Wyniki wyszukiwania - BazTech

1

Assessing the usefulness of simplified project management frameworks in a small enterprise context

Wawak Sławomir, Zakrzewska Małgorzata

Zeszyty Naukowe. Organizacja i Zarządzanie / Politechnika Śląska

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2025

|

z. 224

621--642

EN

Purpose: The study aims to evaluate the applicability and perceived usefulness of a light¬weight project management methodology tailored for small-scale projects, particularly within environments with limited project management experience and resources. Design/methodology/approach: An experimental research design involving multiple student¬led teams executing real-world small projects over four months was employed. The methodology under evaluation was systematically applied by each team, supported by trained mentors. Data were collected through structured surveys assessing various dimensions of the methodology’s practicality and effectiveness, including documentation, role clarity, stakeholder engagement, and risk management. Findings: The findings indicate that simplified project management approaches can effectively support small project environments. Respondents reported high satisfaction levels with the ease of use, clarity of documentation, and effectiveness of core tools such as role assignment mechanisms, project boards, and deliverables mapping. The methodology also demonstrated utility in enhancing stakeholder communication and managing evolving project requirements. Minor challenges were observed, primarily related to stakeholder engagement variance and unforeseen risks. Research limitations/implications: The study’s limitations include student teams in an academic setting, not fully reflecting commercial pressures or dynamics. Mentor involvement may have inflated performance, limiting findings’ generalizability and needing further research. Practical implications: The study suggests that small enterprises and nonprofit organisations can benefit from adopting streamlined methods that emphasise clarity, frequent feedback, and simple documentation. Originality/value: This study contributes to the limited empirical literature on project management in small-scale and resource-constrained environments. It provides evidence-based insights into minimalist project management methodologies' practical benefits and limitations, offering value for researchers, practitioners, and educators seeking adaptive, accessible tools for managing small projects in SMEs, NGOs, and student settings.

2

Wpływ kąta opasania łopatki dzielonej na parametry pracy pompy odśrodkowej

Zaręba Filip, Nycz Aneta, Szulc Przemysław

Rynek Energii

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2025

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Nr 4

71--77

PL

W artykule poruszono istotne zagadnienie zwiększenia sprawności pompy odśrodkowej poprzez zastosowanie modyfikacji w budowie łopatek wirnika. Modyfikacja ta polegała na wprowadzeniu szczeliny w łopatce – tzw. łopatki dzielonej – mającej na celu poprawę warunków przepływu cieczy w kanale międzyłopatkowym oraz ograniczenie strat energetycznych wynikających z występowania zawirowań. Dla danej wartości kąta opasania łopatki przygotowano model referencyjny z łopatką ciągłą oraz model z zastosowaniem w niej przerwy. Otrzymane wyniki pozwoliły na określenie parametrów pracy pompy oraz wpływu zastosowania szczeliny w łopatkach na charakterystykę pompy dla różnych wariantów kąta opasania łopatki. Na podstawie przeprowadzonych badań eksperymentalnych wyciągnięto wnioski dotyczące zakresów geometrycznych, w których modyfikacja ta prowadzi do wzrostu sprawności, a także wskazano przypadki, gdzie jej zastosowanie może być niekorzystne.

EN

This article discusses the important issue of increasing the efﬁciency of a centrifugal pump through the use of " odiﬁcations to the impeller blade design. This modiﬁcation consisted of the implementation of a gap in the blade- the so“called split blade- with the aim of improving the ﬂuid ﬂow conditions in the interscapular channel and reducing energy losses due to turbulence A reference model with a continuous blade and a model with a gap in the blade were prepared for a given blade wrap angle value The results obtained allowed the determination of pump performance and the effect of using a gap in he blades on pump characteristics for different variants of blade wrap angle. On the basis of the experimental studies carried _ ut conclusions were drawn regarding the geometric ranges in which this modiﬁcation leads to an increase in efﬁciency, as [ ell as indicating cases where its application may be unfavorable.

3

Transient analysis of electrodynamic forces in low-voltage compact busbar

Szulborski Michał, Łapczyński Z., Szulborski Paweł, Kolimas Łukasz, Berowski Przemysław, Owsiński Maciej

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Vol. 73, nr 5

art. no. e154204

EN

The paper concerns the effects of electrodynamic forces that act on the current paths of the industrial low-voltage busbar. This work is composed of experimental and simulation sections. In the experimental section, the short circuit tests were presented, and the occurrence of electrodynamic forces was demonstrated. The formation of electrodynamic forces in the current circuits of electrical energy distribution systems is related to the flow of high currents, mostly short circuit currents. To highlight those phenomena a detailed specification of parameters during tests was displayed. In the simulation section, the physical phenomenon of electrodynamic forces is captured by employing a detailed real-scale model of a commercial busbar. Therefore, the authors proposed the employment of the FEA (finite element analysis) to obtain values of electrodynamic forces acting on the current paths by executing a detailed 3D coupled simulation. The analysis of the results and aftermath effects of their interactions led to interesting conclusions that concerned the operation of such power distribution circuits under short-circuit conditions.

4

Experimental testing of a rocket motor thrust vector control actuation system demonstrator

Nocoń Łukasz Krzysztof, Szmidt Piotr Krzysztof

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2025

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Vol. 73, nr 6

art. no. e155040

EN

This paper presents the results of simulation and experimental studies concerning the control of a rocket motor thrust vector direction. The change in direction was achieved using a developed and constructed control actuation system demonstrator. The first part of the article focuses on presenting the demonstrator for a hypothetical rocket missile equipped with this system and simulations of the missile flight control. Simulation results determined the required thrust vector deflection angles. Subsequently, this data was used to program the control actuation system (CAS) and conduct experiments on the physical demonstrator. By commanding specific deflections of the actuator system over time, the resulting forces and moments were measured during thrust generation, simulating flight scenarios for approximately 8 seconds. The results indicate that the proposed actuator system performs its function effectively, deflecting the thrust vector largely in line with simulation predictions, after adopting system efficiency coefficients. The novelty of this work lies in comparing real-time actuator testing with a simulation control for subsonic ATGMs and finding deflection efficiency coefficients to improve the simulation model.

5

Experimental study of raster angle effects on crack propagation in SENT specimens of PLA manufactured by FDM

Aourik O., Chouaf A.

Archives of Materials Science and Engineering

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2025

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Vol. 134, nr 1

5--13

EN

Purpose: The study aims to investigate the impact of raster angle and filament configuration on crack propagation mechanisms in 3D-printed PLA parts. Although numerous studies have addressed surface quality, stiffness, and strength, there is still a lack of understanding regarding fracture behaviour and damage propagation in printed polymers. This paper aims to fill that gap by analysing how specific printing parameters affect fracture resistance. Design/methodology/approach: An experimental approach was adopted using Single Edge Notched Tension (SENT) specimens printed in PLA. Two filament configurations were considered: parallel and crossed between layers. Each configuration was tested under three raster angles (0°, 45°, and 90°). The critical stress intensity factor (KIC) was used to evaluate and compare resistance to crack propagation. The measured KIC values ranged from 0.75 MPa^m (90°/90°) to 4.52 MPa^m (45°/-45°). Findings: The results show that both raster angle and filament configuration significantly influence crack propagation behaviour. Crossed filament configurations generally demonstrated higher resistance to crack propagation compared to parallel ones. Raster angle also played a critical role: toughness decreased with increasing angle in the a/a configuration, while the 45°/-45° configuration achieved the highest resistance (KIC = 4.52 MPa^m). Overall, crack propagation mechanisms varied between filament breakage at 0°/0° and filament separation at larger angles. Research limitations/implications: The study is limited to PLA material and specific raster angles. Future research should investigate a broader range of materials, environmental conditions, and loading types to generalise findings and enhance predictive models for fracture in printed parts. Practical implications: The findings provide practical guidance for optimising print parameters to improve fracture resistance in functional parts. The knowledge can be applied to the design of lightweight structural components, biomedical implants, and customised mechanical parts where fracture toughness is critical. Originality/value: The paper contributes original insights into the underexplored area of fracture behaviour in 3D-printed materials, supported by quantified fracture toughness values. It is particularly valuable to researchers and practitioners seeking to improve the structural performance of additively manufactured components.

6

Noise testing of multi-disc fan

Wójciak Kamil, Gaj Patryk, Kopania Joanna Maria

Vibrations in Physical Systems

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2024

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Vol. 35, nr 2

art. no. 2024216

EN

The impeller of a multi-disc fan was made of rotating smooth discs spaced close together. The concept of such a machine came from Nikola Tesla in 1909. The fluid, based on the principle of friction against the rotating surfaces of the discs, flows outwards from the disc pack into an outlet. According to the literature, such a design is characterized by low noise emissions. Based on calculations, a prototype of a multi-disc fan was designed and then manufactured. Tests were carried out for the sound power level emitted from the fan's outlet. The examination was performed in a reverberation chamber according to the ISO 3741:2010 standard. The noise source was visualized using an acoustic camera. The aerodynamic characteristics were also determined experimentally according to the ISO 5801:2017 standard. The aim of this study is provide insight into the acoustic and aerodynamic characteristics of a multi-disc fan.

7

Change in the dynamic properties of a column as a result of a variable distribution of bending stiffness - numerical and experimental research

Szmidla Janusz, Jurczyńska Anna

Vibrations in Physical Systems

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2024

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Vol. 35, nr 3

art. no. 2024309

EN

The subject of the work is the transverse vibrations of a bar system with a variable cross-section subjected to the follower force directed towards a pole. The issue was formulated on the basis of Bernoulli-Euler’s theory. The solution of the equations of motion substituted for the boundary conditions made it possible to develop a computational algorithm for the frequency of vibrations of the system, taking into account variable stiffness, assuming a constant total volume. On the basis of the obtained results, the relationship between the column stiffness distribution and the eigenvalues of the system was determined. The correctness of the obtained results was verified for selected column outlines, indicating the sources of discrepancies. It was shown that by appropriate shaping of the bar it is possible to control its dynamic properties.

8

Studying the air flow heating process in the vertical type ground heat exchanger

Kaletnik Hryhorii, Yaropud Vitalii, Lutkovska Svitlana, Aliiev Elchyn

Przegląd Elektrotechniczny

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2024

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R. 100, nr 10

46--54

EN

The article presents the results of analytical studies of air losses of vertical ground heat exchangers for two proposed schemes (concentric and U-shaped). The distribution of the temperature field during the summer and winter periods was obtained through numerical simulation of the air heating process in concentric and U-shaped vertical ground heat exchangers using the Simcenter Star-CCM+ software package.

PL

W artykule przedstawiono wyniki badań analitycznych strat powietrza w pionowych gruntowych wymiennikach ciepła dla dwóch zaproponowanych schematów (koncentrycznego i U-kształtnego). Rozkład pola temperatur w okresie letnim i zimowym uzyskano poprzez symulację numeryczną procesu nagrzewania powietrza w koncentrycznych i pionowych gruntowych wymiennikach ciepła w kształcie litery U z wykorzystaniem pakietu oprogramowania Simcenter Star-CCM+.

9

Badania eksperymentalne hamowania hulajnóg napędzanych silnikiem elektrycznym na suchej nawierzchni z kostki brukowej

Tarkowski Sławomir

Paragraf na Drodze

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2024

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Nr 3

9--21

PL

W artykule poruszono zagadnienia dotyczące bezpieczeństwa ruchu w aspekcie wykorzystania lekkich osobistych środków transportu. Omówiono podstawowe zagadnienia dotyczące regulacji prawnych związanych z mikromobilnością, a także układy odpowiedzialne za hamowanie w hulajnogach elektrycznych. Zasadniczą częścią artykułu jest omówienie badań eksperymentalnych hamowania dwóch wybranych modeli hulajnóg elektrycznych wyposażonych w rożne układy hamulcowe. W badaniach mierzono długość drogi hamowania, a następnie obliczano opóźnienie hamowania.

EN

The aim of the paper is to discuss the issues of safety in the context of the use of lightweight personal transportation vehicles. The main aspects of legal regulations concerning micromobility are introduced together with braking systems implemented in electric scooters. The essential part of the paper is devoted to discussion of the experimental studies on the braking of two models of electric scooters with different braking systems. In the tests first the braking distance was measured and next braking deceleration was calculated.

10

Innovative thrust vectoring system with moveable jet vanes integrated with a moveable diffuser – Measurement and analysis of selected nozzle performance parameters

Nocoń Łukasz Krzysztof, Grzyb Marta, Szmidt Piotr, Nowakowski Łukasz Marian

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 2

art. no. e148444

EN

The aim of the study described herein was to design, construct and test a demonstrator of a system to control the direction of the resultant thrust vector of a rocket motor to be used in short range anti-tank missiles with a mass of up to 15 kg. The novelty of the system is that the direction of the resultant thrust vector is manipulated by means of moveable jet vanes integrated with a moveable nozzle diffuser through telescopic connectors. The technology demonstrator was built using different materials and different manufacturing processes. The first versions were 3D printed from plastic materials. Minor modifications to the design were made at an early stage. The final version had the main components made of aluminum using CNC machining. The system, with and without jet vanes, was tested on a specially developed test rig equipped with a multi-axis sensor to measure forces and torques. The nozzle performance parameters measured and analyzed in this study were the components of the thrust vector, the moments and the effective vectoring angle. The findings show that the experimental data are in good agreement with the results of earlier simulations and that the demonstrator is fully operational.

11

Influence of the suspension shape on the dynamic characteristics of the electrodynamic shakers

Augustyn Damian, Fidali Marek

Vibrations in Physical Systems

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2023

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Vol. 34, nr 2

art. no. 2023227

EN

Electrodynamic shakers are being used for years in dynamic tests of machines and devices. One of the main components of electrodynamic shakers is the armature suspension. Suspension is one of the factors responsible for the dynamic characteristics of the shaker. Various types of suspensions are used in shakers [1, 2]. Their role is to ensure the correct stroke of the armature and to keep the coil concentrically in the magnetic gap. As part of the research, the influence of the shape of the suspension springs of the electrodynamic shaker on its dynamic characteristics was evaluated. During the research, self-designed electrodynamic shaker was used, in which a suspension consisting of two-disc springs made of glass fiber with a thickness of 0.5 mm was used. Eight different spring types were prepared for the study. The tests were carried out in laboratory conditions on a previously prepared test bench. For each of the springs tested, dynamic frequency characteristics were determined for three frequency ranges: 10 - 100 Hz with a step of 10 Hz, 100 Hz - 1000 Hz and 1000 Hz - 10000 Hz with a step of 100 Hz. Studies show a significant influence of the shape of the springs used on the dynamic characteristics of the modal shaker. For the preselected springs, tests were carried out without and with a load. The characteristics determined during the research were analyzed, which allowed to indicate the optimal shape of the spring, due to the values of the generated force and the linearity of the dynamic characteristics [3, 4].

12

Diagnostic methods and ways of testing the workability of coal - a review

Biały Witold, Bozek Pavol, Bołoz Łukasz

Production Engineering Archives

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2023

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Vol. 29, Iss. 4

401-412

EN

The need to classify rocks in terms of workability stems primarily from the need to choose the appropriate, most effective diagnostic method (DM) and way of mining the given rock. Studying and measuring the workability of rocks is extremely difficult due to the fact that workability depends on many various factors. There are many DM for determining the workability of rocks, but none of them take into account the influence of all factors, hence the obtained results are only indicative. In the article, many DM and ways of determining the cutting resistance with the use of various devices are presented and characterized. The principles of their operations are presented, as well as the DM of measuring the cutting resistance and its utilitarian usefulness in forecasting the selection of mining machines on the basis of cutting for specific mining and geological conditions. The core of the problem is confirmed by the number of covered DM and tools in various research centers around the world. In the article, new tools measuring and evaluating the mechanical properties of the coal solid, all created in Poland, are presented. Their structure, principles of their operation, as well as the innovation of these solutions, are all presented. In this article, their ad-vantages and disadvantages are highlighted, as well as showing the DM which best represents the way of work of the winning machine. Therefore, the results achieved through the aforementioned DM can be understood as representative values.

13

Bearing capacity of reinforced concrete beams with and without damages of rebar

Khmil Roman, Blikharskyy Zinoviy, Vegera Pavlo, Kopiika Nadiia

Production Engineering Archives

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2023

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Vol. 29, Iss. 3

298-303

EN

The article presents the results of the bearing capacity of reinforced concrete beams with and without damages of internal reinforcement. One of the main elements of the production of the reinforced concrete industry is beams. The analysis of the experimental tests showed that the bearing capacity of reinforced concrete beams with damaged tensile main reinforcement decreases according to control undamaged samples due to the reduction of the reinforcement cross-section. However, the bearing capacity of reinforced concrete beams with tensile main reinforcement Ø20А500C, damaged to the cross-section area equal the rebar Ø16mm is more on 3.7… 24.0% than the bearing capacity of reinforced concrete beams with undamaged Ø16mm rebar. This is due to the non-uniform material properties of used thermally strengthened reinforcement A500C. When during testing the tensile main reinforcement is damaged by drilling a hole, the most damages occur in the core with lower physical and mechanical characteristics. In contrast, the outer thermally strengthened layer with bigger physical and mechanical characteristics is damaged to a lesser extent. The analysis of the obtained results shows that during design of reinforced concrete beams with damaged, it is necessary to consider using thermally strengthened non-uniform steel A500C as tensile main reinforcement.

14

Eksperymentalna nośność na ścinanie blachownic z falistym środnikiem o różnym typie fali

Śledziewski Krzysztof, Górecki Marcin

Materiały Budowlane

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2023

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nr 9

20--23

PL

W artykule przedstawiono wyniki badań laboratoryjnych wykonanych na belkach ze środnikami z blachy fałdowej o różnym profilu sinusoidalnym poddanych działaniu czteropunktowego zginania. Przeprowadzone badania wykazały, że kształt fali ma znaczny wpływ na nośność na ścinanie belek dwuteowych ze środnikiem sinusoidalnym. Uzyskane wyniki odniesiono również do wyznaczonej nośności normowej, która była na niższym poziomie, niż wynika to z badań doświadczalnych.

EN

This paper presents the results of laboratory tests performed on beams with corrugated plate webs of different sinusoidal profiles subjected to four-point bending. The conducted tests showed that the parameters of the waveform have a significant effect on the shear strength of I-beams with sinusoidal webs. The obtained results were also related to the determined norm load capacities, which were at a lower level than the experimental results.

15

The influence of manufacturing technology on the mechanical properties of the layered composite

Komorek Andrzej, Rośkowicz Marek, Janiszewski Jacek, Przybyłek Paweł, Brodzik Robert, Sobieski zu Szwarcenberg Miłosz, Komorek Łukasz

Aviation and Security Issues

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2023

|

No. 2

321--335

EN

The share of composites in today's aerospace industry is steadily increasing. Layered composites are the most popular in aviation. There are a number of methods of their manufacture, each with specific characteristics. One of the most popular simple methods are the technique using a hydraulic press to apply pressure, the vacuum bag method and the infusion method. They are all widely used and useful in individual and mass production, and allow the same types of composites to be made, but due to the differences, the resulting composites, despite having the same structure, may have different properties. In order to verify this observation, an experimenta study of the same carbon fabric-reinforced polymer layered composites made by the methods mentioned above was carried out. The mechanical properties of the composites were studied, with a particular focus on their resistance to low-energy impact loading. The results of the study indicate that the composites produced by the infusion method have the best mechanical properties, and with the selected manufacturing technology parameters, the method using a hydraulic press produced the composite with the lowest surface mass.

PL

Udział kompozytów we współczesnym przemyśle lotniczym stale wzrasta. Największą popularnością w lotnictwie cieszą się kompozyty warstwowe. Istnieje wiele metod ich wytwarzania, z których każda cechuje się określonymi właściwościami. Najpopularniejsze z prostych metod to: technika wykorzystująca prasę hydrauliczną do wywarcia nacisku, metoda worka próżniowego oraz metoda infuzji. Wszystkie są powszechnie stosowane i użyteczne w produkcji jednostkowej i seryjnej oraz umożliwiają wykonywanie takich samych typów kompozytów, jednak ze względu na różnice, uzyskane kompozyty pomimo takiej samej struktury mogą mieć różne właściwości. Celem weryfikacji tego spostrzeżenia przeprowadzono badania eksperymentalne takich samych polimerowych kompozytów warstwowych wzmacnianych tkaniną węglową, wykonanych wymienionymi metodami. Badano właściwości mechaniczne kompozytów, ze szczególnym uwzględnieniem ich odporności na niskoenergetyczne obciążenia udarowe. Wyniki badań wskazują, że kompozyty wytworzone metodą infuzji cechują się najlepszymi właściwościami mechanicznymi, a przy zastosowaniu wybranych parametrów technologii wytwarzania, metoda wykorzystująca prasę hydrauliczną umożliwiła wytworzenie kompozytu o najmniejszej masie powierzchniowej.

16

Experimental studies of the thermal regime of the premise while using heating ceramic panels

Basok B. I., Nedbailo O. M., Bozhko K. M., Bozhko I. K., Markin M. O., Markina O. M., Marteniuk V. O.

Archives of Materials Science and Engineering

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2023

|

Vol. 124, nr 2

56--61

EN

Purpose: The purpose of this paper is to analyse the obtained experimental data, which is advisable to use to verify the thermophysical model of the thermal regime of a separate premise while using ceramic electric heating panels for heating purposes. Design/methodology/approach: The experimental studies were carried out at the scientific thermophysics laboratory with the help of up-to-date equipment (including the design for these studies). After gathering experimental data, it was analysed, and with its help, a CFD model of the thermal regime of the laboratory premise would be verified. Findings: The conducted experimental studies showed that in the artificially created quasi- stationary thermal regime of the laboratory premise, the air temperature varied with height in a small interval. This makes it possible to state that when using ceramic electric heaters as heating devices, the air temperature is relatively evenly distributed over the height of the premise. Research limitations/implications: The research provides original experimental data and findings for further CFD modelling of the thermal regime of the premise while using heating ceramic panels. Practical implications: The mentioned in the paper research methods as well as obtained experimental data, could be used in further studies of modern heating systems. Another use of the results – during the validation of CFD models. Originality/value: The paper includes the design and methodology of creating the original experimental stand for research of the different heating systems types.

17

Analysis of a crash on a vehicle system by adjusting appropriate input parameters to manage energy absorption capacity for enhancing passenger safety

Dhamone Sagar Parashuram, Padmakumar Arunkumar

Acta Innovations

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2023

|

no. 50

5--17

EN

The aim of the research is to develop a front bumper system that absorbs maximum impact energy as compared to the current bumper available in the market, Bumper design is based on increasing the area of the crumping zone to slow down the collision and observe the impacts taking place at the time of jerks and reduces the percentage of damage. To develop the system, the number of load cases tested numerically in passive safety simulation has increased significantly in recent years. The variety of applications may be divided into three main topics: structural crashworthiness of the whole car, passenger protection, and crashworthiness of components. Present theories and practices. To absorb impact, the front bumper of the car uses a spring-loaded system that is installed between the bumper and the support for the chassis structure. This system is made of metal and serves as the bumper's structural foundation. A honeycomb structure is being added to the bumper as a composite material together with a layer of galvanized iron as it is being created in this manner, which increases strength while weighing less. This arrangement design is suitable for psychoacoustics, varying velocity explicit analysis is performed with the approach of finite element analysis, experimental testing is carried out for the validation of the value and advanced manufacturing methods are implemented with statistical results, and one of the cheapest systems is developed as compared to the current bumper systems.

18

Approximation of flow characteristics of steam traps based on experimental research

Ziemiański Paweł, Grzebielec Andrzej, Szelągowski Adam, Śmiechowicz Mateusz

Modern Engineering

|

2022

|

1

20--35

EN

This study aimed to approximate the operating characteristics of steam traps through experimental research and mathematical analysis. The research presented the phenomena leading to the development of steam traps, their relevance to power engineering and production plants, and the energy properties of water vapor for heat transport and exchange. The study also discusses problems that can occur in steam systems and how steam traps can prevent adverse phenomena. The experimental studies allowed the researchers to determine the operating characteristics of steam traps, and mathematical analysis extended the results to other cases.

19

Modelling of linear elasticity and viscoelasticity of thermosets and unidirectional glass fibre-reinforced thermoset-matrix composites. Part 2, Homogenization and numerical analysis

Klasztorny Marian, Nycz Daniel B.

Composites Theory and Practice

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2022

|

R. 22, nr 1

25--39

EN

The study continues the advanced analytical modelling of the linear elasticity and viscoelasticity of thermosets and unidirectional glass fibre-reinforced thermoset-matrix (UFRT) composites. The thermosets are isotropic materials with viscoelastic shear strains and elastic bulk strains, and the fibres are isotropic and elastic. The modified homogenization theory for UFRT composites, based on the selected tasks of the linear theory of elasticity, is developed. The modifications include a volumetrically equivalent cylindrical representative volume cell, solutions determined for an isotropic fibre based on the solutions for a monotropic (transversely isotropic) fibre, and certain modifications in the third task of the theory of elasticity. The viscoelastic constants of the thermoset are derived analytically and validated by fitting of the simulation and experimental shear strains on a logarithmic time scale in the unidirectional tension creep test. The viscoelastic constants of the UFRT composite are derived analytically and validated by fitting of the storage compliances corresponding to the new viscoelastic model and one obtained from the viscoelastic-elastic correspondence principle. The tension creep experiment is performed on the selected structural unsaturated polyester resin. Identification and validation are carried out for that thermoset and the corresponding UFRT composite with long E-glass fibres. All the modelling hypotheses are confirmed.

20

Mechanical and hygrothermal performance of fly-ash and seashells concrete: in situ experimental study and smart hygrothermal modeling for Normandy climate conditions

Bouasria Manal, Benzaama Mohammed-Hichem, Pralong Valéry, El Mendili Yasmin

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e100, 1--22

EN

The aim of this study is to investigate the effect of partial substitution of cement by a smart mixture of waste materials, fly ash and Crepidula shells. The cement is replaced by fly ash and Crepidula accordingly in the range of 5, 10 and 15% by weight. This study focuses on three steps: (i) find the best formulation in terms of compression and hygrothermal behavior, (ii) build a prototype and follow the hygrothermal behavior with sensors, (III) data collection and development of a neural network model to predict the hygrothermal behavior of the prototype. The results showed that for a fly ash-Crepidula incorporation rate up to 10%, the mechanical properties are higher than the control mortar. Furthermore, the cement substitution by fly ash and Crepidula improves the thermal conductivity of concrete. With the cement replacement of 30%, a prototype was built to monitor the hygrothermal behavior. The data collected from the wireless sensors placed in the prototype are used to train and validate the artificial neural network model. The model used in this study is conducted with eight inputs and two outputs data. The investigation of the condensation risk and the mould growth shows that the chosen concrete mixture can avoid the condensation phenomenon. Indeed, the smart fly ash-Crepidula mixture provides high silica, aluminate, and calcium contents, which react with water originating from humid ambient air to form additional hydrates as a result of pozzolanic reaction and lead to a continuous strengths enhancement.