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Experimental and computational approach to human brain modelling – aHEAD

Ptak Mariusz, Dymek Mateusz, Sawicki Marek, Fernandes Fábio A. O., Wnuk Maciej, Wilhelm Johannes, Ratajczak Monika, Witkowska Daria, Kwiatkowski Artur, Poźniak Błażej, Kubicki Konrad, Tikhomirov Marta, Druszcz Adam, Chybowski Leszek

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e218, 2023

EN

The human head is a highly complex structure, with a combination of hard and soft tissues and a variety of materials and interactions. Many researchers have used computational approaches to model the head, and several human finite element head models can be found in the literature. However, most of them are not geometrically accurate – for instance, the brain is simplified to a smooth spherical volume, which poses some concerns regarding boundary conditions and geometrical accuracy. Therefore, an advanced head model of a 28-year-old, designated as aHEAD 28 yo (aHEAD: advanced Head models for safety Enhancement And medical Development), has been developed. The model consists entirely of hexahedral elements for 3D structures of the head such as the cerebellum, skull and cerebrum, with detailed geometry of the gyri and sulci. Additionally, it is one of the first human head approaches published in the literature that includes cerebrospinal fluid simulated by Smoothed Particle Hydrodynamics (SPH) and a detailed model of pressurized bridging veins. To support the model’s credibility, this study is focused on physical material testing. A novel comprehensive experimental-computational approach is presented, which involves the brain tissue’s response to induced vibrations. The experiment successfully aimed to validate the material models used in the numerical analysis. Additionally, the authors present a kinematical model validation based on the Hardy experimental cadaver test. The developed model, along with its verification, aims to establish a further benchmark in finite element head modelling and can potentially provide new insights into injury mechanisms.

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Comparison of selected models useful in ranking the root causes of explosions in marine engine crankcases

Wiaterek Daniel, Chybowski Leszek

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2022

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nr 72 (144)

77--85

EN

This article aims to compile, describe and compare three different models taken from the literature describing the causes of explosions in the crankcases of marine engines. Each of the models has a different level of detail and was prepared with a different purpose. However, the same process, explosions in crankcases, was analyzed in all cases. A statistical evaluation of the frequency of events leading to explosions, a model built using failure mode and effects analysis (FMEA) and a model based on fault tree analysis (FTA) are described in turn. The FTA model drawn from the literature formed the basis for further analysis. Values of important measures of all elementary events of the fault tree were calculated using the Birnbaum reliability measure, Vesely-Fussell measure, Birnbaum structural measure, criticality measure and improvement potential. The percentage importance values of all events determined using these importance measures were compared. The results obtained from the application of each model were evaluated. The results of the models were compared with each other, and an approach using all three models supplemented with diversion analysis was proposed.

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Assessing the topicality of the problem related to the explosion of crankcases in marine main propulsion engines (1972–2018)

Wiaterek Daniel, Chybowski Leszek

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2022

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nr 71 (143)

33--40

EN

The purpose of this paper is to present the results of a query aimed at assessing the validity of the topic of crankcase explosions prevention in the main marine engines. The study takes into account the engine type, engine manufacturer, ship’s age, accident severity, ship’s location at the time of the incident, and the share of fatal accidents in the analyzed population of crankcase explosions. One of the primary hazards associated with offshore and deep-sea ship operations – and primarily ship power plants – are fires and explosions that result in accidents and incidents with an average frequency of 60 days. This paper discusses the actuality of crankcase explosion hazards in the main propulsion engines of various types of sea vessels. The assessment was made based on the results of a statistical analysis of historical data from 1972 to 2018. The methodology consisted of three stages: (1) a selection query to obtain the source data, (2) analysis of the obtained results (data separation, extraction of additional information, and statistical analysis), (3) synthesis of the obtained information, and drawing conclusions about the numerical indicators describing the statistical distribution of individual events for the given evaluation criteria. The analysis showed that the risk of crankcase explosions affects ships of all ages – both in crosshead (31%) and trunk piston engines (61%) – and that the number of serious incidents (67%) remained constant over the investigated period. Half of all incidents occurred on vessels younger than 15 years old. 58% of explosions took place in engines of the most popular prime movers manufacturers. The probability that a main engine crankcase explosion will result in injury or death is 17.34%.

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Simulation-based training in fire prevention and fire-fighting of scavenge air receivers fires

Chybowski Leszek, Strojecki Seweryn, Markiewicz Włodzimierz

System Safety : Human - Technical Facility - Environment

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2020

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Vol. 2, nr 1

100--111

EN

This article presents topics concerning fire hazards during the use of low-speed diesel engines in marine vehicles. The causes and effects of fires in the spaces of scavenge air receivers in marine diesel engines are presented. Methods to prevent and fight these fires are shown, including the operating procedures required from ship engine room operators. The possibility of training personnel to apply the abovementioned procedures during operation using simulations of a Kongsberg MC-90 IVship engine room is presented. Simulations were conducted which included a fire in a scavenge air receiver occurring during the operation of a MAN B&W 5L90MC main engine, with loads corresponding to 50% and 100% of the machine’s recommended setting.

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Quantitative Indicators of the Instantaneous Speed of a Ship’s Main Engine and its Usability in Assessing the Quality of the Combustion Process

Chybowski Leszek, Kazienko Damian

Multidisciplinary Aspects of Production Engineering

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2020

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Vol. 3, Iss. 1

93--106

EN

A graph of the changes in an engine’s operating speed can be used to assess the quality of the combustion in its cylinders. In this paper, the authors carried out tests on a Buckau-Wolf R8VD-136 ship engine, which was directly driving the propeller. This engine is owned by the Laboratory of Marine Engine Rooms at the Maritime University of Szczecin. For standard rotational speeds ranging from 200 to 280 rpm, with increments of 20 rpm, the authors measured the changes in the instantaneous speed for the engine’s normal operating conditions (reference graphs) as well as with one of the cylinders being out of operation. A no-combustion situation was successively introduced into each cylinder for each preset rotational speed. The obtained graphs of the instantaneous speed were then used to determine certain quantitative indicators, which the authors believe can provide information about the technical condition of the engine. The analysis concerned the averaged graphs of the speed under the conditions set for five consecutive engine operating cycles. The indicators that were calculated included the maximum difference in the speed over the engine’s full operating cycle, the uniformity of the engine speed and the differential speed area factor, the latter a term that has been proposed by the authors. The values of the individual indicators that were obtained from the reference graphs and the graphs with no combustion in one of the cylinders were compared. All indicators are sensitive to cylinder misfire. Conclusions were then drawn on the usefulness of these indicators in assessing the condition of an engine.

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The development of an explosion protection system in the starting air manifold of a high power engine

Chybowski Leszek, Kozienko Damian

System Safety : Human - Technical Facility - Environment

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2019

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Vol. 1, nr 1

26--34

EN

In this paper, the authors have discussed the subject of fire and explosion hazards during the operation of a modern ship's high-power internal combustion engines. The causes of the occurrence of and the methods of preventing explosions in the starting manifolds of modern piston combustion engines equipped with a pneumatic starting system, with starting valves on the cylinder heads, have been specified. The concept of an active system for monitoring the technical condition of the starting valves has been presented in order to quickly diagnose leakages and reduce the risk of explosion. A conceptual design of a prototype of a non-invasive, new generation leak detector for starting valves and its technical design have been presented. Exemplary implementations of the prototype detector have been shown and its selected functionalities have been discussed. This paper has ended with an assessment of the possibility of further development and the applications of this device.

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A review of TRIZ tools for forecasting the evolution of technical systems

Chybowska Dorota, Chybowski Leszek

Management Systems in Production Engineering

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2019

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nr 3 (27)

174--182

EN

This article presents tools used in the Theory of Inventive Problem Solving (TRIZ) which are useful when assessing the evolution direction of technical systems. The following matters are discussed: the S-shaped curve, laws (trends and lines) of the evolution of technical systems, multi-screen diagrams, as well as analysis of evolutionary potential. Inventive laws formulated by Gienrich Altshuller as well as laws previously formulated by a Polish writer and promoter of knowledge, Aleksander Głowacki, writing under the pen name Bolesław Prus, have been presented. Finally the innovation roadmaps have been shown. The use of individual tools has been supported by practical examples taken from research performed by the authors, and the usefulness of individual methods was evaluated. All methods have been compared and evaluated.

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Analysis of the opportunities to implement the BIZ-TRIZ mechanism

Chybowska Dorota, Chybowski Leszek, Wiśnicki Bogusz, Souchkov Valeri, Krile Srećko

Engineering Management in Production and Services

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2019

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Vol. 11, no. 2

19--30

EN

Aiming to strengthen cooperation between scientific entities and enterprises and to overcome related obstacles, the authors propose to create a mechanism of incentives called BIZ-TRIZ, which is an abbreviation for “TRIZ for Business”. This mechanism is used to support cooperation between scientific entities and companies. Close cooperation is achieved by implementing R&D&I services, which is the responsibility of the scientific unit operating for the benefit of the companies involved. Research services are used together with the scientific instrument that reflects achievements in the modern theory of innovative problem solving (TRIZ). The analysis was made using the Maritime University of Szczecin and SME-type companies as an example. This paper describes the basic assumptions concerning the implementation of the BIZ-TRIZ mechanism. Also, it presents the use of SWOT analysis, needs/stakeholder analysis and risk analysis for the implementation of the BIZ-TRIZ mechanism. The paper describes preventative actions for the most important implementation risks and discusses the results of the analyses. Finally, it introduces the main conclusions regarding the purpose of implementing the BIZ-TRIZ mechanism.