Analysis of the impact of an operator’s workstation on the safety of functioning of selected road transport systems

Modern times are characterized by fast economic and social development. However, not all spheres of life have developed in a sustainable manner, for example some elements of anthropotechnical systems are still far from being sustainable. This results in low safety level of these systems involving high risk of injury or death caused by road accidents. Transport systems of the type Human-Machine-Environment , where undesired events are caused by human behavior, belong to such systems. The author of this study has addressed the issues connected with the impact of man-made objects on their operation safety. The objects in question are selected transport systems and the study subject is assessment of the equipment operator’s behavior. The main goal of this study is to provide assessment and analysis of the impact of transport means ergonomics on the quality of transport services they provide. The research object are delivery trucks with the maximum vehicle weight up to 3.5t. The first part of the study contains identification of the factors and threats which affect functioning of transport systems. Further, ergonomics criterion is defined and the factors affecting ergonomics of selected transport means are provided. A questionnaire survey was performed with participation of professional drivers who were asked to identify the factors which have an adverse effect on the safety of the transport process as well as factors that increase the drivers’ comfort of work. Basing on this, an analysis of the results was performed and negative aspects involved in driving ergonomics were identified. Document type: Articl

Simulation of rolling bearing vibration in diagnostics

This article presents results on simulation of deep groove ball bearings vibrations. Contacts between rolling elements and the races can be modelled as the Hertzian contact. This contact is on-linear, thus introduces non-linear spring forces, in consequence this vibrations are non-linear. Positions of rolling elements are functions of time, thus these vibrations can be considered as parametric vibrations. In consequence rolling bearings are active non-linear elements, which excite vibrations. This approach reflects the nature of rolling bearings vibrations. The following phenomena have been observed: bistability, jump of amplitude, opposing period-doubling bifurcations “a bubble”, period-doubling bifurcations leading to chaos, bifurcation directly leading to chaos, chaotic vibrations, windows of periodic vibrations, “noisy periodicity”, and chaotic explosion. Moreover, amplitudes of vibrations have been presented against clearance. This provides an opportunity to select failure modes. Unfortunately, relations clearance-amplitude and amplitude-clearance are ambiguous, which makes machinery diagnostic a difficult issue

Rotating systems misalignment identification using fuzzy clustering method

In the phase of operation, a technical system accomplishes goals which were the reason of the system designing and creation. The execution of operation tasks by the system causes changes in the system state. The changes in the dynamic state of rotating systems can be early identified by means of vibrations measurement. Therefore, the operational tests were performed in order to register time histories of vibrations. Next, characteristics of the collected vibration signals were recorded and the most significant of them were taken as an input for further studies. The studies were performed to formulate a method of identifying the rotating systems misalignment with high reliability. The method consists in fuzzy clustering implementation. According to the method the input signals were used to formulate the fuzzy clusters of the ability and inability states of the system. Thanks to the method, it is possible to identify the operation position of the system on base of the vibration signals analysis. In the paper the proposed method was described. The results of the method application for a gas turbine engine as an example of a rotating system are also presented. It should be emphasized that the reliability of the described operation state identification is higher than other methods implemented by the authors previously

Analysis of vibration time histories in the time domain for propulsion systems of minesweepers

This paper presents the results of research carried out on the basis of vibration analysis for propulsion systems of ships used on the same basin. Six propulsion systems, identical in terms of mechanics, placed on three seagoing vessels, have been analyzed. The considered files have been divided into catalogues, separately for each measurement point, each direction, each rotational speed, and separately for usable and unusable shaft lines. Thus, it was possible to obtain vibration time histories of particular shaft lines for every combination point/direction/rotational speed. The mean value and standard deviation have been calculated separately for usable and unusable shaft lines and for each combination and each calculated characteristic. Next, the characteristic of time histories was calculated in the time domain: integral, mean value, energy, mean power (rms squared), simple moment of I order, simple moment of II order, central moment of I order, central moment of II order, normalized simple moment of I order, normalized simple moment of II order, normalized central moment of I order, normalized central moment of II order, as well as the abscissa of the signal square gravity center, variance of the signal square, the signal equivalent diameter. It has been established that the characteristic for standard deviation lower than 15 % of the mean value is of concentrated type. On this basis the abscissa of the signal square gravity center, variance of the signal square and the value of normalized correlation function have been determined. A module and the sum of standard deviations have been calculated from the difference of mean values for usable and unusable objects for each combination and characteristic. Basing on this, it has been determined whether a given characteristic is reliable, that is, whether the module from the difference of mean values is higher than the sum of standard deviations

Analysis of vibration time histories in the time domain for propulsion systems of selected engineering objects

This paper presents the results of research carried out on the basis of vibration analysis for propulsion systems of ships used on the same basin. Six propulsion systems, identical in terms of mechanics, placed on three seagoing vessels, have been analyzed. The considered files have been divided into catalogues, separately for each measurement point, each direction, each rotational speed, and separately for usable and unusable shaft lines. Thus, it was possible to obtain vibration time histories of particular shaft lines for every combination point/direction/rotational speed. The mean value and standard deviation have been calculated separately for usable and unusable shaft lines and for each combination and each calculated characteristic. Next, a characteristic of time histories were calculated in the time domain: integral, mean value, energy, mean power (rms squared), simple moment of I order, simple moment of II order, central moment of I order, central moment of II order, normalized simple moment of I order, normalized simple moment of II order, normalized central moment of I order, normalized central moment of II order, an abscissa of the signal square gravity center, variance of the signal square, the signal equivalent diameter. It has been established that the characteristic is of concentrated type for standard deviation lower than 15 % of the mean value. On this basis the abscissa of the signal square gravity center, variance of the signal square and the value of normalized correlation function have been determined. A module and the sum of standard deviations have been calculated from the difference of mean values for usable and unusable objects have been calculated for each combination and characteristic. Basing on this it has been determined whether a given characteristic is reliable, that is, whether the module from the difference in mean values is higher than the sum of standard deviations

Correlation analysis of vibrationtime history of shaft lines for drive units of ships used for naval mines disarmament

This paper presents comparative assessment of operation quality of drive shaft lines for the same type of seagoing vessels used on the same basin. The assessment has been made on the basis of vibration analysis. The considered objects differ from each other in terms of operation range and time. 3 ships with two shafts of lines each, have been studied. Measurements were taken in 6 measuring points: for 4 engine rotational speeds: 850, 1100, 1300 and 1500. A macro has been developed to be used for division of files into axes and time histories, each including 1024 separate measurements for each point, for every direction, each rotational speed and usable and unusable shaft lines. A correlation characteristic of time histories – normalized value of correlation function for signals suitable and unsuitable in reference to a randomly selected suitable signal, has been calculated for each combination. A characteristic of concentrated type has been accepted for standard deviation lower than 15 % of the average. A module and the sum of standard deviations have been calculated from the difference of mean values of usable and unusable for use objects, for each combination of particular characteristics. It has been assumed that the characteristic is reliable if the module of mean values difference is higher than the sum of standard deviations. Since the concentration of value for normalized correlation function of signals for usable and unusable for use units is relatively high it has been assumed that this characteristic can be worked out so as to provide reliable data to be used for assessment of their operation quality in the analyzed period of time

Analysis of the Use of Fatty Acid Methyl Esters as an Additive to Diesel Fuel for Internal Combustion Engines

This study presents pro-ecological activities focused on an analysis of the use of biofuels as an environmentally friendly fuel. The research objects were different concentration mixtures of diesel fuel and fatty acid methyl esters, that is, transesterified plant oils. The tests involved an assessment of the performance parameters of a drive unit in a vehicle powered by diesel fuel for different mixtures of diesel oil and fatty acid methyl esters in the following proportions: 10%, 30%, 50% and 50% with chemical additives. The tests were comparative and were conducted for ‘pure’ diesel (ON). The study presents test results of selected performance parameters of the analyzed power unit. The object of the tests was a self-injection engine with a maximum power of 81 kW. The main tests which were most important for assessment of the mixtures, from the point of view of their effect on the analyzed performance parameters, involved measuring power and torque, and the toxic components of exhaust gases. Based on the obtained results, a statistical analysis was carried out, and a model for the evaluation of how the research object functions when fed with different fuel mixtures was developed. The research found which mixture can be considered the most optimal, and what the influence of individual fuel mixtures is on the analyzed performance parameters of the tested power unit

Analysis of the impact of an operator’s workstation on the safety of functioning of selected road transport systems

Modern times are characterized by fast economic and social development. However, not all spheres of life have developed in a sustainable manner, for example some elements of anthropotechnical systems are still far from being sustainable. This results in low safety level of these systems involving high risk of injury or death caused by road accidents. Transport systems of the type Human-Machine-Environment , where undesired events are caused by human behavior, belong to such systems. The author of this study has addressed the issues connected with the impact of man-made objects on their operation safety. The objects in question are selected transport systems and the study subject is assessment of the equipment operator’s behavior. The main goal of this study is to provide assessment and analysis of the impact of transport means ergonomics on the quality of transport services they provide. The research object are delivery trucks with the maximum vehicle weight up to 3.5t. The first part of the study contains identification of the factors and threats which affect functioning of transport systems. Further, ergonomics criterion is defined and the factors affecting ergonomics of selected transport means are provided. A questionnaire survey was performed with participation of professional drivers who were asked to identify the factors which have an adverse effect on the safety of the transport process as well as factors that increase the drivers’ comfort of work. Basing on this, an analysis of the results was performed and negative aspects involved in driving ergonomics were identified

The Multiple Criteria Assessment on the selected vegetable oils for the lubricating engine

Vegetable oils are considered to be an alternative and environmentally friendly resource of lubricants. Suitable for almost all industrial applications. They are obtained from natural raw materials, which are renewable and non-toxic to humans, living organisms, and the environment. Chemically, green oils are triacylglycerols with varying fatty acids compositions depending on the plant or seed, the crop, the growing conditions and the season, etc. The conducted research concerning matching the proper of type of vegetable oil to lubrication of the engine. The main objectives of engine oil have been drawn to the attention. To project of assessment has selected four roles of engine oil: lubrication, cooling, corrosion protection, and others (including oxidative stability, ash content, saponification value, and foam property). Each objective is described by a couple of detailed parameters of lubricants (for example viscosity index, coefficient of friction, wear scar diameter, pour point, cloud point, melting point, smoke point, flash point, iodine value, thermal conductivity, specific heat capacity, density, water content, acid number, anti-corrosion properties, etc.). In the evaluation process, AHP (Analytic Hierarchy Process) methods were used to determine the weights of individual criteria. Everything creates multiple criteria assessment of green oil. As a result of the multi-criteria assessment, most high scores have soybean oil, linseed oil, cottonseed oil, and olive

Analysis of Exhaust Gas Content for Selected Biofuel-Powered Combustion Engines with Simultaneous Modification of Their Controllers

The use of renewable resources for powering self-ignition engines in European Union countries involves a high demand for renewable energy which is not accompanied by the development of its production infrastructure. The application of biofuel in vehicle powering is supposed to provide reductions in greenhouse gas emissions and an increase in the share of renewable energy resources in the total energy consumption. The study includes the analyses of power unit exhaust components, such as oxygen, carbon monoxide, nitric oxides, carbonizers, carbon dioxide and a quantity of exhaust particles contained in exhaust gases. Tests using an exhaust gas analyzer and a vapor analyzer were conducted. Three high-pressure engines, characterized by direct fuel injection, were tested. The vehicle computer software adjustments included increasing the fuel dose and the air load. Mixtures of diesel oil and fatty acid methyl esters were used in the tests. Based on the results, a statistical analysis was performed and an assessment model was developed to understand the functioning of the research objects fueled with these mixtures, with simultaneous software changes in the vehicle computers. On the basis of the conducted analysis, it was found that only 30% of fatty acid methyl ester additives to diesel oil reduced the performance parameters of the drive units