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Negative Poisson's ratio in auxetic structures plays a crucial role in energy absorption and impact mitigation. Origami-based lattices within the realm of auxetic structures offer the advantage of facile fabrication and design. Nevertheless, the utilization of periodic lattices in origami-based auxetic structures constrains the available design space for achieving diverse mechanical properties. Addressing this limitation, our study introduces origami-based auxetic structures with functionally graded thickness, utilizing origami-based lattices known as Tachi–Miura polyhedra. We investigated the impact of functionally graded thickness on buckling behavior and force responses through dynamic loading experiments employing 3D-printed test pieces. The experimental results indicate that functionally graded thickness induces partial auxetic deformation in lattices, and the resulting nonsymmetric deformation prevents global buckling, thereby averting bounded forces observed in structures with uniform thickness. These findings extend the applicability of auxetic structures, spanning from energy absorption to the design of cushioning structures. [ABSTRACT FROM AUTHOR]

The ride comfort of vehicles traveling on the road has always been a concern. In addition, the braking force of vehicles will aggravate the damage to road structures and reduce the comfort of drivers and passengers. In the present study, the dynamic response of pavement, road friendliness, and human comfort are investigated by setting up the human-bus-road coupled vibration system considering the braking forces. Firstly, the three-dimensional finite element model of asphalt pavement with interlayer contact and the human-bus model with multiple degrees of freedom (2n + 7) were established to analyze the dynamic responses of asphalt pavement, human body, and bus under different braking conditions. Then, the dynamic load coefficients of wheels under different combined conditions were investigated to evaluate the road friendliness and the human annoyance rate was adopted to evaluate the human comfort. The results show that for the asphalt pavement, the shear stress of the pavement is larger than the normal stress due to the bus braking, and the combined effect of road surface roughness and braking force on the road friendliness is the largest. For the human comfort, the pitch acceleration of human body increases more than the roll acceleration due to bus braking, resulting in the decreased human comfort and increased annoyance rate. [ABSTRACT FROM AUTHOR]

Bone behaves as a complex composite material, and is highly heterogenous and anisotropic in nature due to its hierarchical structure. The effect of the location and orientation of bone specimens on the viscoelastic properties of bovine femoral cortical bone was examined in this study. The bone samples were extracted from different locations i.e., proximal, central and distal along the direction of longitudinal and transverse and underwent sinusoidal loading. The longitudinal orientation shows more values of loss tangent and loss modulus in comparison to transverse orientation bone samples. Across locations reveal no significant difference in the storage modulus, loss tangent, loss modulus and complex modulus. The trends in the complex and storage moduli remain consistent within both types of orientations. Significant differences were observed across the locations for both storage and recovered energy, with no variance in the hysteresis loss. The findings from the study shall help in a deep understanding of the bone biomechanics, offering insights for material design and orthopedic interventions in biomechanical engineering. [ABSTRACT FROM AUTHOR]

The Hoek–Brown strength criterion is commonly employed to anticipate rock mass failure, considering influential factors including rock mass quality and static stress conditions. Nevertheless, extensive experiments have revealed that the strength of intact rock also depends on the loading rate. Since rock masses frequently experience dynamic loading in practical scenarios, extending the application of this criterion into the dynamic domain is both valuable and challenging. This paper initiates an exploration into the dynamic strength criterion of rock masses, drawing from experimental studies on the dynamic mechanical response of jointed rock specimens. A dynamic three-dimensional strength test was carried out on artificially jointed rock specimens using SHPB equipment with confining pressure. Specimens contain a set of sub-horizontal joint and a set of sub-vertical joint. The research shows that the dynamic compressive strength and Young's modulus of jointed rock specimens increase with the increase of loading rate. The dynamic scale effect of rocks is more related to the structure, rather than being solely dictated by scale. Discussion is undertaken regarding the fundamental form of dynamic strength criterion of rock mass, which is modified from the Hoek–Brown (H–B) criterion. Subsequently, the dynamic compressive strength and Young's modulus of jointed rock specimens are analyzed. By accounting for dynamic size effects, the geological strength index (GSI) was evaluated, which is closely consistent with GSI calculated through dynamic Young's modulus. The relationship between GSI and loading rate is discussed. According to the GSI chart, the joint spacings of rock masses as reflected by the specimen's structures under different loading rates are derived. These findings contribute valuable guidance on utilizing laboratory-scale jointed rock specimens to assess the mechanical behavior and strength characteristics of rock masses under dynamic loads such as blasting. Highlights: Dynamic experiment on jointed rock specimens using SHPB equipment Dynamic mechanical properties of jointed rock specimens Dynamic Hoek-Brown strength criterion for rock masses Dynamic size effect of jointed rock mass and dynamic GSI [ABSTRACT FROM AUTHOR]

Research on the evolutionary behavior of the particle breakage processes in coarse-grained soil under the action of train load is of practical significance for subgrade construction and maintenance. However, existing studies have not addressed the prediction of particle size distribution evolution. In this paper, the MTS loading system is used to simulate the dynamic train load effect on coarse-grained soil fillers. The study analyzes the influence of dynamic stress amplitude, loading frequency, and vibration times on both the macro-characteristics and micro-characteristics of particle breakage. The characteristics of particle fragmentation in coarse soil filler under high-speed train load are elucidated. Furthermore, a predictive model for the evolution of particle size distribution curves in relation to particle content and relative particle size is established using the ZHU continuous grading curve equation. This model captures the evolution process of particle breakage characteristics in coarse-grained soil fillers subjected to high-speed train loads. The applicability of this model has been verified. Based on the grading prediction model, an integral expression for the breakage rate index is derived, and the evolution characteristics of particle breakage in coarse-grained soil fillers under the action of train load are analyzed. The results indicate that during filling, the particle breakage mode of coarse-grained soil fillers during filling is primarily characterized by fracture and fragmentation; conversely, under dynamic cyclic loading conditions, it is predominantly characterized by fracture and grinding. The breakage rate aligns with the measured results, suggesting that the breakage rate index established in this study can effectively describe the evolution process of particle breakage in railway subgrade coarse-grained soil. After the reaching one million loading cycles, both deformation and particle breakage degree in coarse-grained soil fillers tend to stabilize. Under the action of dynamic stress amplitudes ranging from 10 to 200 kPa and loading frequencies between 2 and 12 Hz, the particle breakage index stabilizes below 1.1%. These research findings contribute to a deeper understanding of the evolutionary processes affecting engineering characteristics of railway subgrade coarse-grained soils and provide a theoretical as well as experimental foundation for railway subgrade construction and maintenance. [ABSTRACT FROM AUTHOR]

Load distribution is a very important indicator that has a great effect on bearing service performance. Unreasonable load distribution is likely to accelerate the bearing failures. The dynamic effects of the moving parts of the rolling bearing have significant influence on the load distribution. In order to study the load distribution of rolling bearings, the dynamic interaction between raceways and balls is considered in detail and a dynamic model of ball bearings subjected to radial loads is presented. The results of the proposed model are compared with those of the traditional static model and the quasi‐static model. The dynamic load coefficient and the dynamic angular extent coefficient are defined to show the characteristics of the dynamic load distribution. The effects of radial clearance, the radial load, and the rotational speed on the dynamic load distribution are studied. Through the above research, this paper concludes that the load distribution is greatly influenced by the dynamic effects of moving parts, especially under the conditions of large clearance, light load, or high speed. [ABSTRACT FROM AUTHOR]

Effective identification of dynamic loads on vehicle systems is crucial for evaluating the structural integrity of railway vehicles. The inverse problem method has been proposed for dynamic load identification to determine the impact load on the carbody. Due to the sparse nature of the impact load, the combination of the l1-norm and TwIST (two-step iterative threshold shrinkage method) methods is used to reconstruct the impact load, taking into account the influence of sensor placement on the identification results. The MOHBA (Multi-objective Optimisation Honey Badger Algorithm) was proposed to simultaneously select the regularisation and iteration parameters. This algorithm aims to improve the accuracy of subsequence load reconstruction by considering the influence of noise levels when selecting the measured data. The impact load experiment was conducted on the scale carbody, and the single-point impact load and multi-point impact load matched well with the actual load. Satisfactory load identification results can still be achieved when the noise level is within 15%. When arranging measurement points on the boundary of the vehicle body, satisfactory load identification results can also be achieved. [ABSTRACT FROM AUTHOR]

Android malware has been emerged as a significant threat, which includes exposure of confidential information, misrepresentation of facts and execution of applications without the knowledge of the users. Malware analysis plays an essential role in dealing with the unlawful behaviour of such malicious applications. Android malware analysis involves examining and understanding malware behaviour and its characteristics. It also includes potential adversarial impacts on Android devices. This paper presents a quick understanding and a holistic view of malware detection and analysis. The current investigation conducted a systematic literature review (SLR) to recognize the salient shifts in malware detection by examining a range of scholarly journals and conference papers. The SLR investigated 99 articles published between the years 2018 and 2023. The key observation of this SLR is that static analysis is the most implemented approach for detecting Android malware; Apktool and Androguard are the most frequently used tools. This study also conceded that deep learning and machine learning models have more potential to analyse the malicious behaviour of malware. Certain challenges are faced in Android malware analysis, that is, obfuscation techniques, dynamic code loading, and issues related to experimented datasets. Further, this study focuses on the following areas: the definition of the sample set, data optimisation and processing, feature extraction, machine learning application, and classifier validation. This investigation differs from previous analyses of Android malware detection by emphasizing additional methods based on machine learning. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate a non‐resorbable implant for the focal repair of chondral defects in eight adult horses with 12‐month follow‐up. The bi‐layered construct composed of a polycarbonate‐urethane‐urea biomaterial which was printed in 3D fashion onto a bone anchor was implanted into surgically created osteochondral defects into the femoropatellar joints of eight horses. The analysis of post‐mortem outcomes were compared to defects treated with microfracture in the same animal on the contralateral femoropatellar jointfemoropatellar joint. The overall macroscopic scoring after 12 months yielded higher scores in the OCI‐treated stifles compared to MF treatment (p = 0.09) with better quality and filling of the defect. Histology revealed good anchorage of repair tissue growing into the 3D structure of the implant and histopathology scoring for adjacent native cartilage showed no difference between groups. MRI and micro‐CT showed overall less sclerotic reactions in the surrounding bone in the implant group and no foreign body reaction was detected. Biomechanical analysis of the repair tissue revealed a significantly higher peak modulus (p < 0.05) in the implant group (0.74 ± 0.45) compared to the microfracture control group (0.15 ± 0.11). Dynamic loading yielded higher values for the repair tissue overgrowing the implant group (0.23 ± 0.17) compared to the microfracture control (0.06 ± 0.06) (p < 0.05). The bi‐layered osteochondral implant provided a safe implant for focal repair of full‐thickness osteochondral defects, as no adverse reaction was seen within the joints and the level of degeneration of adjacent cartilage to the repair site was not different compared to that seen in defects treated with microfracture after 12 months. [ABSTRACT FROM AUTHOR]

Accurate prediction of the dynamic response of a structure is crucial for its system identification, reliability analysis, and health monitoring. However, uncertainties in physics-based models and parameters may cause a significant discrepancy between predictions and actual responses. The neural network–augmented physics (NNAP) model aims to address this issue by augmenting physics-based models with deep-learning models trained by real data. While promising, such an approach has yet to be applied to large multi-degree-of-freedom (MDOF) structures under response-dependent forces. This paper presents a novel method incorporating modal truncation into the NNAP model for more accurate prediction of the dynamic responses of nonlinear MDOF systems. The proposed NNAP-m uses modal truncation to describe a physics-based model by lower-dimension coordinates and augments it with a neural network representing phenomena with more significant epistemic uncertainties. This hybrid modeling approach relies on information about mode shapes and natural frequencies to improve prediction capability. The proposed method is successfully verified using a numerical example of the Lysefjord bridge structure exhibiting nonlinear behaviors, including the interaction between wind loads and dynamic responses. The proposed approach is expected to provide accurate response predictions of real-world structures using measurement data and to promote the development of physics-based deep-learning approaches for complex structures with large DOFs. [ABSTRACT FROM AUTHOR]

This paper presents the results of a laboratory investigation into the response of stone column–improved soft clay under dynamic traffic load conditions. Six reduced-scale model tests were performed with vertical traffic load composed of three consecutive stages: initial static load, cyclic load, and postcyclic load. The principal parameters were comprehensively investigated, such as loading frequency (1, 3, and 5 Hz), bearing stratum, and reinforcement conditions. The results show that dynamic settlement of a floating geosynthetic-encased stone column (F-ESC) increases rapidly with the increase in the time of cyclic loading at high loading frequency (5 Hz), accounting for 36.8% of total settlement. The geogrid encasement showed great benefits to the settlement improvement of stone columns under traffic loading. High-frequency traffic load generally decreased the bearing capacity and load transfer efficiency of F-ESC. Excess pore-water pressure (EPWP) is sensitive to the load frequency, and the value in F-ESC under the 5 Hz cyclic load is 1,420.5% larger than that under 1 Hz cyclic load. Rapid increase and accumulation of EPWP may cause significant foundation settlement at high loading frequency. The end-bearing geosynthetic-encased stone column shows a high strain increment ratio (up to 96.2%) under cyclic loads, which should be duly considered in the selection and design of reinforcement materials. [ABSTRACT FROM AUTHOR]

With only a few floating offshore wind turbine (FOWT) farms deployed anywhere in the world, FOWT technology is still in its infancy, building on a modicum of real‐world experience to advance the nascent industry. To support further development, engineers rely heavily on modeling tools to accurately portray the behavior of these complex systems under realistic environmental conditions. This reliance creates a need for verification and validation of such tools to improve reliability of load and dynamic response prediction and analysis capabilities of FOWT systems. The Offshore Code Comparison Collaboration, Continued with Correlation and unCertainty (OC6) project was created under the framework of the International Energy Agency to address this need and considers a three‐sided verification and validation between engineering level models, computational fluid dynamics (CFD), and experimental results. In this paper, a novel floating offshore wind platform, the Stiesdal TetraSpar, is simulated using CFD under the load conditions defined by Phase IV of the OC6 project. The comparison of these CFD results against the experimental results demonstrated the ability to predict the platform response to waves when imposing the measured wave signals as input. Although validation versus experiment was largely successful, the damping behavior was impacted by uncertainties likely originating from the mooring system and sensor umbilical cable. This extensive comparison effort with multiple CFD practitioners offers insight into best practices to achieve reliable results. [ABSTRACT FROM AUTHOR]

In the field of gun launched missile extended range rocket, the propellant grain in the rocket needs to withstand significant launch loads during their firing phase, and also bear the high pressure caused by ignition, and the impact of launch overloads and ignition shocks on the structural integrity of propellants becomes very important. So this work investigated the dynamic initiation fracture toughness of the composite modified double-base (CMDB) propellant by both experiments and numerical simulations. The dynamic mechanical properties test of the cracked straight through flattened Brazilian disc (CSTFBD) specimens were conducted using a modified Split Hopkinson pressure bar (SHPB). By comparing the results of quasi static and dynamic numerical simulations, it was found that dynamic fracture initiation toughness can be determined by time-to-fracture using the quasi-static theory. The numerical simulation results combined with the ZWT constitutive model agree well with the experimental results, indicating that ZWT constitutive model is suitable for numerical simulation calculation of propellant structural integrity under dynamic load, and provides a theoretical basis for propellant structural integrity analysis under dynamic load. During the measurement of the mechanical response, the fracture surfaces of the dynamic test specimens were observed by electron microscopy scanning. Then the evolution of the microstructure synchronously was obtained. The scanning electron microscope (SEM) results revealed that fracture modes and breakage of the ammonium perchlorate (AP) particles in the surface layer played an important role in determining the failure mechanism, which revealed the failure mechanism of the propellant under dynamic load. The result of experimental measurement showed the influence of loading rate on the dynamic fracture initiation toughness of CMDB propellant. [ABSTRACT FROM AUTHOR]

The mechanical behavior and fracture mechanisms of deep fractured rocks under explosive dynamic loads are critical for understanding rock instability in engineering applications such as blasting operations. This study aims to investigate how the presence of pre-existing cracks and different stress states affect the mechanical properties and fracture patterns of rock-like specimens under dynamic loading conditions. We utilized a Split Hopkinson Pressure Bar (SHPB) with an active confining pressure loading device to conduct impact compression tests on rock-like specimens containing pre-existing cracks. These tests were performed under uniaxial and triaxial stress states to simulate various in-situ stress conditions. The study revealed three key findings: (1)The dynamic compressive strength of specimens with pre-existing cracks exhibited a non-monotonic relationship with crack inclination angle under uniaxial stress, contrasting with an increasing trend under confining pressure, highlighting the significant effects of confining pressure and strain rate. (2)Confining pressure significantly altered the failure modes, with specimens failing predominantly in axial tension at 0° and 90° crack inclinations, and a mix of axial tension and shear at 30° and 60°, indicating complex failure mechanisms. (3)The pre-existing crack angle under confining pressure influenced the propagation path and fractal dimension of the specimen, with an increasing angle correlating to higher fractal dimensions and a positive impact on compression peak stress. The research provides valuable insights into the complex fracture behavior of fractured rocks under dynamic loads, which can inform the design of blasting parameters in deep engineering. It also offers critical knowledge for preventing rock instability-related disasters, thus holding significant theoretical and practical importance in the field of rock mechanics and engineering. [ABSTRACT FROM AUTHOR]

ABSTRACT This work examines the effect of loading rate (K·$$ \overset{\cdotp }{K} $$) on the mode III fracture behavior of sandstone. Edge‐notched diametrically compressed (ENDC) disc sandstone specimens were tested under different static and dynamic mode III fracture loadings, revealing a clear loading rate effect on both mode III and mode I fractures. Specifically, the peak load and fracture toughness (KIIIC, KIC) increase as the K·$$ \overset{\cdotp }{K} $$ increases across both static and dynamic scales. At the static scale, the KIIIC is about 1.28–1.38 times of the KIC, whereas at the dynamic scale, the KIIIC is less than the KIC. The relationship between KIIIC and KIC is affected by the loading scale and the shape of the specimen, but the data collected thus far indicate that the origin and type of rock have minimal effect on this relationship. In addition, the fracture surface morphology characteristics were quantitatively analyzed. [ABSTRACT FROM AUTHOR]

The behavior of PET foam under quasi-static and dynamic compressive loads is analyzed. An experimental study is performed to evaluate its mechanical behavior and energy absorption characteristics at different strain rates. Also, a numerical model is developed to reproduce the dynamic compression behavior of the PET foam. Differences between the properties obtained in the quasi-static and dynamic tests show that the strength, stiffness and energy absorption efficiency are dependent on strain rate. The evolution of the Poisson ratio with strain and strain ratio is studied. A decrease in the Poisson ratio is observed as the strain rate increases. [ABSTRACT FROM AUTHOR]

This work is dedicated to fabricated Chitosan-reinforced bamboo and nano bio-silica (1%, 2%, and 3% by volume) using the hand-layup method and investigate their mechanical properties. Mechanical characterization of samples proves that 2% volume nano bio silica-reinforced composites (C2) exhibit the highest tensile, flexural, and compressive strengths. Finite element analysis of dental implants for static and dynamic loading (60 cycles per minute) also confirmed the suitability of the C2 composites for dental implant applications, with Von-Mises stresses below the yield strength in human jaw bones. These findings highlight the potential use of bio-composite material for the dental implants in future. [ABSTRACT FROM AUTHOR]

The behavior of cracked structures made of functionally graded materials (FGMs) under different types of dynamic loading is investigated by calculating the dynamic stress intensity factor (DSIF). Material properties, i.e. Young's modulus E and mass density ρ vary exponentially and continuously along a given direction, but Poisson's ratio υ is assumed to be constant. Therefore, this work addresses the effect of FGM grading orientation as well as the effect of dynamic loading properties on DSIF. To achieve this goal, a computer code based on the extended finite element method (XFEM) combined with the Level-Set method was developed. DSIF is assessed using an interaction integral technique. To validate the developed code, the results were compared with other work in the literature on structures under step function loading. The good correlation between the results demonstrates the efficiency of the code. Then, as part of a parametric study, the structure is subjected to triangular and rectangular loadings, which change the graded value and orientation of the FGM. The quality of the results demonstrates the robustness of the developed code. [ABSTRACT FROM AUTHOR]

This article discusses the experimental investigation of the dynamic mechanical behavior of polyethylene (PE) foam under shock wave loading. The experiments were conducted using a two-stage light shock tube, and the dynamic response of the foam was characterized by measuring the pressure wave transmitted through the foam and the load on the foam specimen using a pressure sensor and a load cell, respectively. High-speed imaging was also used to capture the deformation of the foam specimen during the shock loading. The results show that the deformation of the foam under shock wave loading is non-uniform along the length of the specimen and is influenced by the presence of metal plates inserted along the length of the foam specimen. The degree of compression of the foam specimen was quantified and found to depend on the number of segments and the presence of metal caps on the specimen. The results provide insight into the mechanical behavior of PE foam under dynamic loading conditions and can be useful for designing protective structures for impact and blast resistance applications. [ABSTRACT FROM AUTHOR]

The Software‐Defined Networking (SDN) paradigm represents a fundamental shift in networking by decoupling the control plane from the data plane in network devices. This architectural change offers numerous advantages, including network programmability and centralized management capabilities, which improve scalability and efficiency compared to conventional network architectures. However, the dynamic nature of network traffic presents overload challenges, both temporally and spatially, especially in multi‐controller SDN settings. To address these challenges, this paper presents an approach leveraging network traffic patterns for dynamic load balancing. The proposed framework optimizes migration strategies to reduce costs and enhance in‐packet request‐response rates. By exploiting load ratio variance across controllers, the architecture identifies optimal migration triplets, encompassing migration‐in and migration‐out domains by selecting a subset of switches. The architecture utilizes online Q‐learning technology to achieve optimal controller load balancing while minimizing associated expenses. The proposed approach ensures stability and scalability by imposing limits to maintain maximum efficiency and reduce migration conflicts. It iteratively converges to an optimal policy through a comprehensive set of simulations performed on switches under a wide range of load distribution situations. These results highlight the effectiveness and adaptability of the proposed methodology in addressing the intricacies present in dynamic network settings, encouraging further progress in the field of SDN technologies and their real‐world applications. [ABSTRACT FROM AUTHOR]

This study examines the vibration characteristics of static drill-rooted nodular (SDRN) piles in elastic soils under time-harmonic torsional loads via an analytical approach. SDRN piles, which are characterized by uniformly distributed nodes and enhanced surrounding cemented soil, are able to increase the vertical bearing capacity of piles in soft soils. Piles are modelled using elastic rod theory, while surrounding soils are separated into two sublayers along radial direction: a core zone made up of cemented soil and an outer semi-infinite natural soil layer. An analytical method is proposed to solve the problem after formulating the wave equations for pile and radial soil layer. This methodology rigorously considers the continuity of twist angle and shear stress across the interface of the pile and radial soil layers. The simulation of nodes in the SDRN pile involves discretizing the pile-soil system and applying the principle of impedance function recursion to accurately compute the torsional stiffness at the top of the pile. Developed results are validated against the existing benchmarks for a cylindrical pile in elastic soil. Detailed numerical examples are carried out to assess the effect of major factors on the torsional impedance of the pile. For improved comprehension in engineering applications, the impedance function is applied to derive the twist angle of the rigid foundation, with the amplitude-frequency response expressed in a closed form. Results indicate that the vibration behavior of the piles is significantly influenced by the inner radius, outer radius, the dimension of the node, the radial width of the cemented soil and the damping ratio of the radial soil layer. The developed solution offers valuable insights for the optimization design of SDRN piles under dynamic torsional loads. [ABSTRACT FROM AUTHOR]

Stiffness modeling is an essential subject for the composition of robot control. Accurate stiffness modeling is helpful for improving the control accuracy of industrial robots, particularly under dynamic load circumstances. The classic virtual joint modeling (VJM) method is challenging in predicting the deformation of the end-effector throughout the full workspace due to the nonlinear deformation of the robot joint and its serial articulated structure. This paper proposes a full-space stiffness modeling method for robots based on the integration of a multi-layer perceptual (MLP) model and VJM. To provide enough training data for the MLP model, VJM is used to build a stiffness model with a small set of experimental data to generate 106,400 training data. A model-based transfer learning approach is proposed to improve the model's accuracy and generalization regarding the difference between generated training data and actual experimental data. The VJM stiffness model is compared with the MLP stiffness model and the existing CNN-based transfer learning model based on the same experimental data. Considering the deformation prediction in the three directions in Cartesian space, the mean absolute error, standard deviation, and maximum error of the MLP model are decreased by at least 24.90%, 14.20%, and 8.50%, respectively, than the VJM. These prediction results demonstrate that the proposed modeling technique can significantly increase the accuracy of robot stiffness modeling, which is essential for position compensation in precise motion control of robots under dynamic load. [ABSTRACT FROM AUTHOR]

For large‐scale complex nonconservative systems such as high‐speed rolling stock, the rigid‐flex coupling simulation technique is one of the effective methods in reducing lateral vibration and dynamic load sensitivity. Since two uncertain influences of wheel spin dissipation are caused by wheelset yaw oscillations and alternative load path variation due to nonstatically determined systems or redundant components/constraints, preliminary achievements of self‐adaptive improved design make wheel–rail matching returns to rational conditions, managing and maintaining better data integrity of high‐speed wheel–rail contact. A supporting platform was then established for multidisciplinary collaborative design optimization to scientifically promote the design speed, including inherent rigid‐flex coupling relationship and integrity protection of nonconservative systems and associated individual structures. Combined with analysis results of long‐term tracking online testing conclusions from Chinese practices of high‐speed rails, relevant theoretical deductions find that the magnitude of quasistatic strain energy is one of the critical influencing factors in determining the dynamic interactions on coupling interfaces of interest. With this regard, two key technologies were further put forward, i.e., rational eigenstructure assignment based on modal modification responding technique and multiaxial weld fatigue damage assessment tool based on the correctness of modal stress recovery, both of which have been examined and verified in specific case investigations. [ABSTRACT FROM AUTHOR]

This paper proposes a rate-dependent cohesive zone model for simulating the evolution and growth of cracks under dynamic loading. This model takes into consideration the effects of cohesive separation rate and crack growth speed on the cohesive traction-separation relationship to reflect the rate-dependent characteristics of both material viscosity and energy dissipation of micro-crack branches. The evolution algorithm of the cohesive law is presented, wherein separation rate and crack growth speed are evaluated using the backward difference method explicitly in incremental computation, leading to the determination of rate-dependent critical traction and fracture toughness. The proposed model was implemented in ABAQUS software via UEL subroutine and utilized in an example of interfacial crack growth simulation, with satisfactory agreement found among the present results, experimental data, and numerical results from the literature. The effectiveness of the rate-dependent model and numerical algorithm in simulating high speed crack growth is validated through further numerical tests. [ABSTRACT FROM AUTHOR]

In this paper, a study in the dynamic fracture assessment of Variable Angle Tow (VAT) composite laminates is presented. An interaction integral, which includes extra terms to guarantee its domain independency, is developed to extract the mixed-mode Stress Intensity Factors (SIFs) for a dynamically propagating crack in VAT composite laminates. Besides, comprehensive tip enrichment functions are implemented in the framework of XFEM. According to results, the crack in quasi-stationary loading follows the fiber path, generally. But this path may change in dynamic loading conditions. [ABSTRACT FROM AUTHOR]

Civil engineering structures are subject to both static and dynamic loadings. This applies especially to buildings in seismic areas as well as bridges, viaducts, and road and railway structures loaded with road or rail traffic. One of the solutions used to repair and strengthen such structures in the event of emergency damage are fibre-reinforced polyurethanes (FRPUs). The article proposes a laboratory method for determining the dynamic complex modulus of FRPU composite tape. The theoretical basis for determining the complex modulus for the tested material is presented. Laboratory tests were carried out using the tensile method for four cyclic loading frequencies and a cyclic load ratio equal to 0.5. Under the assumed test conditions, the material showed a viscoelastic performance with a dominant elastic part (storage modulus). For a frequency of 0.1 Hz, the viscous part (loss modulus) was about 8% of the storage modulus value, while for a frequency of 10 Hz, this value was about 5%. For a loading frequency of 0.1 Hz, the elastic part of the complex modulus was about 1160 MPa, while for a frequency of 10 Hz, it was about 1790 MPa. With the increase in loading frequency, the absolute value of the complex modulus increased. [ABSTRACT FROM AUTHOR]

Dynamic loads are inevitably generated during the operation of rotating machinery. In situ monitoring the dynamic loads is of great significance for assessing shafting health. Triboelectric nanogenerator (TENG) is sensitive to motion but not suitable for load monitoring, while piezoelectric nanogenerator (PENG) is just the opposite. Therefore, the combination of the two can complement each other. From this, a dynamic load monitoring smart bearing (DLMSB) integrated with TENG and PENG is proposed. The specially designed TENG can produce an "M‐waveform", which can be used to extract rotation frequency and distinguish the quadrant of the rotor. Meanwhile, applying PENG to capture the load condition of the bearing, and referring to the main frequency of M‐waveform, it is convenient to obtain the dynamic loads of shafting. Furthermore, a real‐time monitoring system is developed, which can realize not only real‐time monitoring of the rotation speed and dynamic loads magnitude but also the quadrant discriminating of dynamic loads. The results have shown that the monitoring error for dynamic loads is 3 N or 5.5%, and the accuracy rate for determining the quadrant of the dynamic loads can reach 93%. This study provides a novel approach for the in situ monitoring of mechanical operating status via nanogenerators. [ABSTRACT FROM AUTHOR]

We present a novel approach utilizing two-level dynamic load balancing for p -adaptive discontinuous Galerkin (DG) methods in compressible Computational Fluid Dynamics (CFD) simulations. The high-order explicit first stage, specifically the singly diagonal implicit Runge–Kutta (ESDIRK) method, is employed for time integration, where the pseudo-transient continuation is integrated with the restarted generalized minimal residual (GMRES) method to handle the solution of nonlinear equations at each stage of ESDIRK, excluding the initial stage. Relying on smoothness indicators, we carry out the refinement/coarsening process for p -adaptation with dynamic load balancing. This approach involves a coarse level (distributed memory) decomposition based on MPI paradigm and a fine level (shared memory) decomposition based on OpenMP paradigm, enhancing parallel efficiency. Dynamic load balancing is achieved by computing weights based on degrees of freedom, ensuring balanced computational loads across processors. The parallel computing framework adopts either a graph-based type (ParMETIS and Zoltan) or space-filling curves type (GeMPa) for coarse level partitioning, and a graph-based type (METIS and Zoltan) for fine level partitioning. The effectiveness of the method is demonstrated through numerical examples, highlighting its potential to significantly improve the scalability and efficiency of compressible flow simulations. The numerical simulations were conducted using the CODA flow solver, a state-of-the-art tool developed collaboratively by the French National Aerospace Center (ONERA), the German Aerospace Center (DLR), and Airbus. • Superior performance of p-adaptive DG solvers. • Runtime reduction with accuracy. • Enhanced numerical scalability by two-level dynamic load balancing. [ABSTRACT FROM AUTHOR]

The interface between the fiber and polymer matrix is a crucial region that plays a major role in the mechanical performance of fiber reinforced polymer composites (FRPCs) materials. The properties of this zone are recognized to have a significant influence on the fracture and failure of FRPCs. As a result, strong adhesion at the interface is required for effective stress transfer and load distribution within the composite material. In light of this, the aim of this work is to provide an up-to-date review of test methods for assessing fiber/matrix interface adhesion in FRPCs under static and dynamic loadings, along with advancements in interface modification techniques. At the outset, we give an overview of the different modification treatments used thus far, alongside interface testing methods, in order to optimize fiber/matrix compatibility, improve interfacial bonding and scrutinize their impact on interfacial adhesion properties. Particular attention is then focused on the description of the main mechanical characterization techniques used to assess the fiber/matrix interfacial properties. In the final outlook, we highlight the key findings and discuss potential directions for characterization of the fiber/matrix interface. [ABSTRACT FROM AUTHOR]

Due to the necessity of virtualization in a fog environment with limited resources, service providers are challenged to reduce the energy consumption of hosts. The consolidation of virtual machines (VMs) has led to a significant amount of research into the effective management of energy usage. Due to their high computational overhead, the existing virtualization techniques may not be suited to minimize the energy consumption of fog devices. As containers have recently gained popularity for encapsulating fog services, they are an ideal candidate for addressing this issue, particularly for fog devices. In the proposed work, an ensemble model is used for load prediction on hosts to classify them as overloaded, underloaded, or balanced. A container selection algorithm identifies containers for migration when a host becomes overloaded. Additionally, an energy-efficient container migration strategy facilitated by a dynamic inertia weight-based particle swarm optimization (DIWPSO) algorithm is introduced to meet resource demands. This approach entails migrating containers from overloaded hosts to others in order to balance the load and reduce the energy consumption of hosts located on fog nodes. Experimental results demonstrate that load balancing can be achieved at a lower migration cost. The proposed DIWPSO algorithm significantly reduces energy consumption by 10.89% through container migration. Moreover, compared to meta-heuristic solutions such as PSO, ABC (Artificial Bee Colony), and E-ABC (Enhanced Artificial Bee Colony), the proposed DIWPSO algorithm shows superior performance across various evaluation parameters. [ABSTRACT FROM AUTHOR]

This article presents an extended numerical approach for evaluating the dynamic response of corrugated cardboard transport packaging under simulated transport conditions. Building upon a simplified method previously introduced, this study integrates a more comprehensive Finite Element Analysis (FEA) framework to capture the non-linear behaviour of packaging subjected to vertical random vibrations. The proposed model employs dynamic, modal, and contact analyses to simulate the deformation of packaging and subsequent strength reduction over multiple impact cycles, reflecting real-world conditions more accurately. The developed approach gives detailed insights into the structural degradation of packaging due to repetitive transport loads and validates the findings through comparative compression tests. The results show that enhanced numerical methods improve the accuracy of load-bearing predictions, thereby supporting optimisation in packaging design for various geometries and transport scenarios. This method offers a valuable tool for evaluating the sustainability and cost-effectiveness of packaging solutions in logistics. [ABSTRACT FROM AUTHOR]

In order to study the instability characteristics of interlayer rock strata (IRS) in shallow buried close-distance coal seams under insufficient mining areas, based on the background of interval mining under goaf in Nanliang Coal Mine, this paper studies the instability characteristics of interlayer strata in interval mining under goaf by means of similar simulation, numerical simulation, and field measurement. The results indicated that the first weighting interval of the main roof during mining in the lower coal seam was 49 m, while small and large periodic weightings with intervals of 10–14 m and 15–19 m were identified. During periodic weighting, the support resistance ranged from 6813 to 10,935 kN, with a dynamic load factor of 1.07–1.74, and the peak abutment pressure in front of the working face was 5.85–9.85 MPa. The mining under the interval coal pillar (ICP) was the 'stress increase zone', and the mining under the temporary coal pillars (TCPs) and the interval goaf was the 'stress release zone'. During the working face mining out of the ICP, the support resistance reached 10,934 kN, the dynamic load factor reached 1.74, and the abutment pressure (AP) reached 9.85 MPa, which was 60% higher than the AP mining under the "stress release zone". Analysis suggests that the cutting instability of the IRS was the root cause of the increased AP in the working face of the lower coal seam. A numerical simulation was performed to verify the instability characteristics of the IRS in the interval goaf. The relationship between support strength and roof subsidence during the period of the working face leaving the coal pillar was established. A dynamic pressure prevention method involving pre-splitting and pressure relief of the ICP was proposed and yields superior field application performance. The findings of the study provide a reference for rock strata control during mining under the subcritical mining area in shallow and closely spaced coal seams. [ABSTRACT FROM AUTHOR]

An interchange is a pivotal traffic facility that connects highways and controls access. It is necessary to study their dynamic response characteristics to analyze the operational safety of ramp bridges on interchanges. Based on the numerical simulation results of the finite element model of the Fuxing Interchange Bridge, non-destructive measurement techniques were used to conduct field dynamic load tests on the bridge, including ramp strain testing and acceleration testing. These tests aimed to study the dynamic response characteristics of the ramp bridge under moving loads. Due to the design speed limitation of the ramp bridge, the grey prediction GM(1, 1) model was used to predict the maximum dynamic deflection, maximum dynamic strain, and vibration acceleration when the vehicle speed was 60 km/h. Subsequently, finite element software was used to simulate the dynamic deflection under vehicle speeds ranging from 30 to 60 km/h. The simulated value was compared with the predicted value, and the difference between the simulated value and the predicted value was slight. This model can evaluate the operational safety performance of off-ramps at different speeds. [ABSTRACT FROM AUTHOR]

An improved dual‐source SC‐MLI topology is developed in this article for medium‐voltage and high‐power applications. This topology can perform symmetrically and asymmetrically to generate 9 levels and 13 levels, respectively. It consists of 10 unidirectional switches, a dual DC source, and two capacitors to provide high‐gain output voltage with lower TSV. Since the capacitor's voltages are self‐balanced, therefore no need for an auxiliary circuit or sensors, which brings down the complexity of the circuit. To check the viability of the proposed topology, a simple and fundamental control strategy based on nearest‐level pulse width modulation is opted for. From the comparative analysis, it was observed that the proposed topology outperformed similar topologies in terms of switch counts, cost factor, power quality, and total standing voltage. The proposed topology's feasibility is evaluated using MATLAB/Simulink under both static and dynamic loads. Furthermore, a thermal analysis is conducted in PLECS software to calculate the losses across the components and consecutively the efficiency of the proposed circuit. It has been found that the proposed topology can generate 9 levels and 13 levels while having an efficiency of over 96% in symmetric and asymmetric configurations, respectively. Finally, the simulation results are verified by using the experimental prototype to validate the performance of the improved circuit under different loading conditions. [ABSTRACT FROM AUTHOR]

As large-scale renewable energy sources are integrated into the receiving-end grid, their interaction with load demands careful examination. This paper begins by analyzing the characteristics of active and reactive power fluctuations in renewable energy sources during low-voltage ride-through (LVRT). For a typical single-machine system connected to the grid, the mathematical relationship between the output power of renewable energy sources and the voltage at the point of common coupling is derived, determining the operating range without entering the LVRT state. By incorporating load models into the mathematical analysis, it is shown that the correlation between active power and voltage varies according to the load proportion. This leads to the identification of two types of "repeated LVRT" mechanisms dominated by either active or reactive power. Furthermore, considering the dynamic load model, motor slip is shown to affect the stable operating range of renewable energy sources, contributing to LVRT phenomena. Finally, from the perspective of the relationship between the operating point of renewable energy and the LVRT threshold curve, optimization strategies are proposed to address several types of new voltage stability issues caused by the interaction of various loads. The feasibility of these voltage phenomena and control strategies is validated using a simulated model. [ABSTRACT FROM AUTHOR]

Lower marine riser package/blowout preventers (LMRP/BOPs) play a crucial role in transferring the dynamic loads from the slim drilling risers to the subsea wellhead (SW). Generally, the LMRP/BOPs are usually modelled as the combination of pipe and mass elements in the finite element analysis. In this paper, an optimised equivalent modelling approach for LMRP/BOPs was proposed to improve the calculation accuracy of dynamic cyclic bending moment of SW. In the proposed methodology, the equivalent model of LMRP/BOPs was established based on the deformation analysis of the local fine model of LMRP/BOPs. Using the Newton–Raphson method, the equivalent model was optimised to acquire the optimal equivalent model of LMRP/BOPs. A case study indicated the modelling accuracy of LMRP/BOPs was improved by 14.6% compared to the conventional approach by using the proposed approach, thus the calculation accuracy of the dynamic cyclic bending moment of SW was improved accordingly. [ABSTRACT FROM AUTHOR]

To further enhance the ride comfort of vehicles, a new type of fluid inerter-based hydro-pneumatic suspension (FI-HPS) is proposed. First, this paper combines the fluid type inerter with the dual-chamber hydro-pneumatic suspension (DHPS) and fully considers the nonlinear factors. The nonlinear dynamic model of the fluid inerter is derived, and three structural models, namely the traditional DHPS S0, the ideal FI-HPS S1, and the nonlinear FI-HPS S2, are established. Then, the non-dominated sorting genetic algorithm II (NSGA-II) is employed to optimize the key parameters of the S1 and S2 suspensions. With the S0 suspension as a comparison subject, the simulation results show that the S2 suspension can significantly improve the vehicle’s ride comfort performance. In terms of the time-domain analysis, the root-mean-square (RMS) value of the vehicle body acceleration is reduced by 20.5%, the RMS value of the suspension working space is reduced by 12.7%, and the RMS value of the dynamic tire load is reduced by 8.0%. The frequency domain results indicate that the S2 suspension can effectively reduce the suspension offset frequency vibration, with a more significant effect at low frequencies. Upon analysis of impulsive road conditions, the peak-to-peak (PTP) value of the vehicle body acceleration is reduced by 14.2%, and the PTP value of the suspension working space is reduced by 6.3%. It is revealed that the inclusion of the nonlinear parasitic damping force in the fluid inerter can effectively enhance the overall performance of the hydro-pneumatic suspension system. [ABSTRACT FROM AUTHOR]

AbstractCurrent investigation is aimed to develop the concept of fractional derivatives proposed by Atangana–Baleanu that captures the memory effects of heat transfer and stress–strain relation inside a nonlocal viscoelastic polymer micro rod affected from a mobile heat input. Laplace Transform algorithm is bestowed to stimulate the closed-form solutions of temperature, displacement, thermal stress. Structured mechanism of numerical inversion of Laplace Transform is carried out for obtaining the quantitative outcomes in physical domain. Impacts of the fractional parameter, fractional order strain quantity, nonlocal parameter, and heat source velocity are analyzed. Results under fractional derivatives reveal stable characteristics of thermal waves. [ABSTRACT FROM AUTHOR]

AbstractMechanical structures built using the additive manufacturing (AM) process are generating significant interest due to their ability to design structural components with complex geometries. Indeed, additive processes, by adding material layer by layer, enables the creation of geometries that would be unfeasible using standard processes. However, while mechanical tests have extensively validated the use of conventional processes, the characterization of parts generated by less conventional processes, such as additive manufacturing, remains open to discussion. Specifically, will a part manufactured by AM meet the specifications in terms of mechanical strength? This paper contributes to answering this question by comparing identical AlSi10Mg plates manufactured using the AM process with a LASER powder bed fusion (L-PBF) machine (additive) and by conventional subtractive process (SM), subjected to high-velocity impacts. The impacts have been conducted on additive and subtractive 70*150*2 mm plates up to 300 m/s.” Based on measurements of projectile impact and residual velocities, as well as the study of deformation profiles of the different plates, the damage domains were identified. These tests highlighted significant differences between the different processes. [ABSTRACT FROM AUTHOR]

A bottom–up multi-scale performance transfer chain is developed to ascertain the gradual change in the law of vibration characteristics in spatial steel truss structures under fatigue loading. This chain derives the interrelationship between vibration characteristics and the performance of each structural component. Based on the evolution characteristics of the performance model of the member scale in the transfer chain, a new analytical model of the shape function is established. Building on these foundations, a refined model was formulated to depict the gradual change of vibration characteristics in spatial steel truss systems under fatigue loading. This model integrates the cumulative damage rule, the structural residual performance rule, the finite element method and other pertinent theories. The gradual change in vibration characteristics of a steel truss girder bridge subjected to train loads was analyzed using a self-developed three-dimensional finite element analysis framework tailored explicitly for assessing gradual change issues in spatial steel truss structures. The analysis results indicate that the effective residual cross-sectional area and the structural frequency continuously decline as the service time increases. This comprehensive study advances the understanding of fatigue-induced changes in spatial steel truss structures. It offers analytical perspectives for predicting and mitigating the long-term impacts of dynamic loads on large-scale infrastructural components. [ABSTRACT FROM AUTHOR]

In this paper, the electrochemical and corrosion behavior of pure titanium (TA1) in simulated Proton Exchange Membrane Water Electrolysis (PEMWE) anodic environment was investigated. In this condition, the corrosion potential of TA1 was −689 mV, with a self-corrosion current density of 232.5 μA cm–2, and a polarization resistance of 125.9 Ω cm2. During potentiostatic polarization at 2 V, the current density was maintained at approximately 6 mA cm–2. However, the passivation process exhibited instability. Furthermore, this process has been shown to significantly facilitate the formation of surface oxides, and the passive film that formed displays the lowest bound water and OH−, and the highest content of O2–, exhibiting the highest average valence. Notably, dynamic potentials caused current transients, among which square wave potential was the most remarkable. The square wave potential shows an O2– content just below that of 2V potential polarization when fluctuating potentials are applied. The interfacial contact resistance (ICR) of 2 V potentiostatic polarization was slightly higher than that of square, sine and triangular waves. Additionally, the high temperature condition of PEMWE will aggravate the corrosion of TA1 by fluoride ions. [ABSTRACT FROM AUTHOR]

Purpose: The dynamic effects of load fluctuation and the non-orthogonal behaviour of an axial active magnetic bearing (AMB) is enhanced from the dynamic model. The main purpose of the manuscript is to maintain the stability at the time of axial displacement of the rotor at both load and no load condition. Methods: Two loop controllers are used to maintain the stability of the proposed active magnetic bearing system. Inner loop is used to control the current and outer loop control the position. Proportional integral controller is used to control the current of the proposed system. Lead controller is used as a position controller to control the rotor position. Results: The axial model of an active magnetic bearing is simulated in simulation software, and the results are presented. These results show that overshoot is less in the fuzzy logic controller, but it is lagging in the other controller. Lead controller overshoot is less and better output is obtained compared to others. The hardware output of the AMB system is the same as the outcome of the simulation. The overshoot in the hardware output is comparable to the simulation result. Conclusion: In this manuscript, PI and LEAD controller based two loops active magnetic bearing system has been designed to control the axial displacement in both load and no load condition. A hardware setup is designed according to the simulation data and the system is successfully tested, and stable rotor levitation is achieved at the required gap between the actuator and rotor. [ABSTRACT FROM AUTHOR]

Purpose: With the advantages of simple structure, low energy consumption, and wide controllable damping range of magnetorheological (MR) damper, semi-active suspension with MR damper has become a promising application in the existing vehicle suspension system. However, the response time of MR fluid, the operation time of control system and the driving time of MR damper will result in response time delay together, which severe affect the vibration attenuating performance of the vehicle semi-active suspension system with MR damper. In this paper, a LQR controller incorporating NAGA-II algorithm considering response time delay (NSGA-II-TLQR) was developed to compensate for the response time delay of vehicle semi-active suspension system. Methods: Firstly, the mechanical property experiments of MR damper were carried out, and the direct model and the inverse model of MR damper were established by using genetic algorithm, respectively. Secondly, the model of a two-degree-of-freedom (2DOF) quarter vehicle semi-active suspension system with MR damper was built. Subsequently, the NSGA-II algorithm was introduced to optimize the weighting coefficient matrix of the LQR controller. Then the first-order Taylor series expansion was applied to the NSGA-II-LQR controller to predict the control force, which compensate for the response time delay. Finally, the performance was verified by simulation and experimental tests. Results: The results show that the body acceleration RMS values with NSGA-II-TLQR controller are decreased by 15.5% and 4.48%, the suspension deflection RMS values are decreased by 22.54% and − 1.22%, and the tire dynamic load RMS values are decreased by 10.32% and 5.38% compared with the passive suspension and the suspension with NSGA-II-LQR controller, respectively. Conclusions: The semi-active suspension with NSGA-II-TLQR controller has better performance in the ride comfort and handling stability. [ABSTRACT FROM AUTHOR]

Purpose: The improvement of passive and active suspension performance is often constrained by fixed parameters and high energy consumption. The emergence of semi-active suspension provides a potential solution to this challenge. However, most of the existing semi-active suspensions focus on damper control strategies without inertial characteristics. This paper aims to address this gap by designing and analyzing a semi-active inerter control for vehicle suspensions. Methods: An inerter control is proposed from the perspective of vibration power flow and realized by power driven inerter (PDI) control and power driven inerter-damper (PDID) control, respectively. To evaluate the coupling effect among the inerter, spring, and damper under different control strategies, two new indexes are also proposed: (1) the ratio of vibration power from the vehicle body to the suspension; (2) the spring contribution ratio to total body vibration power. Results and Conclusions: Analysis based on the new indexes reveals that suspensions incorporating inerter control exhibit a widened frequency bandwidth for vibration isolation. The simulation results of semi-active suspension demonstrate that PDI and PDID both provide better performance than acceleration driven damping control (ADD) in ride comfort (body acceleration), road handling (dynamic tire load), and suspension stroke (suspension working space), and improve the ride comfort performance over 23%. [ABSTRACT FROM AUTHOR]

Due to the particularity of the construction technology of the CRTS I slab track bagging method, there is a certain roughness between the track slab and the mortar layer in the actual project. In this work, the W–M fractal function was used to simulate the cement asphalt mortar layer in unit slab track with roughness rough surface morphology. To investigate the effects of interlayer rough contact surfaces, an interactive modeling approach using Python–Abaqus was developed, namely, the track structure performance, interlayer contact behavior, and vertical dynamic responses. The fastener pivot point reaction of the vehicle–track coupled model interacts with the track structure to examine the impact of different fractal dimensions and scale coefficients under the dynamic train load. The numerical results demonstrate that as the fractal dimension D and characteristic scale factor G increase, the dynamic response of the track slab gradually increases, and the contact area between layers decreases. The stress of rough contact surface is pointing distribution. Among the components of the track structure, the displacement of the track slab is most affected by the roughness. The rough surface affects the fatigue life of the mortar and consequently affects the service performance of the track structure. This study explores the effect of rough surfaces on the performance of CRTS I slab track structures under dynamic train load and provides a reference for improving the design of track structures and enhancing its life. [ABSTRACT FROM AUTHOR]

As of now, there are no standard guidelines for implementing data from Traffic Speed Deflection Devices (TSDDs) into Pavement Management Systems (PMS). This is primarily due to the complexities in analysing TSDD data. Several variables might potentially influence TSDD measurements. This study evaluates the effect of changing loading configurations, moving speed, temperature and pavement structure characteristics on the measurements of TSDDs through software modelling. The viscoelastic behaviour of the surface layer and the dynamic loads applied by all the vehicle axles are reflected in the modelling process. It is shown that pavement temperature can significantly affect TSDD measurements, primarily by changing the modulus of asphalt layer. At speeds exceeding 60 km/h, the effect of vehicle speed on TSDD measurements is negligible. Among the pavement structure characteristics, the subgrade modulus has a significant effect on TSDDs' deflection basin. Also, this study demonstrates device-specific models for estimating critical strains from TSDD data. The proposed models are validated using field measurements from a road in the Norwegian road network. [ABSTRACT FROM AUTHOR]

Ultra-thin concrete overlay (UTO) is an effective solution for repairing functional deficiencies in airport rigid pavements, with interface bonding properties critical to pavement performance and longevity. This study systematically investigates methods to enhance UTO interface bond strength under heavy dynamic loads. Aircraft dynamic simulations were performed to analyze stress states during landing, taxiing, and turning, identifying the required ultimate bond strength to prevent interface failure. Laboratory tests measured the shear and pull-out strengths of new and old concrete interfaces. A styrene–butadiene rubber (SBR) modified cement quartz mortar adhesive was developed with optimal curing conditions, and the effects of grooving intervals on bonding strength were assessed. Results demonstrated that the interface treatment increased the safety factor for tensile failure from 0.69 to 1.25 and for shear resistance from 0.61 to 1.12 under dynamic loads. This research provides a scientific basis for enhancing UTO applications in the functional rehabilitation of airport rigid pavements, offering a practical solution to improve safety and durability in high-stress environments. [ABSTRACT FROM AUTHOR]

The transportation sector is responsible for significant greenhouse gas (GHG) emissions, with medium- and heavy-duty trucks (MHDTs) being major contributors. In response, medium- and heavy-duty electric trucks (MHDETs) are being explored as zero-emission alternatives. However, the weight of high-capacity batteries needed for long-haul trips and heavy loads could increase the axle loads as well as the gross vehicle weight (GVW) of heavy-duty electric trucks (HDETs), leading to extra damage on flexible highway pavements. This study simulated the GVW increment of HDETs and assessed its effects on pavement damage, environmental impacts, and life-cycle costs of four typical highway pavement structures in Illinois (known as thick–weak, thick–strong, thin–weak, and thin–strong). The utilisation of electric trucks resulted in significant reductions in diesel combustion related global warming potential (GWP) emissions and costs (in $2022) by 73% and 11.5%, respectively. However, the results demonstrated that with a 100% penetration of HDETs carrying an additional weight of 8 kips per truck, the pavement deterioration accelerated compared to traffic with conventional trucks. As a consequence, GWP and costs were reduced by 69% and 10.6%, respectively. [ABSTRACT FROM AUTHOR]