Search results for: IMPACT LOADING
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Consideration of Pseudo Strain Energy in Determination of Fatigue Life and Microdamage Healing of Asphalt Mastics
PublicationRest periods between cyclic loads can lead to recovery of damage and extension of fatigue life. This phenomenon is referred to as healing. Healing is clearly observed in bituminous materials, such as asphalt mastics, which belong to the components of asphalt mixtures. Due to the nature of road pavement traffic loading, which is characterized by series of intermittent pulses with rest periods, consideration of healing is necessary...
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Enhanced Mechanical and Electromechanical Properties of Compositionally Complex Zirconia Zr1–x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2−δ Ceramics
PublicationCompositionally complex oxides (CCOs) or high-entropy oxides (HEOs) are new multi-element oxides with unexplored physical and functional properties. In this work, we report fluorite structure derived compositionally complex zirconia with composition Zr1- x(Gd1/5Pr1/5Nd1/5Sm1/5Y1/5)xO2-δ (x = 0.1 and 0.2) synthesized in solid-state reaction route and sintered via hot pressing at 1350 °C. We explore the evolution of these oxides'...
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Strain energy density and entire fracture surface parameters relationship for LCF life prediction of additively manufactured 18Ni300 steel
PublicationIn this study, the connection between total strain energy density and fracture surface topography is investigated in additively manufactured maraging steel exposed to low-cycle fatigue loading. The specimens were fabricated using laser beam powder bed fusion (LB-PBF) and examined under fully-reversed strain-controlled setup at strain amplitudes scale from 0.3% to 1.0%. The post-mortem fracture surfaces were explored using a non-contact...
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Cyclic behaviour modelling of additively manufactured Ti-6Al-4V lattice structures
PublicationThe present work is concerned with the numerical modelling of the cyclic behaviour of Ti-6Al-4V lattice structures. In the study, diamond structures of titanium alloy produced by the additive laser powder bed fusion (LPBF) method with different degrees of relative density were used. Realistic geometric models of the studied mesostructures were generated using computed microtomography, taking into account the imperfections of the...
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Experimental observations on the creep behaviour of frozen soil
PublicationConstitutive models in the literature for creep of frozen soil are based on the direct use of time counted from the onset of creep. An explicit time dependence in a constitutive equation violates the principles of rational mechanics. No change in stress or temperature is allowed for during creep, using the time-based formulations. Moreover, the existing descriptions need much verification and improvement on the experimental side...
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Dimensional Synthesis of Coupled-Resonator Pseudoelliptic Microwave Bandpass Filters with Constant and Dispersive Couplings
PublicationIn this paper, we propose a novel technique for the dimensional synthesis of coupled-resonator pseudoelliptic microwave filters with constant and dispersive couplings. The proposed technique is based on numerical simulations of small structures, involving up to two adjacent resonators, and it accounts for a loading effect from other resonators by replacing them with terminations coupled through appropriately scaled inverters. The...
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Fracture Energy of Bonded Joints with 2D Elastic Adhesive Layer
PublicationWhen bonded joint is subjected to mode I fracture loading, the adhesive joints analytical solutions treats the adhesive layer, usually, as not existing or 1D Hooke elastic layer. In the case of 1D elastic layer, represented as Hookes spring element, is acting, only, in direction contrary to the applied load. Basing on the information yielded from sensitive laser profilometry technique, where deflections of bonded part of the joint...
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Surface sliding in human abdominal wall numerical models: Comparison of single-surface and multi-surface composites
PublicationDetermining mechanical properties of abdominal soft tissues requires a coupled experimental-numerical study, but first an appropriate numerical model needs to be built. Precise modeling of human abdominal wall mechanics is difficult because of its complicated multi-layer composition and large variation between specimens. There are several approaches concerning simplification of numerical models, but it is unclear how far one could...
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Pathways of Nitrogen Removal in Hybrid Treatment Wetlands
PublicationHybrid Treatment Wetlands (HTWs) are composed of two or more filters with different modes of flow, allowing the benefits of both types of bed to be combined, resulting in better effluent quality (nitrogen and organic compounds removal). Such a heterogeneous environment creates possibilities for different mechanisms of nitrogen removal. The objective of the present study was to investigate the removal of nitrogen versus a range...
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The Taste of Waste: The Edge of Eggshell Over Calcium Carbonate in Acrylonitrile Butadiene Rubber
PublicationRubber technology experiences a new age by the use of biowaste or natural fillers. In this regard, taking properties of reinforcing agents from biowaste fillers remains as the challenging matter. Chicken eggshell (ES) biowaste has recently been introduced to substitute calcium carbonate (CaCO3) duo to its superior properties and low price. In this work, composites based on acrylonitrile butadiene rubber (NBR) reinforced with ES...
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THE APPLICATION OF PHENOMENOLOGICAL METHODOLOGY FOR DESIGNING PILE FOUNDATION IN PORT STRUCTURES
PublicationIt is of utmost importance in the design process that a suitable, safe and concurrently economic solution be chosen. Issues connected with foundations require adopting a special approach. Soil is a composite medium, and it is essential to describe as precisely as possible the interaction taking place between the subgrade and the structure. There are many design methods of pile foundation that are based on in-situ test of soils....
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Diagnosis of Damage in a Steel Tank Model by Shaking Table Harmonic Tests
PublicationDiagnosis of damage in civil engineering structures has recently become an important issue in the safety assessment procedure. Among a number of different approaches, a method of measuring the changes in natural frequencies is one of the most effective indicators of global damage. It has been successfully applied to relatively small. structures, however, the tests on large structures are very difficult and the practical application...
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Non-uniqueness of fracture parameter choice in simulations of concrete cracking at mesoscale level
PublicationIn the paper a non-uniqueness of fracture parameter choice in simulations of cracking process in plain concrete specimens at mesoscale level under monotonic static loading is analysed. The Finite Element Method is used, where cracks are defined in a discrete way using interface cohesive elements with nonlinear material law including softening. The concrete mesostructure (such as: cement matrix, air voids, aggregates, and Interfacial...
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Effect of bending-torsion on fracture and fatigue life for 18Ni300 steel specimens produced by SLM
PublicationIn this study, different fracture surfaces caused by fatigue failure were generated from 18Ni300 steel produced by selective laser melting (SLM). Hollow round bars with a transverse hole were tested under bending-torsion to investigate the crack initiation mechanisms and fatigue life. Next, the post-failure fracture surfaces were examined by optical profilometer and scanning electron microscope. The focus is placed on the relationship...
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Experimental investigations on the mechanical properties and damage detection of carbon nanotubes modified crumb rubber concrete
PublicationThis study presents a modified crumb rubber (MCR) concrete design mix reinforced with multi-walled carbon nanotubes (MWCNTs), mechanical characterization, and cracking monitoring using the acoustic emission (AE) technique. The results showed that the bridging effect of MWCNTs and MCR in the concrete mix mitigated the shortcomings of MWCNT-MCR concrete and improved the flexural and compressive strengths by 18.3% and 26.5%, respectively,...
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Atomic-Scale Finite-Element Modeling of Elastic Mechanical Anisotropy in Finite-Sized Strained Phosphorene Nanoribbons
PublicationNanoribbons are crucial nanostructures due to their superior mechanical and electrical properties. This paper is devoted to hybrid studies of the elastic mechanical anisotropy of phosphorene nanoribbons whose edges connect the terminals of devices such as bridges. Fundamental mechanical properties, including Young’s modulus, Poisson’s ratio, and density, were estimated from first-principles calculations for 1-layer, 3-layer, and...
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Prediction of fracture toughness in fibre-reinforced concrete, mortar, and rocks using various Machine learning techniques
PublicationMachine Learning (ML) method is widely used in engineering applications such as fracture mechanics. In this study, twenty different ML algorithms were employed and compared for the prediction of the fracture toughness and fracture load in modes I, II, and mixed-mode (I-II) of various materials, including fibre-reinforced concrete, cement mortar, sandstone, white travertine, marble, and granite. A set of 401 specimens of “Brazilian...
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On the non-linear dynamics of torus-shaped and cylindrical shell structures
PublicationIn this study, the non-linear dynamic analysis of torus-shaped and cylindrical shell-like structures has been studied. The applied material is assumed as the functionally graded material (FGM). The structures are considered to be used for important machines such as wind turbines. The effects of some environmental factors on the analysis like temperature and humidity have been considered. The strain field has been calculated in...
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4-Point beam tensile test on a soft adhesive
PublicationAn adhesive butt joint with a soft bondline has been studied. A series of experiments was conducted on test pieces constituted of aluminium adherends bonded with a low modulus epoxy adhesive, ScotchWeld™ 2216. The joint was subjected to four point bending, in tension/compression loading, under constant deflection rate, with the bondline being parallel to the applied load. The objective was to examine and evaluate crack nucleation...
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A novel in vivo approach to assess strains of the human abdominal wall under known intraabdominal pressure
PublicationThe study concerns mechanical behaviour of a living human abdominal wall. A better mechanical understanding of a human abdominal wall and recognition of its material properties is required to find mechanically compatible surgical meshes to significantly improve the treatment of ventral hernias. A non-invasive methodology, based on in vivo optical measurements is proposed to determine strains of abdominal wall corresponding to...
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Electrostatic Zipping Actuators—Analysis of the Pull-In Effect Depending on the Geometry Parameters
PublicationContinuous work on a new generation of actuators, referred to as artificial muscles, resulted in the initiation of work on electrostatic zipping actuators, the concept of which is derived from micro electro-mechanical devices. Despite partial knowledge of their basic operating parameters, a question remains whether electrostatic zipping actuators are able to meet the expectations in the context of generated forces and control possibilities....
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The Dominant Influence of Plastic Deformation Induced Residual Stress on the Barkhausen Effect Signal in Martensitic Steels
PublicationThe paper presents the results of investigation of the influence of plastic deformation on the magnetic properties of martensitic steel (P91 grade). The properties of the hysteresis loops as well as of the Barkhausen effect (BE) signal are analysed for both tensile and compressive loading up to ε = 10% of plastic deformation. The choice of the steel and of the deformation range is unique, since for such combination one can expect...
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POM/EVA Blends with Future Utility in Fused Deposition Modeling
PublicationPolyoxymethylene (POM) is one of the most popular thermoplastic polymers used in the industry. Therefore, the interest in its potential applications in rapid prototyping is understandable. Nevertheless, its low dimensional stability causes the warping of 3D prints, limiting its applications. This research aimed to evaluate the effects of POM modification with ethylene-vinyl acetate (EVA) (2.5, 5.0, and 7.5 wt.%) on its processing...
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Verification of the new viscoelastic method of thermal stress calculation in asphalt layers of pavements
PublicationThe new viscoelastic method of thermal stress calculations in asphalt layers has been developed and published recently by the author. This paper presents verification of this method. The verification is based on the comparison of the results of calculations with results of testing of thermal stresses in Thermal Stress Restrained Specimen Test. The calculations of thermal stresses according to the new method were based on rheological...
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Analytical approach for membrane action in laterally-restrained reinforced concrete square slabs under uniformly distributed loads
PublicationLaterally-restrained reinforced concrete slabs can mobilise compressive membrane action and subsequent tensile membrane action under extreme loading conditions, thereby enhancing the load resistance under uniformly distributed loads. Previous analytical study focuses primarily on tensile membrane action in simply-supported slabs. This paper describes an analytical approach for membrane action in laterally-restrained square slabs....
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Cellulosic bionanocomposites based on acrylonitrile butadiene rubber and Cuscuta reflexa: adjusting structure-properties balance for higher performance
PublicationDesign and manufacture of cellulosic nanocomposites with acceptable performance is in the period of a transition from fantasy to reality. Typically, cellulosic nanofillers reveal poor compatibility with polymer matrices. Thus, adjusting the balance between structure and properties of cellulosic bionanocomposites by careful selection of parent ingredients is the first priority. Herein, we incorporated Cuscuta reflexa derived cellulose...
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Design and Analysis of Artificial Neural Network (ANN) Models for Achieving Self-Sustainability in Sanitation
PublicationThe present study investigates the potential of using fecal ash as an adsorbent and demonstrates a self-sustaining, optimized approach for urea recovery from wastewater streams. Fecal ash was prepared by heating synthetic feces to 500 °C and then processing it as an adsorbent for urea adsorption from synthetic urine. Since this adsorption approach based on fecal ash is a promising alternative for wastewater treatment, it increases...
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Aerodynamic Shape Optimization for Delaying Dynamic Stall of Airfoils by Regression Kriging
PublicationThe phenomenon of dynamic stall produce adverse aerodynamic loading which can adversely affect the structural strength and life of aerodynamic systems. Aerodynamic shape optimization (ASO) provides an effective approach for delaying and mitigating dynamic stall characteristics without the addition of auxiliary system. ASO, however, requires multiple evaluations time-consuming computational fluid dynamics models. Metamodel-based...
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S-scheme heterojunction Bi2O3-ZnO/Bentonite clay composite with enhanced photocatalytic performance
PublicationThe industrial waste water is always a bottleneck problem in the modern civilization of the present era. In a quest to develop effective methods for the elimination of lethal pollutants from the waste water and water remediation, this work is focused on the development of a rapid and proficient approach for preparing supported binary metal oxide catalyst for photocatalytic advance oxidation process used in waste water treatment...
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Non-linear static stability of bi-layer carbon nanosheets resting on an elastic matrix under various types of in-plane shearing loads in thermo-elasticity using nonlocal continuum
PublicationIn this research, the shear and thermal buckling of bi-layer rectangular orthotropic carbon nanosheets embedded on an elastic matrix using the nonlocal elasticity theory and non-linear strains of Von-Karman was studied. The bi-layer carbon sheets were modeled as a double-layered plate, and van der Waals forces between layers were considered. The governing equations and boundary conditions were obtained using the first order shear...
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The influence of α,ω-diols and SiO2 particles on CO2 absorption and NH3 escaping during carbon dioxide capture in ammonia solutions
PublicationAmmonia solutions are widely used solvents for CO2 capture. However, a significant disadvantage of these solvents is secondary pollution of the purified gas stream by desorbed ammonia. In this work, α,ω-diols, and colloidal silica have been proposed to reduce this undesired effect. Ammonia solutions with the addition of ethylene glycol (EG), 1,3-propanediol (PRD), 1,4-butanediol (BUD), 1,5-pentanediol (PED), or 1,6-hexanediol (HED)...
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Effect of kenaf fibre modification on morphology and mechanical properties of thermoplastic polyurethane materials
PublicationThe presented study examined the morphology and mechanical properties of biocomposites obtained from kenaf natural fibre and thermoplastic polyurethane. Kenaf was modified using various methods, namely: acetylation, blocked isocyanate, maleic anhydride and permanganate treatment. Those methods and ways of carrying out of surface modifications were not studied before on kenaf/thermoplastic polyurethane composites. Different fibre...
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Perovskite-type KTaO3–reduced graphene oxide hybrid with improved visible light photocatalytic activity
PublicationNovel rGO–KTaO3 composites with various graphene content were successfully synthesized using a facile solvothermal method which allowed both the reduction of graphene oxide and loading of KTaO3 nanocubes on the graphene sheets. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX), Fourier...
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Experimental and Numerical Study on Dynamics of Two Footbridges with Different Shapes of Girders
PublicationThe paper presents the experimental and numerical results of the dynamic system identification and verification of the behavior of two footbridges in Poland. The experimental part of the study involved vibration testing under different scenarios of human-induced load, impulse load, and excitations induced by vibration exciter. Based on the results obtained, the identification of dynamic parameters of the footbridges was performed...
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The early failure of the gamma nail and the dynamic hip screw in femurs with a wide medullary canal. A biomechanical study of intertrochanteric fractures
PublicationBackground: Intertrochanteric fractures may occur in a bone with a wide medullary canal that may lead to significant mobility of a intramedullary nail, contrary to an extramedullary device. This study evaluates the Dynamic Hip Screw and the gamma nail in AO 31.A2.1 fractures in these circumstances. Methods: Synthetic femora with canals drilled to 18 mm were used. Five fixation types were examined: a 2 - hole and a 4 – hole Dynamic...
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Properties of nano-Fe3O4 incorporated epoxy coatings from Cure Index perspective
PublicationThe mission of an advanced epoxy-based nanocomposite coating is to provide a given substrate with protection against an unwelcome guest; e.g. corrosive molecules/media, environmental stress, flame, thermal degradation or microorganisms. In such systems, the degree to which superior properties can be guaranteed depends on the state of network formation in the epoxy in the presence of nanoparticles. For low-filled epoxy nanocomposite coatings,...
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ENERGY ANALYSIS OF PROPULSION SHAFT FATIGUE PROCESS IN ROTATING MECHANICAL SYSTEM PART I TESTING SIGNIFICANCE OF INFLUENCE OF SHAFT MATERIAL FATIGUE EXCITATION PARAMETERS
PublicationThe article discusses the problem of mathematical modelling of energy conversion processes in a rotating mechanical system for the purpose of identifying fatigue states of propulsion shafts in this system. A simplified physical model of the analysed system, constructed in an appropriate scale, has made the basis for the experimental research. The research programme took into consideration mechanical fatigue excitation of the model...
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Polygons vs. clumps of discs: A numerical study of the influence of grain shape on the mechanical behaviour of granular materials
PublicationWe performed a series of numerical vertical compression tests on assemblies 01 20 granular material using a Discrete Element code and studied the results with regard to the grain shape. The samples consist of 5000 grains made from either 3 overlapping discs (clumps - grains with concavities) or six-edged polygons (convex grains). These two grain type have similar external envelope, which is a fund ion of a geometrical parameter...
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Broad Stopband, Low-Loss, and Ultra-Compact Dual-Mode Bandpass Filter Based on HMSIRC
PublicationIn this investigation, an ultra-compact dual-mode bandpass filter (BPF) with a wide stopband re-sponse is realized by using a half-mode substrate-integrated rectangular cavity (HMSIRC). The HMSIRC resonator is designed with a cavity that is rectangular in shape and has metallic vias along three of the sides. The fourth side is open-ended and contains microstrip feed lines. For the purpose of constructing a magnetic wall, a rectangular...
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Recent advances in hydrogen production from biomass waste with a focus on pyrolysis and gasification
PublicationThis paper presents the results research on the optimal fuel compositions and the control parameters of the spark ignition engine fueled with syngas-biogas-hydrogen for the purpose of setting up a flexible electronic control unit for the engine working in a solar-biomass hybrid renewable energy system. In syngas-biogas-hydrogen mixture, the optimal content of hydrogen and biogas is 20% and 30%, respectively. Exceeding these thresholds,...
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Feasibility Study of Biohydrogen Production from Acid Cheese Whey via Lactate-Driven Dark Fermentation
PublicationThe high loading of lactic acid bacteria (LAB) present in cheese whey still limits its use as hydrogen feedstock. This study aims to investigate the feasibility of producing hydrogen from acid cheese whey via lactate-driven dark fermentation (LD-DF). Mesophilic batch fermentations were performed with delipidated acid cheese whey at a fixed pH of 5.8 and driven by an acidogenic bacterial culture containing LAB and lactate-oxidizing...
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Optimization of carbamazepine photodegradation on defective TiO2-based magnetic photocatalyst
PublicationIn this work, carbamazepine (CBZ) degradation over defective Fe3O4@SiO2/d-TiO2/Pt photocatalyst was studied. Within the titania structure, Ti vacancies and Pt nanoparticles were introduced to enhance the photocatalyst’s light absorption and influence charge carriers’ mobility. For the carbamazepine degradation, process parameters, e.g., temperature, flux intensity, photocatalyst loading, aeration, pH, and addition of H2O2, were optimized...
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One More Step Towards a Circular Economy for Thermal Insulation Materials—Development of Composites Highly Filled with Waste Polyurethane (PU) Foam for Potential Use in the Building Industry
PublicationThe rapid development of the building sector has created increased demand for novel materials and technologies, while on the other hand resulting in the generation of a severe amount of waste materials. Among these are polyurethane (PU) foams, which are commonly applied as thermal insulation materials. Their management is a serious industrial problem, due to, for example, their complex chemical composition. Although some chemical...
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Highly-Miniaturized Dual-Mode Bandpass Filter Based on Quarter-Mode Substrate Integrated Waveguide with Wide Stopband
PublicationThis paper presents a novel design of a highly-miniaturized dual-mode bandpass filter (BPF) employing a quarter-mode substrate integrated waveguide (QMSIW). The QMSIW resonator is based on a square cavity with metallic vias along two sides, and open-ended edges at the remaining sides that contain orthogonal feed lines. An open slot is introduced along the two sides of the square cavity with metallic vias to form a magnetic wall....
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Flexible syngas-biogas-hydrogen fueling spark-ignition engine behaviors with optimized fuel compositions and control parameters
PublicationThis paper presents the results research on the optimal fuel compositions and the control parameters of the spark ignition engine fueled with syngas-biogas-hydrogen for the purpose of setting up a flexible electronic control unit for the engine working in a solar-biomass hybrid renewable energy system. In syngas-biogas-hydrogen mixture, the optimal content of hydrogen and biogas is 20% and 30%, respectively. Exceeding these thresholds,...
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Optimum number of actuators to minimize the cross-sectional area of prestressable cable and truss structures
PublicationThis paper describes a new computational method for determining the optimum number of actuators to design the optimal and economic cross-sectional area of pin-jointed assemblies based on the conventional force method. The most active members are selected to be prestressed to redistribute stress in the whole structure, resulting in regulating the internal force of bars that face high stress. Reducing stress in critical members allows...
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High gain/bandwidth off‑chip antenna loaded with metamaterial unit‑cell impedance matching circuit for sub‑terahertz near‑field electronic systems
PublicationAn innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance...
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THE ANALYSIS OF THE INFLUENCE OF STRESS DISTRIBUTION ON WEAR PROFILE IN LUBRICATED SLIDING CONTACT OF UHMW-PE VS TITANIUM Ti-13Nb-13Zr ALLOY
PublicationMetal – polymer sliding contacts are a typical combination in industry and medicine. For decades such a set of materials has been the primary choice in human joints endoprosthetic technology. In this paper tribological issues of are presented from a research on the potential for practical use of Ti-13Nb-13Zr/UHMW-PE couple for orthopedic endoprosthesis. In tests on simplified models it is critically important to carefully...
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Improving the procedure of probabilistic load testing design of typical bridges based on structural response similarities
PublicationThis paper concerns load testing of typical bridge structures performed prior to operation. In-situ tests of a two-span post-tensioned bridge loaded with three vehicles of 38-ton mass each formed the input of this study. On the basis of the results of these measurements, an advanced FEM model of the structure was developed for which the sensitivity analysis was performed for chosen uncertainty sources. Three uncorrelated random...
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Optimization of the Aeration Strategies in a Deammonification Sequencing Batch Reactor for Efficient Nitrogen Removal and Mitigation of N2O Production
PublicationIn deammonification systems, nitrite-oxidizing bacteria (NOB) suppression and nitrous oxide (N2O) mitigation are two important operational objectives. To carry out this multivariable analysis of response, a comprehensive model for the N cycle was developed and evaluated against experimental data from a laboratory-scale deammonification granular sludge sequencing batch reactor. Different aeration strategies were tested, and the manipulated...