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1

Study on failure modes and calculation method of the cast steel joint with branches in treelike structure

Chen Feng, Sun Yun, Sun Shuxuan, Song Da, Liu Yangbing

Archives of Civil Engineering

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2024

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Vol. 70, nr 1

589--604

EN

The treelike structure links members and transfers loads via its solitary cast steel joint with branches. Therefore, the joint’s bearing capacity significantly affects the treelike structure’s stability, security, and economics. This paper utilized experimental verification and numerical modeling to examine the mechanical behavior of cast-steel joints with branches in the treelike structure under various loading conditions. Then, researchers investigated the failure process and mechanism of joints, and the three most common failure modes were outlined. Furthermore, the researchers proposed the bearing capacity calculation formula based on the common failure modes. The results show that the three common failure modes of the cast-steel joints with branches under different loading conditions are the failure in the joint core area under the axial load, the failure in the main pipe compression side under eccentric load, and the failure in the compression side of the single branch pipe root when the single branch pipe is under the uneven load. The suggested empirical calculation method can serve as a reference point for similar engineering practices design.

2

Seismic behavior of interior polyvinyl chloride-carbon fiber-reinforced polymer-confined concrete column-ring beam joints

Yu Feng, Wang Shisi, Fang Yuan, Zhang Nannan, Wang Yan, Nuermaimaiti Maimaiti

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e49, 2023

EN

Eleven interior polyvinyl chloride (PVC)-carbon fiber-reinforced polymer (CFRP)-confined concrete (PCCC) column-ring beam joints are fabricated and experimentally investigated. The impacts of axial compression ratio, frame beam reinforcement ratio, CFRP strips spacing, ring beam width and ring beam reinforcement ratio, on seismic behaviors are analyzed. All specimens show obvious failure signs, and the frame beam reinforcement ratio exerts a degree of effect on failure positions, exhibiting different failure modes, such as shear failure in the joint zone, shear-bending failure at the junction and bending failure at the frame beam. The experimental results show that the hysteresis curves are relatively full, which have roughly experienced four stages as elastic, elastic-plastic, stable and decline stages, reflecting that the interior joints have considerable seismic behavior. The increment of ring beam reinforcement ratio or ring beam width enhances the load capacity, mitigates degradation of strength and stiffness. The peak load increases by 38.63% as the ring beam reinforcement ratio increases from 0.88 to 1.5%. When the ring beam width increases from 75 to 125 mm, the peak load increases by 37.24%. Appropriately increasing axial compression ratio can raise the load capacity, alleviate strength degradation, and enhance the initial stiffness. As the axial compression ratio increases from 0.2 to 0.4, the peak load increases by19.41%. The joints with larger frame beam reinforcement ratio show higher load capacity, while the frame beam reinforcement ratio exerts marginal impacts on strength and initial stiffness degradation. The existing classical shear models and specification design formulae are used to evaluate the shear capacity of the interior joints, and the reasons for the deviations of prediction results are expounded, which provides the theoretical basis and useful reference for the subsequent establishment of a new shear capacity formula of the joints.

3

Service behaviour of the self-stressed members reinforced with FRP bars

Semianiuk Volha, Semianiuk Siarhei, Tur Victar

Inżynieria Bezpieczeństwa Obiektów Antropogenicznych

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2020

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Nr 2

1--10

EN

Fiber reinforced polymer (FRP) bars, as a structural reinforcement, are characterized by the number of advantages, such as: high strength-to-density ratio; absence of corrosion; resistance to the negative influence of the different aggressive mediums. Nevertheless, a wide practical application of such a bars finds an embarrassment because of the law modulus of elasticity (it varies from 30 GPa to 60 GPa), that leads to the development of the excessive crack opening as well as deflections under the loading. To enhance structural performance of the FRP reinforced concrete members, pretensioning of FRP bars can be considered as a good option. Opposite to the concrete members mechanical pretensioning, physico-chemical method of bars pretensioning based on the self-stressing concrete utilizing is considered. Influence of the controlled initial stress-strain state obtained during early age concrete expansion on the mechanical resistance of the self-stressed concrete members reinforced with both steel and FRP bars was studied.

4

The diagnostics of the emergency modes of the variablefrequency electric drive of the pumping complex

Zagirnyak Mykhaylo, Manko Roman, Korenkova Tetyana

Przegląd Elektrotechniczny

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2019

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R. 95, nr 2

104--107

EN

The paper deals with the demonstration of the fact that the emergency modes that occur in the pipeline networks are accompanied by wave processes resulting in the variation of all parameters of the hydrosystem. We worked out the mathematical model of the automatic control system with the function of the pressure stabilization at the consumer. We obtained the curves representing the alteration of the dynamic processes in the pumping complex during emergency modes occurrence. We formulated the diagnostic signs and proposed the algorithm of the determination of the emergency modes.

PL

W artykule wskazano na fakt, iż tryby awaryjne występujące w sieci rurociągowej związane są z procesami falowymi wynikłym ze zmiany wszystkich parametrów hydrosystemu. Opracowany został model matematyczny systemu sterowania automatycznego z funkcją stabilizacji ciśnienia u odbiorcy. Otrzymano krzywe, reprezentujące zmienność procesów dynamicznych w układzie pompowania podczas wystąpienia trybów awaryjnych. Sformułowane zostały oznaczenia diagnostyczne oraz opracowano algorytm określający tryby awaryjne.

5

Collapse of the single layered cylinder shell with model experimental study

Nie Gui-bo, Zhang Chen-xiao, Zhi Xu-dong, Dai Jun-wu

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 3

883--897

EN

With the rapid development of the large-span space structure, it has been widely used in the public buildings such as gymnasiums, exhibition hall, airplane terminal, etc. in China recently. The large-span latticed shell buildings are usually the landmark buildings in a city, so its collapse will cause serious economic and personal loss, which will affect national security and social stability. The shaking table test was conducted on the single layered cylinder shell model in this paper, and the dynamic amplification effects of the lower support frame and the dynamic responses of the whole model were obtained under different seismic motion inputs. The seismic performance of the single layered cylinder shell was evaluated under different ground motion inputs and input principal directions, and the collapse mode was obtained. The results show that the input principal direction has great effect on the dynamic characteristics of the model, and the dynamic amplification effect of the lower support frame increases with the magnitude increase of the ground motion inputs. There is no obvious impact effect and the dynamic strain responses behave elastic during the collapse process, and the whole shell collapse because of local instability. It concludes that the single layered cylinder shell has the risk of progressive collapse under the seismic motions, so the collapse resistance of single layered cylinder shell should be enhanced or it should be optimum designed to prevent the progressive collapse. This experimental study will provide references to the seismic design and engineering practices.

6

Potential Risks and Their Analysis of the Apparel & Textile Industry in Turkey: A Quality-Oriented Sustainability Approach

Erdil A., Taçgın E.

Fibres & Textiles in Eastern Europe

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2018

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Vol. 26, no. 6 (132)

30--42

EN

The most significant issues in businesses within the scope of manufacturing and services are the sustainability of production quality, setting quality standards and reducing the waste amount during the manufacturing process. From this point of view, the aim of this study is to provide a better quality level of supplying households’ apparel needs while reducing the environmental, economic and social problems of the sustainable supply chain of the apparel sector and extending the lifecycle of apparel. The importance of risk analyses and calculations in the applications of industrial sectors plays a vital role in evaluating the factors of sustainability dimensions. In order to address this risk analysis in this research, quality-oriented implementations are applied to determine the failure modes and effect analysis (FMEA). The significant factors are determined via Pareto Analysis (PA) to control and prevent potential errors and failures in the manufacturing systems of the textile industry. To achieve the aim of this study, the methodology of the research focuses on discovering failures of negative impact based on the primary factor degrees with the computing of risk priority numbers (RPNs) in the manufacturing process of the textile-apparel industry in Turkey. According to the ranking of the RPNs, FMEA application and PA enable to decrease the effects of negative factors and risks as well as the waste amount of the apparel-textile industry, as well as to increase the lifecycle of apparel and products.

PL

Najważniejszymi zagadnieniami w biznesie w zakresie produkcji i usług są: trwałość jakości produkcji, nabywanie standardów jakości i zmniejszanie ilości odpadów przy wytwarzaniu produktach. W związku z tym spostrzeżeniem, celem przeprowadzonych badań było zapewnienie lepszej jakości zaspokojenia potrzeb w zakresie odzieży dla gospodarstw domowych przy jednoczesnym zmniejszeniu problemów środowiskowych, ekonomicznych i społecznych związanych ze zrównoważonym łańcuchem dostaw w sektorze odzieżowym i wydłużeniem cyklu życia odzieży. Znaczenie analiz ryzyka i obliczeń w zastosowaniach sektorów przemysłowych odgrywa istotną rolę w ocenie czynników związanych z wymiarami zrównoważonego rozwoju. Aby uwzględnić tę analizę ryzyka w badaniach zastosowano implementację zorientowaną na jakość w celu określenia trybów awarii i analizy skutków (FMEA), a istotne czynniki określono za pomocą analizy Pareto (PA) w celu kontroli i zapobiegania prawdopodobnym błędom i awariom systemów produkcji przemysłu włókienniczego. Metodologia badania skoncentrowana była na wykryciu wad o negatywnym wpływie na proces produkcji przemysłu tekstylno-odzieżowego w Turcji, w oparciu o podstawowe współczynniki z obliczaniem liczb priorytetowych ryzyka (RPN). Zgodnie z rankingiem RPN, aplikacje FMEA i PA zapewniają zmniejszenie negatywnych czynników, zmniejszenie ryzyka, wsparcie wydłużonego cyklu życia produktów, zmniejszenie ilości odpadów w przemyśle odzieżowym i włókienniczym oraz wydłużenie cyklu życia odzieży.

7

Experimental and numerical study on lateral stability of temporary structures

Liu C., He L., Wu Z., Yuan J.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1478--1490

EN

This paper investigates the lateral performance of temporary structures, which consist of slender members and corresponding joints, under both vertical and horizontal loads. The ultimate bearing capacity, failure modes and the strain distribution of members are illustrated. Experimental results indicate that the lateral stability of the temporary structures is weaker than the vertical stability. Diagonal bracings are the main load-bearing members which resist horizontal loads while the horizontal bars are used to keep stress low. Based on the joint mechanical parameters and the probabilistic models of initial geometric imperfection, the stochastic finite element models (SFEMs) using the Monte Carlo method have been established. The models can consider the semi-rigid performances of joints and initial geometric imperfection. The numerical results demonstrate consistency with structural tests data. Moreover, the influences of structural layers and spans are analysed based on the SFEM. Multiple factors, including spans, layers and upper vertical loads, should be considered when the lateral capacity of temporary structures is calculated. A rapid prediction formula of the lateral stability of temporary structure has been obtained.

8

Ultimate strengths of FRC rectangular columns subjected to simulated seismic loading: Experimental database and new models

Cai G., Degée H.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 1

96--120

EN

While there are many experimental investigations focusing on seismic behaviour of fibre reinforced concrete (FRC) columns, the studies regarding the accuracies and conservativeness of existing seismic strength models of FRC columns are limited. This paper presents a seismic research database of 322 FRC columns obtained from a comprehensive literature investigation. The characteristic of the database and the effects of main variables on the seismic strengths of FRC columns are analyzed in detail, the accuracies of existing strength models of FRC column are also examined as well. In addition, using the database, considering the effects of fibre and other structural factors on FRC columns, Priestley et al. shear and CFB-FIP moment models are modified respectively. Results show that the two proposed strength models both present better evaluation than other models. On the other hand, a detailed method for assessing the potential failure mode of FRC column subjected to seismic loads is also suggested using the two strength models. The comparative results verify the feasibilities and accuracies of the assessment method in FRC columns.

9

On the failure mode of resistance spot welded HSLA 420 steel

Pouranvari M.

Archives of Metallurgy and Materials

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2013

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Vol. 58, iss. 1

67-72

EN

Failure mode of resistance spot welds (interfacial vs. pullout) is a qualitative measure of resistance spot weld performance. Considering adverse effect of interfacial failure mode on the vehicle crashworthiness, process parameters should be adjusted so that the pullout failure mode is guaranteed ensuring reliability of spot welds during vehicle lifetime. In this paper, metallurgical and mechanical properties of HSLA 420 resistance spot welds are studied with particular attention to the failure mode. Results showed that the conventional weld size recommendation of 4t0:5 (t is sheet thickness) is not sufficient to guarantee pullout failure mode for HSLA steel spot welds during the tensile-shear test. Considering the failure mechanism of spot welds during the tensileshear test, minimum required fusion zone size to ensure the pullout failure mode was estimated using an analytical model. Fusion zone size proved to be the most important controlling factor for peak load and energy absorption of HSLA 420 resistance spot weld.

PL

Tryb uszkodzenia zgrzein (pękanie na granicy faz a wyrywanie) jest jakościowa miara zachowania zgrzein. Biorąc pod uwagę niekorzystny wpływ uszkodzenia na granicy faz na odporność pojazdu na uderzenia, parametry zgrzewania powinny być ustawione tak, ze trybem uszkodzenia jest wyrywanie co gwarantuje niezawodność zgrzein w czasie eksploatacji pojazdu. W pracy, badane sa metalurgiczne i mechaniczne właściwości zgrzein stali HSLA 420 ze szczególnym uwzględnieniem trybu uszkodzenia. Wyniki próby rozciągania i ścinania wykazały, ze konwencjonalne zalecenie rozmiaru spoiny 4t0:5 (t - grubość) nie jest wystarczające, aby zapewnić ze trybem uszkodzenia jest wyrywanie. Biorąc pod uwagę mechanizm uszkodzenia zgrzein w czasie próby rozciągania i ścinania, minimalna wielkość strefy stopionej wymagana do zapewnienia, ze trybem uszkodzenia jest najbardziej istotnym czynnikiem decydującym o maksymalnym obciążeniu i pochłanianiu energii przez zgrzewana stal HSLA 420.