Cyclic Behavior Research Articles

Water vapor corrosion and cyclic oxidation behavior of SiCf/SiC coated with Si/YbDS-YbMS/YbMS/LMA coating

Water vapor corrosion and cyclic oxidation behavior of SiCf/SiC coated with Si/YbDS-YbMS/YbMS/LMA coating

Microstructure evolution and cyclic thermal behavior of Ta‒10W cladded onto the inner surface of steel tube by explosive welding

Microstructure evolution and cyclic thermal behavior of Ta‒10W cladded onto the inner surface of steel tube by explosive welding

Cyclic load behavior of PC and CIP interior beam-column connections in moment resisting frames

Cyclic load behavior of PC and CIP interior beam-column connections in moment resisting frames

Cyclic pseudoelastic behavior of friction stir processed NiTi shape memory alloy: Microstructure and W-alloying

Cyclic pseudoelastic behavior of friction stir processed NiTi shape memory alloy: Microstructure and W-alloying

Cyclic mechanical behaviours of polydimethylsiloxane / multi-walled carbon nanotube micro-composites sensor: Effects of strain range and strain rate

Cyclic mechanical behaviours of polydimethylsiloxane / multi-walled carbon nanotube micro-composites sensor: Effects of strain range and strain rate

Impact of plane strain state on the long-term cyclic behavior of sand under true triaxial tests

Impact of plane strain state on the long-term cyclic behavior of sand under true triaxial tests

Experimental and numerical investigation on cyclic behavior of high-strength steel (HSS) H-section columns

Experimental and numerical investigation on cyclic behavior of high-strength steel (HSS) H-section columns

Inelastic cyclic behaviour of steel tubes infilled with rubberised alkali-activated concrete

Inelastic cyclic behaviour of steel tubes infilled with rubberised alkali-activated concrete

Predictive Equations for Modeling Shear Behavior in RC Columns with Non-Seismic Details for Enhanced Seismic Performance Assessment

Accurate modeling of the hysteretic behavior of reinforced concrete columns with non-seismic detailing is crucial for assessing the seismic performance of reinforced concrete structures. While shear spring models are commonly used to capture nonlinear shear deformation in shear-critical reinforced concrete columns, determining appropriate parameters for these models remains challenging and often relies on expert judgment. This study proposes predictive equations for shear spring parameters that can be integrated into fiber-section elements to enhance the accuracy of modeling reinforced concrete columns. Specifically, empirical equations are developed for the nonlinear modeling parameters of the Pinching4 model implemented in OpenSees. Experimental data of flexural–shear and shear-critical reinforced concrete columns are used to calibrate the modeling parameters for predicting strength, stiffness, pinching, and cyclic degradation behavior. The predictive equations, derived through regression analysis, are validated against experimental data and demonstrated relatively high accuracy in capturing the shear behavior. To evaluate the impact of the shear behavior of reinforced concrete columns on the seismic fragility of non-conforming reinforced concrete frames, two types of numerical models are established with and without the Pinching4 material using the proposed predictive equations. Analytical results indicate that neglecting the appropriate shear behavior of reinforced concrete columns could lead to an overestimation of the seismic performance of non-conforming reinforced concrete frames.

Three New Multifunctional Supramolecular Compounds Based on Keggin-Type Polyoxoanions and 3,5-di(1H-Imidazol-1-yl)benzoic Acid: Syntheses, Structures, and Properties

Three new inorganic-organic hybrid compounds, (H3DIBA)2·SiMo12O40·H2O (1), (H3DIBA)2·SiW12O40·H2O (2), and [(H2DIBA)(H3DIBA)]·PMo12O40·2H2O (3) (HDIBA = 3,5-di(1H-imidazol-1-yl)benzoic acid) were synthesized by the hydrothermal method. The structures were characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. These three compounds are all 3D supramolecular structures formed by Keggin-type polyoxometalate anions and HDIBA through intermolecular weak interactions, which have been studied via Hirshfeld surface analysis. The electrochemistry properties of 1 and 3 have been studied, including cyclic voltammetric behaviors and electrocatalytic properties. The study on the removal of organic dye pollutants in water showed that compounds 1 and 3 had an adsorption effect on cationic dye RhB, and the adsorption process conforms to the Langmuir isotherm model. Compound 2 can photocatalytically degrade cationic organic dyes RhB, MB, and CV, and the photocatalytic mechanism study indicates that h+ plays a major role in the photocatalytic process.

Mechanical and Microstructural Behavior of Cemented Paste Backfill Under Cyclic Loading

Understanding the mechanical and physical behavior of aged CPB under cyclic loading is a significant area of research. Many parameters such as cementation (hydration) and the microstructure, which dictate the arrangement of particles and permeability, affect the mechanical features of cemented paste backfill (CPB). The impact of a wide range of external energy sources within the mining environment, such as cyclic loading resulting from long-term blasting, can significantly alter the applied stresses on the backfill mass. This paper aims to delve into this crucial area of research. A series of uniaxial cyclic tests were conducted on CPB, utilizing samples made from tailing materials sourced from a copper mine in South Australia. Different loading levels were applied at various curing times. All samples exhibited cyclic loading hardening behavior for cyclic loading levels between 80% and 93% of monotonic unconfined compressive strength (UCS), and a cyclic loading damage behavior was observed for 96% of UCS loading level for both 14- and 28-day curing periods. To further investigate these findings, scanning electron microscope analysis as well as sonic velocity tests were conducted for capturing microstructural changes in the samples before and after tests. These findings can be used to indicate a safe firing distance to a filled mass.

Isothermal low-cycle fatigue and fatigue-creep of Alloy 709 using an unified viscoplasticity modelling

An improved unified viscoplastic model (UVM) is proposed to simulate the cyclic viscoplastic behaviors of Alloy 709 under low-cycle fatigue (LCF) and creep fatigue interaction (CFI) loadings. And the effects of strain amplitudes and hold times on the model parameters as well as the relationship between the static recovery parameter and the accumulated inelastic strain are considered to reflect the evolutionary behavior of strain-stress hysteresis loops, the varying stress relaxation and cyclic hardening behavior. Moreover, an efficient numerical implementation is proposed using Voigt notation and implicit radial return method with Newton-Raphson iteration, and the consistent tangent operator (CTO) for the improved UVM can be simply solved using matrix operations. The proposed model accurately depicts the mechanical behavior of Alloy 709 at 750°C.

Microstructure and Thermal Cyclic Behavior of FeNiCoAlTaB High-Entropy Alloy.

This study investigates the grain morphology, microstructure, magnetic properties and shape memory properties of an Fe41.265Ni28.2Co17Al11Ta2.5B0.04 (at%) high-entropy alloy (HEA) cold-rolled to 98%. The EBSD results show that the texture intensities of the samples annealed at 1300 °C for 0.5 or 1 h are 2.45 and 2.82, respectively. This indicates that both samples were formed without any strong texture. The grain morphology results show that the grain size increased from 356.8 to 504.6 μm when the annealing time was increased from 0.5 to 1 h. The large grain size improved the recoverable strain due to a reduction in the grain constraint. As a result, annealing was carried out at 1300 °C/1 h for the remainder of the study. The hardness decreased at 24 h, then increased again at 48 h; this phenomenon was related to the austenite finish temperature. Thermo-magnetic analysis revealed that the austenite finish temperature increased when the samples were aged at 600 °C for between 12 and 24 h. When the aging time was prolonged to 48 h, the austenite finish temperature value decreased. X-ray diffraction (XRD) demonstrated that the peak of the precipitates emerged and intensified when the aging time was increased from 12 to 24 h at 600 °C. From the three-point bending shape memory test, the samples aged at 600 °C for 12 and 24 h had maximum recoverable strains of 2% and 3.6%, respectively. The stress-temperature slopes of the austenite finish temperature were 10.3 MPa/°C for 12 h and 6 MPa/°C for 24 h, respectively. Higher slope values correspond to lower recoverable strains.

Influence of Geometrical Features on the Cyclic Behavior of S-Shaped Steel Dampers Used in Sustainable Seismic Isolation: Experimental Insight with Numerical Validation

Influence of Geometrical Features on the Cyclic Behavior of S-Shaped Steel Dampers Used in Sustainable Seismic Isolation: Experimental Insight with Numerical Validation

Evaluation and Future Prospects of Data‐Driven Intelligence‐Based Framework for Predicting Cyclic Behavior of Reconstituted Sand

ABSTRACTMost of the robust artificial intelligence (AI)‐based constitutive models are developed with synthetic datasets generated from traditional constitutive models. Therefore, they fundamentally rely on the traditional constitutive models rather than laboratory test results. Also, their potential use within geotechnical engineering communities is limited due to the unavailability of datasets along with the model code files. In this study, the data‐driven constitutive models are developed using only laboratory test databases and deep learning (DL) techniques. The laboratory database was prepared by conducting cyclic direct simple shear (CDSS) tests on reconstituted sand, that is, PDX sand. The stacked long short‐term memory (LSTM) network and its variants are considered for developing the predictive models of the shear strain (γ [%]) and excess pore pressure ratio (ru) time histories. The suitable input parameters (IPs) are selected based on the physics behind the generation of ru and γ (%) of the liquefiable sands. The predicted responses of γ (%) and ru agree well in most cases and are used to predict the dynamic soil properties of the PDX sand. The same modeling framework is extended for other sand and compared with existing AI‐based constitutive models to verify its practical applicability. In summary, it is observed that though the trained models predicted the time histories of ru and γ reasonably well; however, they struggled to predict the hysteresis loops at higher cycles. Therefore, more research is needed to verify and enhance the predictability of existing AI‐based models in the future before using them in practice for simulating cyclic response.

An Investigation of Exchange Rate Volatility using Econometric Model: Evidence from Cambodia

The examination of foreign exchange dynamics was performed utilizing the Autoregressive Integrated Moving Average (ARIMA) model, which integrates both Autoregressive (AR) and Moving Average (MA) components. The analysis focused on the monthly exchange rate between the Khmer Riel and the US dollar, spanning from December 2018 to September 2024, to assess the variations in exchange rates. According to the results of the Augmented Dickey-Fuller (ADF) test, the foreign exchange data series was determined to be integrated of order zero, or I(0). The model identified as the most appropriate, based on the Akaike Information Criterion (AIC), was the ARIMA(3,0,3) model, which indicated the optimal lag lengths for this analysis. The reaction of the foreign exchange market to the disturbance shock revealed a cyclical behavior and demonstrated a downward trajectory over the 30-period forecast horizon. Importantly, the impulse response function (IRF) stayed within the 95% confidence interval, signifying that the response to the shock was statistically significant and remained within a tolerable level of uncertainty. This observation implies that the predictions generated by the model can be regarded as trustworthy.

Cyclic Behavior of Seismically Non-Conforming Interior Reinforced Concrete Beam–Column Joints

The cyclic behavior of reinforced concrete (RC) beam–column joints (BCJs) is still one of the critical issues in structural engineering. In this context, for the purpose of gaining a more in-depth insight about the sophisticated behavior of BCJs under cyclic loading scenarios, the current work aims to investigate the cyclic behavior of reinforced concrete beam–column joints. The cyclic behavior of four interior reinforced concrete beam–column joints, with plain and deformed bars, which are representative of the seismically non-conforming structures from the 1970s, were experimentally investigated. The corresponding results of the specimens were compared with each other to better understand and highlight the differences between the force–drift curves and envelopes and damage patterns of each of the specimens. Furthermore, a numerical validation of the laboratory testing results was established with the DIANA FEA code for both monotonic and cyclic loading scenarios, and the force–displacement plots were compared with the associated laboratory results for validation purposes. The crack propagation and final damage states of the numerical models of beam–column joints are presented and discussed in detail. The results showed good agreement between the numerical and experimental behavior, and a graphical representation of the critical regions affected by damages was also shown, which could ultimately contribute to future retrofitting solutions for strengthening the BCJ region in existing RC structures.

Modeling precaution, immunity loss and dispersal on disease dynamics: a two-patch SIRS model

An SIRS model is developed to account for precautionary measures and immunity loss. The existence and stability of equilibria are studied. It is shown that precautionary measures can induce Hopf bifurcations leading to the occurrence of cyclical behavior. The model is then extended to a two-patch scenario to explore how disease spread patterns are influenced by dispersal (travel). Theoretical analyses establish the stability of the disease-free equilibrium, the basic reproduction number, and thresholds related to travel rates. The persistence of the system, as well as the existence of boundary and endemic equilibria, are also discussed. Using Hopf bifurcation theory, we further examine the interaction between nonlinear incidence functions, travel rates, and precaution delay effects in shaping the stability of the endemic equilibrium. The findings reveal a strong connection between reduced infection rates due to precaution and the emergence of Hopf bifurcations, emphasizing the importance of timely and accurate disease information in curbing the spread of diseases. Additionally, the study highlights the significant impact of different infection force functions on equilibrium stability, underscoring the critical role of precautionary measures in disease transmission mechanisms. The results also show the diverse effects of travel rates on disease spread, suggesting that restricting travel may not always lead to favorable outcomes. This underscores the necessity for governments to consider multiple factors comprehensively in their efforts to prevent and control diseases.

Cyclic Combined Bending-Torsion Behaviour of Reinforced Concrete-Filled Thin-Walled Corrugated Steel Tubes

Cyclic Combined Bending-Torsion Behaviour of Reinforced Concrete-Filled Thin-Walled Corrugated Steel Tubes

Influence of sintering process on high temperature cyclic deformation behavior and fatigue creep damage mechanism of sintered silver

Influence of sintering process on high temperature cyclic deformation behavior and fatigue creep damage mechanism of sintered silver