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Notch fatigue analysis and life assessment using an energy field intensity approach in 7050-T6 aluminium alloy under bending-torsion loading
- Ricardo Branco
- José Domingos Costa
- L.p. Borrego
- Wojciech Macek
- Filippo Berto
2022 Pełny tekst INTERNATIONAL JOURNAL OF FATIGUE
This paper studies the fatigue crack initiation and fatigue crack propagation of notched cylindrical bars made of 7050-T6 aluminium alloy subjected to multiaxial bending-torsion loading. The sites of crack initiation and the angles of crack initiation were successfully predicted from the distribution of the first principal stress at the notch surface. Fatigue crack initiation lives were computed through the new concept of energy field intensity formalised in a linear-elastic framework along with a local stress-strain model for notch plasticity analysis. Regardless of the model used to compute the cyclic response at the geometric discontinuity, the fatigue life predictions were in good agreement with the experimental observations.
Novel amides of mycophenolic acid and some heterocyclic derivatives as immunosuppressive agents
- Juliusz Walczak
- Dorota Iwaszkiewicz-Grześ
- Michalina Ziomkowska
- Magdalena Śliwka-Kaszyńska
- Mateusz Daśko
- Piotr Trzonkowski
- Grzegorz Cholewiński
2022 Pełny tekst JOURNAL OF ENZYME INHIBITION AND MEDICINAL CHEMISTRY
The group of new amide derivatives of mycophenolic acid (MPA) and selected heterocyclic amines was synthesised as potential immunosuppressive agents functioning as inosine-5'-monophosphate dehydrogenase (IMPDH) uncompetitive inhibitors. The synthesis employed uronium-type activating system (TBTU/HOBt/DIPEA) while or phosphonic acid anhydride method (T3P/Py) facilitating amides to be obtained in moderate to excellent yields without the need of phenolic group protection. Most of optimised protocols did not require complicated reaction work-ups, including chromatographic, solvent- consuming methods. The biological activity assay was performed on the T-Jurkat cell line and peripheral mononuclear blood cells (PBMCs) which are both dedicated for antiproliferative activity determination. Each of designed derivatives was characterised by reduced cytotoxicity and benzoxazole analogue revealed the most promising activity. Subsequently, an observed structure-activity relationship was discussed.
Novel Binary Mixtures of Alkanolamine Based Deep Eutectic Solvents with Water—Thermodynamic Calculation and Correlation of Crucial Physicochemical Properties
- Bartosz Nowosielski
- Marzena Jamrógiewicz
- Justyna Łuczak
- Dorota Warmińska
2022 Pełny tekst MOLECULES
This paper demonstrates the assessment of physicochemical and thermodynamic properties of aqueous solutions of novel deep eutectic solvent (DES) built of tetrabutylammonium chloride and 3-amino-1-propanol or tetrabutylammonium bromide and 3-amino-1-propanol or 2-(methylamino)ethanol or 2-(butylamino)ethanol. Densities, speeds of sound, refractive indices, and viscosities for both pure and aqueous mixtures of DES were investigated over the entire range of compositions at atmospheric pressure and T = (293.15 - 313.15) K. It was concluded that the experimental data were successfully fitted using the Jouyban–Acree model with respect to the concentration. Obtained results showed that this mathematical equation is an accurate correlation for the prediction of aqueous DES properties. Key physicochemical properties of the mixtures—such as excess molar volumes, excess isentropic compressibilities, deviations in viscosity, and deviations in refractive indices—were calculated and correlated by the Redlich–Kister equation with temperaturedependent parameters. The non-ideal behavior of the studied systems were also evaluated by using the Prigogine−Flory−Patterson theory and the results were interpreted in terms of interactions between the mixture components.
Novel chalcone-derived pyrazoles as potential therapeutic agents for the treatment of non-small cell lung cancer
- Natalia Maciejewska
- Mateusz Olszewski
- Jakub Jurasz
- Marcin Serocki
- Maria Dzierżyńska
- Katarzyna Cekała
- Ewa Wieczerzak
- Maciej Bagiński
2022 Pełny tekst Scientific Reports
Lung cancer is considered to account for approximately one-fifth of all malignant tumor-related deaths worldwide and is therefore one of the most lethal malignancies. Pyrazole scaffold possesses a wide range of biological and pharmacological activities, which play important roles in medicinal chemistry. The present study reports the synthesis and in vitro biological characterization of nine pyrazoles derived from chalcones as potential anticancer agents for non-small cell lung cancer A-549, H226, and H460 cell lines. Most of the compounds efficiently inhibited the growth of all the tested cancer cell lines at micromolar concentrations. One of the most active compounds (PCH-1) was further evaluated for its effect on cell cycle distribution, apoptosis, migration, epithelial–mesenchymal transition, and oxidative stress. Furthermore, studies on the mechanism of action revealed that PCH-1 disrupts microtubule assembly, leading to cancer cell death. Molecular modeling studies confirmed the potent interaction of PCH-1 with the vinblastine binding site on tubulin. Overall, this study provides novel opportunities to identify anticancer agents in the pyrazole series.
Novel composite of Zn/Ti-layered double hydroxide coupled with MXene for the efficient photocatalytic degradation of pharmaceuticals
- Anna Grzegórska
- Izabela Wysocka
- Paweł Głuchowski
- Jacek Ryl
- Jakub Karczewski
- Anna Zielińska-Jurek
2022 Pełny tekst CHEMOSPHERE
In the present study, a hybrid photocatalyst of Zn/Ti layered double hydroxide (LDH) coupled with MXene – Ti3C2 was synthesized for the first time and applied in photocatalytic degradation of acetaminophen and ibuprofen, two commonly present in the natural environment and prone to accumulate in the aquatic ecosystem pharmaceuticals. The effect of MXene content (0.5 wt%, 2.5 wt%, and 5 wt%) on the photocatalytic activity of LDH/MXene composite was investigated. The composite of LDH/MXene containing 2.5 wt% of MXene revealed the highest photocatalytic activity in the degradation of acetaminophen (100% within 40 minutes) and ibuprofen (99.7% within 60 minutes). Furthermore, an improvement in acetaminophen and ibuprofen mineralization was observed for the composite material. Meanwhile, the introduction of interfering ions (Na+, Ca2+, Mg2+, Cl-, SO42-) in the model seawater did not affect the removal efficiency of both pharmaceuticals. The photocatalytic experiment performed in the four subsequent cycles, as well as FTIR, TEM, and XPS analyses after the photodegradation process confirmed the excellent stability and reusability of the prepared composite material. In order to evaluate the effect of various reactive oxidizing species (ROS) on the photocatalytic process, the trapping experiment was applied. It was noticed that •O2- had the main contribution in photocatalytic degradation of acetaminophen, while •OH and h+ mainly affected the degradation of ibuprofen. Finally, based on the results of Mott Schottky analysis, bandgap calculation, and ROS trapping experiment, the possible mechanism for pharmaceuticals degradation was proposed. This research illustrates the feasibility and novelty of the treatment of pharmaceuticals by LDH/MXene composites, implying that MXene plays a significant role in the electron-hole separation and thus high photocatalytic activity.
Novel Interpolation Method of Multi-DFT-Bins for Frequency Estimation of Signal with Parameter Step Change
- Kai Wang
- Shan Liu
- Lanlan Wang
- Janusz Smulko
- He Wen
2022 Pełny tekst IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
The IpDFT(Interpolation Discrete Fourier Trans-form) method is one of the most commonly used non-parametric methods. However, when a parameter (frequency, amplitude or phase) step changes in the DFT period, the DFT coefficients will be distorted seriously, resulting in the large estimation error of the IpDFT method. Hence, it is a key challenge to find an IpDFT method, which not only can eliminate the effect of the step-changed symbol, but also can sufficiently eliminate the fence effect and the spectrum leakage. In this paper, an IpDFT based method is proposed to estimate the frequency of the single tone signal with the step-changed parameters in the sampling signal sequence. The relationship between the DFT bins and the step changed parameters is given by several linear equations. At most six different DFT bins are used to eliminate the effect of symbol.
Novel Low-Loss Substrates for 5G Applications
- Krzysztof Babicki
- Adam Lamęcki
- Michał Mrozowski
- Michał Baranowski
- Anna Wroblewska
- Mariusz Zdrojek
- Bartlomiej Salski
- Jerzy Krupka
2022
This paper presents a feasibility study of a new type of microwave low-loss dielectric substrates for 5G network applications. The new substrate materials are composites of polypropylene and high-dielectric-constant micro-ceramics. This combination is expected to form a very low-loss dielectric material at low fabrication cost. Two substrate samples with different dielectric properties are fabricated and their characteristics at microwave frequencies are investigated in this paper. The investigation covers two scenarios for the metallization of the substrates to form printed circuit boards. The dielectric properties of the materials are measured using the split post dielectric resonator technique. Furthermore, the quality of the materials is experimentally verified though the design, fabrication, and measurement of simple resonator structures
Novel method of estimation of inertial and dissipative parameters of a railway pantograph model
- Andrzej Wilk
- Len Gelman
- Sławomir Judek
- Krzysztof Karwowski
- Mirosław Mizan
- Tadeusz Maciołek
- Miroslaw Lewandowski
- Aleksander Jakubowski
- Karolina Klimowska
2022 Pełny tekst VEHICLE SYSTEM DYNAMICS
An increase in electric railway vehicles service velocity requires that correct interaction between the pantograph and the catenary is ensured. This implies the need for developing mathematical models of pantographs and catenaries and determining their parameters. The article presents a method to determine parameters of mechanical joints of a railway pantograph based on analysis of pantograph subassemblies in swinging motion. The experimental tests consisted in disassembling the pantograph and creating partial subassemblies which were then analysed with respect to their damped linear or angular oscillations. The simulation analysis required developing, in CAD, 3D models of individual pantograph parts and their subassemblies. Defined were joints between particular elements, which represent of real pantograph structure. The inertia parameters of the model were determined, based on structural characteristics and physical properties of materials, used for manufacturing individual pantograph elements, and then verified experimentally. The dissipative parameters of the mechanical joints were calculated iteratively. The model of complete pantograph assembly was also subject to verification and in this case, good convergence between simulation and experiment results was achieved. The obtained parameter values can be used in simulation models of other railway pantographs having a similar structure.
Novel Nonlinear High Order Technologies for Damage Diagnosis of Complex Assets
- Tomasz Ciszewski
- Len Gelman
- Andrew Ball
2022 Pełny tekst Electronics
For the first time worldwide, innovative techniques, generic non-linear higher-order unnormalized cross-correlations of spectral moduli, for the diagnosis of complex assets, are proposed. The normalization of the proposed techniques is based on the absolute central moments, that have been proposed and widely investigated in mathematical works. The existing higher-order, crosscovariances of complex spectral components are not sufficiently effective. The novel technology is comprehensively experimentally validated for induction motor bearing diagnosis via motor current signals. Experimental results, provided by the proposed technique, confirmed high overall probabilities of correct diagnoses for bearings at early stages of damage development. The proposed diagnosis technology is compared with existing diagnosis technology, based on the triple cross-covariance of complex spectral components.
Novel Tools as New Challenges to HRM Communicational Practices (and the Increasingly Important Social Role of the Manager)
- Marta Szeluga-Romańska
- Anna Modzelewska
2022 Pełny tekst
Each communicational process consists inseparably of three aspects: the linguistic (which means the whole language content of the message), technical (which states the form of the message) and the social (meaning social relations, emotions, behaviours). The recent COVID-19 pandemic deeply influenced several layers of our lives. But the main aim of this chapter is to focus on the communicational processes that normally take place in organisations. We conducted a qualitative study based mostly on in-depth interviews and observations among managers and management students. The analysis revealed the enormous expansion of technical dimensions of communication, where personal direct communication was often replaced by indirect ones, supported by the usage of modern tools like internet communicators and interactive software. This resulted in abnormal reduction of the social – highly needed and obviously important – dimension. Such ‘new normal’ organisational reality forced the HR managers to re-think the flow and quality of existing communicational processes within which they are always situated, also considering its deep, multidimensional influence on the existing social relations. This chapter presents the results of qualitative studies from in-depth interviews, structured interviews and focus group interviews from 2012 to 2020. We aim to answer the question of the changes which were brought into organisations by the pandemic as our long-term research allows to follow the changes. As a result, we received characteristics of the organisational changes and the shift in expectation from the role of a manager in the altered social reality. Practical implications are included in this chapter and provide guidelines for communication in crisis situations while maintaining a high quality of interpersonal relations.
Novel Vision Monitoring Method Based on Multi Light Points for Space-Time Analysis of Overhead Contact Line Displacements
- Andrzej Wilk
- Len Gelman
- Jacek Skibicki
- Sławomir Judek
- Krzysztof Karwowski
- Aleksander Jakubowski
- Paweł Kaczmarek
2022 Pełny tekst SENSORS
The article presents an innovative vision monitoring method of overhead contact line (OCL) displacement, which utilizes a set of LED light points installed along it. A light point is an, LED fed from a battery. Displacements of the LED points, recorded by a camera, are interpreted as a change of OCL shape in time and space. The vision system comprises a camera, properly situated with respect to the OCL, which is capable of capturing a dozen light points in its field of view. The monitoring system can be scaled by increasing the number of LED points and video cameras; thus, this method can be used for monitoring the motion of other large–size objects (e.g., several hundred meters). The applied method has made it possible to obtain the following novel results: vibration damping in a contact wire is nonlinear by nature and its intensity depends on the wire vibration amplitude; the natural frequency of contact wire vibration varies, and it is a function of vibration amplitude; the natural frequency of contact wire vibration also depends on the wire temperature. The proposed method can be used to monitor the uplift of contact and messenger wires in laboratory conditions, or for experimental OCL testing, as well as for verifying simulation models of OCL.
Nowe potrójne związki w układzie RE2TGe3 (RE – ziemia rzadka, T – metal przejściowy)
- Leszek Litzbarski
2022 Pełny tekst
Celem niniejszej pracy była synteza nowych związków międzymetalicznych z rodziny RE2TGe3, gdzie RE to metale ziem rzadkich, a T to metal przejściowy (Pd, Pt). Dokonano tego stosując metodę topienia w łuku elektrycznym. Za pomocą proszkowej dyfrakcji rentgenowskiej ustalono, że udało się otrzymać następujące materiały: Pr2Pd1.15Ge2.85, Sm2PdGe3, Tb2Pd1.25Ge2.85, Dy2Pd1.25Ge2.85, Ho2Pd1.3Ge2.7, Ce2Pt0.9Ge3.1, Pr2Pt1.15Ge2.85, Nd2PtGe3, Gd2Pt1.1Ge2.9, Tb2Pt1.2Ge2.8, Dy2Pt1.15Ge2.85 i Ho2Pt1.1Ge2.9. Aby uzyskać jednofazowe próbki należało w większości przypadków odejść od znamionowej stechiometrii i odpowiednio zmienić stosunek atomów T i Ge. W oparciu o analizę Rietvelda stwierdzono, iż związki te krystalizują w heksagonalnej strukturze o grupie przestrzennej P6/mmm. Obliczone wartości stałych sieci pokazują, że objętość komórki elementarnej maleje wraz ze wzrostem liczby atomowej RE, co jest zgodne z regułą tzw. „kontrakcji lantanowców”. Następnie scharakteryzowano własności fizyczne zsyntezowanych materiałów poprzez pomiary namagnesowania, oporu elektrycznego oraz ciepła właściwego. Na tej podstawie stwierdzono, że zbadane próbki można zaklasyfikować jako szkła klastrowe. Wyjątek stanowią Pr2Pt1.15Ge2.85 i Ho2Pt1.1Ge2.9, w których nie występuje uporządkowanie magnetyczne w zmierzonym zakresie temperatur (T = 1.8 – 300 K) oraz Gd2Pt1.1Ge2.9 zaliczający się do antyferromagnetyków.
Nowy system monitoringu korozji zastosowany w zakładzie produkcyjnym PKN Orlen SA
- Radosław Gospoś
- Anna Plis
- Iwona Łuksa
- Kazimierz Darowicki
- Juliusz Orlikowski
2022 Chemia Przemysłowa
Przedstawiono efekty projektu badawczo-rozwojowego związanego z opracowaniem, budową oraz wdrożeniem monitoringu korozji pracującego w trybie online. Opracowana przez PKN Orlen i Politechnikę Gdańską nowa technologia łączy funkcje monitoringu intensywności korozji ogólnej oraz kruchości wodorowej. Jednoczesny pomiar online kluczowych parametrów pozwala uzyskać zdolność szybkiej oceny postępowania procesu korozji oraz reakcji na bieżące wahania poziomu zagrożenia.
NOx Photooxidation over Different Noble Metals Modified TiO2
- Kinga Skalska
- Anna Malankowska
- Jacek Balcerzak
- Maria Gazda
- Grzegorz Nowaczyk
- Stefan Jurga
- Adriana Zaleska-Medynska
2022 Pełny tekst Catalysts
We compared the activity enhancement effect of noble metal deposited on TiO2 in photocatalytic nitrogen oxides oxidation. Titanium dioxide was decorated with Ag, Au, Pt or Pd in the sol-gel process. Synthesized catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller measurement (BET), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX). All catalysts together with pure TiO2 obtained by sol-gel (SG) technique were tested for their photocatalytic activity towards nitrogen oxide oxidation (high concentrations of 50, 150 and 250 ppm). FTIR spectrometry was used to determine the gas phase composition and identify TiO2 surface species. The Ag0.1 sample turned out to be deactivated within 60 min of UV/Vis irradiation. Photocatalytic oxidation rate towards NO2 turned to be the highest over SG (photocatalyst without metal deposition). NO2 formation was also observed for Au0.1, Au0.5, Pt0.1, Pt0.5 and Pd0.1. The best NOx removal, i.e., conversion to final product HNO3 was obtained with the Au0.5 photocatalyst.
Numbers, Please: Power- and Voltage-Related Indices in Control of a Turbine-Generator Set
- Paweł Sokólski
- Tomasz Rutkowski
- Bartosz Ceran
- Daria Złotecka
- Dariusz Horla
2022 Pełny tekst ENERGIES
This paper discusses the proper selection and interpretation of aggregated control performance indices values mirroring the quality of electrical energy generation by a turbine-generator set cooperating with a power system. Typically, a set of basic/classical and individual indices is used in energy engineering to ensure the mirroring feature and is related to voltage, frequency and active or reactive power deviations from their nominal values desired in the power system. In this paper, aggregated indices based on the sum of weighted integral indices are proposed, veriﬁed and built based on the well-known indices originating from control theory. These include an integral of the squared error (ISE) and an integral of the squared error multiplied by time (ITSE), applicable whenever an in-depth analysis and evaluation of various control strategies of the generation system is to be performed. In the reported research, the computer simulation tests veriﬁed their effectiveness in assessing the generated electricity on the example of a turbine-generator set controlled using a predictive control technology as well as applicability, proven by numerous simulation results to take various and different in nature requirements into account efﬁciently, in the form of a single aggregated index.
Numerical analysis of CO2-water separation in a horizontal double T-junction
- Milad Amiri
- Paweł Ziółkowski
- Kamil Stasiak
- Dariusz Mikielewicz
2022 Pełny tekst
Carbon dioxide is considered one of the main factors leading to global warming. Considering the significant impacts of CO2 on climate change, various technologies have been developed in recent decades to control carbon emission, such as for example CO2 capture and storage. The developed cycle of a negative CO2 emission power plant includes some devices, out of which, separator plays an indispensable role. To this end, T-junction separator is widely used as a phase separation component to separate two-phase flow because of its simple structure and low cost. Previous studies suggest that an increase in the number of T-junction branches is conducive to raise phase separation efficiency. In this paper, the numerical simulation in a single T-junction separator is compared with the predicted values generated by experimental models based on air-water. Then, air has been replaced with CO2 and such separation process in a double T-junction separator has been scrutinized. In addition, the pressure distribution and phase separation performance of two-phase flow of CO2-water in a horizontal double T-junctions is studied.
Numerical analysis of high temperature minichannel heat exchanger for recuperative microturbine system
- Jan Wajs
- Tomasz Kura
- Dariusz Mikielewicz
- Elżbieta Fornalik-Wajs
- Jarosław Mikielewicz
2022 Pełny tekst ENERGY
Considering the development of energy sector, distributed small-scale power generation, e.g., gas micro-CHP, is attracting considerable interest. In such installations, the heat exchanger is one of the key components possessing a significant influence on overall performance. Most studies concentrate on units operating below 900C, which do not fulfil the requirements of gas micro-CHP. Therefore, there remains a challenge to design a compact heat exchanger with passive technologies of heat transfer enhancement. This work describes the implementation of the own construction of a plate minichannel heat exchanger for high-efficiency gas microturbine engines with an external combustion chamber, supplied with air at a temperature of about 1000C. The results of this study will greatly contribute to the increase of system efficiency. To understand transport phenomena occurring inside it, a numerical model of the entire heat exchanger was developed in OpenFOAM. Defined boundary conditions were based on experimental data used also to validate the numerical model. The pressure drop experimental and numerical results agreed within the 2%-14% range, while the heat rate ones e within the 1%-8% of the range. In addition, numerical analysis exhibited the limits of thermal and exergetic efficiency values possible to be obtained, when the boundary conditions are strongly controlled.
Numerical analysis of lumbar spine injury during road safety barrier collision
- Łukasz Pachocki
2022
Purpose: Enhancing road safety is a critical goal worldwide, necessitating the development of clear standards for road safety systems. This study focuses on lumbar spine (L-spine) compression injuries during collisions with concrete road safety barriers (RSBs). It aims to analyze internal forces during impact to understand L-spine injury biomechanics in such accidents. Methods: The research included a literature review, analyzing American guidelines and European standard EN1317. A normative TB41 crash test with a concrete RSB class H2/W5/B was conducted, followed by a finite element model creation and validation. Additionally, a TB32 test simulation with the same barrier and a 50th percentile female body model was performed to analyze L-spine displacements. These displacements were applied to a detailed L-spine model based on THUMS v.6.1, modified for validation test compliance. Results: Numerical models for the concrete RSB and L-spine were validated against experimental data. The TB41 crash test showed that connections between barrier segments experienced splitting failure, with a maximum dynamic compressive force of 350 kN and bending moments up to 130 kNm. The TB32 crash test indicated that vehicle collision energy dissipation caused the car to launch upwards and land along the barrier. This resulted in high internal forces in the L-spine, particularly in the L3 vertebra with a compressive force of about 2.7 kN and a bending moment of 39.5 Nm. Conclusions: The study observed splitting failure in the H2/W5/B concrete barrier during the TB41 test. Discrepancies were noted between the safety levels indicated by impact severity indices and those suggested by L-spine injury measures. These findings suggest a need to reevaluate the current standards for road safety systems, considering both barrier integrity and potential spinal injuries.
Numerical analysis of vacuum drying of a porous body in the integrated domain
- Milad Amiri
- Mohammad Bagher Ayani
- Paweł Ziółkowski
- Dariusz Mikielewicz
2022 Pełny tekst JOURNAL OF FOOD PROCESS ENGINEERING
n the present study, the vacuum drying process of an apple slice is numerically modeled based on a control volume method. Transient two-dimensional Navier– Stokes, energy, moisture, and Luikov equations are solved by numerical coding (Fortran) to simulate the simultaneous heat and mass transfer in the ambient and apple slice, respectively. The privilege of using Luikov's model is that the capillary forces are considered, and a differentiation between air, vapor, liquid, and solid is made. Luikov described the two phenomena associated with the transport of air, vapor, and liquids through the porous media as molecular transport and molar transport. The ambient pressure linearly reduced within a minute until it reached a constant value. One of the intellectually demanding preoccupations among researchers is how to simulate the sample and its surroundings with high accuracy of boundary conditions, which enables to avoid the use of empirical transfer coefficients. This study can be scrutinized from various dimensions, among which nonuse of boundary condition between a porous sample and its surroundings is the most conspicuous novelty. Results showed that although at 50 s, isothermal and iso-moisture lines inside the sample are symmetric, they are not symmetric at 100, 200, and 400 s. In addition, at first minute, pump operation leads to vary the density of the isothermal and isomoisture lines around the sample, but at 100, 200, and 400 s, higher temperature and moisture gradients have been achieved at the right and top of the sample surface
Numerical analysis on axial capacity of steel built-up battened columns
- Paweł Pieczka
- Piotr Iwicki
2022 Pełny tekst Archives of Civil Engineering
This paper deals with the numerical analysis aimed at study the bearing capacity of pinended steel built-up columns under axial compression. Finite element (FE) models were performed for the columns presented in the literature. The main problem discussed in the article is the shape and magnitude of geometric imperfections introduced into the numerical FE model, necessary to obtain the load capacity consistent with the experimental strength tests. Three types of numerical analysis that can be used in Abaqus program to calculate the load bearing capacity have been described. The imperfections possible to introduce for built-up columns were presented and an equivalent imperfection corresponding to both imperfections recommended by Eurocode 3 (global of the entire column and local of the chord) for built-up members was proposed. The results of the geometrically and materially nonlinear static analysis were compared with the calculations according to the code procedures (Eurocode 3 and PN-B03200:1990) and the results of experimental tests.