Статті в журналах: "Structural Joints Testing"

1

Sadowski, T., T. Balawender, R. Sliwa, P. Golewski, and M. Knec. "Modern Hybrid Joints in Aerospace: Modelling and Testing / Nowoczesne Połaczenia Hybrydowe W Lotnictwie: Modelowanie I Badania Eskperymentalne." Archives of Metallurgy and Materials 58, no. 1 (March 1, 2013): 163–69. http://dx.doi.org/10.2478/v10172-012-0168-3.

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The aim of the paper is to review different types of modern hybrid joints applied in aerospace. We focused on three particular cases: 1) spot welding - adhesive, 2) rivet-bonded and 3) clinch-bonded joints. The numerical models presented in the paper for these joints describe their complex behaviour under mechanical loading. The numerical calculations performed using ABAQUS code were compared to experimental results obtained by application of the Digital Image Correlation system (DIC) ARAMIS. The results investigated within the paper lead to the following major conclusions: - the strengthening of joints by application of adhesive significantly improve static strength, - the final failure of the joined structural system significantly depends on the surface adhesive area, - the stiffening effects of the hybrid joint lead to higher reliability and durability of the structural joints.

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2

Milčić, Dragan, Dragan Mitić, Nenad Radović, Miodrag Milčić, and Aleksija Đurić. "Characterization of welded joints with Partial penetration on S355N structural steel." Zavarivanje i zavarene konstrukcije 66, no. 4 (2021): 149–59. http://dx.doi.org/10.5937/zzk2104149m.

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Existing standards require welded joints with full penetration. It is considered that welded joints with complete penetration minimize the stress concentration in the root passage. However, there are numerous situations in the industry, in which the load-bearing capacity of the welded joint with partial penetration is satisfactory. If the tests of partially penetrated welds show satisfactory load capacity, the benefits compared to fully penetrated welds are reflected in lower costs, ie less time is required to prepare the joint, less additional material is needed, ie shorter time is required to make the welded joint. The paper presents the testing of butt welded joints of structural steel S355N, with partial penetration, achieved by the MAG welding in the overhead position (PD) in the protection of the gas mixture. The samples were welded with different welding parameters and with different joint preparation, and the tests were performed by non destructive methods (visual inspection, testing with penetrants and magnetic particles) and destructive methods - tension and bending tests, Vickers hardness testing.

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3

Jasiński, Radosław, and Iwona Galman. "Testing Joints between Walls Made of AAC Masonry Units." Buildings 10, no. 4 (April 2, 2020): 69. http://dx.doi.org/10.3390/buildings10040069.

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Joints between walls are very important for structural analysis of each masonry building at the global and local level. This issue has often been neglected in the case of traditional joints and relatively squat walls. At present, the issue of wall joints is becoming particularly important due to the continuous drive for simplifying structures, introducing new technologies and materials. Eurocode 6 and other standards (American, Canadian, Chinese, and Japanese) recommend inspecting joints between walls, but no detailed procedures have been specified. This paper presents our own tests on joints between walls made of autoclaved aerated concrete (AAC) masonry units. Tests included reference models composed of two wall panels joined perpendicularly with a standard masonry bond (six models), with classic steel and modified connectors (twelve models). The shape and size of test models and the structure of a test stand were determined on the basis of the analysis of the current knowledge, pilot studies and numerical FEM (Finite Element Method) - based analyses. The analyses referred to the morphology and failure mechanism of models. Load-displacement relationships for different types of joints were compared and obtained results were related to results for reference models. The mechanisms of cracking and failure was found to vary, and clear differences in the behaviour and load capacity of each type of joint were observed. The individual working phases of joints were determined and defined, and an empirical approach was proposed for the determination of forces and displacement of wall joints.

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4

Adamus, K., and P. Lacki. "Assessment of Aluminum FSW Joints Using Ultrasonic Testing." Archives of Metallurgy and Materials 62, no. 4 (December 1, 2017): 2399–404. http://dx.doi.org/10.1515/amm-2017-0353.

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AbstractThe paper concerns aluminum joints made using friction stir welding. Although in the aerospace industry there is a tendency to replace metal components with composites, aluminum continues to be a valuable material. Its share in the aircraft structures is the biggest among all structural metals. Lots of aluminum components are made of sheets and most of them require joining. Friction stir welding is a relatively new joining technology, particularly with regard to the sheets having a thickness of 1 mm or lower. The paper is dedicated to non-destructive testing of such joints using ultrasonic inspection. It was found that ultrasonic testing allows for distinguishing between joints without material discontinuities, joint with material discontinuities at the advancing side and joint with discontinuities extending through the whole width of the stir zone. During research only horizontally aligned defects were taken into account.

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5

Alqaryouti, Yousef, Dilum Fernando, and Joseph Gattas. "Structural Behavior of Digitally Fabricated Thin-Walled Timber Columns." International Journal of Structural Stability and Dynamics 19, no. 10 (October 2019): 1950126. http://dx.doi.org/10.1142/s0219455419501268.

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This paper aims to investigate the structural behavior of digitally fabricated thin-walled timber sections with edge connectivity provided by integral mechanical press-fit joints. Experimental, numerical, and analytical investigations have been developed to accurately characterize the press-fit section behavior and their failure modes. Plywood fiber orientation, material thickness, and connection tightness are considered as potential factors that may affect the performance of the press-fit jointing system. Experimental testing of square hollow sections (SHSs) under uniaxial compressive loading showed failure of sections through both conventional crushing and novel pop-off bifurcation failures. Pop-off buckling behaviors were shown to be governed by the integral joint transverse stiffness and its magnitude relative to a critical edge stiffness value. Columns with joint transverse stiffness value less than the critical edge stiffness value exhibited pop-off failures. These joint stiffness values were obtained from testing of unloaded joints and were used to obtain accurate predictions of column failure modes. Joint stiffness values for loaded joints were then predicted with an interpolation model mapping axial strain to a tighter connection tolerance and these were used to obtain accurate estimations for column failure load in most of the tested column types. Comparative investigations showed thin-walled sections with integral joints only to be capable of matching the compressive capacities of glued sections, for instances where crushing governed. Similarly, the weight-specific compressive capacity of timber sections was found to be comparable to thin-walled steel sections when crushing governs.

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6

Zhang, Dongfang, Junhai Zhao, and Shuanhai He. "Cyclic Testing of Concrete-Filled Double-Skin Steel Tubular Column to Steel Beam Joint with RC Slab." Advances in Civil Engineering 2018 (July 26, 2018): 1–15. http://dx.doi.org/10.1155/2018/7126393.

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The design of composite joints for connecting concrete-filled double-skin tubular (CFDST) columns to steel beams supporting reinforced concrete (RC) slabs is presented in this paper. Five half-scale specimens were designed, including four composite joints with RC slab and one bare steel beam joint, and were tested under a constant axially compressive force and lateral cyclic loading at the top end of the column to evaluate their seismic behavior. The main experimental parameters were the construction of the joint and the type of the column. The seismic behaviors, including the failure modes, hysteresis curves, ductility, strength and stiffness degradation, and energy dissipation, were investigated. The failure modes of the composite joints depended on the joint construction and on the stiffness ratio of beams to columns. Joints of stiffening type had significantly higher load-bearing and deformation capacities than joints of nonstiffening type. Compared with the bare steel beam joint, the bearing capacities of the composite joints with RC slabs were markedly increased. The composite action was remarkable under sagging moments, resulting in larger deformation on the bottom flanges of the beams. Overall, most specimens exhibited full hysteresis loops, and the equivalent viscous damping coefficients were 0.282∼0.311. The interstory drift ratios satisfied the requirements specified by technical regulations. Composite connections of this type exhibit excellent ductility and favorable energy dissipation and can be effectively utilized in superhigh-rise buildings erected in earthquake zones.

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7

Bu, Yonghong, Qi Yang, Yihong Wang, and Dongfang Zhang. "Cyclic Testing of Bolt-Weld Joints Reinforced by Sleeves Connecting Circular CFST Columns to Steel Beams." Advances in Civil Engineering 2020 (January 28, 2020): 1–12. http://dx.doi.org/10.1155/2020/9674128.

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This study examined the design of joints reinforced by sleeves for connecting circular concrete-filled steel tube columns to steel beams. Six half-scale specimens, including four bolt-weld joints reinforced by sleeves and two bolt and stiffened end-plate joints, were designed and tested under cyclic loading to evaluate the seismic behavior of these joints. The joint construction and beam-column stiffness ratio were taken as the main parameters in the tests. The seismic behaviors, including the failure modes, hysteretic curves, ductility, strength and stiffness degradation, and energy dissipation, were investigated. The experimental results showed that no obvious bolt loosening, fracture, or widespread weld cracking appeared in the joints reinforced by sleeves. Furthermore, the joint strength and stiffness were markedly increased by the sleeves in the joint core area. Overall, most specimens exhibited full hysteresis loops and excellent ductilities, the equivalent viscous damping coefficients were 0.263∼0.532, and the ductility coefficients were 1.77∼3.42. The interstory drift ratios satisfied the requirements specified by technical regulations. The connections of these types exhibit favorable energy dissipations and can be effectively utilized for building construction in earthquake-prone areas. This research should contribute to the future engineering applications of concrete-filled steel tube to composite structure.

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8

Ullah, Sami, Faiz Ahmad, and Anildav Singh. "Development and Testing of Intumescent Fire Retardant Coating on Various Structural Geometries." Applied Mechanics and Materials 699 (November 2014): 360–65. http://dx.doi.org/10.4028/www.scientific.net/amm.699.360.

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Materials are prone to fire and in modern construction their protection from fire is required. In any structure, various joints such as T-joint, I-beam and elbows are used. The geometry of the component has significant role in protection of structure. A weak joint may lead to failure of main structure. In order to meet these challenges, Intumescent fire retardant coating (IFRC) were developed and tested on various structural geometries such as T-joints, elbows, I-beams and pipe. The control coating formulation (IFC-C) was developed from main ingredients; Ammonium Polyphosphate (APP), expandable Graphite (EG), Melamine (Mel), Boric Acid (BA) mixed with bisphenol A epoxy resin and polyamide hardener. Another set of formulations containing various percentage of aluminium Tri-Hydrate (ATH). Fire test results of ATH based formulation showed that I-beam geometry showed the high expansion of 19 mm. T-joint showed the average surface temperature of 55°C after one hour of Bunsen burner test. The X-ray Diffraction (XRD) showed the presence of boron oxide, boron phosphate, sassolite and aluminium oxide in IFC-ATH5 residual char. The 5wt% ATH filler in IFC-C enhanced the fire protection performance of intumescent fire retardant coating formulation.

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9

Mironovs, Viktors, Vjaceslavs Zemcenkovs, Dmitrijs Serdjuks, Vjaceslavs Lapkovskis, Aleksejs Tatarinovs, and Viktors Kurtenoks. "Method and apparatus for dynamic testing of structural joints." Journal of Physics: Conference Series 2423, no. 1 (January 1, 2023): 012017. http://dx.doi.org/10.1088/1742-6596/2423/1/012017.

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Abstract The dynamic testing technique is used during the design phase of structures and series production. This test evaluates the structural capacity, especially of the assemblies, to withstand different forces and rates of impact encountered under realistic operational conditions. This study proposes a magnetic pulse exciter for high-speed impact loading in dynamic tests because of its capability to provide single and repeatable pulse loading over a wide range of force up to 20 kN and pulse durations from 10 up to 1000 ms. The method transforms accumulated electrical energy in a capacitor bank into mechanical energy. For experimental investigations, flat and cylindrical coil devices were used for a capacitor-type pulse current generator. The proposed method has been experimentally validated on timber beams in a specified volume of force loading. The technique demonstrated a potential for controlling force and energy parameters. The effects of operating voltage on coil and ‘metal plate - coil’ distance on the amplitude of dynamic loading have been investigated. Aluminium and steel plates fastened to the object at the point of impact were used to improve excitation efficiency. The developed technique can be used in experimental studies on model joints and real objects.

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10

Morelli, Piero. "An Experimental Study on the Shear Strength of Steel Structures Joints." Applied Mechanics and Materials 268-270 (December 2012): 279–82. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.279.

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The results of an experimental investigation on the shear strength of structural joints are presented and discussed. Joint typologies generally employed in structural frames of industrial warehouses and intermediate floors are taken into consideration. Specimens were supplied by an industrial shelving manufacturer, in two different configurations: the first one characterized by steel pressed geometrical connectors and the second one consisting in bolted fittings to angular welded supporting plates. A specific testing device has been designed in order to transfer axial loading into shear loading applied to a couple of joints in a symmetrical testing configuration. Quasi-static loads were applied with increasingly intensity steps, until the yielding of the material or the overall structure collapse were reached. Failure modes of the tested joints are analyzed and discussed.

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11

Sancaktar, Erol. "Recent Approaches in Constitutive Behavior and Testing of Structural Adhesives." Applied Mechanics Reviews 49, no. 10S (October 1, 1996): S128—S138. http://dx.doi.org/10.1115/1.3101964.

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Adhesively bonded joints are complex composite structures with at least one of the constituents, namely the adhesive, most often, being a composite material itself due to the presence of secondary phases such as fillers, carriers, etc. The joint structure possesses a complex state of stress with high stress concentrations, and often, singularities due to the terminating adhesive layer where the substrates may possess sharp corners. With these issues in mind, this article discusses the following: Typical joint stress distributions; Stress concentrations and the effect of joint scarf angle on stress concentrations; Singularity methods; Reductions in stress concentrations due to viscoelastic adhesive behavior, as well as increases in joint strength due to rate dependent viscoelastic adhesive behavior; Geometrical methods to reduce stress concentrations; Bulk adhesive as composite material; The concept of the interphase; Damage models; The effects of cure and processing conditions on the mechanical behavior.

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12

Ledford, Noah, and Michael May. "Modeling of multimaterial hybrid joints under high-rate loading." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 234, no. 5 (April 15, 2020): 446–53. http://dx.doi.org/10.1177/0954408920919012.

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Joint failure plays a key role in determining structural stability and crash or impact response. Characterizing the joints at high loading rates is challenging as oscillations are often overlaid on the measured data, making interpretation of the results more difficult. This paper builds upon the experimental testing three different mixed-material joints using a split-Hopkinson tension bar. The correction proposed in this work is verified using a finite element model of the entire testing system. The modeling efforts also investigate the differences in a specimen only model and a model including the entire testing system. The failure mechanisms of bolted and bonded joints are investigated, where the substrate stress state is found to play a large role in determining the failure mode for bolted joints. This work lays the foundations needed to investigate the mixed-material bolted and bonded joints in detail.

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13

Aribert, Jean-Marie, Marc Braham, and Alain Lachal. "Testing of “simple” joints and their characterisation for structural analysis." Journal of Constructional Steel Research 60, no. 3-5 (March 2004): 659–81. http://dx.doi.org/10.1016/s0143-974x(03)00135-4.

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14

Lavisci, P., B. Pizzo, J. M. Gagliano, P. Triboulot, and M. De Ciechi. "Fracture energy testing of thick joints with structural wood adhesives." Holz als Roh- und Werkstoff 61, no. 5 (October 1, 2003): 355–57. http://dx.doi.org/10.1007/s00107-003-0385-6.

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15

Humphreys, Matthew F., Gerard Van Erp, and Charles H. Tranberg. "The Structural Behaviour of Monocoque Fibre Composite Truss Joints." Advanced Composites Letters 8, no. 4 (July 1999): 096369359900800. http://dx.doi.org/10.1177/096369359900800405.

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This paper presents early experimental results of an ongoing research project into the structural behaviour of monocoque fibre composite truss joints. The testing of three different types of joints will be discussed. Descriptions of the test procedures are presented as well as design and analysis of each jointing method.

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16

Mahadik, Vinay, and Akanshu Sharma. "Bidirectional Loading History for Seismic Testing of 3D Frame Joints." CivilEng 2, no. 2 (May 3, 2021): 349–69. http://dx.doi.org/10.3390/civileng2020019.

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Beam-column-joints (BCJ) in reinforced concrete (RC) frames are known to be critical against seismic actions. Hence, several researchers have conducted related investigations. The loading history used in the experimental investigations must be a sufficiently accurate and conservative representation of seismic loading on the structure and should trigger all possible critical failure mechanisms in the subassembly. Presently, there is significant diversity in the loading histories used for seismic investigation of structural subassemblies. This paper intends to propose an optimum loading history for considering bidirectional (horizontal) seismic action on 3D-RC BCJ subassemblies. To this end, the available loading histories (unidirectional and bidirectional) for simulation of seismic loads on RC joint subassemblies are reviewed in the context of the demands they impose on the joints. Finite element modeling and analyses are used as a tool for investigating the response of 3D-BCJ subassembly under different bidirectional loading states.

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17

Braga, Daniel F. O., Lucas F. M. Da Silva, and Pedro M. G. P. Moreira. "Single Lap Joints Numerical Modelling and Comparison with Experimental Testing." U.Porto Journal of Engineering 2, no. 1 (March 19, 2018): 11–20. http://dx.doi.org/10.24840/2183-6493_002.001_0002.

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Adhesive bonding is a joining technique which has been extensively employed in structural design as its ability to join different types of materials allows higher freedom for designers when choosing materials. One of the most common joint configuration used is the single lap joint configuration. In this work a set of experimental procedures were undertaken to characterize a structural adhesive and model the behaviour of a single lap joint manufactured using this adhesive. Two types of surface preparations were used to study its effect in single lap joint strength.

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18

Schrader, Peer, and Stephan Marzi. "Mode III testing of structural adhesive joints at elevated loading rates." International Journal of Adhesion and Adhesives 113 (March 2022): 103078. http://dx.doi.org/10.1016/j.ijadhadh.2021.103078.

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19

Baurova, N. I., and A. Yu Sergeev. "Structural studies of fracture patterns in adhesive joints after pullout testing." Polymer Science Series D 7, no. 4 (October 2014): 298–302. http://dx.doi.org/10.1134/s1995421214040030.

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20

Barat, Vera, Artem Marchenkov, Vladimir Bardakov, Marina Karpova, Daria Zhgut, and Sergey Elizarov. "Features of Acoustic Emission in Tensile Testing of Dissimilar Welded Joints of Pearlitic and Austenitic Steels." Applied Sciences 11, no. 24 (December 14, 2021): 11892. http://dx.doi.org/10.3390/app112411892.

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This paper presents a study of acoustic emission (AE) during the deformation of dissimilar welded joints of austenitic steel to pearlitic steel. One of the specific problems in these welded joints is the presence of decarburized and carbide diffusion interlayers, which intensively increase in width during long-term high-temperature operation. The presence of wide interlayers negatively affects the mechanical properties of welded joints. Moreover, welded defects are difficult to diagnose in welded joints containing interlayers: due to the high structural heterogeneity, interlayers create structural noises that can hinder the detection of defects such as cracks, pores, or a lack of penetration. The AE method may become a complex decision for diagnosing dissimilar welded joints due to applicability to the testing of heterogenic materials with a complex microstructure. Specimens cut from dissimilar welded joints of austenitic steel to pearlitic steel were tested by tension to rupture, with parallel AE data registration. According to the research results, the characteristic features of the AE were revealed for specimens containing defects in the form of lack of penetration as well as for specimens with diffusion interlayers. The results obtained show that the AE method can be used to test both typical welding defects and diffusion interlayers in welded joints of steels of different structural classes.

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21

Roozbahany, Ehsan Ghafoori, Manfred N. Partl, and Patryk Jakub Witkiewicz. "Fracture testing for the evaluation of asphalt pavement joints." Road Materials and Pavement Design 14, no. 4 (December 2013): 764–91. http://dx.doi.org/10.1080/14680629.2013.812979.

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22

Guo, Jiaqi, Lipan Cheng, Yongbiao Lai, Yongchao Tian, and Lu Li. "Study on Shear Mechanical Properties and Microscopic Failure Mechanism of Dentate Joints Based on DEM and Laboratory Tests." Buildings 12, no. 9 (September 19, 2022): 1485. http://dx.doi.org/10.3390/buildings12091485.

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The stability control of the surrounding rock is greatly influenced by the rock joint’s shear mechanical characteristics and deformation failure mechanism. A numerical model of the dentate joints was created using a particle flow discrete element method (DEM). To study the shear mechanical behavior and damage evolution characteristics of the joints, a numerical simulation of the joints shear test under the same normal stress was conducted. Additionally, the joints’ shear failure mechanism and failure mode were investigated from a microscopic perspective in conjunction with laboratory tests. The results show that the shear strength steadily increases as the roughness of the rock joints increases and that it rapidly decreases after reaching its peak shear strength, indicating an obvious brittle failure. Varied rock joints exhibit significantly different micro-crack evolution, with rougher rock joints (r = 0.30, r = 0.37) exhibiting greater micro-crack production and crack extension into the model’s interior. Rock joint specimens with lower roughness (r = 0.17) had less concentration and fewer areas of contact force concentration. The shear failure mode of the rock joints gradually shifts from abrasion failure mode to snip failure mode as the roughness rises, which is largely compatible with the failure characteristics shown in the laboratory testing. The pattern of micro-crack development within the model specimen and the failure characteristics of the laboratory tests are in good agreement with the distribution characteristics of contact force on the rock joints.

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23

Gopal, Balamurugan A., Farzad Hejazi, Milad Hafezolghorani, and Voo Yen Lei. "Numerical analysis and experimental testing of ultra-high performance fibre reinforced concrete keyed dry and epoxy joints in precast segmental bridge girders." International Journal of Advanced Structural Engineering 11, no. 4 (October 23, 2019): 463–72. http://dx.doi.org/10.1007/s40091-019-00246-6.

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Abstract Although ultra-high performance fiber reinforced concrete (UHPFRC) has been used recently as a sustainable construction technique for many precast segmental bridges (PSBs), no exhaustive numerical and experimental studies exist to assess the shear capacity and failure pattern of the joints in these bridges. Hence, to accurately investigate the shear behavior of the joints in UHPFRC precast segmental bridges, a numerical analysis model based on finite-element code was established in this study. Concrete damaged plasticity model was used to analyze the UHPFRC joint models by considering all the geometries, boundaries, interactions and constraints. In this paper, the numerical model was calibrated by two full-scale UHPFRC keyed dry and epoxy joints under confining pressure effect. The excellent agreement between the numerical results and experimental data demonstrated the reliability of the proposed numerical model. The validated numerical model was then utilized to investigate the parameters affecting shear behaviour of the joints in PSBs. For this purpose, 12 FE models were analyzed under different variable parameters namely, number of shear keys, confining stress, and types of joints (dry or epoxy). Furthermore, the numerical results were also compared with the five existing shear design provision models available in literature in terms of ultimate shear capacity.

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24

Carboni, M., and A. Bernasconi. "Acoustic emission-based monitoring of fatigue damage in CFRP-CFRP adhesively bonded joints." Insight - Non-Destructive Testing and Condition Monitoring 64, no. 7 (July 1, 2022): 393–97. http://dx.doi.org/10.1784/insi.2022.64.7.393.

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Adhesively bonded joints are being increasingly applied in modern structures. However, manufacturing defects and particularly harsh operative conditions may cause local debonding and catastrophic failures. Structural health monitoring (SHM) and non-destructive testing (NDT) procedures are then needed to evaluate the in-service structural integrity of adhesively bonded joints. In this research, an adhesively bonded single-lap joint, both adherends of which are manufactured using a carbon fibre-reinforced polymer (CFRP) composite, is subjected to constant amplitude fatigue loading. During such a test, the integrity and damage condition of the joint is continuously monitored using acoustic emission (AE), while the test itself is periodically interrupted in order to apply micro-computed tomography (μCT) to the specimen, with the aim of investigating the real features of the developing fatigue damage. The results show that, after suitable elaboration and filtering by means of pattern recognition algorithms, acoustic emission-based monitoring allows for effective identification and characterisation of the development of fatigue damage in adhesively bonded joints.

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25

Lau, Peter W. C. "Factors affecting the behaviour and modelling of toothed metal-plate joints." Canadian Journal of Civil Engineering 14, no. 2 (April 1, 1987): 183–95. http://dx.doi.org/10.1139/l87-030.

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An efficient approach to determine the behaviour of toothed metal-plate joints is to use analytical techniques to model the behaviour on the basis of known properties of plate and wood, and loading conditions, backed by an actual testing of the joints for verification or calibration of the models. Existing computer-based techniques such as the Structural analysis of trusses (SAT) and Purdue plane stress analyzer II (PPSA II) were developed for modelling wood trusses. The applicability and usefulness of these techniques can be expanded if better joint models can be incorporated into SAT, or if PPSA II can be advanced to describe the behaviour of joints. The present experiment included obtaining load–deformation data on specimens of two designs — one for the shear properties of plate and the other resembling the heel joint of a truss. These data were compared with predictions given by SAT. In addition, data from the heel joint specimens were used to calibrate the property requirements of fictitious members used in PPSA II to model semirigid joint behaviour. Predictions of joint stiffness by SAT were reasonably accurate, but the ultimate load was overestimated when the joint failed in plate buckling. The heel joint test method shows potential as a proper and efficient test method for assessing joint behaviour. However, as is normal with any joint testing, a significant frictional force can develop between joint members and contribute to the ultimate strength and stiffness of the joint. This frictional force should be accounted for in modelling. Key words: design, interface friction, modelling, shear strength, stiffness, structural analysis, truss plate, wood truss.

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26

Dimogianopoulos, Dimitrios G., and Dionysios E. Mouzakis. "Nondestructive Contactless Monitoring of Damage in Joints between Composite Structural Components Incorporating Sensing Elements via 3D-Printing." Applied Sciences 11, no. 7 (April 3, 2021): 3230. http://dx.doi.org/10.3390/app11073230.

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A vibration-testing framework for detecting and identifying failing joints between composite structural members without dedicated equipment (accelerometers, amplifiers) or time-consuming system modeling methods is introduced. The sensing element is a 2826MB Metglas® magnetoelastic strip embedded in one of the members during its 3D-printing (layer-by-layer) fabrication process in fused deposition modeling mode. External dynamic loading of the structure causes changes to the strip’s magnetization, thus inducing voltage to a nearby placed coil in a contactless manner. The resulting signal depends on the structure’s behavior under loading (and therefore its condition), and may be recorded without amplification or filtering by conventional oscilloscopes. Its frequency analysis reveals patterns of shifted frequency and/or altered damping at specific modes attributed to failing joints. Apart from yielding results using less dedicated equipment than other vibration-testing methods, the current framework offers two additional benefits: (i) Excitation may be applied to the same structural point for all monitored joints; (ii) estimation of damping values for a given mode does not have to rely on empirical or system modelling techniques (both requiring dedicated expertise). Test runs with structures formed by two or three composite slabs joined in-series indicate promising results with successful detection and identification of failing joints.

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27

Abdalla, Omer M. O., Gianluca Massimino, Fabio Quaglia, Marco Passoni, and Alberto Corigliano. "PMUTs Arrays for Structural Health Monitoring of Bolted-Joints." Micromachines 14, no. 2 (January 25, 2023): 311. http://dx.doi.org/10.3390/mi14020311.

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Micro-electro-mechanical systems (MEMS) have enabled new techniques for the miniaturization of sensors suitable for Structural Health Monitoring (SHM) applications. In this study, MEMS-based sensors, specifically Piezoelectric Micromachined Ultrasonic Transducers (PMUT), are used to evaluate and monitor the pre-tensioning of a bolted joint structural system. For bolted joints to function properly, it is essential to maintain a suitable level of pre-tensioning. In this work, an array of PMUTs attached to the head and to the end of a bolt, serve as transmitter and receiver, respectively, in a pitch-catch Ultrasonic Testing (UT) scenario. The primary objective is to detect the Change in Time of Flight (CTOF) of the acoustic wave generated by the PMUT array and propagating along the bolt’s axis between a non-loaded bolt and a bolt in service. To model the pre-tensioning of bolted joints and the transmission of the acoustic wave to and from a group of PMUTs through the bolt, a set of numerical models is created. The CTOF is found to be linearly related to the amount of pre-tensioning. The numerical model is validated through comparisons with the results of a preliminary experimental campaign.

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Wernicke, R., and R. Pohl. "Underwater Wet Repair Welding and Strength Testing on Pipe-Patch Joints." Journal of Offshore Mechanics and Arctic Engineering 120, no. 4 (November 1, 1998): 237–42. http://dx.doi.org/10.1115/1.2829546.

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The underwater wet welding method for repairing of submerged structural members has been intensively developed during the last years. It is an economical and especially more time-independent procedure. The shortened repair duration is a major advantage in regions with rough sea climate as the North Sea area. During research projects the weldability and fatigue performance of pipe-patch connections have been tested. These joints are in use for repairing of collision indents. The shape of the actual used repair patch was optimized to the requirements of underwater wet welding at high tensile strength steels as BS4360 Gr 50D. Steel materials in this grade show problems in regard to high hydrogen susceptibility, and therefore cold cracking. The fatigue behavior of the patch-welded pipe structural member has been investigated. First test series were carried out using as-welded joints. In a second part of the project, post-weld-treated connections were tested. The weld seams on these joints were partially ground or hammer peened. The test results have been evaluated by means of the hot-spot concept and then faced with actual code requirements. Extensive strain gage measurements and finite-element calculations have been carried out to provide the stress state in the structural details.

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29

Barat, Vera, Artem Marchenkov, Vladimir Bardakov, Daria Zhgut, Marina Karpova, Timofey Balandin, and Sergey Elizarov. "Assessment of the Structural State of Dissimilar Welded Joints by the Acoustic Emission Method." Applied Sciences 12, no. 14 (July 18, 2022): 7213. http://dx.doi.org/10.3390/app12147213.

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In this study, we investigated defect detection in dissimilar welded joints by the acoustic emission (AE) method. The study objects were carbide and decarburized interlayers, which are formed at the fusion boundary between austenitic and pearlitic steels. Diffusion interlayers, as a structural defect, usually have microscopic dimensions and cannot be detected using conventional non-destructive testing (NDT) methods. In this regard, the AE method is a promising approach to diagnose metal objects with a complex structure and to detect microscopic defects. In this paper, the AE signatures obtained from testing defect-free specimens and specimens with diffusion interlayers are analyzed. We found that the AE signature for defective and defect-free welded joints has significant differences, which makes it possible to identify descriptors corresponding to the presence of diffusion interlayers in dissimilar welded joints.

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30

Blyberg, Louise, Erik Serrano, Bertil Enquist, and Magdalena Sterley. "Adhesive joints for structural timber/glass applications: Experimental testing and evaluation methods." International Journal of Adhesion and Adhesives 35 (June 2012): 76–87. http://dx.doi.org/10.1016/j.ijadhadh.2012.02.008.

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31

Hajro, Ismar, and Petar Tasić. "Properties mismatching and distribution on structural steels welded joints." Advanced Technologies & Materials 43, no. 2 (December 15, 2018): 15–20. http://dx.doi.org/10.24867/atm-2018-2-003.

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The paper presents results of combined, conventional and non-conventional, approach for evaluation of mechanical and technological properties of structural steel's welded joints. The selected structural steels are in the range of most common used strength level(s), as well as corresponding various chemical composition concept(s) and processing routes. A short review regarding weldability is presented based on recommendation provided in EN 1011-2, manufacturers recommendation, and own results. However, even it is a well-known fact, mismatching of properties is presented rather to provide sense of its level for particular steel grades. Moreover, the level of under-matching of weakest weld zone (coarse grained heat affected zone), provided by mean of welding thermo-cycle simulation is presented. This is due to the fact that such estimation is not possible with everyday conventional (standardized) testing. The most important design and technological properties of welded joint(s) are considered; e.g. strength, ductility, hardness, microstructure and toughness.

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32

Song, Baoxi, Dongsheng Du, Weiwei Li, Shuguang Wang, Yue Wang, and Decheng Feng. "Analytical Investigation of the Differences between Cast-In-Situ and Precast Beam-Column Connections under Seismic Actions." Applied Sciences 10, no. 22 (November 22, 2020): 8280. http://dx.doi.org/10.3390/app10228280.

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At present, the engineering designers generally design and analyze the precast structural models according to the equivalent cast-in-situ principle, and have a vague understanding of non-identical problems. However, these issues cannot be ignored, especially for high-intensity areas. This paper considers the differences of the hysteretic relationship between two typical precast joints and cast-in-situ (RC) joints, and researches the influence of these differences on the seismic response of frame structures. For the monolithic precast joint, the force mechanism was analyzed based on its assembly form, and the differences with the RC joint in the testing phenomena were explained accordingly. The dimensionless hysteresis models of two types of joints were proposed, and the rationality of the monolithic precast joint model was verified according to the existing experimental results. Different performances of joints were realized by assigning the constitutive models calculated from sectional reinforcement to the spring elements of analysis models. Considering two possible performance deficiencies of each type of precast joint separately, a total of seven structural analysis models were formed. Nonlinear static analysis and dynamic time-history analysis methods were adopted to reveal the differences between precast frames and the RC frame in terms of structural capacity curve, displacement response, ductility demands of components and structural residual deformation. The results showed that under strong seismic excitation, the response differences between precast frames and the RC frame were significant, so it is worthwhile to establish nonlinear models suitable for precast frames in seismic analysis. This study is valuable for understanding and distinguishing the nonlinear response of precast frames and traditional RC frames.

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33

Yu, Zeliang, Bin Yang, Bin Jia, Yuhong Yan, Shaowen Xiao, and Ke Lei. "Test and Numerical Study on Monotonic Behavior of Complex CFT Column Joints." Advances in Civil Engineering 2019 (September 24, 2019): 1–20. http://dx.doi.org/10.1155/2019/5105934.

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This paper presents a test and numerical investigation into the monotonic behavior of three different complex steel trusses to concrete-filled tubular (CFT) column joints. Based on an engineering structure, 1 : 4 reduced-scale specimens are manufactured and the three-dimensional subassembly testing system is designed to apply the monotonic load. Test phenomena and load-stress curves show that all three types of joints have a considerable load-carrying capacity and joint rigidity. Finite element (FE) analysis is adopted, and the stress distribution shows good agreement with test data. Both test and FE results show that local buckling and yielding in the root region of steel truss are the main failure modes of test joints and the core area of the CFT column remains intact which are in accordance with the design conception of “strong column and weak beam.” Design conception of proposed overlap joint form is then investigated based on the FE model, and results show that the optimized overlap joint can effectively reduce the stress concentration in the adjacent steel tube and beam member when compared to the traditional N-type overlap joint. Finally, the influence of the outer diaphragm on the stiffness of joint is analyzed. By comparing the end-displacement of the beam member, conclusion can be obtained that the beam flange thickness is suggested to be chosen as the outer diaphragm thickness. The forms of three different proposed joints and their design conceptions can provide good guidance for designers and engineers.

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34

Kam, J. C. P., D. A. Topp, and W. D. Dover. "Fatigue Fracture Mechanics Modeling and Structural Integrity Assessment of Offshore Welded Tubular Joints." Journal of Offshore Mechanics and Arctic Engineering 111, no. 3 (August 1, 1989): 170–76. http://dx.doi.org/10.1115/1.3257144.

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Evaluation of the structural integrity of offshore structures requires information on the reliability of nondestructive testing, the accuracy of fatigue crack growth modeling and other data. The University College London Underwater NDE Centre has been set up to provide information on the effectiveness and reliability of different nondestructive testing methods. To achieve this aim, a large library of cracked specimens will be assembled. In the preliminary phase of producing this library, a series of large-scale welded tubular joints were fatigue tested and the crack growth was fully monitored with the ACPD technique. This paper will describe briefly the background to the crack library and present the data obtained from fatigue tests. It will also describe a new model for fatigue crack growth prediction in tubular joints using fracture mechanics. This model allows the prediction of the size effect noted previously in the stress/life curves for tubular joints.

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35

Gallou, M., B. Temple, C. Hardwick, M. Frost, and A. El-Hamalawi. "Potential for external reinforcement of insulated rail joints." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 232, no. 3 (December 22, 2016): 697–708. http://dx.doi.org/10.1177/0954409716684278.

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This paper aims to investigate the alternative ways of reducing the deterioration and failure of insulated rail joints of railway tracks. Joints deteriorate faster than rails due to the presence of structural discontinuity. This weakness results in extra displacement due to the applied load and dynamic force that results as a consequence. Overtime, this situation worsens as the impacts and applied stresses damage and soften the ballast and the supporting subgrade under the joint. This study initially presents a static finite element model designed to simulate the mechanics of insulated rail joints, and then a comparison is made between the plain rail and a suspended insulated rail joint under various support stiffnesses. The product design options of the reinforced insulated rail joints are then chosen as input variables of the model. The results of the model are compared with the field and laboratory data acquired via the Video Gauge, which is a new high-resolution optical measurement technique. The results show that the use of strap rails or more robust I-beam sections in the vicinity of the insulated rail joint to stiffen the support structure can significantly reduce the displacement and the subsequent dip angle seen in an insulated rail joint. This potentially presents a means of improving the behaviour of the insulated rail joints. Their impact becomes more significant for soft support conditions. Although these results are indicative of new conditions for insulated rail joints, the field measurements indicate that the magnitude of deflection of insulated rail joints is a result of the structural discontinuity of the rails, the dynamic P2 force, the wheel condition, the degraded ballast and it significantly increases with time under repeated load. Thus, it is recommended that a careful field implementation and testing will indicate the effect of an external enhancement on the timely degradation of insulated rail joints.

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36

Iakovlev, N. O., A. A. Selivanov, I. V. Gulina, and A. V. Grinevich. "REVISITING THE DURABILITY OF HINGED-BOLT CONNECTIONS." «Aviation Materials and Technologies», no. 4 (2020): 79–85. http://dx.doi.org/10.18577/2071-9140-2020-0-4-79-85.

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The paper considers the issue of durability of hinged-bolt joints under the influence of a corrosive environment. There has been performed the analysis of the stress-strain state of the eyes’ material in the preloaded joints. Possibility of corrosion cracking of the eyes in case of exposure to a corrosive medium has been determined. Experimental confirmation of The destruction of the eyes’ material in a preloaded joint has been confirmed experimentally. The article proposes the development of the testing methodology of structural materials under the prolonged exposure to constant stress and corrosive medium under the conditions of a given deformation.

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37

Bach, Michael, Ali Merati, and Michael Gharghouri. "Effects of Fatigue on the Integrity of a Friction Stir Welded Lap Joint Containing Residual Stresses." Advanced Materials Research 996 (August 2014): 794–800. http://dx.doi.org/10.4028/www.scientific.net/amr.996.794.

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This research uses a non-destructive method of neutron diffraction to measure the tri-axial residual stresses in a friction stir welded aerospace fuselage component: a stringer-to-skin lap joint. Two different specimens were examined. Fatigue testing was performed on both specimens to determine their fatigue lives. Effects of the different components of residual stresses were examines and related to fatigue performance. A combination of fractography, hardness testing, and residual stress measurement was used to predict areas of high probability of structural failure in the friction stir welded lap joints.

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38

Berezovskaya, Vera V., A. V. Berezovskiy, and D. H. Hilfi. "Laser Welded Joints of High-Nitrogen Austenitic Steels: Microstructure and Properties." Solid State Phenomena 284 (October 2018): 344–50. http://dx.doi.org/10.4028/www.scientific.net/ssp.284.344.

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High nitrogen austenitic steels are used as structural materials required possessing high strength and fracture toughness. The present study is concerned with the characteristic features (shape, size, properties and structure) of the laser welded joints in Cr-Mn-, Cr-Mn-Mo-high nitrogen steels compared to the ones of Cr-Ni-steel joint. Butt welded joints were made using carbon dioxide laser with a maximum output of 5 kW in the continuous wave mode. The hardness and tensile tests of welded joints in the air and 3.5 vol.%-solution of NaCl, as well as the theoretical studies were carried out by optical and transmission electron microscopy (TEM). The results are achieved by testing that the welded joints of HNS had satisfactory weldability, adequately high mechanical and corrosion properties. The austenite of the investigated HNS retains high stability throughout the welding cycle.

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39

Sadowski, T., and P. Golewski. "Modelling and Experimental Testing of Hybrid Joints Made of: Aluminium Adherends, Adhesive Layers and Rivets for Aerospace Applications." Archives of Metallurgy and Materials 62, no. 3 (September 26, 2017): 1577–83. http://dx.doi.org/10.1515/amm-2017-0241.

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AbstractThe contemporary demands in different branches of engineering require application of new multi-component materials and structural systems. Appropriately chosen joining technology can offer significant enhancement of structural system performance in terms of effectiveness, reliability, safety and other design criteria. The modern applications of complex joints are of great technological interest as they permit to combine and to enhance the individual effects of each kind of joint. This is of great importance for modern applications in different branches of engineering: aerospace, mechanical and civil. Therefore in this paper we will focus on the analysis of mechanical response of adhesive joint of aluminium strips reinforced by rivets. The aim of the paper is to investigate experimentally the mechanical behaviour of adhesive joint of aluminium strips reinforced by rivets for industrial applications in aerospace. The considered joint was subjected to uniaxial loading. The tests in this paper were performed for: • classical adhesive joint in order to investigate material parameters for numerical modelling of the hybrid joint • hybrid joining of the structural elements in order to investigate the reinforcement effect. The experiments with application of digital image ARAMIS system allowed for on-line monitoring of the deformation process of the considered joining elements. The particular distributions of displacement fields at the joint surface were estimated for any stage of loading process. Numerical modelling was performed for experimentally investigated specimens. The materials parameters, necessary for calculation, were estimated from experiments. FEA modelling was done with the help of ABAQUS code.

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40

Megget, Leslie M. "The seismic behaviour of small reinforced concrete beam-column knee joints." Bulletin of the New Zealand Society for Earthquake Engineering 31, no. 4 (December 31, 1998): 215–45. http://dx.doi.org/10.5459/bnzsee.31.4.215-245.

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The majority of research into beam-column knee joints has been conducted with monotonic loading. Many of these joints failed to reach their member moment capacity, especially under opening moments, while a few cyclic knee joint tests have been completed in the United States this decade. This paper describes the cyclic testing of 8 small knee joints designed to the 1995 New Zealand Concrete Standard. In addition two joints designed and detailed to the 1965 N.Z. Concrete Code were also tested. Joints with U-bar anchorages performed better than joints with standard 90 degree hook details on beam and column bars. The current Concrete Standard (NZS3101:1995) designs usually attained their nominal moment capacity in both directions up to and including ductility 4 displacements, but subsequently strengths fell off at higher ductilities. Joints with extra diagonal bars across the inner comer were able to sustain their nominal member strengths to higher ductility levels, especially under opening moments. A maximum horizontal joint shear stress of 0.12 f’c, for knee joints, in ductile frame buildings is recommended, where this limit is 60% of the current NZS3101:1995 Standard recommendation. An approximate 25% degradation of the joint shear stress occurred as displacement ductility factors increased from 1 to 8. The 1960's designed joints behaved poorly, as expected, with joint shear and anchorage failures occurring, in both moment directions, at strength levels below the beam's nominal strength. A maximum joint shear stress of only 0.072 f’c was reached and this fell to about a third of that stress between displacement ductility factors of 1 and 4 under closing moments.

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41

Zhao, Jack Q., Lyne Daigle, and Denis Beaulieu. "Effect of joint contamination on the quality of butt-fused high-density polyethylene (HDPE) pipe joints." Canadian Journal of Civil Engineering 29, no. 5 (October 1, 2002): 787–98. http://dx.doi.org/10.1139/l02-078.

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Butt fusion is an effective method for joining high-density polyethylene (HDPE) pipe on job sites. However, there is lack of quantitative methods to evaluate pipe joint quality. The objective of this study was to develop such a quantitative approach to determine the effect of joint contamination on the quality of the fused joints. The study included testing a total of 21 butt-fused HDPE pipe joints that were made under different dust conditions. The results of the tests were then used to determine the effect of dust contamination on the quality of the fused joints. Microscopic examination of the fracture surfaces of the test specimens showed that not all the contaminants at the welding interface were squeezed out into the beads formed during the fusion process. Four failure modes were identified and a failure criterion was established to categorize the quality of a fused joint into four grades: bad, poor, good, and excellent. Among the properties of the materials considered, tensile energy to break (TEB) and maximum strain were found to be the most acceptable parameters for distinguishing between joints of different quality. Furthermore, the results showed that under optimum joining conditions, the quality of butt-fused joints can be as good as that of the parent pipe.Key words: polyethylene pipe, butt fusion, joint contamination, tensile energy to break, failure criterion.

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42

Bramel, Brian K., Charles W. Dolan, Jay A. Puckett, and Khaled Ksaibati. "Asphalt Plug Joints: Refined Material Tests and Design Guidelines." Transportation Research Record: Journal of the Transportation Research Board 1740, no. 1 (January 2000): 126–34. http://dx.doi.org/10.3141/1740-16.

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Highway builders and rehabilitators throughout the United States use asphalt plug joints (APJs) in bridge expansion joints according to manufacturers’ recommendations. Joint performance varies widely, as indicated in recent surveys. State departments of transportation are installing joints in unsuitable sites or are overlooking other sites where APJs may work well. Rational design guidelines for APJs have been developed. The research suggests suitable applications, material characterization, design guidelines, and validation procedures. Two critical material properties are required to qualify APJ material: relaxation and glass-transition temperature. Both properties may be obtained by using a slight modification of the AASHTO standard thermal specimen, restrained specimen asphalt test. This modified standard test was conducted, and the results were compared with those of the near-full-scale test. Design guidelines are based on field observations, material tests, near-full-scale testing, analytical evaluations, and a survey of the experiences of state departments of transportation. Design recommendations are provided, and joint design changes are proposed to help mitigate the present shortcomings.

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43

Machado, JJM, EAS Marques, and LFM da Silva. "Mechanical behaviour of adhesively bonded composite single lap joints under quasi-static and impact conditions with variation of temperature and overlap." Journal of Composite Materials 52, no. 26 (March 29, 2018): 3621–35. http://dx.doi.org/10.1177/0021998318766641.

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The use of adhesively bonded joints in structural components for the automotive industry has significantly increased over the last years, supported by the widespread integration of composite materials. This synergy allows vehicle manufacturers to offer a significant weight reduction of the vehicle allowing for fuel and emissions reduction and, at the same time, providing high mechanical strength. However, to ensure vehicle safety, the crashworthiness of these adhesive joints must be assessed, to evaluate if the structures can sustain large impact loads, transmitting the load and absorbing the energy, without damaging the joint. The novelty of this work is the study of the strain rate dependent behaviour of unidirectional composite adhesive joints bonded with a ductile epoxy crash resistant adhesive, subjected to low and high testing temperatures and using different overlap lengths. It was demonstrated that joints manufactured with this type of adhesive and composite substrates can exhibit excellent quasi-static and impact performance for the full range of temperatures tested. Increasing the overlap length, and independently of the testing temperature, it was observed an increase of energy absorbed for both quasi-static and impact loads, this is of considerable importance for the automotive industry, demonstrating that composite joints exhibit higher performance under impact.

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44

Lach, R., Pavel Hutař, P. Vesely, E. Nezbedova, Zdeněk Knésl, and W. Grellmann. "Structural Changes, Evolution of Damage Parameters and Crack Propagation Behaviour in Welded Plastic Pipes." Key Engineering Materials 465 (January 2011): 427–30. http://dx.doi.org/10.4028/www.scientific.net/kem.465.427.

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The microstructure as well as the local mechanical and fracture behaviour of welded joints in plastic pipes made form polyethylene and material zones outside of the welded joints have been analysed using recording microhardness testing, laser extensometry and crack resistance curve tests. In has been found that the mechanical basic properties and damage kinetics are clearly depending on the welding parameters and additional notching.

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45

COMAN, Calin-Dumitru, Ion DIMA, Stefan HOTHAZIE, George PELIN, and Tiberiu SALAORU. "Temperature Effects on Damage Mechanisms of Hybrid Metal – Composite Bolted Joints Using SHM Testing Method." INCAS BULLETIN 11, no. 1 (March 5, 2019): 61–67. http://dx.doi.org/10.13111/2066-8201.2019.11.1.5.

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This paper presents the quasi-static thermo-mechanical loading effects on the progressive damage mechanisms and failure modes of the single-bolt, single-shear, hybrid metal-composite, bolted joints in aerospace applications. A three-dimensional finite element method (FEM) technique was used to model the countersunk head bolted joint in details, including geometric and frictional based contact full nonlinearities and using commercial software PATRAN as pre/post-processor. The progressive damage analysis (PDA) in laminated (CFRP/ vinyl ester epoxy) composite material including nonlinear shear behavior, Hashin-type failure criteria and strain-based continuous degradation rules for different values of temperatures was made using SOL 400 NASTRAN solver. In order to validate the numerical results and close investigation of the fracture mechanisms for metal-composite bolted joints by determining ultimate failure loads, experiments were conducted in temperature controlled chamber using SHM (Structural Health Monitoring) technique. The results show that the thermal effects are not negligible on failure mechanism in hybrid aluminum-CFRP bolted joints having strong different thermal expansion coefficients. The complex 3D FEM model using advanced linear continuum solid-shell elements proved computational efficiency and ability to accurately predict the various failure modes as bearing and shear-shear out, including the temperature effects on the failure propagation and damage mechanism of hybrid metal-composite bolted joints.

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46

Li, Zhenbao, Yanwei Cui, Kun Song, Hua Ma, and Zhenyun Tang. "The shearing performance of a beam-column joint in a reinforced concrete frame subjected to bidirectional loading." Advances in Structural Engineering 22, no. 15 (June 28, 2019): 3176–89. http://dx.doi.org/10.1177/1369433219859475.

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The anti-seismic capability of beam-column joints in reinforced concrete frame structures undergoing bidirectional loading may be lower than the designed capability for unidirectional earthquake action. To date, detailed calculation methods for the shear capability and shearing performance for joints in reinforced concrete frames subjected to bidirectional loading have not been reported. In this work, the shear mechanism of the beam-column joint in a reinforced concrete frame under bidirectional loading is analyzed. The study shows that when a synthetic shear force is imposed on the joint, the oblique compression zone comes into being at the corner of the joint, and the oblique compression strut is formed in the core area of the joint, which is different from the shear mechanism of the joint under unidirectional loading. A shear capacity calculation model is established based on the strut-and-tie model. Through the testing of reinforced concrete frame joints under bidirectional monotonous loading, the combined shear and deformation in the joint are obtained, the mechanical properties in each principal plane and in the combined shear action plane are analyzed, the shearing performance of the joints in a reinforced concrete frame under bidirectional loading is defined, and the shear contributions of hoop and column reinforcement are verified. The predicted values of the shear capability in this work are in good agreement with the reported experimental results.

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47

Schroeder, J. A., T. Ahmed, B. Chaudhry, and S. Shepard. "Non-destructive testing of structural composites and adhesively bonded composite joints: pulsed thermography." Composites Part A: Applied Science and Manufacturing 33, no. 11 (November 2002): 1511–17. http://dx.doi.org/10.1016/s1359-835x(02)00139-2.

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48

Mitaľ, Dušan, Peter Michalik, Jozef Zivčak, Andrej Czan, Dana Stanceková, Svetlana Radchenko, and Jaroslav Vybostek. "Study the Quality of Welded Joints of Steel S235." Applied Mechanics and Materials 718 (December 2014): 88–92. http://dx.doi.org/10.4028/www.scientific.net/amm.718.88.

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Presented article is focused on welding of structural steel using coated electrode. Weld can be defines as a permanent join of two or more materials. Welder unit was Inventor 140 GC, where was weld 6 samples with different parameters of welding. Samples were tested by non-destructive methods such as visual control, capillary method and ultrasound method. Detection of defects in microstructures was made by destructive method – metallographic method. Testing of quality provide the most suitable welding parameters for welding constructions from structural steel S 235.

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49

Zhang, Zhaoqiang, Yanru Sa, Yong Yao, and Junhai Zhao. "Seismic Performance of Exterior Steel Ring-Stiffener Joint." Advances in Civil Engineering 2019 (November 7, 2019): 1–22. http://dx.doi.org/10.1155/2019/8107103.

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We study the seismic performance of the exterior steel ring-stiffener (ESRS) joint, a member that is used to connect a steel beam to a square steel tubular column filled with steel fibre recycled concrete for seismic resistance. To this end, the influence of seismic factors such as axial compression ratio and beam-column linear stiffness ratio on seven specimens is studied. A physical test is conducted on the specimens with a series of cyclic loadings. The testing and analysis of hysteretic loops and skeleton curves of the ESRS joints revealed the seismic performance characteristics including failure mode, rigidity, ductility, bearing-capacity degradation, and energy dissipation capacity. The results reveal (a) damage to the specimens at the beam-end near the joint, (b) no failure at the joints’ core area and column, (c) appearance of a plastic hinge at the beam-end near the joint, and (d) plump spindle-shaped hysteretic loops and normal rigidity degradation curves in the specimens. The specimens are then simulated with the finite element method (FEM) and the results are compared with those of the physical test.

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50

Hussain, Sida, Hamna Shakeel, Asif Ali, Muhammad Rizwan, and Naveed Ahmad. "Shaking Table Testing of a Low-Rise Reinforced Concrete Intermediate Moment Resisting Frame." Buildings 12, no. 12 (December 1, 2022): 2104. http://dx.doi.org/10.3390/buildings12122104.

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Анотація:

Multi-level shaking table tests were performed on a 1:3 reduced scale two-story reinforced concrete (RC) intermediate moment resisting frame (IMRF) conforming to the requirements given in the ACI-318-19. The exterior joints lacked shear reinforcement to assess the viability of the ACI model recommended for determining the design shear strength of the beam–column joint panel. One of the horizontal components of the 1994 Northridge earthquake accelerogram (090 CDMG Station 24278, Source: PEER strong motion database) was input to the frame for multi-level shaking table testing. Plastic hinges developed in beams under base input motion with a maximum acceleration equal to 0.40 g. The exterior joints incurred extensive damage under base input motion with a maximum acceleration equal to 0.70 g. The frame achieved displacement ductility and overstrength factors (determined as the ratio of the maximum resistance of the frame to the design base share force) equal to 2.40 and 2.50, respectively. This gives a response modification factor equal to 6. The satisfactory performance of the frame is attributed to the high efficiency of the beam–column joint, which was confined by spandrel beams on two faces and the high strength of the concrete. The inherent minimal confinement is sufficient to ensure satisfactory seismic behavior. The analysis confirmed overstrength equal to 1.58 for joint shear strength in comparison to the design strength determined using the ACI model. The data might serve as a reference for calibrating and validating numerical modeling techniques for performance evaluation, which are crucial in the context of performance-based engineering.

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