽  
Vol 46 (01) ◽  
pp. 27-33
Author(s):  
Pekka Ruponen ◽  
Jerzy Matusiak ◽  
Janne Luukkonen ◽  
Mikko Ilus
Keyword(s):  
Large Scale ◽  
Hydraulic Cylinder ◽  
Operating Conditions ◽  
Swimming Pool ◽  
Scale Model ◽  
Longitudinal Motion ◽  
Sea State ◽  
Passenger Ship ◽  
Large Scale Model ◽  
Computer Controlled

The water in a swimming pool on the top deck of a large passenger ship can be excited to a resonant motion, even in a moderate sea state. The motion of the water in the pool is mainly caused by longitudinal acceleration, resulting from the ship's pitch and surge motions. At resonance, there can be high waves in the pool and splashing of water. In this study the behavior of the Solarium Pool of the Freedom of the Seas was examined in various sea states and operating conditions. The motions of the pool were calculated on the basis of a linear seakeeping method, and the behavior of the water in the pool was studied with experimental model tests. A large-scale model of the pool was constructed and fitted to a purpose-built test bench that could be axially moved by a computer-controlled hydraulic cylinder. Water elevation in the pool was measured, and all tests were video recorded. Different modifications of the pool were tested to improve the behavior of the pool. A strong correlation between the longitudinal motion and the behavior of the water in the pool was found.

scholarly journals Test Results of a Polymer Radiator of MTZ-80 Tractor Cooling System

2020 ◽  
Vol 14 (1) ◽  
pp. 55-60
Author(s):  
O. N. Didmanidze ◽  
R. T. Khakimov ◽  
E. P. Parlyuk ◽  
N. A. Bol’shakov
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Cooling System ◽  
Operating Mode ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Hydrodynamic Resistance ◽  
Measuring Instruments ◽  
Research Areas ◽  
In Series

Global car manufacturers wish to increase the number of manufactured products, reduce their cost and labor input. The choice of research areas, design and technological developments in radiator construction is an extremely important and urgent task, due to the mass production of radiators for tractors and automobiles on the one hand, and the favorable development prospects of these interrelated industries, on the other. (Research purpose) To substantiate theoretically and experimentally the use of a combined cooling system containing both aluminum and polymeric water radiators and similarly liquid-oil heat exchangers based on the four principles listed above on automobiles and tractors. (Materials and methods) The authors performed bench tests using a special wind tunnel to study the thermal and aerodynamic characteristics of a prototype tractor radiator with a polyurethane core. After reaching the steady-state operating mode of the installation, the experimental values were determined for the control and measuring instruments. (Results and discussion) The authors carried out measurements of all parameters of both coolants in series at each steady-state operating mode of the bench. They obtained the main indicators dependences (reduced heat transfer, aerodynamic and hydraulic drag) of the heat exchanger, close to the operating conditions of the vehicles. (Conclusions) A prototype MTZ-80 radiator with a polyurethane core has great prospects as a future alternative radiator. An increase by 10-15 percent in the radiator heat transfer is possible by using aluminum fi ns on the surface of the polyurethane plate. A 15-20 percent reduction in hydrodynamic resistance is achieved by increasing the diameter of the capillary throughput in a polyurethane plate and the number of plates themselves in the radiator cell.

scholarly journals The influence of centrial forces on crankshaft bearing lubrication is in emergency modes of the engine of the car

2021 ◽  
Vol 12 (2) ◽  
pp. 112-121
Author(s):  
Oleksandr Khrulev ◽  
◽  
Olexii Saraiev ◽  
Iryna Saraieva ◽  
◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Operating Mode ◽  
Internal Combustion ◽  
Technical Condition ◽  
Operating Conditions ◽  
Combustion Engines ◽  
Connecting Rod ◽  
Oil Supply ◽  
Technical Expert ◽  
The Difference

The analysis of the crankshaft bearing condition of the automotive internal combustion engines in the case of insufficiency and breakage of oil supply to them is carried out. It is noted that this fault is one of the most common causes of damage to rubbing pairs in operation. At the same time, the different groups of bearings are often damaged, which cannot be explained within the framework of existing models of plain bearing lubrication. The objective of the work is to develop a mathematical model of oil supply to connecting rod bearings in emergency mode, taking into account the characteristic features of the bearing design. The model also, depending on the nature of the damage, should help to determine and explain the causes of bearing failures if they occur in different modes when operating conditions are broken. A computational model has been developed that makes it possible to assess the effect of design differences in the features of oil supply and the action of the centrifugal forces during crankshaft rotation on the oil column in the lubrication hole where oil is supplied to the conrod bearing. Calculations of the change in time of the oil supply pressure to the connecting rod bearings for the various designs of the crankshaft lubrication holes have been performed. It is shown that, depending on the operating mode of the engine and its design, the oil pressure in front of the connecting rod bearings does not disappear immediately after oil supply failure to crankshaft. Moreover, the lower the crankshaft speed is, the longer the lubrication of the conrod bearings will continue. The calculation results are confirmed by the data of the expert studies of the engine technical condition, in which the crankshaft was wedged in the damaged main bearings was found in the absence of serious damage to the connecting rod ones. It has been found that such features of the damage correspond to an rapid breakage of the oil supply to the crankshaft in the case of such operational damage as the oil pump and pressure reducing valve failure, the oil filter seal and oil pan destruction, etc. The developed model explains the difference in lubrication conditions and in the damage feature to the main and connecting rod bearings in the emergency cases of the oil supply breakage, which are observed during operation, and helps to clarify the failure causes. This makes it possible to use the model and the obtained data when providing auto technical expert studies of the failure causes of automobile internal combustion engines This makes it possible to use the model and the obtained data when providing auto technical expert studies of the failure causes of automobile internal combustion engines when the operating conditions are broken.

scholarly journals Modeling and Analysis of a Ship’s Diesel Engine Thermal System

2020 ◽  
Vol 165 ◽  
pp. 06039
Author(s):  
Chen Zuotian ◽  
Lu Jia ◽  
Dong Qingfeng ◽  
Hu cun
Keyword(s):  
Diesel Engine ◽  
Simulation Models ◽  
Operating Conditions ◽  
Pipeline System ◽  
Thermal System ◽  
Thermal Coupling ◽  
Modeling And Analysis ◽  
Temperature Changes ◽  
Modular Model ◽  
System Nodes

This article takes the diesel thermal system as the research object, which simplifies the diesel engine system into four subsystems. This article conducts a thermodynamic analysis of the specific equipment of the host thermal system. Simulink tools in MATLAB are used to build simulation models of specific equipment in the thermal system, and a modular model is used to build a subsystem model based on the specific equipment model. Then, the thermal coupling relationship between the subsystems is used to form the thermal system. The overall model obtains the temperature values of the key nodes of the thermal system network, so that it can predict the temperature changes of the thermal pipeline system nodes of the diesel engine under various operating conditions.

Modeling and analysis of soft robotic fingers using the fin ray effect

2020 ◽  
Vol 39 (14) ◽  
pp. 1686-1705
Author(s):  
Xiaowei Shan ◽  
Lionel Birglen
Keyword(s):  
Contact Forces ◽  
Accurate Estimation ◽  
Modeling And Analysis ◽  
Physical Experiments ◽  
Fin Ray ◽  
And Performance ◽  
Difficult Challenge ◽  
Kinetostatic Model ◽  
Individual Contact ◽  
The Impact

Soft grasping of random objects in unstructured environments has been a research topic of predilection both in academia and in industry because of its complexity but great practical relevance. However, accurate modeling of soft hands and fingers has proven a difficult challenge to tackle. Focusing on this issue, this article presents a detailed mathematical modeling and performance analysis of parallel grippers equipped with soft fingers taking advantage of the fin ray effect (FRE). The FRE, based on biomimetic principles, is most commonly found in the design of grasping soft fingers, but despite their popularity, finding a convenient model to assess the grasp capabilities of these fingers is challenging. This article aims at solving this issue by providing an analytic tool to better understand and ultimately design this type of soft fingers. First, a kinetostatic model of a general multi-crossbeam finger is established. This model will allow for a fast yet accurate estimation of the contact forces generated when the fingers grasp an arbitrarily shaped object. The obtained mathematical model will be subsequently validated by numerically to ensure the estimations of the overall grasp strength and individual contact forces are indeed accurate. Physical experiments conducted with 3D-printed fingers of the most common architecture of FRE fingers will also be presented and shown to support the proposed model. Finally, the impact of the relative stiffness between different areas of the fingers will be evaluated to provide insight into further refinement and optimization of these fingers.

scholarly journals Impact of Number of Operators and Distance to Branch Piles on Woodchipper Operation

Forests ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 598 ◽  
Author(s):  
Łukasz Warguła ◽  
Mateusz Kukla ◽  
Piotr Krawiec ◽  
Bartosz Wieczorek
Keyword(s):  
Low Power ◽  
Adaptive Systems ◽  
Operating Time ◽  
Operating Mode ◽  
Operating Conditions ◽  
Operating Condition ◽  
Time Frequency ◽  
Drive Speed ◽  
Type Machine ◽  
Volume Output

Branch chipping machines with low-power engines are distinguished with an intermittent operation due to a periodical supply of branches. A conventional drive speed control of these machines is not adapted to adjust the operating mode depending on frequency of material supply for shredding. This article discusses the issues related to the assessment of the application of adaptive systems similar in design to start–stop systems used in vehicles, as necessary in the driving of this type machine. During testing, an impact of a distance between a branch pile from the woodchipper, a number of operators on frequency of drive unit operating condition changes, and the mass and volume output (productivity) were considered. A percentage ratio of the active and passive (idle) operation in selected conditions of use was also determined. A low-power 9.5 kW engine-powered cylindrical-type woodchipper was used for testing. Material chopped in the chipper was freshly cut branches of oaks (Quercus L. Sp. Pl. 994. 1753) with a diameter in the largest cross-section ca. 80 mm and moisture content ca. 25%. Piles of branches were located at three different distances from the chipper, i.e., 3 m, 9 m and 15 m. Branches to the chipper were fed by one or two operators. It was demonstrated that the idle run time in tested conditions with one operator could be from 43% to 71% of the entire operating time. Frequency of operating condition changes when only one operator worked and fluctuated from ca. 6 to 2 times per minute. Increasing the number of operators from one to two had a slight impact on the frequency of operating condition changes (by ca. 7%) at the shortest distance from the chipper (3 m). However, at larger distances, the additional operator may increase the frequency of operating condition changes of the chipper by 77% for 9 m distance and 85% for 15 m distance. The mass and volumetric output of the cylindrical chipper in the most advantageous case is equal to 0.66 t/h and 3.5 m3/h, respectively. The increase of the branch pile distance from the chipper causes a drop in mass output by 32%, and volumetric output by 33.5%. The results of the tests confirmed the necessity for the development of low-power chipping machines designed for clearing operations rather than industrial production of biomass. A direction for development could be systems that adapt driving units to operating conditions, depending on a demand for the chipping process.

Semi-Quantitative Reliability-Based Ranking Method for Assessment of Pipeline Dents With Stress Risers

2018 ◽  
Author(s):  
Doug Langer ◽  
Sherif Hassanien ◽  
Janine Woo
Keyword(s):  
Complex Geometry ◽  
Limit State ◽  
Operating Conditions ◽  
Pipeline System ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
Base Level ◽  
Stress Risers ◽  
Short Period ◽  
Detailed Assessment

Current regulations for prediction and management of potential delayed failures from existing pipeline dents rely primarily on depth and conservative assumptions related to threat interactions, which have shown limited correlation with industry failures. Such miscorrelation can lead to challenges in managing effectiveness and efficiency of pipeline integrity programs. Leading integrity techniques that entail detailed assessment of complex dent features rely on the use of finite element analysis, which tends to be inefficient for managing large pipeline systems due to prohibitively complex modeling and analysis procedures. While efforts are underway to improve dent assessment models across the industry, these often require significant detailed information that might not be available to operators; moreover, they suffer scattered model error which makes them susceptible to unclear levels of conservatism (or non-conservatism). Nevertheless, most techniques/models are deterministic in nature and neglect the effect of both aleatory and epistemic uncertainties. Operators typically utilize conservative assumptions based on subject matter experts’ opinions when planning mitigation programs in order to account for different types of uncertainties associated with the problem. This leads to inefficient dig programs (associated with significant costs) while potentially leaving dents on the pipeline which cannot be quantitatively risk assessed using current approaches. To address these concerns, the problem calls for a dent assessment framework that balances accuracy with the ability to assess dent and threat integration features at a system-wide level with available information in a practical timeframe that aligns with other integrity programs. This paper expands upon the authors’ previously published work regarding a fully quantitative reliability-based methodology for the assessment of dents interacting with stress risers. The proposed semi-quantitative reliability model leverages a strain-based limit state for plain dents (including uncertainty) with semi-quantitative factors used to account for complex geometry, stress riser interactions, and operating conditions. These factors are calibrated to reliability results from more detailed analysis and/or field findings in order to provide a simple, conservative, analytical-based ranking tool which can be used to identify features that may require more detailed assessment prior to mitigation. Initial validation results are provided alongside areas for continued development. The proposed model provides sufficient flexibility to allow it to be tailored/calibrated to reflect specific operator’s experience. The model allows for a consistent analysis of all types of dent features in a pipeline system in a short period of time to support prioritization of features while providing a base-level likelihood assessment to support calculation of risk. This novel development supports a dent management framework which includes multiple levels of analysis, using both deterministic and probabilistic techniques, to manage the threat of dents associated with stress risers across a pipeline system.

scholarly journals Nonlinear Modeling and Analysis of Pressure Wave inside CEUP Fuel Pipeline

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Qaisar Hayat ◽  
Liyun Fan ◽  
Enzhe Song ◽  
Xiuzhen Ma ◽  
Bingqi Tian ◽  
...  
Keyword(s):  
Wave Equation ◽  
Pressure Wave ◽  
Fuel Injection ◽  
Nonlinear Modeling ◽  
Operating Conditions ◽  
Fuel Properties ◽  
Injection System ◽  
Modeling And Analysis ◽  
Large Pressure ◽  
Realistic Description

Operating conditions dependent large pressure variations are one of the working characteristics of combination electronic unit pump (CEUP) fuel injection system for diesel engines. We propose a precise and accurate nonlinear numerical model of pressure inside HP fuel pipeline of CEUP using wave equation (WE) including both viscous and frequency dependent frictions. We have proved that developed hyperbolic approximation gives more realistic description of pressure wave as compared to classical viscous damped wave equation. Frictional effects of various frequencies on pressure wave have been averaged out across valid frequencies to represent the combined effect of all frequencies on pressure wave. Dynamic variations of key fuel properties including density, acoustic wave speed, and bulk modulus with varying pressures have also been incorporated. Based on developed model we present analysis on effect of fuel pipeline length on pressure wave propagation and variation of key fuel properties with both conventional diesel and alternate fuel rapeseed methyl ester (RME) for CEUP pipeline.

Parametric Modeling and Analysis of Self-Loading Container Vehicle Based on ANSYS

2014 ◽  
Vol 620 ◽  
pp. 137-142
Author(s):  
Wen Bin Wang ◽  
Kai Cheng ◽  
Lei Cheng
Keyword(s):  
Parametric Modeling ◽  
Operating Conditions ◽  
Design Stage ◽  
Original Structure ◽  
Modeling And Analysis ◽  
Domestic Enterprise ◽  
Technical Requirements ◽  
Design Cycle ◽  
Research Achievement ◽  
New Generation

For the technical requirements of a domestic enterprise to develop a new generation of self-loading container truck products, this paper creatively puts forward a set of suitable reduction standards for special structure. Based on ANSYS and Visual Studio 2008 platform, the parametric modeling and automatic analysis of side loader container structure are achieved independently. Several operating conditions, such as stacking, self-loading and unloading etc. can be analyzed rapidly and automatically. The research achievement can be not only used for the conceptual design stage of forward design process, but also applied in the modification of the original structure, thus effectively shortening the product design cycle, reducing design cost, providing useful guidance for independent research of domestic enterprise.

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