Bronislovas Spruogis

Influence of manufacturing methods on the tribological properties of rapeseed oil lubricants

Tribological properties of rapeseed oils manufactured and processed by different methods and modified by the anti-wear additives were analysed. Tribological tests presented that unrefined rapeseed oil has better wear resistance compared to refined oil. Modification of rapeseed oil with 2% of special biological anti-wear additives has the greatest influence on refined rapeseed oil. Chemical analysis shows that refinement removes acids from oil. Refinement and lower acidity allows more efficient operation of special biological anti-wear additives.

The influence of Oxidation on Tribological Properties of Rapeseed Oil

Abstract Approximately a half of all consumed lubricants, in one or another way, end up in the environment. Some countries put forward recommendations or even requirements for the use of environmentally friendly bio-lubricants the purpose of which is to reduce a negative influence of lubricants. The priority areas of using environmentally friendly lubricants cover water transport, hydraulic systems in forestry machinery, railway applications, road building machines etc. Particularly it is the case when an increased possibility of putting a lubricant in the environment occurs. Regarding good lubricity and excellent biodegradability, vegetable oils are widely used as environmentally friendly lubricants. The biggest disadvantage of vegetable oils as base stock for lubricants is pure oxidation stability. This article deals with the influence of thermal oxidation on tribological properties of rapeseed oil. The obtained results show that oxidation decreases lubrication ability due to structural changes in oil. ...

Overhead crane anti-swing system based on the Pontryagin’s maximum principle

Overhead cranes are widely used at industrial enterprises for transportation of materials and products. They are successfully adaptable to technological processes used at an enterprise and their exploitation is inexpensive; in addition, the price of cranes is relatively low. However, extension of requirements set for technological processes results in shortened time for transportation and stiffened requirements for accuracy of cargo delivery and cargo safety. In the attempts to satisfy the latter requirements, particular attention is paid to swings of the cargo-holding rope. There is a number of factors that cause increased requirements for the control system of the crane drive. The slewing movement affects the total system of the crane and aggravates the crane movement control. In modern overhead cranes, the abilities and qualification of an operator (who is assisted by a certain anti-swing system) predetermine the cargo swings and the accuracy of its positioning. The said circumstance latterly caused a particular attention to computerisation of overhead crane control. However, a nonlinearity of the mechanical system of a crane and complicated control of swings often cause undesirable swings, in particular in the beginning and the end of cargo transporting process, thus reducing the efficiency of usual crane control systems. In addition, it should be taken into account that the parameters of a crane, as a controlled mechanical system, depend on the cargo and the conditions of its transportation. Consequently, a development of an effective cargo swing reduction system is a currently topical engineering problem.

Pipeline Robots With Elastic Elements

Abstract In the article constructions of the pipeline robots with elastic elements are reviewed and the scheme of new original construction is presented. The mathematical models of a robot with one-dimensional vibration exciter with two degrees of freedom were developed and the equations of movement were formed and written. The mathematical model of the pipeline robot with circular elements is formed and its motion equations are presented.

Wall Press Walking In-Pipe Robot

This paper reviews a new wall press walking in-pipe robot. The provided design method is based on pneumatic actuators. This mobile robot can move in pipe of 300 mm diameter. In the first part of this paper, we explain the locomotion principle of the robot, and then we present the design method of the wall press walking in-pipe robot parts.

Dynamic Reaction Forces of an Overhead Crane on Lifting

Abstract In the recent period, girder bridge cranes are replaced with double-beam overhead cranes with a rectangular cross-section of the beams. In addition, new materials are used for producing them thus applying other values of allowable loads and deformations. The paper focuses on two overhead cranes working for JSC Vilniaus kranai (Vilnius Cranes). The presented mathematical model provides an opportunity to assess the structural peculiarities of the above introduced cranes. The calculated results of dynamic loads appearing in the beginning and the end of the lifting process and having an impact on the lifting mechanism and metal structure are provided in the article.

Development of pipe crawling robots with vibratory drives and investigation of their kinematic parameters

Abstract In the article the classification of pipe crawling robots with vibratory drives is presented, their advantages and imperfections are reviewed. The schemes of the construction of a pipe crawling robot with a vibratory impulse drive and a pipe crawling robot with a vibratory pneumatic drive are discussed. The dynamic models of a robot with a vibratory impulse drive and of a robot with a vibratory pneumatic drive were developed and the equations of their movement were formed and written.

The Dynamic Errors of Mechatronically Controlled Lifting Equipment

Upon striving to ensure the cargo safety and precizity of its delivery, mechatronic control systems are more and more widely applied in lifting mechanisms. They get information from various sensors, including those involved in registering the rope’s deformations. The got information may be distorted because of the appearance of cargo swinging that’s level depends on the mode of operation of the lifting mechanism and the rope’s elasticity. The latter varies dependently on the length of the unwound rope and the way of deformation of rope’s wires. In the paper, a mathematical model of a lifting mechanism that describes its dynamics on lifting when both the cargo and the rope swing in respect of a vertical axis is provided. The model was examined by a special program developed upon using MATLAB and SIMULINK program packages. The obtained dependences of the swing parameters on the mode of operation of the lifting mechanism and the rope’s parameters enable assessing a possible application of the lifting mechanism.

Analysis of wearing-out causes for revolving-blade mixers and their reliability improvement

Abstract In road coverings and structures of transport infrastructure, composite mixes of various compositions are used made with either organic or mineral binding agents. Most often they are made in a discreet revolving-blade forced mixer, and the final product quality is subject to the mixer construction and parameters. The present paper analyzes wear causes of a revolving-blade mixer with the most important of them-sticking of grains between the blade end and the bottom. Forces are defined effecting various-sized grains found between the blade end and the mixer bottom. Mixer quality assessment methodology is presented, based on analysis principles of homogeneity dynamics for mix being made by it. It is demonstrated that construction homogeneity estimates are different for mixers with various wearing-out levels. Wearing- out of mixer elements may be reduced and mixing quality for mix may be improved by choosing the optimum distance between the blade end and the bottom fretting and changing blade metal a...

A simultaneous parametric analysis of the in-cylinder processes for diesel engines

This paper describes the basic methodological principles and the results of development and practical application of simultaneous complex parametric analysis of the in-cylinder processes and thermal load on Cylinder Piston Units (CPU) in diesel engines. The application of this method to research and conceptualise engine design allows us to choose an optimal combination of the CPU parameters and diesel engine control. As a result, an admissible level of thermal stress in the CPU and low fuel consumption are achieved. The method was practically used for upgrading high-speed diesel engines of the trademarks CHN 16.5/18.5, BMD and D20.