Search results for: THERMAL STRESS
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 2,7 V at 1281 mA. Sample J51, run #1.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 2,7 V and discharged to 10 mV by constant current 1098 mA. Sample J51, experiment run #1. The current is extremely high for this type of sample to accelerate ageing processes.The images were taken...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 2,7 V at 534 mA. Sample J53, run #7.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 2,7 V and discharged to 10 mV by constant current 534 mA. Sample J53, experiment run #7. The period of images is 30 minutes in order to observe slow temperature fluctuations.The images were taken...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 2,9 V at 420 mA. Sample 103, run #3.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 2,9 V and discharged to 10 mV by constant current 420 mA. Sample 103, experiment run #3. Voltage was increased to accelerate the ageing process.The images were taken with thermographic camera VigoCAM...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 2,7 V at 534 mA. Sample J53, run #6.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 2,7 V and discharged to 10 mV by constant current 534 mA. Sample J53, experiment run #6. The period of images is 30 minutes in order to observe slow temperature fluctuations.The images were taken...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,6 V at 420 mA. Sample 103, run #3.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,6 V and discharged to 10 mV by constant current 420 mA. Sample 103, experiment run #3. Continuation of experiment at high voltage to accelerate the ageing process.The images were taken with thermographic...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,4 V at 420 mA. Sample 103, run #1.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,4 V and discharged to 10 mV by constant current 420 mA. Sample 103, experiment run #1. Voltage was increased to accelerate the ageing process.The images were taken with thermographic camera VigoCAM...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,6 V at 420 mA. Sample 103, run #2.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,6 V and discharged to 10 mV by constant current 420 mA. Sample 103, experiment run #2. Voltage was increased to accelerate the ageing process.The images were taken with thermographic camera VigoCAM...
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What makes them dream big? Determinants of business growth aspirations among Polish students
PublicationThe objective of the article is to explore the concept of business growth aspirations and identify its determinants at an early stage of the entrepreneurial process. In this exploratory study, I focused on the underexplored approach to entrepreneurial process i.e. to study the growth aspirations and its determinants alongside entrepreneurial intentions. Studying growth aspirations and their determinants provides valuable insights...
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Therapeutic Potential of Multifunctional Derivatives of Cholinesterase Inhibitors
PublicationThe aim of this work is review of tacrine analogues from the last three years, which were not included in the latest review work, donepezil and galantamine hybrids from 2015 and rivastigmine derivatives from 2014. In this account we summarize the efforts toward the development and characterization of non-toxic inhibitors of cholinesterases based on mentioned drugs with various interesting additional properties such as antioxidant,...
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Modern Material Solutions Applied in Pediatric Facilities
PublicationNew tendencies in forming of the health services functional buildings’ systems shaped along with the emergence of caring for patient’s mental condition in medical sciences. The interior design harmonized with the medical function became an incredibly important feature. This opened up new opportunities for the architecture of health care facilities. A positive architecture’s impact on the user’s well-being is remarkably important...
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On the plastic buckling of curved carbon nanotubes
PublicationThis research, for the first time, predicts theoretically static stability response of a curved carbon nanotube (CCNT) under an elastoplastic behavior with several boundary conditions. The CCNT is exposed to axial compressive loads. The equilibrium equations are extracted regarding the Euler–Bernoulli displacement field by means of the principle of minimizing total potential energy. The elastoplastic stress-strain is concerned...
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EIA in teaching sustainable development and environmental protection in engineering education
PublicationA multifaceted approach in teaching the environmental impact assessment (EIA) as a way to stress the role of environmental education in technical sciences is the focus of this article. The EIA is an example of an effective tool that supports spatial planning in implementing sustainable development. The aim is to present the idea and benefits of a facilitative and collaborative approach in teaching the EIA, stressing the role of...
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Proton Transfer Reaction Mass Spectrometry for Plant Metabolomics
PublicationVolatile organic compounds (VOCs) emitted by plants are a valuable source of information on their growth, theirresponse to stress, and the condition of their habitat. The recent trend in the analysis of low-mass molecules ofplant origin is metabolomics, which in the context of volatiles is often referred to as volatolomics. It requires theuse of modern analytical instrumentation...
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2-D constitutive equations for orthotropic Cosserat type laminated shells in finite element analysis
PublicationWe propose 2-D Cosserat type orthotropic constitutive equations for laminated shells for the purpose of initial failure estimation in a laminate layer. We use nonlinear 6-parameter shell theory with asymmetric membrane strain measures and Cosserat kinematics as the framework. This theory is specially dedicated to the analysis of irregular shells, inter alia, with orthogonal intersections, since it takes into account the drilling...
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Discrete-continuous optimisation of an axial flow blood pump
PublicationThis paper presents results of discrete-continuous optimisation of an axial flow blood pump. Evolution Strategies (ES) are used as a global optimisation method in order to localise the optimal solution in relatively short time. The whole optimisation process is fully automated. This also applies to geometry modelling. Numerical simulations of the flow inside the pump is performed by means of the Reynolds-Average Navier-Stokes...
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An experimental study on polymer mass
PublicationA new method of repairing damaged structures by filling the cracks with specially prepared polymer mass has been recently proposed. The technique is mainly dedicated to historical objects where minimum intervention is permitted. The flexible joint bonds the disrupted elements and ensures further safe exploitation of a damaged structure. The aim of the present paper is to show the results of an experimental study on polymer mass...
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Problems of analytical determination of journal bearing bush fatigue strength estimates
PublicationProblems connected with determination of stress distribution in sliding layer of thinwalled bearing bushes, investigated in bearing fatigue test rigs, have been presented. Using an example of plain bearings tested in the fatigue machine SMOK (built at the Gdask University of Technology) problems with obtaining a convergence of iterative procedure for determining the fatigue strength estimators of bearing alloy surface layer are...
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The Influence of Selected Parameters of Numerical Modelling on Strains and Stresses at Weld Toe Notch
PublicationLatest development in the field of welding technology and prefabrication enabled massive production of thin-walled sandwich structures. Multi-layered sandwich structures are fabricated with the use of high-power CO2 lasers, friction welding, arc welding, hybrid welding, or other technique designed for the special purpose. Steel or aluminium alloy plates with thickness between 1 and 5 mm are connected by internal stiffeners. Strength...
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The effect of elevated temperature on LCF damage growth in 2024AA – Experiment and modeling
PublicationThis paper presents the results of experimental low-cycle fatigue (LCF) tests conducted on EN-AW 2024 alloy in T3511 temper at 100 ◦C, 200 ◦C and 300 ◦C. The material’s basic fatigue characteristics were determined, such as fatigue life curve and cyclic strain curve. Both the hysteresis loop and nature of fracture surfaces obtained in macro- and microscopic observations (scanning electron microscope, SEM) were accounted for. The...
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Splice variants of mitofusin 2 shape the endoplasmic reticulum and tether it to mitochondria
PublicationIn eukaryotic cells, different organelles interact at membrane contact sites stabilized by tethers. Mitochondrial mitofusin 2 (MFN2) acts as a membrane tether that interacts with an unknown partner on the endoplasmic reticulum (ER). In this work, we identified the MFN2 splice variant ERMIT2 as the ER tethering partner of MFN2. Splicing of MFN2 produced ERMIT2 and ERMIN2, two ER-specific variants. ERMIN2 regulated ER morphology,...
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Fractographic-fractal dimension correlation with crack initiation and fatigue life for notched aluminium alloys under bending load
PublicationIn this study, fatigue fracture surfaces of aluminium alloy 2017-T4 notched specimens were investigated under cyclic bending to find an alternative failure loading index.. The surface topographies were measured on the entire fracture area with an optical profilometer for different loading conditions. Fatigue crack initiation life Ni and total fatigue life Nf were examined using standard surface topography parameters (such as, root...
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Effect of austempering temperature on microstructure and cyclic deformation behaviour of multiphase low-carbon steel
PublicationThis paper examined the cyclic deformation behaviour of multiphase low-carbon steel that was subjected to austempering heat treatments at four temperatures (190 °C, 230 °C, 275 °C, and 315 °C) below the martensite start temperature (Ms = 353 °C). The tests were conducted at room temperature, under fully reversed strain-controlled conditions, with strain amplitudes in the range 0.5–1.0%. The microstructure was observed by transmission...
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Quasistatic and fatigue behavior of an AISI H13 steel obtained by additive manufacturing and conventional method
PublicationThis work aims to compare the mechanical behavior of an AISI H13 steel obtained by additive manufacturing with that obtained by conventional manufacturing methods. The average values of the ultimate tensile strength (UTS) and ductility obtained for the specimens produced by the conventional method were equal to 658 MPa and 18%, respectively, which compares with 503 MPa and 0.75% registered for the selective laser melting (SLM)...
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Experimental investigations and damage growth modeling of EN‐AW 2024 aluminum alloy under LCF loading accounting creep pre‐deformation
PublicationThis article presents the results of experimental tests of creep rupture and of low-cycle fatigue (LCF) of EN-AW 2024 aluminum alloy devoid of damage and having preliminary damage. The preliminary damage was dealt in the process of creep at elevated temperature 100C, 200C, and 300C until achievement of two different strain values at each temperature. Samples with preliminary damage were subjected to fatigue tests at room temperature....
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Experimental study and numerical simulation of the dynamic penetration into dry clay
PublicationTests of dry clay were carried out in a uniaxial stress state using the experimental setup which implements the split Hopkinson pressure bar method. Based on the results of these experiments, the compressive strength of clay was determined as an important element of S.S. Grigoryan’s model of the soil medium. In addition, the parameters of this model are determined from the results of experiments using the modified Kolsky method...
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Investigations on strength and fracture in RC beams scaled along height or length
PublicationThe objective of the present paper is to identify experimentally and theoretically differing failure mechanisms in reinforced concrete beams subjected to four-point bending for a separate variation of the depth and length at the constant thickness. Experiments were performed on reinforced concrete beams under four-point bending. Different failure mechanisms included steel yielding, diagonal tension or shear- compression depending...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 2,7 V at 64 mA. Sample 91. Image period: 5 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 2,7 V and discharged to 10 mV by constant current 64 mA. Sample 91. Pictures were taken relatively fast, with period of 5 sec in order to examine the fast fluctuations of sample temperature during...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 2,7 V at 120 mA. Sample 103. Image period: 0,5 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 2,7 V and discharged to 10 mV by constant current 120 mA. Sample 103. Thermographic pictures were taken relatively fast, with period of 0,5 sec in order to examine the fast fluctuations of sample...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,4 V at 420 mA. Sample 103. Image period: 0,5 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,4 V and discharged to 10 mV by constant current 420 mA. Sample 103. Pictures were taken with period of 0,5 sec (2 Hz) in order to examine the fast fluctuations of sample temperature during charging...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,3 V at 420 mA. Sample 103, run #1.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,3 V and discharged to 10 mV by constant current 420 mA. Sample 103, experiment run #1. Voltage was increased to accelerate the ageing process.The images were taken with thermographic camera VigoCAM...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,3 V at 420 mA. Sample 103. Image period: 2 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,3 V and discharged to 10 mV by constant current 420 mA. Sample 103. Pictures were taken relatively fast, with period of 2 sec in order to examine the fast fluctuations of sample temperature during...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,6 V at 420 mA. Sample 103. Image period: 0,5 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,6 V and discharged to 10 mV by constant current 420 mA. Sample 103. Pictures were taken with period of 0,5 sec (2 Hz) in order to examine the fast fluctuations of sample temperature during charging...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,5 V at 420 mA. Sample 103. Image period: 0,5 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,5 V and discharged to 10 mV by constant current 420 mA. Sample 103. Pictures were taken with period of 0,5 sec (2 Hz) in order to examine the fast fluctuations of sample temperature during charging...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,6 V at 420 mA. Sample 103. Image period: 1 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,6 V and discharged to 10 mV by constant current 420 mA. Sample 103. Pictures were taken with period of 1 sec (1 Hz) in order to examine the fast fluctuations of sample temperature during charging...
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Thermographic imaging of electrochemical double layer capacitors during cycling charging - discharging 0 - 3,4 V at 420 mA. Sample 103. Image period: 1 sec.
Open Research DataDataset contains thermal images of prototype electrochemical double layer capacitor taken during cyclic charging - discharging. The sample was charged to 3,4 V and discharged to 10 mV by constant current 420 mA. Sample 103. Pictures were taken with period of 1 sec in order to examine the fast fluctuations of sample temperature during charging - discharging...
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Hybrid Finite Element Method Development for Offshore Structures’ Calculation with the Implementation of Industry Standards
PublicationIn the design process of offshore steel structures, it is typical to employ commercial calculation codes in which simulation and evaluation of results are performed on the basis of the available standards (e.g. API, DNV, Lloyds). The modeling and solution rely on finite element methods and cover the simulation of the structure’s properties along with the influence of the marine environment – sea currents, wave and wind loading,...
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On rotational instability within the nonlinear six-parameter shell theory
PublicationWithin the six-parameter nonlinear shell theory we analyzed the in-plane rotational instability which oc- curs under in-plane tensile loading. For plane deformations the considered shell model coincides up to notations with the geometrically nonlinear Cosserat continuum under plane stress conditions. So we con- sidered here both large translations and rotations. The constitutive relations contain some additional mi- cropolar parameters...
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Wyznaczenie obciążeń na poszycie okrętu wywołanych uderzeniem fal i uderzeniem w lód i ich wpływ na bezpieczeństwo okrętu
PublicationThe main problem is the vessels rather accurate determination of the hydrodynamic loads so-called hydroelasticity outside . This can be done by theoretical analysis , computer simulation or by experiment. This gives the hydrodynamic pressure distribution on the walls of the ship's hull and also on the walls of marine vessels .The most dangerous are the impact of extreme storm waves , the impact of the wharf and the impact zone...
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The influence of the welding environment on the properties of Tekken joints made from S355J2C+N steel
PublicationThere are three main methods of underwater welding: dry, wet and intermediate between them, by using the local dry chamber. Due to low costs, the most common method is the wet welding with the use of covered electrodes. Water as a welding environment carries out a lot of problems. The first is limited visibility and instability of the welding arc. The biggest problem during underwater welding is high susceptibility to cold cracking,...
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Mechanical properties of polyester reinforced PVC coated fabric subjected to biaxial loading of creep type
PublicationThe goal of the current study is to analyze the basic mechanical properties of the architec-tural fabric VALMEX, which is a composite material built of reinforcing polyester thread families and both sides PVC coated. The material was firstly subjected to biaxial loading of creep type for about 48 hours. The stress levels of the creep loading in two main or-thogonal directions of the fabric (commonly called the warp and fill directions)...
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Methodology for determination of the selected mechanical properties of wood based on cutting tests
PublicationFrom kiln-dried spruce wood (with steam) as well as in natural conditions were randomly selected 8 samples. After determining the average dimensions, moisture content and density of the samples they have been cut on the frame sawing machine PRW15M for measurement of cutting power. Based on those results from a linear rela-tionship of cutting power versus feed per toot mechanical properties of wood such as facture toughness and...
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Electroelastic biaxial compression of nanoplates considering piezoelectric effects
PublicationIn the present theoretical work, it is assumed that a piezoelectric nanoplate is connected to the voltage meter which voltages have resulted from deformation of the plate due to in-plane compressive forces whether they are critical buckling loads or arbitrary forces. In order to derive governing equations, a simplified four-variable shear deformation plate theory has been employed using Hamilton’s principle and Von-Kármán...
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Evaluation of reformer tubes degradation after long term operation
PublicationPurpose of this paper is to show the effect of long-term service at elevated temperatures on microstructural changes of cast steel reformer tubes made of the alloy IN-519 (24%Cr, 24%Ni, Nb). The relationship between mechanical properties and microstructure degradation is discussed. Investigations were performed on five tubes taken from ammonia reformer furnace. Tubes worked at temperature of 880C and 3,2 MPa pressure. The operation...
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Chemical modifications of graphene and their influence on properties of polyurethane composites: a review
PublicationPolyurethane composites are materials of great interest nowadays due to their wide range of available forms and applications in industry. Controlling and achieving unique properties via matrix modifications and addition of various specific nanofillers seems be one of the key elements to success. The purpose of this work is to briefly present some examples of graphene nanoderivatives, their syntheses, properties and influence on...
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Determination of magnetisation conditions in a Double-Core Barkhausen Noise measurement set-up
PublicationThe magnetic Barkhausen effect is useful forassessing 1D and 2D stress states of ferromagnetic steelobjects. However, its extension to technically importantmaterials, such as duplex anisotropic steels, remains challenging. The determination of magnetisation inside the studied object and the electromagnet for various geometries, materials and magnetisation angles is a key issue.Three-dimensional, dynamic finite element analysis...
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Photogrammetric and total station's measurement of compressed column's model
PublicationModelling studies continue to play an important role. One of such study is stress determination in the reinforcement bars of reinforced columns and determine column's axis deformation. The article presents measurements results of control points located on the model of reinforced concrete column. The column was compressed in few series till it's destruction. In this studies, photogrammetric method and total station measurements...
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A selectively reduced degree basis for efficient mixed nonlinear isogeometric beam formulations with extensible directors
PublicationThe effect of higher order continuity in the solution field by using NURBS basis function in isogeometric analysis (IGA) is investigated for an efficient mixed finite element formulation for elastostatic beams. It is based on the Hu–Washizu variational principle considering geometrical and material nonlinearities. Here we present a reduced degree of basis functions for the additional fields of the stress resultants and strains...
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Saint-Venant torsion based on strain gradient theory
PublicationIn this study, the Saint-Venant torsion problem based on strain gradient theory is developed. A total form of Mindlin's strain gradient theory is used to acquire a general Saint-Venant torsion problem of micro-bars formulation. A new Finite Element formulation based on strain gradient elasticity theory is presented to solve the Saint-Venant torsion problem of micro-bars. Moreover, the problem is solved for both micro and macro...
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Static and dynamic concrete calculations: Breakable aggregates in DEM model
PublicationThe paper deals with the calculations of a 3-point bending beam under static and dynamic loads. The real microstructure was obtained from laboratory tests using micro-tomography images. The quasi-static results were compared directly with experimental data at both macro and micro levels. Subsequently, higher strain rates were applied to investigate dynamic effects. The study focused on the influence of dynamic loading on the macroscopic...
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Numerical investigations of discrete crack propagation in Montevideo splitting test using cohesive elements and real concrete micro-structure
PublicationThe paper is aimed at accurately predicting the discrete fracture process in concrete specimens under complex stress states in two dimensional (2D) simulations. Plain concrete specimens subjected to Montevideo splitting test (MVD) were used for consideration due to non-negligible shear stresses impact in this type of test. In order to reflect the heterogeneous nature of the concrete, the meso-structure of the samples was included...