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1 |
Influence of wire electrical discharge machine cutting parameters on the magnetization characteristics of electrical steel laminations
تاثیر پارامترهای برش دستگاه تخلیه الکتریکی سیم بر ویژگی های مغناطش ورقه های فولادی الکتریکی-2021 This paper presents the influence of wire electrical discharge machine (WEDM) cutting parameters on the
magnetization characteristics of electrical steel. The demand for electrical steel keeps increases because
of the high demand of electrical motor and transformers for electric vehicle and smart grid applications.
The magnetization characteristics of the laminated steel used in these machines have dominates the performance of these machines. The cuttings methods and cutting parameters have huge role in deciding the
magnetization characteristics. In this work, WEDM is used to cut the electrical steel in to small pieces.
The cutting parameters such as current, feed rate and on-time of WEDM are varied by keeping two of
these parameters fixed and one varied. From the electrical steel sheet, 18 sample small electrical steel
pieces are obtained at various cutting parameters of WEDM. The magnetic field – magnetization characteristics are obtained using vibrating sample magnetometer (VSM). This analysis shows that higher current, lower on-time and higher feed rate is providing higher magnetization.
Keywords: Wire electrical discharge machine | Vibrating sample magnetometer | Electrical steel | Cutting parameter | Magnetization |
مقاله انگلیسی |
2 |
Environmental and economic sustainability of key sectors in Chinas steel industry chain: An application of the Emergy Accounting approach
پایداری محیط زیست و اقتصادی بخش های کلیدی در زنجیره صنعت فولاد چین: استفاده از رویکرد حسابداری ظاهری-2021 Increasing urbanization day–by–day requires new housing and transportation infrastructures. As a consequence,
demand for steel – a basic material for buildings construction as well as for vehicles and railroads – would also
increases. This study applies Emergy Accounting (EMA) to assess the Chinás steel industry environmental per-
formance and to identify key application sectors. Subsequently, this study calculates emergy–based indicators
capable to assess the present economic performance, environmental sustainability, and land resource appropriate
utilization. Building on these indicators, changes of sustainability scenarios in key application sectors are also
investigated, with special focus on increased use of recycled steel. The results show that the environmental
impacts of steel use in downstream sectors, specially in the Housing and Vehicles Sectors, are significantly
higher. Furthermore, the downstream sectors also have a very large requirement for embodied land. Addition-
ally, the Emergy Benefit Ratio (EBR) shows non-negligible advantages to China derived from importing raw iron
from abroad at international market prices. Finally, when the recycling rate of scrap steel increases, the per-
formance of downstream sectors improves, with the Vehicle sector showing the most significant changes.
Although the benefits of steel-based economy to society are clear, multidimensional sustainability concerns and
international competition for primary resources necessitate a transition towards increased recycling and inno-
vative materials within a strictly enforced “circular economy” policy. keywords: بخش های کاربردی فولاد | حسابداری امری | بازیافت فولاد و استفاده مجدد از فولاد | ارزیابی پایداری | Steel application sectors | Emergy accounting | Steel recycling and reusing | Sustainability assessment |
مقاله انگلیسی |
3 |
Artificial intelligence quality inspection of steel bars installation by integrating mask R-CNN and stereo vision
بازرسی کیفیت هوش مصنوعی نصب میله های فولادی با ادغام ماسک R-CNN و دید استریو-2021 Contractors should conduct strict quality inspection of the steel bars used in concrete structures and need to automate the process of quality inspection. The objective of this study is to develop an Artificial Intelligence Quality Inspection Model (AI-QIM) that can execute quality inspection on steel bars at the construction site. The proposed AI-QIM is built on the Mask Region-based Convolutional Neural Network (Mask R-CNN) technique, which can perform instance segmentation of steel bars. This object detection technique is integrated with a stereo vision camera to generate information on steel bar installation. A contractor can use the proposed AI-QIM to estimate the quantity, spacing, diameter, and length of steel bars during quality inspection. A sample case study indicated that the AI-QIM yielded a maximum relative error of 3% when measuring steel bar spacing and a maximum relative error of 8% when measuring steel bar lengths within a range of 1–2 m from a stereo camera. Keywords: Steel bar | Quality inspection | Artificial intelligence | Convolutional Neural Network (CNN) | Mask R-CNN | Stereo vision | Object detection | Object mask | Instance segmentation |
مقاله انگلیسی |
4 |
Development of a knowledge-based tool for waste management of prefabricated steel structure projects
توسعه یک ابزار مبتنی بر دانش برای مدیریت زباله پروژه های ساختمانی فولاد پیش ساخته-2021 Although the construction industry is critical for sustainability goals due to the high amount of waste it gen-
erates, its waste management performance is still not at the desired level. One of the main reasons for this can be
attributed to the lack of enough knowledge of construction companies on the sources/reasons of waste and
amount of waste. The major aim of this study was to develop a knowledge-based tool for capturing, storing, and
disseminating waste-related knowledge for prefabricated steel construction projects. The developed tool can be
used for waste estimation, monitoring, and minimization of all materials used during different phases of pre-
fabricated steel structure projects based on the data captured from current and previous projects. One advantage
of the tool is the integration of all processes of waste management, which have been usually considered inde-
pendently in previous studies. Moreover, being a knowledge-based tool, it can increase awareness and learning
ability of companies about waste and its management. Finally, although the process model of the tool is generic
and can operate in alternative domains, the tool is applicable for only prefabricated steel projects. It is believed
that the process model and the tool presented in this paper can be further customized for different project types
and considering different company needs. keywords: ابزار مدیریت زباله مبتنی بر دانش | پروژه های ساختمانی فولاد پیش ساخته | صنعت ساخت و ساز | زباله های مواد | ابزار مبتنی بر وب | Knowledge-based waste management tool | Prefabricated steel structure projects | Construction industry | Material waste | Web-based tool |
مقاله انگلیسی |
5 |
Bilayer systems based on conjugated polymers for fluorescence development of latent fingerprints on stainless steel
سیستم های Bilayer مبتنی بر پلیمرهای هملند برای توسعه فلورسانس اثرانگشت نهان روی فولاد ضد زنگ-2020 Fingerprints are a key role in criminal investigations and are the most commonly used form of physical evidence
for identifying criminals or to establish a connection between crime scenes. However, visualizing latent (hidden)
fingerprints is steal a great challenge, mainly when they are present on metallic surfaces. In this work, a new
concept based on the electrodeposition of bilayer systems based on conjugated and fluorescent polymers was
used for the development of latent fingerprints on stainless steel. The first layer of Polypyrrole or PEDOY was
electrodeposited onto the surface containing a latent fingerprint by oxidation of the monomer in LiClO4 aqueous
solution. The second layer of a fluorescent Poly(2,2′:5′,2″-terthiophene) was electrodeposited onto the first layer
by using a solution of (C4H9)4NBF4/CH3CN. Such bilayer systems showed fluorescent properties and may be
applied in forensic biometry for development of latent fingerprints on stainless steel, since this strategy affords
images with high definition in both visible and UV light, permitting the recognition of the ridge patterns and
singular points in order to be used for confrontation with other dactyloscopy images. Keywords: Conjugated polymers | Electrodeposition | Fluorescence | Latent fingerprints | Forensic chemistry |
مقاله انگلیسی |
6 |
Automated clash resolution for reinforcement steel design in concrete frames via Q-learning and Building Information Modeling
رزولوشن برخورد خودکار برای طراحی فولاد تقویت کننده در قاب های بتنی از طریق یادگیری Q و مدل سازی اطلاعات ساخت-2020 The design of reinforcing steel bars (rebars) is critical to reinforced concrete (RC) structures. Generally, a good
number of rebars are required by a design code, particularly at member connections. As such, rebar clashes (i.e.,
collisions and congestions) would be inevitable. It would be impractical, labor-intensive, and error-prone to
avoid all possible clashes manually or even using standard design software. The building information modeling
(BIM) technology has been utilized by the present architecture, engineering, and construction (ACE) industry for
clash-free rebar designs. However, most existing BIM-based approaches offer the clash resolution strategy for
moving components with an optimization algorithm, and are only applicable to the RC structures with regular
shapes. In particular, the optimized path of rebars cannot be adjusted to avoid the obstacles, thus limiting the
practical applications. Furthermore, most existing studies lack the learning from design code and constructibility
constraints to realize automatic and intelligent arrangement and adjustment of rebars for avoiding the obstacles
encountered in complex RC joints and frame structures. Considering these shortcomings, the authors have recently
proposed an immediate reward-based multi-agent reinforcement learning (MARL) system with BIM, towards
automatic clash-free rebar designs of RC joints without clashes. However, as the immediate reward is
required in the MARL system for guiding the learning of a rebar design, it will not succeed in clash-free rebar
designs of complex RC structures where immediate reward is often unavailable. In this study, this study further
extends the previous work with Q-learning (a model-free reinforcement learning algorithm) for more realistic
path planning considering both immediate and delayed rewards in clash-free rebar designs for real-world RC
structures. In particular, the rebar design problem is treated as a path-planning problem of multi-agent system,
where each rebar is deemed as an intelligence reinforcement learning agent. Next, by employing the Q-learning
as the reinforcement learning engine, the particular form of state, action, and immediate and delayed rewards
for the reinforcement MARL for automatic rebar designs considering more actual constructible constraints and
design codes can be developed. Comprehensive experiments on three typical beam-column joints and a two-story
RC building frame were conducted to evaluate the efficiency of the proposed method. The study results of paths
of rebar designs, success rates, and average time confirm that the proposed framework with MARL and BIM is
effective and efficient. Keywords: Building Information Modeling | Reinforcement learning | Multi-agent | Q-learning | Rebar design | Clash resolution | Reinforced concrete frame |
مقاله انگلیسی |
7 |
Simulations of isothermal and thermomechanical fatigue of a polycrystal made out of austenitic stainless steels and relation to the Coffin-Manson law
شبیه سازی خستگی ایزوترمال و گرما مکانیکی یک پلی کریستال ساخته شده از فولادهای ضد زنگ آستنیتی و ارتباط آن با قانون تابوت-مانسون-2020 Based on an experimental result of the literature showing that the crack remains in the grain of its
initiation up to about 20% of the lifetime at low cycle fatigue of austenitic stainless steels, the lifetime
of a polycrystal made out of these steels undergoing uniaxial isothermal or thermomechanical
fatigue from 30 to 340 °C at constant total strain amplitude is calculated. The stresses and strains
in the grains and polycrystal are determined in term of mean field with the Hill-Hutchinson model.
Dipolar slip markings in the grains are predicted and assumed sites of initiation and propagation of
the cracks calculated in terms of critical stress and of shear plastic strain, depth and grain boundary,
respectively. There is agreement of the macroscopic stress and plastic strain, but at the residual
stress, making the modelling not suitable for thermomechanical fatigue. For isothermal fatigue, the
lifetime is in agreement. The lifetime - plastic strain power relationships are addressed to the Coffin-
Manson law assumed to derive from the kinetic equation of the crack in a dimensional approach.
The calculated constants of the power relationship of five austenitic steels of the literature are in
qualitative agreement with those measured of the law. The relationships between the constants of
the power relationship, law and kinetic equation are determined. The results and modelling are
discussed. Keywords: Fatigue stage I | austenitic stainless steels | crack initiation | crack propagation | lifetime prediction | Coffin-Manson law |
مقاله انگلیسی |
8 |
Modeling ductile fracture using critical strain locus and softening law for a typical pressure vessel steel
مدل سازی شکستگی انعطاف پذیر با استفاده از جایگاه کرنش بحرانی و قانون نرم شدن برای فولاد فشار معمولی-2020 This work describes the framework to model ductile damage based on phenomenological stress-modified critical
strain criterion (SMCS) coupled with a softening law to predict the onset of ductile initiation and ductile
propagation in typical fracture specimens, extracted from a flat plate made of ASTM A285 Gr. C steel. A very
detailed and well-illustrated methodology has been developed for the identification of material parameters.
Laboratory testing of cylindrical tensile bars and SE(B) specimens, at room temperature, provides necessary and
sufficient information to calibrate the numerical parameters in the proposed model. For either geometry, the
applied loading is measured by a continuous record of the load ðPÞ and displacement ðΔÞ. After the model parameters
have been set, verification studies are carried out for SE(B) specimens having shallow cracks with and
without side-grooves. Consequently, parameter transferability, outside small-scale yielding condition between
specimens having different crack tip conditions, can be addressed and the constraint influence on the driving
force better understood. An additional check is performed by comparing the final crack front profile measured on
the fracture surface of the SE(B) specimens with the numerical calculated in the finite element analyses. The
phenomenological model adopted herein can reproduce and predict reasonably well the experimental data obtained
for specimens with different levels of stress triaxiality (constraint). Overall, it is shown that the SMCS
criterion combined with a softening law can be used to study and to predict the influence of stress state on ductile
failure initiation and ductile crack growth by identifying nine model parameters through testing notched round
bar geometries and SE(B) specimens. The proposed methodology shows great potential as an engineering tool for
assessing the integrity of complex structures such as welded pipelines and pressure vessels. Keywords: Ductile failure | Constraint | SMCS | Crack propagation | Damage model |
مقاله انگلیسی |
9 |
comSensitivity analysis of nondestructive magnetictechniques for the restoration of stamped markson low carbon steel
تجزیه و تحلیل حساسیت تکنیکهای مغناطیسی غیر مخرب برای بازسازی مهر فولادی کم کربن مارکسون-2020 Restoration of obliterated stamped marks is a common investigative technique used incriminal investigation. Considering the evolution of the obliteration techniques used bycriminals, a study of the feasibility of sensitive, effective, and nondestructive techniques isneeded. This study aims to evaluate the performance and sensibility of two nondestructivetechniques: magnetic particle restoration and magneto-optical imaging. To this end, steelsamples from automobile chassis were analyzed. The samples were characterized in orderto obtain information regarding material microstructure, magnetic characteristic, and hard-ness, followed by the restoration of stamp marks. Both magnetic particle restoration andmagneto-optical imaging were capable of partially restoring the identification code obliter-ated by overstamping. In addition, nondestructive techniques showed a restoration depthlimit of 260 m below the cavity. Keywords:Restoration | Sensibility | Obliterated marks | Magneto-optic imaging | Magnetic particle |
مقاله انگلیسی |
10 |
New damage evolution law for modeling fatigue life of asphalt concrete surfacing of long-span steel bridge
قانون جدید تکامل خسارت برای مدل سازی عمر خستگی سطح بتن آسفالت پل فولادی با طول بلند-2020 As the traffic volume and wheel load on the orthotropic deck of a long-span steel bridge increase, longitudinal
cracks often develop in the asphalt concrete surfacing leading to deterioration. The purpose of this
study was accordingly to derive the fatigue failure evolution law of this surfacing. The fatigue damage evolution
mechanism was studied from a micro perspective to derive a general fatigue damage evolution law.
Fatigue tests and theoretical predictions of fatigue life were then performed for different asphalt concrete
surfacing types commonly used in the decks of long-span steel bridges to verify the derived law. Keywords: Long-span steel bridges | Asphalt concrete surfacing | Fatigue life | Damage evolution law | Fatigue experiment |
مقاله انگلیسی |