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Guest editorial: Innovative methods for structural integrity and reliability assessment and material characterisation under environmental effects
No full textAvailable data from practice and case studies can often provide significant data input needed for the analysis and assessment of structural failure and its prevention during the exploitation period, which ensures its reliability and safety. Still, with all the available knowledge nowadays, this cannot be considered a general rule. From the structural integrity point of view (in general), cracks and defects in engineering structures can be researched by applying various scientific and engineering approaches, including classical mechanics, fracture mechanics, standard probabilistic and risk analysis methods used for wider applications, etc. Standards and directives often provide conservative solutions during construction design, sometimes leading to overly conservative and ineffective results, i.e. non-optimized structures. The complexity of new engineering structures and the application of new materials and new manufacturing technologies impose the need for different approaches in structural integrity assessment, modification of existing ones or the application of multidisciplinary methods involving several scientific and engineering disciplines as one.
Taking into account the aforementioned, adequate material characterization has an important role, especially if environmental effects are involved, making the problem of structural integrity and reliability assessment more complex. Depending on environmental effects, caution is paid to damage mechanisms, including corrosion (which mostly refers to process equipment, as an example). The heterogeneity of welded joint areas in engineering structures, combined with environmental effects (or without them), adversely affects their service life. All aforementioned factors impose the need for reliable probabilistic methods of assessment of engineering structures, consisting of compromise solutions for the fulfillment of technical, reliability, safety and economic requirements.
This special issue, dedicated to The Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023), held in Belgrade, Serbia, from April 2–4, 2023, aims to include submissions concerning innovation and recent trends, multidisciplinary approaches, as well as case studies involving structural integrity assessment, risk analysis and the safety of engineering structures, while taking into account environmental effects, material behavior, its characterization, and the specificity of the structure itself.
The following seven papers are accepted for publishing after the peer review process:
(1) The role of the second non-vanishing terms in the material failure curve on APL 5L steel;
(2) Tensile, flexural and free vibration characteristics of sustainable recycled polypropylene filled with spherical SiC through experimental and RVE Analysis;
(3) Comparative study of corrosion-based service life prediction of reinforced concrete structures using traditional and machine learning approach;
(4) Damage assessments of designed sandwich cores against an idealized impact loading of ship accidents: experiment-based validated nonlinear finite element approach;
(5) Sustainability and environmental life cycle analysis of welding processes;
(6) Research of criteria for analyzing the load-bearing capacity of buildings in areas of technogenic impact caused by mining operations and
(7) Determination of the influence of FDM printing parameters on tensile strength and fracture occurrence of additively manufactured ABS material.
Both guest editors would like to express their sincere gratitude to the authors for their valuable contributions and also extend their thanks to the numerous reviewers for their diligent efforts in ensuring the high quality of the manuscripts
TESTING OF X-RAY DETECTION IN TURBULENT FLOW FOR SPACE APPLICATIONS USING SILICON DRIFT DETECTOR
No full textSilicon Drift Detectors (SDD) are widely used in space missions for their high energy
resolution and compact design, particularly in X-ray and particle spectroscopy. The performance
of X-ray detectors in low Earth orbits (LEO) is influenced by environmental conditions. In this
context, testing of such detector is required in controlled laboratory, simulating suitable
conditions. While these detectors are not directly intended to measure fluid dynamics,
environmental conditions encountered in LEO – including rarefied atmospheric gases and
localized, quasi-turbulent flows – can cause thermal instability, mechanical disalignment, and
influence on data accuracy. This paper presents laboratory testing of X-ray detection, simulating
transitional and low-intensity turbulent flow conditions representative of those experienced by
satellites in LEO
SURVEYING THE INFLUENTIAL FACTORS ON WHOLE-BODY VIBRATION AT EARTHMOVING MACHINERY WORKPLACES
No full textThe study aimed to measure whole-body vibrations exposure for operators of various earthmoving machines (bulldozers,
dumpers, excavators, bucket wheel excavators, and loaders) using the V31-A triaxial accelerometer and to survey its
influential factors. The study then compared the obtained results for the A(8) parameter which measures average exposure
over an eight-hour day across different types of earthmoving machines. The comparison focused on determining the
average values, value ranges, and deviations of A(8) m/s² values by machine type. Additionally, the study compared the
measured results with the prescribed whole-body vibrations limit values set by existing regulatory standards. Furthermore,
the dependence of the measured whole-body vibrations values on influential factors such as the age of the earthmoving
machines, the power of the machines, the operators’ age, experience, gender, and body mass index was analyzed. The
research results indicated that bulldozers have the highest mean value of daily average exposure to vibration while
excavators exhibit the widest range of daily average exposure to vibration. The findings also indicated that there is no
correlation between the daily average exposure to vibration and the age of the earthmoving machine, the power of
machines, or the operators’ age or body mass index. Daily average exposure to vibration exceedances occurred in both
older and newer earthmoving machines, regardless of their power, according to the ISO 2631-1 standard, with statistical
significance. The obtained research results were analyzed using correlation analysis and nonlinear models, but none of the
models showed a significant influence of the considered factors on the daily average exposure to vibration. The
recommendation for further research is to expand the range of influencing factors as well as the sample size and to make
additional efforts to identify significant predictors of whole-body vibrations
Efficiency Assessment of a High-Speed Tracked Vehicle Hybrid Powertrain
No full textThe paper analyzes the difference in power balance and efficiency between a modernized, hybrid high-speed tracked vehicle powertrain model and a mechanical powertrain model corresponding to the real vehicle developed and verified in previous research. This is to prove the argument of the efficiency benefits of electrifying the vehicle turning mechanism and eliminating the friction elements slip. The simulation models of both powertrains presented in this paper are subjected to the same simulation conditions, with the powertrain design solutions being the only variables. The results presented show that the vehicle with a hybrid powertrain achieves the required turning radius about four seconds earlier, with about 50 % less internal combustion engine (ICE) power required for the analyzed working regime. The hybrid powertrain offers an infinite number of calculated turning radii within the range of electric motor rpm, instead of one calculated
turning radius in an existing powertrain. This results in a reduction in the total power required for the turning process as there are no losses due to friction element slip
Electrocoagulation as a new and advanced technology for future challenges in the steel industry's water treatment plants
No full textWater is a basic necessity of life, and it may seem inconceivable to imagine living without it. The environmental impact, together with social and the economic impact of past and traditional water treatments in the steel industry plants and inevitable fact of water scarcity are leading and driving a shift to a new paradigm in water treatments. Nowadays, many communities and countries are approaching the limits of their available water supplies and because of that, many steel industry plants are facing a big problem with water availability. Although water reclamation and reuse is practiced in many countries around the world, current levels of reuse constitute a small fraction of the total volume of industrial effluent generated. In addition, to meet their growing water supply needs, communities are considering other non-traditional sources of water which could lead to water saving. Water reclamation and its reuse have become an attractive option for conserving and extending available water supply by potentially applying different solution based on biological, chemical and mechanical improved solutions. Since these trends are emerging developments in the field of water reclamation and reuse, there are a number of research needs associated with these topics. Here proposed research is needed to better understand the issues present in traditional water treatment plants in steel industry plants, to propose and explain innovative technologies, which are improving traditional solutions of the water treatment plants, and to develop tools and other assistance for the steel industry plants to implement successful water reclamation and reuse projects
FLUE GAS HEAT RECOVERY FROM A BIOGAS PLANT FOR INDUSTRIAL THERMAL OIL SYSTEMS
No full textThis study presents a preliminary assessment of waste heat recovery from flue gases at the biogas plant to reduce fossil fuel consumption in the automotive factory, which uses thermal oil for process and space heating. The proposed solution involves directing 435°C flue gases from the biogas boiler to a gas-to-oil heat exchanger, where thermal oil is heated up to 260–300°C and transported through a 900-meter insulated pipeline to automotive factory. The thermal oil is then partially used to heat process water during winter via an additional heat exchanger. The available thermal energy from the flue gases is estimated at 387.4 kW, which covers approximately 60% of the factory’s current demand, reducing the load on the existing 1512 kW fuel oil boiler and two 400 kW solid fuel boilers. The required thermal oil mass flow is calculated at 0.89 kg/s, and the pipeline insulation must be optimized to minimize heat losses due to the significant distance between source and consumer. The study highlights the technical feasibility and energy-saving potential of this system, including reduced CO₂ emissions, enhanced energy efficiency, and increased sustainability. To ensure optimal implementation, a detailed design project is recommended, including heat exchanger dimensioning, pipeline layout with thermal insulation, pump and control system design, and a comprehensive techno-economic analysis. Although the preliminary results are promising, exact values should be validated through detailed field measurements and engineering calculations. This project represents a rational and environmentally responsible approach to energy use, aligning with modern industrial efficiency goals
Aerodynamic analysis of field wind turbine: a comparative study of computational methods with experimental validation
No full textThe study compares performance predictions from Blade Element Momentum Theory, Computational Fluid Dynamics methods, and experimental results for a 2.5 MW horizontal wind turbine across various wind speeds. The results indicate that Computational Fluid Dynamics or in complex flow conditions, although Blade Element Momentum Theory remains useful during the initial design stages. The analysis also underscores the influence of wind speed and shear stress transport on performance metrics such as turbine power output and flow characteristics. Despite certain modeling simplifications, such as the omission of detailed blade tip geometries, the findings suggest that both numerical methods exhibit trends consistent with the field experimental data. The study highlights the importance of detailed simulations for optimizing wind turbine performance and outlines future research focused on noise reduction and its impact on biodiversity
Cracking of HSLA Steel Nioval 47 Caused by Exploitation Condition and Repair Welding
No full textThe metallurgical characteristics of high-strength low-alloyed (HSLA) steel and the effects that could lead to crack initiation, especially in the heat affected zone, have to be taken into account during defining welding technology. Primary aim of this study is dealing with the thermal effect caused by repair welding of HSLA Nioval 47, along with the damage analysis of a water supplying pipeline made of this steel and the circumferential welded joints. Analysis has shown the involvement of different damage mechanisms on reconstructed pipeline. Thermal cycle during repair welding with a focus on cooling time (t8/5) and with heat input (E) was thoroughly defined, along with recommended technological measures. After repair welding (using E 50 6 1 Ni B 42 electrode), microstructure analysis was performed on the surfaces at the most critical locations, i.e., the repaired circumferential welds A and B. In addition to martensite structure in the coarse grain heat affected zone, crack initiated in the weld metal, ending at the fusion line, was detected, despite the adequately defined welding technology. One of the major remarks is related to the importance of available data needed for analysis and failure prevention during the exploitation period, guarantying reliability and safety of the pipeline
Techno-Economic Comparison of a Large-Scale Nuclear Power Plant, Small Modular Reactors, and Wind and Solar Power Plant Deployment
No full textA comparison of the net present value, the payback period, and the levelized
cost of electricity for three different projects of construction and exploitation of plants for
electricity production with the aim of decarbonizing the energy sector is conducted. The
first project is the building of a large-scale nuclear power plant with a light-water reactor,
the second one is the deployment of several identical small modular reactors, and the
third project is based on solar and wind power plants. Given that the sun and wind are
intermittent renewable energy sources, it is inevitable to take into account the construction
of an energy storage facility in the last project. The results show that the most profitable
are the small modular reactors, while the investment into solar and wind power plants
is burdened with the necessary electricity storage plant costs. Another drawback of an
investment in solar and wind power plants is their shorter exploitation lifetime of 25 years
compared to the long-term operation of nuclear power plants of 60 years or even more
