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This paper investigates the integration of Structural Health Monitoring (SHM) within the frame of Industry 4.0 (I4.0) technologies, highlighting the potential for intelligent infrastructure management through the utilization of big data analytics, machine learning (ML), and the Internet of Things (IoT). This study presents a success case focused on a novel SHM methodology for detecting and locating damages in metallic aircraft structures, employing dimensional reduction techniques such as Principal Component Analysis (PCA). By analyzing strain data collected from a network of sensors and comparing it to a baseline pristine condition, the methodology aims to identify subtle changes in local strain distribution indicative of damage. Through extensive Finite Element Analysis (FEA) simulations and a PCA contribution analysis, the research explores the influence of various factors on damage detection, including sensor placement, noise levels, and damage size and type. The findings demonstrate the effectiveness of the proposed methodology in detecting cracks and holes as small as 2 mm in length, showcasing the potential for early damage identification and targeted interventions in diverse sectors such as aerospace, civil engineering, and manufacturing. Ultimately, this paper underscores the synergistic relationship between SHM and I4.0, paving the way for a future of intelligent, resilient, and sustainable infrastructure. [ABSTRACT FROM AUTHOR]

The paper introduces a geometrically unfitted finite element method for the numerical solution of the tangential Navier–Stokes equations posed on a passively evolving smooth closed surface embedded in \mathbb {R}^3. The discrete formulation employs finite difference and finite elements methods to handle evolution in time and variation in space, respectively. A complete numerical analysis of the method is presented, including stability, optimal order convergence, and quantification of the geometric errors. Results of numerical experiments are also provided. [ABSTRACT FROM AUTHOR]

This paper presents a design, model, and comparative analysis of two internal MEMS vibrating ring gyroscopes for harsh environmental conditions. The proposed design investigates the symmetric structure of the vibrating ring gyroscopes that operate at the identical shape of wine glass mode resonance frequencies for both driving and sensing purposes. This approach improves the gyroscope's sensitivity and precision in rotational motion. The analysis starts with an investigation of the dynamic behaviour of the vibrating ring gyroscope with the detailed derivation of motion equations. The design geometry, meshing technology, and simulation results were comprehensively evaluated on two internal vibrating ring gyroscopes. The two designs are distinguished by their support spring configurations and internal ring structures. Design I consists of eight semicircular support springs and Design II consists of sixteen semicircular support springs. These designs were modelled and analyzed using finite element analysis (FEA) in Ansys 2023 R1 software. This paper further evaluates static and dynamic performance, emphasizing mode matching and temperature stability. The results reveal that Design II, with additional support springs, offers better mode matching, higher resonance frequencies, and better thermal stability compared to Design I. Additionally, electrostatic, modal, and harmonic analyses highlight the gyroscope's behaviour under varying DC voltages and environmental conditions. Furthermore, this study investigates the impact of temperature fluctuations on performance, demonstrating the robustness of the designs within a temperature range from −100 °C to 100 °C. These research findings suggest that the internal vibrating ring gyroscopes are highly suitable for harsh conditions such as high temperature and space applications. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive finite element analysis (FEA) of pre-stressed Ultra High-Performance Concrete (UHPC) girders, showcasing intricate structural behaviors under various loading conditions. Utilizing advanced finite element modeling techniques, the study accurately simulates the flexural response of UHPC girders, integrating experimental results from large-scale laboratory tests conducted by researchers at the Turner-Fairbank Highway Research Center. This paper shows the effectiveness of simulating pre-stressing forces via initial equivalent temperature load with relatively accurate stress and strain predictions. The paper also delves into the moment–deflection relationships at critical stages, such as first concrete crack appearance, yielding, and strain localization, to capture the non-linear behavior of UHPC girders under pre-stressed conditions. Additionally, crack propagations were characterized by investigating the damage in tension (DAMAGET) plots. In summary, the results of the finite element model agree well with the experimental observations. Moreover, this study not only demonstrates the effectiveness of FEA in accurately simulating the complex structural behaviors of UHPC girders but also highlights its broader applicability to the design and analysis of other girder types, offering valuable insights compared to ordinary concrete beams. [ABSTRACT FROM AUTHOR]

The PWM voltage pulses output by the inverter reaches the stator winding of the wind turbine generator through the cable. Due to the impedance mismatch between the motor and the cable, the voltage at the motor end rises under the action of the circuit wave process; on the other hand, electromagnetic oscillation occurs within the motor winding. Higher overvoltage is generated under the combined effect of both, which greatly accelerates the aging and breakdown of the insulation layer of the permanent magnet synchronous wind turbine. In this paper, a three-dimensional electromagnetic model of the permanent magnet synchronous wind turbine generator is established. The distribution circuit parameters of the stator winding of the permanent magnet machine are calculated using the finite element method, and its circuit model is based. The voltage distribution of the stator winding under different PWM excitations is investigated by simulation software, and the effects of the time of the rising edge and the pulse width of the PWM pulse on the stator winding voltage to ground and the turn-to-turn voltage distribution are studied. The results show that the effect of the rising edge time is larger when the rising edge time is shorter, the maximum voltage to ground occurs in the first coil, and the amplitude can be up to 1.5 times of the output voltage. When the rising edge time is longer, the maximum voltage to ground occurs in the end coil, and the amplitude is slightly higher than the output voltage. The trend of turn-to-turn voltage variation is similar for different rising edges; only the maximum turn-to-turn voltage amplitude is different. Pulse width has a small effect on overvoltage and only occurs when the pulse width is less than 10 μs. The research results of this paper are of great significance in revealing the aging and breakdown mechanism of the generator stator insulation, as well as the insulation coordination and design. [ABSTRACT FROM AUTHOR]

Segmentally assembled bridges are increasingly finding engineering applications in recent years due to their unique advantages, especially as urban viaducts. Vehicle loads are one of the most important variable loads acting on bridge structures. Accordingly, the influence of overloaded vehicles on existing assembled bridge structures is an urgent concern at present. This paper establishes the finite element model of the segmentally assembled bridge based on ABAQUS software and analyzes the influence of vehicle overload on an assembled girder bridge structure. First, a finite element model corresponding to the target bridge is established based on ABAQUS software, and the load is controlled to simulate vehicle movement in each area of the traveling zone at different times. Second, the key cross-sections of segmental girder bridges are monitored in real time based on the force characteristics of continuous girder bridges, and they are compared with the simulation results. Finally, a material damage ontology model is introduced, and the structural damage caused by different overloading rates is compared and analyzed. Results show that the finite element modeling method is accurate by comparing with on-site measured data, and it is suitable for the numerical simulation of segmental girder bridges; Dynamic sensors installed at 1/4L, 1/2L, and 3/4L of the segmental girder main beams could be used to identify the dynamic response of segmental girder bridges; The bottom plate of the segmental girder bridge is mostly damaged at the position where the length of the precast beam section changes and the midspan position. With the increase in load, damage in the direction of the bridge develops faster than that in the direction of the transverse bridge. The findings of this study can guide maintenance departments in the management and maintenance of bridges and vehicles. [ABSTRACT FROM AUTHOR]

The bottom platform is an important underwater sensor that can be used in communications, early warning, monitoring, and other fields. It may be affected by earthquakes, winds, waves, and other loads in the working environment, causing changes in posture and affecting its sensing function. Therefore, it is of practical engineering significance to analyze the force conditions and posture changes in the bottom platform. In order to solve the problem of postural stability of the underwater bottom platform, this paper establishes a fluid and structural simulation model of the underwater bottom platform. First, computational fluid dynamics (CFD) technology is used to solve the velocity distribution and forces in the watershed around the bottom platform under a 3 kn ocean current, where the finite element method (FEM) numerical calculation method is used to solve the initial equilibrium state of the bottom platform after it is buried. On this basis, this paper calculates the forces on the bottom platform and the posture of the bottom platform at different burial depths under the action of ocean currents. Additionally, the effects of different burial depths on the maximum displacement, deflection angle, and postural stability of the bottom platform are studied. The calculation results show that when the burial depth is greater than 0.6 m, and the deflection angle of the bottom platform under the action of the 3 kn sea current is less than 5°, the bottom platform can maintain a stable posture. This paper could be used to characterize the postural stability of underwater bottom platforms at different burial depths for the application of underwater sensors in ocean engineering. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to comprehensively explore techniques for reducing solution time in finite element analysis (FEA), addressing the critical need for expediting computations to facilitate agile design exploration within project timelines. Design/methodology/approach: Drawing from a wide array of literature sources, this paper synthesizes and analyzes various methodologies used to enhance the efficiency of FEA. Techniques are scrutinized in terms of their applicability, effectiveness and potential limitations. Findings: The review signifies application of linear assumptions across multiple facets of analysis and delves into matrix order reduction strategies, geometry simplification, symmetry exploitation, submodeling and mesh attribute control. It reveals how these techniques can effectively reduce computational burdens while maintaining acceptable levels of accuracy. Research limitations/implications: While this review provides a comprehensive overview of existing efficiency enhancement techniques in FEA, it acknowledges inherent limitations of any synthesis-based study. Future research should focus on refining these methodologies. Practical implications: The insights provided in this paper offer practical guidance for structural engineers and researchers seeking to optimize FEA workflows. By implementing these techniques, practitioners can expedite solution times and enhance their ability to explore design alternatives efficiently ultimately leading to cost savings and more robust structures. Originality/value: This review contributes to the existing literature by offering a comprehensive synthesis of efficiency enhancement techniques in FEA. By highlighting the originality and value of each discussed methodology, this paper provides a roadmap for future research and practical implementation in the field of structural engineering. [ABSTRACT FROM AUTHOR]

Marine platforms are located in complex environments, and safety deteriorates throughout the day. It is necessary to analyze the jacket platform structure by the finite element method. Problems such as platform structure variation and fatigue corrosion lead to model deviation. In this paper, a finite element model correction method based on deep learning is proposed with a jacket platform as the engineering background. First, different platform design parameters are selected, and the corresponding fundamental frequencies are obtained by finite element simulation. Second, the input features are extended as necessary to increase the damage-sensitive information, with the nonlinear differences between the two reduced by an improved ResNet50 network. Finally, the correction values of the finite element model are obtained by combining the measured data with the inherent structural frequencies obtained by covariance-driven stochastic subspace identification (Cov-SSI). The results show that the error after correction is less than 4%, which can reflect the real marine platform state well. [ABSTRACT FROM AUTHOR]

Kalman filter has emerged as a powerful tool for unbalance identification in rotating machinery. Recently, the augmented Kalman filter combined with the finite element model has grown up and projects its potential for complex rotor systems. This paper investigates the application of the augmented Kalman filter (AKF) to a practical turbofan engine. The current study reveals that using steady-state responses as measurements can cause fluctuation in the estimated results, even divergence for some cases, while the available signals in practice are steady-state responses generally. To the authors' knowledge, this practical problem is revealed for the first time. To address the problem, the convergence criterion is employed to improve the AKF and formulates the adaptive fading augmented Kalman filter (AFAKF) proposed in this paper. Results indicate that the increase of the amplification factor, the insufficient measurement points, and the complexity of the dynamic model can all lead to the deterioration of the estimated unbalance. The proposed AFAKF method shows favorable convergence and can achieve accurate estimation with less than 5% relative errors, and the superiority over AKF in computation cost is also observed. [ABSTRACT FROM AUTHOR]

With the rapid expansion of offshore wind capacity worldwide, minimising operation and maintenance requirements is pivotal. Regarded as a low-maintenance alternative to conventional drivetrain systems, direct-drive generators are increasingly commonplace for wind turbines in hard-to-service areas. To facilitate higher torque requirements consequent to low-speed operation, these machines are bulky, greatly increasing nacelle size and mass over their counterparts. This paper therefore details the structural optimisation of the International Energy Agency 15 MW Reference Wind Turbine rotor through iterative Parameter and Topology Optimisation and the inclusion of additional structural members, with consideration to its mechanical, modal, and thermal performances. With temperature found to have a significant impact on the structural integrity of multi-megawatt direct-drive machines, a Computational Fluid Dynamics analysis was carried out to map the temperature of the structure during operation and inform a consequent Finite Element Method analysis. This process, novel to this paper, found that topologically optimised structures outperform parametrically optimised structures thermally and that integrated heatsinks can be employed to further reduce deformation. Lastly, generative design techniques were used to further optimise the structure, reducing its mass, deformation, and maximum stress and expanding its operating envelope. This study reaches several key conclusions, demonstrating that significant mass reductions are achievable through the removal of cylinder wall geometry areas as well as through the implementation of structural supports and iterative parametric and topology optimisation techniques. Through the flexibility it grants, generative design was found to be a powerful tool, delivering further improvements to an already efficient, yet complex design. Heatsinks were found to lower generator structural temperatures, which may yield lower active cooling requirements whilst providing structural support. Lastly, the link between the increased mass and the increased financial and environmental impact of the rotor was confirmed. [ABSTRACT FROM AUTHOR]

Wire ropes are widely observed in many industries such as marine engineering and civil engineering, as a type of structure that can bear huge axial force. There are various kinds of wire ropes in practical engineering, corresponding to different usage scenarios. This paper focuses on 6 × 36SW + 1WR with a diameter of 16 mm. The axial mechanical properties of the wire rope are investigated by experimental, theoretical, and numerical methods. The stress–strain curve and ultimate strength of the steel wire rope obtained in the test are compared with the corresponding results from the finite element simulation. The comparison demonstrates the accuracy and reliability of the finite element model. In addition, a series of parametric studies are conducted to investigate the influence of pitch length and friction coefficient, etc. The purpose of this paper is to propose an accurate and efficient finite element model for the mechanical analysis of wire ropes. [ABSTRACT FROM AUTHOR]

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The technology of plastic film mulching is widely applied in Xinjiang, but it also brings about serious issues of residual film pollution. Currently, the 1MSF-2.0 residual film recovery machine can effectively address the problem. However, it faces challenges such as high overall machine weight and noticeable frame vibrations, which affect the stability of the entire machine operation. The frame, as the installation foundation, needs to bear loads and impact. Therefore, the reliability of the frame is crucial for the stability of the entire machine. Improving the frame's vibration is of great importance. In response to the significant vibration issues during the operation of the 1MSF-2.0 residual film recovery machine, this paper utilized Workbench 2020 R2 to establish a finite element model of the machine frame and conducted static analysis to obtain strength information, thereby initially understanding the optimization space of the frame. Building upon this, Mechanical was employed to solve the first 14 natural frequencies and mode shapes of the frame, and the accuracy of the theoretical analysis was verified through modal testing. After analyzing the frequency characteristics of external excitation forces, it was found that the fourth-order natural frequency of the frame fell within the frequency range of the excitation force of the shaft of the straw grinder, causing resonance in the frame and necessitating structural optimization. The optimal results indicated that the optimized frame increased in mass by 4.41%, reduced the maximum stress value by 2.56 MPa, and increased the fourth-order natural frequency to 22.7 Hz, avoiding the frequency range of the excitation force of the shaft of the straw grinder, thus improving the resonance issue. This paper provides a reference for optimizing the design of the frame of the residual film recovery machine. [ABSTRACT FROM AUTHOR]

Reducing carbon emissions during belt grinding is of great significance for environmentally friendly production in the manufacturing industry. In this paper, in order to better grinding aero-engine titanium alloy blades with the abrasive belt, an improved NSGA-II multi-objective optimization algorithm was proposed, which reduced the carbon emissions during the grinding process while ensuring the same surface roughness and material removal rate. Firstly, through analysis and finite element simulation, the model of abrasive belt grinding force is established and the rationality of the model is verified by experiments; furthermore, the carbon emission model of abrasive belt grinding and the multi-objective optimization model based on the improved NSGA-II algorithm are established; finally, the results of the algorithm are verified and compared through numerical simulation and experiments. Compared with the NSGA-II algorithm and the multiple objective particle swarm optimization algorithm, the optimization results of the algorithm in this paper have better diversity and uniformity and can find better non-dominated optimal solutions; the process parameters selected by the algorithm in this paper can more effectively reduce the carbon emissions during grinding. The optimization method proposed in this paper has certain reference significance for engineering practice. [ABSTRACT FROM AUTHOR]

The steel liner plays a key role in ensuring the leak-tightness of nuclear containment structures (NCSs). Once the liner is subjected to corrosion, its corrosion effects can severely impact the leak-tight function of the NCS, especially in severe accident scenarios. Therefore, evaluating the corrosion effects of the liner is essential to guaranteeing the safe operation of nuclear power plants. This paper presents a probabilistic safety analysis of the NCS under liner corrosion conditions. Firstly, the corrosion mechanism of the liner is elucidated, and a refined simulation method is developed to investigate the localized corrosion effects of the liner. Utilizing a probabilistic finite element method, the fragility of the NCS under loss-of-coolant accident (LOCA) conditions is evaluated. Finally, the leakage risk of the NCS at different degrees of liner corrosion is discussed. The results indicate that liner corrosion has a significant impact on the median pressure capacity and high-confidence–low-probability pressure capacity of the NCS. With the aggravation of liner corrosion, the safety margin of the NCS decreases, and the total probability of failure increases. Within the scope of this paper, the NCS can fulfill the probabilistic safety requirements. [ABSTRACT FROM AUTHOR]

The reliability of high-voltage circuit breakers (HVCBs) depends critically on the dynamic characteristics of their hydraulic operating mechanisms (OMs). However, previous analyses have been limited to discrete components due to the lack of models capturing multi-physics couplings. This paper proposes a novel co-simulation approach for hydraulic OMs that enables system-level analysis. Specifically, the hydraulic system is modelled using the lumped parameter method, and the transmission mechanism is modelled via finite element analysis. The subsystem models exchange inputs and outputs through shared memory, realizing coupling without compromising simulation performance. Experiments on a 550 kV HVCB validate that the model accurately captures OM transient responses. The co-simulation framework has diverse capabilities, including predicting dynamics under varied operating parameters and quantifying stress distributions and response evolution patterns. Overall, this paper proposes an advanced multi-physics analysis capability for hydraulic OMs to support reliabilityoriented design and optimization. [ABSTRACT FROM AUTHOR]

The study presented in this paper was undertaken in response to two instances of unexpected blade breakage in the cutting blade used in a Carton Wrap machine (CW). Failure of the Al7075 alloy blade occurred at an indentation during typical operational loading conditions. Subsequent metallographic examinations of the fractured samples confirmed that both cases were attributed to fatigue failure. The main objective of this study is to investigate potential causes of fatigue failure in the CW blade using simplified linear elastic static numerical simulations through Finite Element Analysis (FEA). In this research, we employed the well-established Theory of Critical Distance (TCD), and this case study provided a contextualization at an industrial level. Furthermore, the analysis focused on a second key aspect: proposing a new blade geometry aimed at mitigating the identified issues and eliminating possible causes of failure. In this context, the actual stress concentration at the indentation was determined using the TCD with Line Method (LM). The results from the numerical simulations indicated that the new blade geometry significantly reduced stress concentration, resulting in a risk factor reduction of approximately four compared to the original blade design, even under non-optimal operating conditions. Overall, in conjunction with simple linear static FEA, the proposed numerical approach provided substantial support for designers, especially in fault analysis and when comparing different industrial solutions. [ABSTRACT FROM AUTHOR]

Traditional design methods for single-story steel structure factories are characterized by low levels of digitalization and high error rates. To deal with these problems, a building information modeling (BIM) platform for the design of single-story steel structure factories was developed in this paper, which aimed to improve the design process for such structures. Firstly, the components of the factory were categorized, and the Revit API was employed to automate the generation of the BIM model. Load applications and combinations were then established using the Revit API, which relied on a set of predefined parameters. Secondly, this paper proposed the creation of a dedicated database for data exchange between BIM software and finite element analysis software. Additionally, the SAP2000 Open Application Programming Interface (OAPI) was employed for the automated construction and analysis of the SAP2000 structural model. Finally, the innovative use of Dynamo–Revit API hybrid programming allowed for the visualization of internal forces directly within the Revit environment, significantly diminishing the dependency on standalone FEA software. The application results obtained on a project demonstrated that the developed platform markedly improves the efficiency of design single-story steel structure factories and ensures the accuracy of the structural analysis. This confirms that the developed platform can transform the traditional design process by integrating advanced digital tools, thereby providing a novel approach to the design of single-story steel structure factories. [ABSTRACT FROM AUTHOR]

In this paper, we present a comprehensive study of wavelet theory with a focus on structural damage detection. A new example of the application of operational modal analysis (OMA) techniques to a concrete railway arch bridge located over the Kalix river in Lingforsen, Sweden is presented. Results from the OMA techniques are used for finite element model (FEM) updating of this concrete railway arch bridge. Further, a new case study for sensor placement on Her0ysund bridge located in Nordland, Norway to conduct OMA is discussed in detail. Moreover, artificial intelligence algorithms that can be useful for addressing the problem of missing data sets in structural health monitoring technologies are reviewed. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive study of the dynamic responses of machine foundations, both block and pile foundations, on stratified residual soils in Duri and Ulubelu, Indonesia. The evaluation was conducted using two widely recognized methods: the lumped mass method (LMM) and the finite element method (FEM). LMM and FEM were performed by utilizing DYNA and ABAQUS, respectively. The analysis results showed that LMM generally predicted more conservative displacements compared to FEM. This conservatism in predicted displacement was more pronounced for pile group foundations, which are inherently more flexible than block foundations. Additionally, this study found that the resonance frequencies obtained through both analysis methods were not the same. Furthermore, this paper includes a parametric study and presents its results to assess the influence of key factors, i.e., pile cap thickness, pile diameter, number of piles, and vertical dynamic loads, on displacement. [ABSTRACT FROM AUTHOR]

In this paper, analyses of Francis turbine failures for powerful Pumped Hydraulic Energy Storage (PHES) are conducted. The structure is part of PHES Chaira, Bulgaria (HA4—Hydro-Aggregate 4). The aim of the study is to assess the structure-to-concrete embedding to determine the possible causes of damage and destruction of the HA4 Francis spiral casing units. The embedding methods that have been applied in practice for decades are discussed and compared to those used for HA4. A virtual prototype is built based on the finite-element method to clarify the influence of workloads under the generator mode. The stages of the simulation include structural analysis of the spiral casing and concrete under load in generator mode, as well as structural analysis of the spiral casing under loads in generator mode without concrete. Both simulations are of major importance. Since the failure of the surface between the turbine, the spiral casing, and the concrete is observed, the effect of the growing contact gap (no contact) is analyzed. The stresses, strains, and displacements of the turbine units are simulated, followed by an analysis for reliability. The conclusions reveal the possible reasons for cracks and destruction in the main elements of the structure. [ABSTRACT FROM AUTHOR]

The mountainous areas of the Loess Plateau in China are crisscrossed with ravines, fragile ecological environment, and frequent landslide hazards. Landslides often cause building collapses and casualties, seriously affecting the sustainability of economic and social development in the region. In order to study the damage of loess landslides to village and town buildings, the paper takes the Xingwang landslide in Fugu County, Shaanxi Province, China as an example, and uses discrete element method and finite element method to study the dynamic process of landslide and its damage to houses. Firstly, the geological characteristics of the landslide were identified by means of investigation, surveying, engineering exploration and geotechnical testing. Secondly, a threedimensional numerical model of the landslide area was established by using the particle flow code system (PFC[sup 3D]). Finally, the entire movement process of the landslide was simulated, and the impact damage to houses induced from landslide was analyzed and predicted. The results show that the whole movement of the landslide lasted a total of 180 s, with a maximum average velocity of 2.01 m/s and a maximum average displacement of 73.7 m. The first and second rows of houses located at the foot of the landslide will suffer serious damage, with most bricks displacement ranging from 0.1 to 2.5 m and a maximum displacement of 10.3 m, posing a serious safety risk to the houses. Only a portion of the third row houses will be damaged, and the fourth row houses will not be threatened by landslide. By comparing with the prediction results of other methods and the current situation of buildings deformation, the results of this paper have a certain credibility. This study provides a numerical method for quantitative assessment of the risk and building damage for loess landslide, which can be used as a reference. It also provides technical support for formulating hazard prevention and reduction plans for the Xingwang landslide. [ABSTRACT FROM AUTHOR]

In this paper, a unified method is proposed to predict the free and forced vibration behavior of the combined conical-cylindrical shell (CCS) structure in the steady-state thermal environment. The first-order shear deformation theory (FSDT) and the thermal strain are utilized to establish the energy equation of the combined structure, and the artificial virtual spring technique is introduced to realize the coupling between the substructures and the arbitrary boundary conditions of the CCS. The displacement function of the structure is constructed by the spectral-geometry method, and the vibration equation is solved by using the Rayleigh–Ritz method. The accuracy of the present model is verified by comparing the numerical results with the finite element method. The factors that may affect the vibration behavior of the CCS under thermal environment are analyzed specifically, and the results demonstrate that point constraints on the shell surface can effectively suppress shell vibration. This paper provides a compelling reference for vibration control of CCS in practical applications. [ABSTRACT FROM AUTHOR]

Capacitive and optical-based pressure sensors are considered for wide application in industries and R&D labs due to their superior performance. In general, these sensors use a diaphragm as a sensing element that needs to be designed accurately to achieve the desired level of accuracy for a higher operating range of the sensor. To design such a diaphragm, the conventional strain-based model cannot be used efficiently as the strain gradient starts dominating to introduce non-linear deformation with respect to the applied load when the diaphragm thickness reduces or the operating range increases beyond a certain value. Thus, there is a need to establish a comprehensive understanding and accurate modeling method to establish the underlying mechanism of the strain gradient. In view of this, a finite element analysis is carried out with moving-mesh to investigate the effect of the strain gradient phenomenon extensively in this paper. For the investigation, a few parameters are studied such as strain, strain gradient, bending rigidity, and deflection. It shows that the strain gradient spreads radially on the diaphragm and its zone of influence depends on the thickness as well as the applied pressure. This increases the bending rigidity significantly and the diaphragm deflection becomes non-linear as compared to the classical theory of bending. For validation of the present model, the bending rigidity and the deflection behavior are also compared with an earlier developed mathematical model as well as experimental results, and the same is discussed in this paper. The present work is useful for an accurate design and optimization of a diaphragm or a flexure for small size or/and higher operating range of pressure sensors and actuators. [ABSTRACT FROM AUTHOR]

To analyze the dynamic response of a rigid M-shaped jumper subjected to combined internal and external flows, a one-way coupled fluid–structure interaction process is applied. First, CFD simulations are conducted separately for the internal and external fluid domains. The pressure histories on the inner and outer walls are exported and loaded into the finite element model using inverse distance interpolation. Then, FEA is performed to determine the dynamic response, followed by a fatigue assessment based on the obtained stress data. The displacement, acceleration, and stress distribution along the M-shaped jumper are obtained. External flow velocity dominates the displacements, while internal flow velocity dominates the vibrations and stresses. The structural response to the combined effect of internal and external flows, plus the response to gravity alone, equals the sum of the structural responses to internal flow alone and external flow alone. Fatigue damage is calculated for the bend exhibiting the most intense vibration and higher stress levels, and the locations with significant damage correspond to areas with high maximum von Mises stress. This paper aims to evaluate multiple flow fields acting simultaneously on subsea pipelines and to identify the main factors that provide valuable information for their design, monitoring, and maintenance. [ABSTRACT FROM AUTHOR]

A hybrid excitation variable-leakage-flux machine (HE-VLFM) for electric vehicles is presented in this paper, which places the excitation windings on the outer side of the stator and provides an axial magnetic field through the magnetic-conducting ring and magnetic-conducting bridge. The HE-VLFM proposed in this paper has a rotor permanent magnet to provide the main magnetic field and an excitation winding to provide a variable auxiliary magnetic field, which can fulfill the requirements of the electric vehicle drive system with large torque at low-speed and wide speed regulation range. The electromagnetic performance of the proposed HE-VLFM is evaluated using the equivalent magnetic circuit method and three-dimensional finite element analysis, and the results show that the HE-VLFM has a well-developed regulating flux capability. [ABSTRACT FROM AUTHOR]

Rainfall is a pivotal factor resulting in the cause of slope instability. The traditional finite element method often fails to converge when dealing with the strongly nonlinear fluid–solid coupling problems, making it impossible to fully analyze the sliding process under the state of slope instability. Therefore, this paper uses the coupling of peridynamics (PD) and the finite element method (FEM) to propose a data exchange mode between the seepage field and the deformation field. The influencing factors of fine particle erosion during rainfall are further considered. According to the damage mechanism of the slope sliding process to the original structure of the soil, a modified erosion constitutive relationship is proposed, which takes into account the destructive effect of plastic deformation on coarse particles. Then, the influence of rainfall duration, rainfall intensity, erosion, and initial saturated permeability coefficient on slope stability was simulated and analyzed. This paper provides a novel concept for slope stability analysis and safety evaluation under rainfall conditions. [ABSTRACT FROM AUTHOR]

To address the frequent failure of hydraulic seals under high-pressure and high-flow continuous working conditions, optimizing the seal structure through intelligent optimization algorithms can improve performance. This paper proposes an improved intelligent optimization algorithm and finite element analysis to determine the optimal design parameters for the seal. Initially, a visual inspection and analysis of the failed Y-shaped seal revealed causes such as wear failure, damage failure, and leakage. Finite element analysis of the seal under actual working conditions confirmed the previous analysis. The study considered six control design parameters: lip base height, short-long lip length, short lip height, short lip angle, long lip angle, and lip base fillet radius. Using ANSYS, 50 parameter combinations were selected through Latin hypercube sampling for finite element simulation runs, with the maximum shear stress and maximum contact stress as optimization targets. A BP neural network was established and optimized using a genetic algorithm to design the unequal height Y-shaped seal structure based on NSGA-II, with optimization of the root chamfer to increase net pump backflow. The research results show a 7.29% reduction in maximum contact stress of the seal, a 21.4% decrease in maximum shear stress, and an increase of 0.066 mm3 in net pump backflow through chamfer optimization. The results indicate that this method effectively addresses design issues of seals in industrial applications. [ABSTRACT FROM AUTHOR]

Living organisms are constructed from proteins that assemble into biomolecular complexes, each with a unique shape and function. Our knowledge about the structure–activity relationship of these complexes is still limited, mainly because of their small size, complex structure, fast processes, and changing environment. Furthermore, the constraints of current microscopic tools and the difficulty in applying molecular dynamic simulations to capture the dynamic response of biomolecular complexes and long-term phenomena call for new supplementary tools and approaches that can help bridge this gap. In this paper, we present an approach to comparing biomolecular and origami hierarchical structures and apply it to comparing bacterial microcompartments (BMCs) with spiral-based origami models. Our first analysis compares proteins that assemble the BMC with an origami model called "flasher", which is the unit cell of an assembled origami model. Then, the BMC structure is compared with the assembled origami model and based on the similarity, a physical scaled-up origami model, which is analogous to the BMC, is constructed. The origami model is translated into a computer-aided design model and manufactured via 3D-printing technology. Finite element analysis and physical experiments of the origami model and 3D-printed parts reveal trends in the mechanical response of the icosahedron, which is constructed from tiled-chiral elements. The chiral elements rotate as the icosahedron expands and we deduce that it allows the BMC to open gates for transmembrane passage of materials. [ABSTRACT FROM AUTHOR]

Personalized orthopedic devices are increasingly favored for their potential to enhance long-term treatment success. Despite significant advancements across various disciplines, the seamless integration and full automation of personalized orthopedic treatments remain elusive. This paper identifies key interdisciplinary gaps in integrating and automating advanced technologies for personalized orthopedic treatment. It begins by outlining the standard clinical practices in orthopedic treatments and the extent of personalization achievable. The paper then explores recent innovations in artificial intelligence, biomaterials, genomic and proteomic analyses, lab-on-a-chip, medical imaging, image-based biomechanical finite element modeling, biomimicry, 3D printing and bioprinting, and implantable sensors, emphasizing their contributions to personalized treatments. Tentative strategies or solutions are proposed to address the interdisciplinary gaps by utilizing innovative technologies. The key findings highlight the need for the non-invasive quantitative assessment of bone quality, patient-specific biocompatibility, and device designs that address individual biological and mechanical conditions. This comprehensive review underscores the transformative potential of these technologies and the importance of multidisciplinary collaboration to integrate and automate them into a cohesive, intelligent system for personalized orthopedic treatments. [ABSTRACT FROM AUTHOR]

Permanent-magnet-assisted synchronous reluctance motors (PMA-SynRMs) are widely used in modern industry as a kind of electromagnetic energy conversion device with high output torque, high power density, high efficiency, and excellent speed regulation. In this paper, an asymmetric-rotor PMA-SynRM combined with a Halbach array is proposed based on the conventional PMA-SynRM without modifying the amount of permanent magnet. With the finite element no-load analysis, it is proven that the permanent magnet arrangement of this method can achieve better flux focusing effect and magnetic-axis-shift (MAS) effect. A significant increase and shift of the air-gap magnetic density has also been observed. Meanwhile, the load simulation demonstrated that the proposed model possesses higher utilization of permanent magnet torque and reluctance torque compared to the conventional model. In addition, a multi-objective optimization has been performed for the rotor structure of the proposed model, and the optimized model improved the average torque by 25.32% and reduced the torque ripple by 76.92% compared to the conventional model. Finally, the constant power speed range (CPSR) performance and anti-demagnetization performance have been analyzed for the three models. The results showed that the proposed and optimized models performed better on constant power speed range, and all three models of permanent magnets had good anti-demagnetization performance. The maximum demagnetization rate of the optimized model is reduced by 13.84% compared to the proposed model at an operating condition of 200 °C and nine times the rated current. [ABSTRACT FROM AUTHOR]

Lateral torsional buckling reduces the moment capacity of steel I-girders. To redress this weakening, one approach is to replace the conventional plate flange with a rectangular tube, which has higher lateral stiffness and is thus helpful to resist lateral buckling. At the same time, web openings are introduced to enable services to pass through, but this causes a reduction in strength. Girders with tubular flange plus web openings have not yet been discussed in the literature. In this paper, finite-element method modelling is used to fill this gap, studying different slenderness classifications, as well as parameters such as size of web openings, spacing and location. The results for a solid web are found to be more comparable to the Eurocodes for steel structures than the American Institute of Steel Construction codes, enabling good prediction of the flexural capacity. By introducing web openings, the flexural capacity is reduced by 10–20%, closer to the higher side for openings with large diameters located near the compression flange. Openings with an oval shape have less reduction in strength, whereas the square is unfavourable. Tubular flange girders, even if perforated, provide flexural strength enhancement and a considerable reduction in material compared with plate flange girders. This section also behaves better in relation to carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

The main challenge faced by many mechanical engineering educators is the implementation of real solutions during their courses. One alternative can be a realistic case study, where the students can be engaged in the development and analysis process currently applied in the industry. This kind of teaching process not only can be used to improve the quality of teaching‐learning process but also the students can have opportunities to solve real engineering problem. Therefore, this paper reports a realistic case implemented in mechanical engineering courses given in bachelor's and master's degrees. The component under evaluation has been selected considering the student's interest, this criterion was also taken to involve several students into a real project process to their learning development. The same problem was solved during an academic semester, it was solved using different approaches and student's abilities. This procedure can be replicated for students and teachers by following steps. The first step in this process was to describe the theoretical basis for modal analysis to understand how it was structured a numerical finite element model. This model was then solved and simulated using Hypermesh, Optistruct, and HyperView software to obtain numerical modal parameters. On the other, hand, the experimental modal parameters were obtained using a three‐dimensional scanning vibrometer on 60 samples. It is well noted that the implementation of engineering software commonly used at the industry would increase students' confidence. This allows students to perform real problem‐solving activities to develop outcomes as establish goals, plan task, meet deadlines. These activities are extremely important to the actual automotive industry. Therefore, this paper shows an engineering solution process to provide a learning alternative to teach the modal finite method solutions correlation with experimental solutions. [ABSTRACT FROM AUTHOR]

This paper proposes a practical approach for data-efficient metamodeling and real-time modeling of laterally loaded monopiles using physics-informed multifidelity data fusion. The proposed approach fuses information from one-dimensional (1D) beam-column model analysis, three-dimensional (3D) finite element analysis, and field measurements (in order of increasing fidelity) for enhanced accuracy. It uses an interpretable scale factor–based data fusion architecture within a deep learning framework and incorporates physics-based constraints for robust predictions with limited data. The proposed approach is demonstrated for modeling monopile lateral load–displacement behavior using data from a real-world case study. Results show that the approach provides significantly more accurate predictions compared to a single-fidelity metamodel and a widely used multifidelity data fusion model. The model's interpretability and data efficiency make it suitable for practical applications. [ABSTRACT FROM AUTHOR]

Transcranial magnetic stimulation (TMS) shows great research potential in human neuroscience. However, when it comes to stimulating deeper brain regions, traditional TMS is restricted by the balance between stimulation focalization and stimulation depth. Temporal interference (TI) stimulation offers a new thought to solve the problem. In this paper, we first discussed the principles of TI-TMS and then established the theoretical model of TI-TMS using the head-surrounded spatial array. Next, we specially designed the parametric characterized spatial array (PCS array) suitable for TI-TMS. The proposed PCS array contains eight special-shaped coils that constitute four sets of difference frequency stimulation pairs and are placed around the human head. Distribution characteristics of the temporally interfering electric fields (E-fields) including stimulation intensity, stimulation focalizations on 1D, 2D, and 3D levels, and attenuation ratios in X, Y, and Z directions were obtained using the finite element analysis method. Our results indicate that the proposed PCS array could form an obvious focusing area with strong stimulation at a stimulation depth of 5 cm below the human scalp while the superficial region is under weak stimulation, which effectively combines the advantages of TMS and TI stimulation. Compared to the traditional TMS systems, the TI-TMS with PCS array can realize selective and focalized stimulation in the deep brain and increase the average attenuation ratio of the induced temporally interfering E-fields by more than 1.93 times. A real human head model containing gray matter was also employed in this paper to verify our results. [ABSTRACT FROM AUTHOR]

This paper introduces a novel approach to assessing structural safety, specifically aimed at evaluating the safety of existing structures. Firstly, a point cloud model of the existing commercial complex was captured utilizing three-dimensional (3D) laser scanning technology. Subsequently, an intelligent method for identifying holes within the point cloud model was proposed, built upon a YOLO v5-based framework, to ascertain the dimensions and locations of holes within the commercial complex. Secondly, Poisson surface reconstruction, coupled with partially self-developed algorithms, was employed to reconstruct the surface of the structure, facilitating the three-dimensional geometric reconstruction of the commercial complex. Lastly, a finite element model of the framed structure with holes was established using the reconstructed 3D model, and a safety analysis was conducted. The research findings reveal that the YOLO v5-based intelligent hole identification method significantly enhances the level of intelligence in point cloud data processing, reducing manual intervention time and boosting operational efficiency. Furthermore, through Poisson surface reconstruction and the self-developed algorithms, we have successfully achieved automated surface reconstruction, where the resulting geometric model accurately reflects the dimensional information of the commercial complex. Additionally, the maximum uniformly distributed surface load that the floor slabs within the framed structure with holes can withstand should not exceed 17.7 kN/m2, and its vertical deformation resistance stiffness is approximately 71.6% of that of a frame without holes. [ABSTRACT FROM AUTHOR]

With the rapid development of the photovoltaic industry, flexible photovoltaic supports are increasingly widely used. Parameters such as the deflection, span, and cross-sectional dimensions of cables are important factors affecting their mechanical and economic performance. Therefore, in order to reduce steel consumption and cost and improve application value, it is crucial to design and optimize their initial morphology. In this paper, the mechanical behavior of a single-cable structure is introduced, and the simplified analytical formulations for internal force and displacement are deduced based on the geometric nonlinear characteristics and small strain assumption of the flexible photovoltaic supports. On this basis, the analytical expressions for the cable force and displacement of a convex prestressed double-layer cable truss flexible photovoltaic support structure under a uniform load are derived, and the correctness of the analytical formulations is verified by comparing the values with the finite element analysis results. In order to reduce the construction costs of the flexible photovoltaic support, a mathematical model for optimizing the initial structure's morphology is established according to the analytical formulations. The initial morphology of the double-layer cable truss flexible photovoltaic support is optimized, and the optimization results of different deflection deformation limits and whether the lower load-bearing cable is allowed to relax are compared. The results indicate that the errors of the displacement formulation and cable force formulation, when compared with the finite element results, are less than 3% and 4%, respectively, which verifies the accuracy of the analytical formulations. By analyzing the cable force and displacement of the structure under static action, it is suggested that the deflection limit of the double-layer cable truss structure should be 1/100 of the single span. The lower load-bearing cables of the double-layer cable truss flexible photovoltaic support are highly susceptible to relaxation under wind suction loads, and, by comparing the optimization results, it is suggested that slack should be allowed in the lower load-bearing cables for a better economic effect. When choosing the most economical structure morphology, it is recommended that the total height of the mid-span struts should be 1/20~1/15 of the single span. The analytical formulation and the mathematical model for the optimization of the initial morphology proposed in this paper can provide certain theoretical references and bases for the design of practical engineering projects and play an important role in promoting its application and promotion. [ABSTRACT FROM AUTHOR]

In saline environments, it is difficult for reinforced concrete structures to meet normal durability requirements, which in turn affects the mechanical properties of the members. In this context, this paper proposes a reinforcement method that involves wrapping corroded reinforced concrete columns with CFRP (carbon fiber reinforced polymer) cloth. By conducting axial compression tests on four specimens, key mechanical performance indicators such as failure mode, ductility, and bearing capacity during the entire stress process of the specimens were analyzed, revealing the failure mechanism of CFRP-confined corroded reinforced concrete columns. A refined finite element model of CFRP-confined corroded reinforced concrete columns was established using ABAQUS software. The influence of key parameters such as the number of CFRP wrapping layers, longitudinal reinforcement corrosion rate, and axial compression ratio on the mechanical properties of the specimens was studied, and the influence of each parameter was determined. Furthermore, a formula for the axial compression bearing capacity of CFRP-confined corroded reinforced concrete columns was proposed. The results indicate that in the presence of corroded steel reinforcement, specimens confined with CFRP undergo substantial lateral constraints during the mid to late stages of loading. This approach effectively alleviates the transverse deformation of the concrete. The specimen demonstrated yield bearing capacities and peak loads of 1441 KN and 1934 KN, respectively, representing a 2.2-fold and 2.5-fold increase compared to the non-reinforced specimen. With the increase in the transverse strain of concrete, CFRP begins to play a restraint role, and a more obvious restraint role in the failure stage of members. It is recommended to apply 1–3 layers of CFRP wrapping for a longitudinal reinforcement corrosion rate of 5%, 3–5 layers for a rate of 10%, and 6–8 layers for an overall corrosion rate of 15%. This paper establishes a theoretical framework for investigating the performance characteristics of such columns and offers technical assistance for practical engineering purposes. [ABSTRACT FROM AUTHOR]

The accuracy of ultrasonic nondestructive examination is limited by the limitation of near field diffraction. With the development of nearfield optical, angular spectrum method is introduced into the acoustic field, which provides a significant direction for the ultrasonic diffraction limit resolution detection. The main research of this paper is the transmission of near field ultrasound in thin workpiece and the law of the interaction of tiny flaws. The paper establishes the relationship between the longitudinal wave signal and the structure of the workpiece and the types of flaws. A method is found that whether there are flaws can be determined near field area by analysing the acoustic field characteristics of workpiece surface. Finally, comparing the calculation results with the finite element simulation, they verify each other, the method turns out to be correct in this paper. The model can also be used to improve the ultrasonic noise reduction algorithm and the extraction of minimal defect feature. It has a greatly practical significance. [ABSTRACT FROM AUTHOR]

In order to achieve a high-precision synchronous detection of two different refractive index (RI) analytes, a D-type surface plasmon resonance (SPR) photonic crystal fiber (PCF) RI sensor based on two channels is designed in this paper. The sensor uses a D-shaped planar region of the PCF and a large circular air hole below the core as the sensing channels. Surface plasmon resonance is induced by applying a coating of gold film on the surface. The full-vector finite-element method (FEM) is used to optimize the structural parameters of the optical fiber, and the sensing characteristics are studied, including wavelength sensitivity, RI resolution, full width at half maximum (FWHM), figure of merit (FOM), and signal-to-noise ratio (SNR). The results show that the channel 1 (Ch 1) can achieve RI detection of 1.36–1.39 in the wavelength range of 1500–2600 nm, and the channel 2 (Ch 2) can achieve RI detection of 1.46–1.57 in the wavelength range of 2100–3000 nm. The two sensing channels can detect independently or simultaneously measure two analytes with different RIs. The maximum wavelength sensitivity of the sensor can reach 30,000 nm/RIU in Channel 1 and 9900 nm/RIU in Channel 2. The RI resolutions of the two channels are 3.54 × 10−6 RIU and 10.88 × 10−6 RIU, respectively. Therefore, the sensor realizes dual-channel high- and low-RI synchronous detection in the ultra-long wavelength band from near-infrared to mid-infrared and achieves an ultra-wide RI detection range and ultra-high wavelength sensitivity. The sensor has a wide application prospect in the fields of chemical detection, biomedical sensing, and water environment monitoring. [ABSTRACT FROM AUTHOR]

Past research efforts have developed several self-centering beam-to-column connections for minimizing structural damage in steel moment frames after severe earthquakes. However, less focus has been on low-damage column base connections. Severe damage at the base of columns in conventional steel structures with moment frames is likely during an intense earthquake, rendering the building nonresilient. This paper evaluates the application of a recently developed viscoplastic damper in low-damage column base connections. The proposed viscoplastic damper is a rubber-steel core damper (RSCD), which consists of a high-damping rubber layer and several ductile steel bolts. The proposed column base connections prevent damage and inelastic deformations in the steel column and its base plate by allowing a rocking mechanism at the base of the column and limiting damage to easily replaceable steel bolts in the dampers. The paper discusses the design and behavior of the column base connections equipped with RSCDs. Continuum finite element models of RSCD dampers were developed and validated using experimental results. The rocking response was validated using experimental results for rocking columns with a silt damper. A total of 21 finite element models of rocking columns with RSCD were used to numerically examine the column response to combined axial loading and cyclic lateral loading. The influence of different parameters on the cyclic response of the proposed column base connections was also evaluated. These parameters are steel bolt diameter-to-length ratio (d/h), rubber thickness, column axial compressive load, number of bolts, and steel material type. The results confirmed the effectiveness of the proposed column base connection for minimizing damage to the steel column and its base plate. An optimal d/h ratio of 0.4 was found for the design of RSCDs. In addition, analytical formulas are presented to evaluate the yield and ultimate strength of the proposed column base connection, and the comparison with FEM results indicates that the presented mechanism has sufficient accuracy. [ABSTRACT FROM AUTHOR]

Hydraulic rolling reshaper is an advanced reshaping tool to solve the problem of casing deformation, which has been widely used in recent years. When it is used for well repair operation, the reshaping force provided by ground devices is generally determined by experience. However, too large reshaping force may destroy the deformed casing, and too small reshaping force may also prolong the construction period and affect the repairing effect. In this paper, based on Hertz contact theory and elastic-plastic theory, combined with the process parameters of shaping, and considering the structural characteristics of the deformed casing and reshaper, we propose a mathematical model for calculating the reshaping force required for repairing deformed casing by hydraulic rolling reshaper. Meanwhile, the finite element model and numerical method of hydraulic rolling reshaper repairing deformed casing are established by using the finite element method, and the reliability of the mathematical model is verified by several examples. On this basis, the control variable method is used to investigate the influence of each parameter on the reshaping force, and the influence degree of each parameter is explored by orthogonal simulation test and Pearson correlation analysis. The research results not only provide an important theoretical basis for the prediction of reshaping force in on-site construction, but also provide a reference for the subsequent improvement of the shaping process. [ABSTRACT FROM AUTHOR]

Short-circuit impedance is an important economic and technical index to test the cost, efficiency and operation safety of transformers. Increasing the short-circuit impedance of the transformer can reduce the influence of the transformer fault current on the system. The short-circuit impedance of a general power transformer is 4~7%. When the short-circuit impedance is too small, the short-circuit current is too large, which will cause harm to electrical equipment. This paper proposes a method to adjust the short-circuit impedance by adding magnetic shunts of different thicknesses between the high and low voltage windings of the transformer. Compared with other methods, this method does not change the structure of the transformer core and winding, and is simple and efficient. In this paper, a three-dimensional simulation model of a single-phase multi-winding transformer is established by Altair Flux to study the influence of the thickness of magnetic shunts on the short-circuit impedance of a transformer. The feasibility of the proposed method is verified by comparing the simulation with the measured values. The magnetic shunt is also introduced into the three-phase transformer. The result shows that adding magnetic shunts of different thicknesses between the high and low voltage windings of the transformer will change the distribution and size of the leakage of the magnetic field. The short-circuit impedance increases significantly with the increase in the thickness of the magnetic shunt, but a certain number of magnetic shunts have minimal effects on the efficiency of the transformer. [ABSTRACT FROM AUTHOR]

Numerical modelling of corrugated paperboard is quite challenging due to its waved geometry and material non-linearity which is affected by the material properties of the individual paper sheets. Because of the complex geometry and material behaviour of the board, there is still scope to enhance the accuracy of current modelling techniques as well as gain a better understanding of the structural performance of corrugated paperboard packaging for improved packaging design. In this study, four-point bending tests were carried out to determine the bending stiffness of un-creased samples in the machine direction (MD) and cross direction (CD). Bending tests were also carried out on creased samples with the fluting oriented in the CD with the crease at the centre. Inverse analysis was applied using the results from the bending tests to determine the material properties that accurately predict the bending stiffness of the horizontal creases, vertical creases, and panels of a box under compression loading. The finite element model of the box was divided into three sections, the horizontal creases, vertical creases, and the box panels. Each of these sections is described using different material properties. The box edges/corners are described using the optimal material properties from bending and compression tests conducted on creased samples, while the box panels are described using the optimal material properties obtained from four-point bending tests conducted on samples without creases. A homogenised finite element (FE) model of a box was simulated using the obtained material properties and validated using experimental results. The developed FE model accurately predicted the failure load of a corrugated paperboard box under compression with a variation of 0.1% when compared to the experimental results. [ABSTRACT FROM AUTHOR]

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Dry–wet cycles can cause significant deterioration of compacted loess and thus affect the safety of fill slopes. The discrete element method (DEM) can take into account the non-homogeneous, discontinuous, and anisotropic nature of the geotechnical medium, which is more capable of reflecting the mechanism and process of instability in slope stability analysis. Therefore, this paper proposes to use the DEM to analyze the stability of compacted loess slopes under dry–wet cycles. Firstly, to solve the complex calibration problem between macro and mesoscopic parameters in DEM models, an efficient parameter optimization method was proposed by introducing the chaotic particle swarm optimization with sigmoid-based acceleration coefficients algorithm (CPSOS). Secondly, during the parameter calibration, a new indicator, the bonding ratio (BR), was proposed to characterize the development of pores and cracks in compacted loess during dry–wet cycles, to reflect the impact of dry–wet action on the degradation of bonding between loess aggregates. Finally, according to the results of parameter calibration, the stability analysis model of compacted loess slope under dry–wet cycling was established. The results show that the proposed optimization calibration method can accurately reflect the trend of the stress–strain curve and strength of the actual test results under dry–wet cycles, and the BR also reflects the degradation effect of dry–wet cycles on compacted loess. The slope stability analysis shows that the DEM reflects the negative effect of dry–wet cycles on the safety factor of compacted loess slopes, as well as the trend of gradual stabilization with dry–wet cycles. The comparison with the finite element analysis results verified the accuracy of the discrete element slope stability analysis. [ABSTRACT FROM AUTHOR]