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Abstract

Composite materials are vulnerable to impacts that may occur during their use. Such transverse loads represent a significant threat to these materials because they can cause damage that is difficult to detect. Thus, understanding the mechanical behavior of composite materials during impacts is crucial for improving their damage resistance. Therefore, this study investigates the response of two commonly used composite panels in maritime transportation—a PVC core sandwich composite and a laminated GFRP composite—under quasi-static indentation (QSI). Using numerical simulations with Abaqus/Explicit, this investigation aims to anticipate mechanical characteristics and damage patterns during low-velocity impact. Results show a strong correlation between numerical and experimental data. The force-displacement curves aid in understanding damage sequences, with predicted maximum loads at 1.43% and 6.45% accuracy for laminated and sandwich composites. Both exhibit significant damage, including permanent indentation, matrix cracks, fiber fractures, and prevalent delamination around the impact point.

Open access

Abstract

This study evaluates metallic yield dampers, specifically slit steel dampers, for protecting steel beam-to-column connections during seismic events. Finite element model simulations were conducted for the damper and its connection. Analysis of circular parameters, like the radius slot, showed that appropriately sized slit dampers exhibit advantageous seismic behavior. Moment-rotation, hysteresis curves, and plastic stresses comparisons indicate efficient energy absorption. The maximum moment was 25% lower than conventional samples. The slit steel damper model with a ductility factor of 3.5 allows significant plastic deformation before potential failure. Results emphasize the slit damper's potential for optimal performance in steel frames, suggesting its use for efficient energy absorption.

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Abstract

Geopolymer concrete (GPC) is a rising eco-conscious substitute for traditional cement-based concrete, bringing the construction industry closer to sustainability. Self-compacting geopolymer concrete (SCGC) enhances the concrete flowability and fills the congested reinforced areas without vibrators in concrete structures such as bridges, tunnels and canals. This study aims to analyze the impact of silicon dioxide nanoparticles (NS) on the rheological and mechanical properties of SCGC to optimize the dosage of NS in SCGC. For this purpose, NS (0–6%) blended in partially distributed binders of fly ash and ground granulated blast furnace slag (50:50) with 0.5 alkaline binder ratio, 2% superplasticizers (9 kg m−3) (MasterGlenium SKY 8233) and 12% extra water (54 kg m−3). Sodium silicate solution and sodium hydroxide ratio of 2.5 was used for this study. It is observed that SCGC with 3% NS replacement complied with the guidelines of EFNARC. According to the T50cm slump flow test, V-funnel test, and L-box test results meet the guidelines of up to 4% NS replacement, and 3% NS addition offers excellent mechanical properties in SCGC. This study concluded that the replacement of 3% of NS improved the fresh and hardened properties of SCGC, which can apply to construction.

Open access

Abstract

Today, the role of humans is changing rapidly in both industrial production activities and services. Mediocre, easy-to-learn activities can be performed more efficiently by machines; mediocre knowledge is being devalued while the importance of high-level skills is increasing. As a result, in all sectors of the economy, and especially in engineering, new approaches to expert training are needed; people must learn to hand over certain decision-making roles and to control the processes supported by AI rather than compete with it. STEM education has a responsibility to achieve these goals and must develop appropriate tools for engineering education. This paper presents a complex didactic methodology for competency-based education in engineering bachelor programs. An important element is the mathematical competency map, which shows the importance and place of mathematical and algorithmic (coding) knowledge in engineering topics. Another element is the systematic testing of mathematical knowledge in non-mathematical contexts in engineering courses. We provide an overview of our achievements in applying the developed toolset and improving the efficiency of mathematics teaching in engineering bachelor programs.

Open access
Pollack Periodica
Authors:
Mahmood Alhafadhi
,
Masar Alsigar
,
Oudah Zahraa A.
,
Zoltán Bézi
,
Alden abd alal Sahm
, and
P. Ravinder Reddy

Abstract

Using finite element methods, residual stresses were estimated in pipe welds. Experiments were also conducted to verify the numerical results. An alternative to a three-dimensional model was used to simplify the numerical calculation for residual stresses investigation. Model predictions were validated by measuring residual stresses using X-ray diffraction. As compared to measured residual stress distributions, the computational approaches developed in this study can accurately predict welding residual stress distributions. The focused welding parameters have a significant impact on residual stresses even when all the other parameters are the same.

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Abstract

The predictive maintenance of permeant magnet synchronous motor is highly required as this kind of motor has been commonly employed in electric vehicles, industrial systems, and other applications owing to its high power density output, as well as the regenerative operation characteristics during braking and deceleration driving conditions. One of the most important causes of PMSM failure is the stator short and drive switches failure. These problems have attracted more attention in the field of deep learning for fault detection purposes in the early stages, to avoid any system breakdown, and to decrease the risk and price of maintenance. In this paper, we investigate the possibility of detecting the electrical faults in PMSM by generating our data which includes current signals that have been analyzed and preprocessed by applying Continuous Wavelet Transform (CWT) to select the reliable features this conversion will be used to train ResNet 50. The evaluation metrics have shown that ResNet 50 achieves an accuracy of 100% for the classification of faults.

Open access
Pollack Periodica
Authors:
Peter Ivanyi
,
Amalia Ivanyi
,
Aarne Jutila
,
Jenő Balogh
,
Barry H. V. Topping
, and
Gabriella Medvegy
Open access

Abstract

The integration of Autonomous Vehicles (AVs) into our modern society hinges on gaining widespread acceptance from potential road users. To indicate the preparedness of these road users and elucidate their perspectives regarding the use of AVs in future, it is imperative to conduct surveys gauging public acceptance and satisfaction with this emerging mode of transportation. This paper reports the results of a comprehensive questionnaire study involving 1,000 individuals in Gyor City. The survey's primary objective was to assess participants' attitudes and willingness to embrace autonomous vehicles within the city's road networks. The study delved into various socio-demographic factors, such as age, gender, and employment status, while also exploring participants' prior knowledge and opinions regarding the advantages and limitations of AVs. The findings reveal a generally favorable disposition among the public toward the inclusion of AVs in urban traffic, paving the way for the acceptance of mixed traffic patterns. Notably, respondents in younger age groups exhibit greater enthusiasm for incorporating AVs into their daily transportation, whereas individuals aged 65 and above express more reservations, displaying a conservative outlook. Furthermore, participants with prior knowledge and a deeper understanding of AVs exhibit a markedly more positive inclination toward this emerging technology compared to those lacking such familiarity.

Open access

Abstract

Design and testing of real materials is a costly process and usually requires some specific equipment. To alleviate this task numerical methods can be leveraged. In this work we show possible modelling technique for closed-cell material structure using Weaire–Phelan unit cells. As an example existing aluminum structures were used and modelled parametrically, allowing to establish different geometrical models for different applications. Numerical simulations for compression was also done on the developed models to reveal the material response. The influence on the cell wall thickness and the friction between the material and the compression plate was investigated. It was found that the friction coefficient has no significant effect on the material response, except in the case where bonded connection was assumed. It was also demonstrated that material response and the porosity controlled by cell wall thickness have an approximately linear relationship with each other. This method proved to be a flexible and alternative solution of real laboratory tests and targeted to reduce costs of material design.

Open access
Pollack Periodica
Authors:
Orest Voznyak
,
Edyta Dudkiewicz
,
Nadiia Spodyniuk
,
Oleksandr Dovbush
,
Iryna Sukholova
,
Olena Savchenko
, and
Mariana Kasynets

Abstract

The immediate vicinity of buildings of different floors causes damages of the smoke and ventilation channels work of the low-rise buildings. This is dangerous for the resident's health and lives. To determine the impact of high-rise buildings on the operation of air channels of a nearby two-story building, experimental research has been carried out in a wind tunnel. Charts and analytical formulas have been designed for determining the buildings aerodynamic coefficients depending on wind directions and the channels height. An increase of the channel height results in an increase in static rarefaction in smoke and ventilation channels. Increasing rarefaction increases the efficiency of the natural ventilation system and ensures the residents health and life.

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