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1

Assessment of concrete damage in structures caused by alkali-silica reaction

Owsiak Zdzisława, Leks Anna

Materiały Budowlane

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2025

|

nr 11

41--50

EN

The alkali-aggregate reaction leads to concrete degradation, affecting durability and safety of use of the structure. The article presents methods for damage assessment: visual field inspection, non-destructive testing and laboratory techniques. It also highlights modern approaches such as digital image analysis and machine learning algorithms. It emphasizes the importance of selecting the proper methods for diagnosis, repair planning and structures management.

PL

Reakcja alkalia-kruszywo prowadzi do degradacji betonu, wpływając na trwałość i bezpieczeństwo użytkowania konstrukcji. W artykule przedstawiono metody oceny uszkodzeń: wizualną inspekcję terenową, badania nieniszczące oraz techniki laboratoryjne. Zwrócono także uwagę na nowoczesne podejście, jak cyfrowa analiza obrazu i algorytmy uczenia maszynowego i podkreślono znaczenie właściwego doboru metod przy diagnozie, planowaniu napraw i zarządzaniu konstrukcjami.

2

Assessment of reinforced concrete beams cracking depending on the concrete class

Derlatka Anna, Jrethi Yassin Ali

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

|

2024

|

Z. 30 (180)

29--34

EN

Cracks in reinforced concrete are a common concern that can arise from various causes such as concrete shrinkage, temperature differences, and structural loads. The aim of the study was an analysis of cracks in concrete on which the reinforcement concrete beam was made. The beam was loaded with an evenly distributed load and subjected to bending. Depending on the concrete class (C20/25, C25/30 and C30/37), the cracks in the concrete, the deflection at a load of 5.35 kN/m2 and the beam’s load-bearing capacity, i.e. the value of the load that the beam can withstand without any cracks were assessed.

PL

Pęknięcia w żelbecie są powszechnym problemem, który może wynikać z różnych przyczyn, takich jak skurcz betonu, różnice temperatur i obciążenia konstrukcyjne. Celem pracy była analiza pęknięć w betonie, z którego wykonano belkę żelbetową. Belka została obciążona równomiernie rozłożonym obciążeniem i poddana zginaniu. Analizowano trzy klasy betonu C20/25, C25/30 i C30/37. W zależności od klasy betonu oceniano pęknięcia w betonie, ugięcie przy obciążeniu 5.35 kN/m2 i nośność belki, tj. wartość obciążenia, jakie belka może wytrzymać bez pęknięć.

3

Water saturation effects on the fracturing mechanism of sandstone excavating by TBM disc cutters

Lin Qibin, Zhang Shenchen, Liu He, Shao Zuliang

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 3

art. no. e154, 2024

EN

Water content is an important factor affecting the rock-breaking efficiency of tunnel boring machine (TBM) disc cutters. However, limited efforts have been made to study the fracturing mechanism of sandstone excavation by TBM disc cutters under varying water content conditions. To investigate the breakage behavior of water-soaked sandstone by TBM disc cutters, five sets of penetration tests on sandstone specimens with different water content levels were performed. The tests were conducted using a modified RYL-600 computer-controlled rock shear rheometer. An acoustic emission (AE) monitoring system was utilized throughout the entire process to track the AE activity of the specimens. The force–depth curves of the penetration process at various water content levels were investigated. The effects of water content on AE characteristics, rock fracture properties, and specific energy were analyzed. The results indicate that AE activity can be divided into three stages: quiet period, slow rise period, and active period. With increasing water content, peak penetration force, consumed energy, and specific energy decrease gradually, while chip volume increases. Water promotes mutual penetration of surface and internal cracks of the specimen, resulting in the formation of larger chip volumes. These findings provide theoretical guidance for designing and improving TBM cutter head parameters in water-rich soft rock formations.

4

Microstructure, mechanical and tribological properties of AA5083‑TiO2 nanocomposite by multi‑pass friction stir processing

Karmiris-Obratański Panagiotis, Papantoniou Ioannis G., Leszczyńska-Madej Beata

Archives of Civil and Mechanical Engineering

|

2024

|

Vol. 24, no. 4

art. 209, 1--20

EN

This study examines the impact of Friction Stir Processing (FSP) with TiO2 nanoparticle incorporation on the microstructural, mechanical, and tribological properties of AA5083 Metal Matrix Composites (MMCs). It offers a detailed analysis of the alterations in the alloy’s characteristics due to FSP. Microstructural examination was conducted using optical microscopy (OM) and scanning electron microscopy (SEM). Significant findings include the microstructural refinement where TiO 2 nanoparticle addition during FSP shrank the grain size from 20 to 3 μm after one pass, which then rose to 7 μm following four passes. Mechanical properties, specifically microhardness and tensile strength, were assessed. Results indicated that after four FSP passes, the material can reach a yield strength of 192 MPa and an ultimate tensile strength (UTS) of 359 MPa, alongside a consistent microhardness of 103 HV0.1. Furthermore, it was observed that increasing FSP passes enhances energy absorption, although it remains lower than that of the base material. Analysis of fracture and wear mechanisms has led to the conclusion that with more passes, fracture mechanisms transition to a mix of ductile and brittle behaviors, and the friction coefficient decreases by up to 22.95%.

5

Effect of Ti micro-addition on the hot tensile behaviour, microstructure and fractography of low-C high-manganese steels

Fojt-Dymara Gabriela, Opiela Marek, Grzegorczyk Barbara, Gołombek Klaudiusz, Grajcar Adam

Archives of Civil and Mechanical Engineering

|

2024

|

Vol. 24, no. 3

art. no. e168, 2024

EN

The aim of the work was to determine the effect of Ti micro-addition on the hot tensile behaviour, microstructure and fractography of two low-C high-manganese steels with additions of Si and Al. The hot tensile tests were performed using the Gleeble 3800 thermomechanical simulator. Samples were stretched at a temperature range from 1050 ℃ to 1200 ℃ at a strain rate of 2.5·10 3 s−1. The microstructure of the tested high-manganese steels under conditions of hot deformation was influenced by strain hardening and simultaneous dynamic recrystallization, as well as precipitation processes-depending on the chemical composition of the alloy and plastic deformation parameters. The analysis of the curves registered in the hot tensile tests indicated that a decrease of strain hardening was the result of the dynamic recrystallization. Hot tensile curves of the Ti-micro-alloyed steel were characterized by higher yield stress compared to the Ti-free steel. The Ti micro-addition with a concentration of 0.075 wt.% guaranteeing stable TiN-type nitrides eliminated the possibility of precipitating AlN-type nitrides and complex MnS-AlN type non-metallic inclusions, which are harmful to hot ductility. Fracture modes of the Ti-free steel showed a mixed nature from 1050 ℃ to 1150 °C, i.e. ductile fracture and numerous cavities and voids were identified. As the deformation temperature increased to 1200 °C, the fracture character was brittle with numerous inter-crystalline cracks along austenite grain boundaries. The addition of Ti improved significantly the hot ductility behaviour characterized by higher values of flow stress and reduction in area as well as ductile fracture modes in the entire high deformation temperature range.

6

Structural integrity of AA7075-T651 UWFSW joints

Kosturek Robert, Ślęzak Tomasz, Torzewski Janusz

Advances in Materials Science

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2024

|

Vol. 24, nr 4(82)

98--110

EN

This investigation is focused on the comparison of selected low-cycle fatigue properties of AA7075-T651 friction stir welded and underwater friction stir welded joints together with the evaluation of their lifetime prediction by the Manson-Coffin-Basquin formula. Additionally, the analysis of the fractured surface was involved to describe the character of joints decohesion. The analysis of the obtained hysteresis loops revealed that FSW joint exhibits cyclic hardening, with a stable maximum stress and a decreasing minimum stress, leading to an increased contribution of compressive stresses and a lower mean stress during stabilized fatigue. In comparison, the UWFSW joint also shows cyclic hardening but with a greater contribution of tensile stresses, a higher mean stress, and a reduced participation of plastic deformation. The Manson-Coffin-Basquin equation effectively predicts the fatigue life of AA7075-T651 alloy joints, with UWFSW joints showing significantly lower standard deviation (0.0035 vs. 0.0135) and narrower dispersion bands (1.61 vs. 1.93) compared to conventional FSW joints.

7

Analiza metalograficzna przyczyn pękania rury w strefie zgrzewu liniowego podczas kształtowania

Tyrała Dorota, Pawłowski Bogdan

Inżynieria Materiałowa

|

2023

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Vol. 44, nr 3

8--11

PL

Celem pracy było określenie przyczyny powstawania pęknięć w partii rur fi 48,3×2,7 mm (stal S355J2H) w obszarze zgrzewu liniowego w trakcie operacji zmniejszania średnicy z 48,3 mm do 38 mm. Część z tych pęknięć nie była widoczna podczas obserwacji makroskopowych, pęknięcia ujawniono dopiero podczas badań z wykorzystaniem mikroskopu świetlnego. W trakcie badań metalograficznych na zgładach nietrawionych nie stwierdzono występowania wad metalurgicznych mogących mieć wpływ na powstawanie i propagacje obserwowanych pęknięć. Badania na zgładach trawionych ujawniły natomiast, że wszystkie badane odcinki rur nie wykazywały mikrostruktury właściwej dla prawidłowo przeprowadzonego procesu zgrzewania prądami wysokiej częstotliwości. Przyczyną powstawania pęknięć wzdłuż linii zgrzewu był nieprawidłowy przebieg procesu zgrzewania, najprawdopodobniej zbyt niska temperatura tego procesu.

EN

The aim of the study was to determine the cause of cracking of pipes fi 48.3×2.7 mm (S355J2H steel) in the seam weld area during the operation of reducing the diameter of 48.3 mm to 38 mm. Some of these cracks were not visible during macroscopic observations, cracks were revealed only during examinations using a light microscope. During the metallographic tests on the non-etched specimens, no metallurgical defects that could affect the formation and propagation of the observed cracks were found. On the other hand, tests on etched specimens revealed that all the examined pipe sections did not show the microstructure appropriate for a proper high-frequency welding process. The reason for the formation of cracks along the weld line is the incorrect course of the HF welding process, most likely too low temperature of this process.

8

Walcowanie poprzeczno-klinowe odkuwki osi kolejowej

Bulzak Tomasz, Winiarski Grzegorz, Wójcik Łukasz

Hutnik, Wiadomości Hutnicze

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2023

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Vol. 90, nr 2

16--20

PL

Artykuł przedstawia wyniki modelowania numerycznego procesu walcowania poprzeczno-klinowego odkuwek osi kolejowych. Na wstępie przedstawiono główny problem, jakim jest pękanie materiału w procesie walcowania poprzeczno-klinowego. Przedstawiono propozycję ograniczenia zjawiska pękania materiału, polegającą na zmianie konstrukcji narzędzi kształtujących. Zaprojektowano trzy warianty narzędzi, których przydatność w procesie walcowania poprzeczno-klinowego osi kolejowych została zweryfikowana na drodze symulacji numerycznych. Symulacje numeryczne przeprowadzono metodą elementów skończonych w oprogramowaniu Simufact Forming. Uzyskane wyniki nie potwierdziły przyjętych założeń. Zastosowanie narzędzi z dwoma kątami kształtującymi wpłynęło na wzrost wartości kryterium pękania, co tym samym zwiększa ryzyko pękania materiału podczas walcowania osi kolejowych.

EN

This paper presents the results of numerical modelling of the cross-wedge rolling process of railway axle forgings. The main problem of material cracking in the cross-wedge rolling process is first presented. A proposal to reduce the phenomenon of material cracking by changing the design of forming tools is presented. Three tool variants were designed, the suitability of which in the process of cross-wedge rolling of railway axles was verified by means of numerical simulations. Numerical simulations were carried out using the finite element method in the Simufact Forming software. The results obtained did not confirm the assumptions made. The use of tools with two forming angles increased the value of the fracture criterion, thereby increasing the risk of material fracture during rolling of railway axles

9

An experimental investigation of fracture modes and delamination behaviour of carbon fiber reinforced laminated composite materials

Musafir Mustafa Abd Alhussein, Ameer Zuhair Jabbar Abdul, Hamzah Ahmed Fadhil

Diagnostyka

|

2023

|

Vol. 24, No. 1

art. no. 2023101

EN

Mechanically, composite laminates perform exceptionally well in-plane but poorly out-of-plane. Interlaminar damage, known as "delamination," is a major issue for composite laminates. Results from Mode-I and Mode-II experimental testing on twill-woven carbon fiber reinforced (CFRP) laminates are analyzed in this paper. Composite Mode-I fracture toughness was determined using three different methods in accordance with ASTM D5528: modified beam theory, compliance calibration, and a codified compliance calibration. Two methods, the Compliance Calibration Method and the Compliance-Based Beam Method, were used to determine the Mode-II fracture toughness in accordance with ASTM D7905. Stick-slip behavior is quite evident in the composite's ModeI fracture toughness test findings. The MBT technique's 𝐺Ic values for initiation and propagation are 0.533 and 0.679 KJ/m2 , respectively. When comparing the MBT approach to the industry-standard ASTM procedure for determining fracture toughness Mode-I, the MBT method was shown to be highly compatible. Furthermore, the 𝐺IIc values for the CBBM technique are 1.65 KJ/m2 for non-pre cracked and 1.4 KJ/m2 for pre-cracked materials. The CBBM method shows a good method to evaluate fracture toughness Mode-II, due to not needing to monitor the length of the crack during delamination growth to get the value of the fracture toughness.

10

Influence of the specific load on stability and vibrations of the multimember column with internal cracks

Sokół Krzysztof, Kuliński Krzysztof

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

|

Vol. 71, nr 4

art. no. e146408

EN

Slender systems are mostly studied when Euler’s load or follower load is considered. The use of those types of external loads results in well-known divergence or flutter shape of the characteristic curve. In this study, one takes into account the specific load which allows one to obtain an interesting divergence – pseudo flutter shape of characteristic curves on the external load–vibration frequency plane. The curves can change inclination angle as well as one can observe the change in vibration modes along them. The shape of those curves depends not only on the parameters of the slender system but also on loading heads that induce the specific load. In this study, one considers the slender multimember system in which cracks are present and weaken the host structure. The results of theoretical as well as numerical simulations are focused on the influence of the parameters of the loading heads on vibrations, stability, and loading capacity of the investigated system as well as on the possibility of partial reduction of unwanted crack effect.

11

Novel drawing technology for high area reduction manufacturing of ultra-thin brass wires

Kustra Piotr, Wróbel Mirosław, Dymek Stanisław, Milenin Andrij

Archives of Civil and Mechanical Engineering

|

2023

|

Vol. 23, no. 3

art. no. e144, 2023

EN

A significant increase in roughness of dieless-drawn wires due to the strain-induced roughness phenomenon has been documented. For small-diameter wires, even a slight surface relief creates stress concentrations that may contribute to the wire breakage during cold drawing. This, in turn, significantly limits the achievable diameter of the product and the efficiency of drawing process. The present study, however, demonstrates that reducing the wire roughness is possible by combining the dieless and conventional drawing methods. Thus, it is possible to improve the process workability threefold when compared to dieless drawing alone, and the product quality is simultaneously improved. In addition, the surface defects typical to the dieless-drawn wires have been significantly reduced, resulting in an increase in the wire strength. This new combined technology enables a significant reduction in the wire diameter and facilitates an economical large-scale production of ultra-thin wires. In addition, based on the classic drawing and dieless drawing process, a brass wire with a diameter of 0.017 mm has been manufactured. Six times thinner than a human hair, it is believed to be the thinnest long brass wire currently manufactured in the world.

12

Pękanie ścian wypełniających w budynku szkieletowym

Kania Tomasz, Matkowski Zygmunt, Nowak Rafał

Materiały Budowlane

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2022

|

nr 11

138--140

PL

Coraz większe tempo projektowania i realizacji inwestycji budowlanych sprawia, że występuje coraz więcej problemów związanych z pękaniem ścian wypełniających. Przyczyną uszkodzeń jest m.in. wykonywanie konstrukcji stropowych o dużej rozpiętości oraz nieprawidłowo zrealizowane ich połączenie z elementami konstrukcji nośnej budynku. W artykule przedstawiono analizę przyczyn uszkodzeń ścian nienośnych w budynku wielorodzinnym o konstrukcji szkieletowej zrealizowanym w technologii monolitycznej, żelbetowej. Ściany nienośne wewnątrz mieszkaniowe wykonano z bloczków z betonu komórkowego, a ściany między mieszkaniowe i wypełniające zewnętrzne z pustaków betonowych. Jeszcze przed oddaniem lokali do użytkowania, podczas prowadzenia prac wykończeniowych, stwierdzono ich intensywne zarysowania i pęknięcia. Na podstawie przeprowadzonych pomiarów i analiz przedstawiono błędy wykonania ścian nienośnych, które doprowadziły do ich awarii.

EN

The ever-increasing pace of design and construction projects is causing an increase in problems related to the cracking of infill walls. The causes of their damage include the construction of slender floor structures with long spans as well as improperly implemented connections to elements of the building's load-bearing structure. The article presents an analysis of the causes of damage to non-load-bearing walls in a multifamily building. The frame building was constructed using monolithic reinforced concrete technology. The walls in the apartments were made of aerated concrete. The walls between the apartments and external infilling walls were made of concrete hollow blocks. Even before the premises were put into use, intensive cracking was found when finishing work was carried out. On the basis of measurements and analysis, errors in the construction of non-load-bearing walls were presented, which led to the walls’ failure.

13

Investigation of probabilistic aspects reliability of isotropic bodies with internal defects

Kvit Roman

Journal of Applied Mathematics and Computational Mechanics

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2022

|

Vol. 21, nr 3

73--84

EN

A study of the stress state and reliability of an isotropic body with the same material crack resistance and evenly distributed internal defects-cracks under the conditions of homogeneous axisymmetric loading is carried out. Defects are characterized by two independent random variables – a radius and orientation angle. The probability density distribution of the defect radius is chosen in the form of an exponential law. The probability density distribution of the defect orientation angle is chosen in the form of a law that corresponds to the material isotropy. The influence of the loading level, type of stress state and body size (number of defects) on the most probable value, the mean value and the dispersion of failure loading (strength) are investigated.

14

Crack growth diagnostic of ball bearing using vibration analysis

Belaidi S., Lecheb S., Chellil A., Mechakra H., Safi B., Kebir H.

International Journal of Applied Mechanics and Engineering

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2022

|

Vol. 27, no. 1

35--45

EN

It is known that supported ball bearings have great effects on the vibrations of the gear transmission system, above in all the presence of local faults as well as the crack growths. For this purpose, this paper focuses on shock and vibration crack growth diagnostic of ball bearing using vibration analysis. Our work is devoted first to a study the static behaviour of the ball bearing by determining the stress, strain and displacement, then its dynamic behaviour by determining the first four natural frequencies. Secondly, a dynamic analysis study of the bearing was carried with defects as a function of crack size and location. The obtained results clearly show that the natural frequencies decrease in a non-linear way with the growth of the length of the crack, on the other hand the stress increases with the presence of the singular points of the crack. Finally, this residual decrease in natural frequencies can be used as an indicator of the state of failure, as well as a parameter used for the diagnosis and screening, and to highlight the fatigue life of the bearing.

15

Zastosowanie rentgenowskiej metody pomiaru naprężeń w diagnostyce przyczyny pękania elementu spawanego turbiny gazowej

Szymański Wojciech

Badania Nieniszczące i Diagnostyka

|

2022

|

1-4

8--12

PL

W pracy przedstawiono metodykę diagnostyki przyczyn pękania detalu turbiny gazowej w miejscu połączenia spawanego dwóch stopów żarowytrzymałych. Wykonano rozkład naprężeń w okolicy złącza spawanego po wykonaniu elementu, co pozwoliło określić przyczynę pękania. Próby wyżarzania i odprężania wibracyjnego, nie przyniosły spodziewanych efektów. W dalszej części pracy przeprowadzono pomiary naprężeń łączonych spoiną elementów detalu na kolejnych etapach jego wytwarzania, co pozwoliło na określenie, w którym momencie produkcji powstają krytyczne naprężenia będące przyczyną przedwczesnego pękania w czasie pracy turbiny. Poprawa technologii produkcji eliminująca niekorzystny rozkład naprężeń pozwoliła na uzyskanie oczekiwanego czasu pracy turbiny bez awarii.

EN

The paper presents the methodology of diagnostics of the causes of cracking of a gas turbine detail in the place of a welded joint of two heat-resistant alloys. The stress distribution in the area of the welded joint was made after the element was made, which allowed to determine the cause of the cracking. Attempts at annealing and vibration stressing did not bring the expected results. In the further part of the work, measurements of the stresses of the elements connected by welding were carried out at subsequent stages of its production, which allowed to determine at which point in production critical stresses arise, which cause premature fracture during the operation of the turbine. The improvement of the production technology eliminating the unfavourable stress distribution allowed to obtain the expected working time of the turbine without failure.

16

AA5052 failure prediction of electromagnetic flanging process using a combined fracture model

Deng Huakun, Mao Yunfei, Li Guangyao, Zhang Xu, Cui Junjia

Archives of Civil and Mechanical Engineering

|

2022

|

Vol. 22, no. 2

art. no. e84, 1--17

EN

Electromagnetic forming process could significantly increase the forming limit of aluminum alloy. However, high-speed fracture prediction of aluminum alloys is a major problem in the development of electromagnetic flanging process. In this study, notched specimen tensile tests with high-speed Digital Image Correlation system were conducted under the strain rate range from 0.001 to 100 s-1. A fracture model of AA5052 alloys which combined of an uncoupled fracture model, Gissmo damage evolution model and Johnson-Cook strain rate effect was established. Electromagnetic flanging experiments were conducted to verify the failure criteria effectiveness. Results showed that failure strain was significantly influenced by strain rate under various loading path. Compared with the experiments, the percentage error of established electromagnetic flanging process FEM model was less than 4%. The fracture model established could well predict notched specimen high-speed failure, and also accurately predict sheet failure model of electromagnetic flanging experiments and, thus, verified the effectiveness of the established dynamic failure criteria in electromagnetic flanging process.

17

Microstructure and mechanical properties of Sc-modified AA2519-T62 laser beam welded butt joints

Kosturek Robert, Grzelak Krzysztof, Torzewski Janusz, Wachowski Marcin, Śnieżek Lucjan

Advances in Materials Science

|

2022

|

Vol. 22, nr 4(74)

57--69

EN

The fundamental aim of the research is to investigate the microstructure and mechanical properties of the AA2519-T62 laser beam welded joints obtained with various values of welding velocity. For the constant value of laser power (3.2 kW) three joints have been produced with various values of welding velocity: 0.8, 1.1, and 1.4 m/min. The joints have been subjected to microstructure analysis (including both light and scanning electron microscope), microhardness measurements, tensile tests, and fractography of tensile samples. The established values of joint efficiency contain within the range of 55-66% with the highest value (66%) reported for the joint obtained with 1.1 m/min welding velocity. The produced welds have noticeable participation of pores, which tends to increase together with the value of welding velocity. In all cases, the failure has occurred in the fusion zone by ductile fracture.

18

Sprawdzenie, czy przeprowadzono test wygrzewania HST [Test wygrzewania szkła hartowanego termicznie]

Calderone Ignatius

Świat Szkła

|

2021

|

R. 26, nr 3

44--48

19

BREAK – kalibracja teselacji stochastycznych w celu przewidywania pęknięć szkła hartowanego termicznie

Kraus Michael A., Pourmoghaddam Navid, Schneider Jens, Siebert Gerald

Świat Szkła

|

2021

|

R. 26, nr 10

66--70

20

Unified methodology for strength and stress analysis of structural concrete members

Oukaili Nazar

International Journal of Applied Mechanics and Engineering

|

2021

|

Vol. 26, no. 1

178--200

EN

In this paper, a methodology is presented for determining the stress and strain in structural concrete sections, also, for estimating the ultimate combination of axial forces and bending moments that produce failure. The structural concrete member may have a cross-section with an arbitrary configuration, the concrete region may consist of a set of subregions having different characteristics (i.e., different grades of concretes, or initially identical, but working with different stress-strain diagrams due to the effect of indirect reinforcement or the effect of confinement, etc.). This methodology is considering the tensile strain softening and tension stiffening of concrete in addition to the tension stiffening of steel bars due to the tensile resistance of the surrounding concrete layer. A comparison of experimental and numerical data indicates that the results, obtained based on this methodology, are highly reliable and highly informative.