Search Results (1,760)

Interlocking permeable pavements (IPPs) are increasingly adopted within sustainable urban drainage systems to reduce runoff, improve water quality, and strengthen climate-resilient urban infrastructure. However, clogging remains the principal constraint on their long-term hydraulic performance and wider implementation. This review synthesises current evidence on clogging mechanisms, hydraulic decline, and lifecycle mitigation strategies for permeable interlocking concrete pavements (PICPs), concrete grid pavements (CGPs), and plastic grid pavers (PGPs). The literature is dominated by PICP studies, with CGP and PGP underrepresented, restricting typology-specific assessment. Sediment accumulation within joints, grid openings, bedding layers, and near-surface interfaces is consistently identified as the primary clogging mechanism, while traffic, rainfall-runoff loading, biological processes, pollutant retention, and sediment inputs from adjacent impervious surfaces further influence hydraulic deterioration. The findings indicate that hydraulic performance is influenced not only by pavement age but also by interactions among pavement design, filler or joint material, drainage configuration, construction quality, sediment exposure, monitoring, and maintenance. Effective mitigation therefore requires lifecycle management, encompassing source control, pretreatment, appropriate material selection, construction quality assurance, routine hydraulic monitoring, and timely preventive and restorative maintenance. Future research should prioritise standardised clogging assessment protocols, improved laboratory–field integration, targeted investigation of CGP and PGP, biological and pollutant-linked clogging processes, climate-driven rainfall extremes, and decision-support. Full article

Homogeneous TC4 titanium alloy suffers from the strength–ductility trade-off and exhibits insufficient anti-penetration capacity under high-strain-rate impact. TiC_p-reinforced functionally graded titanium matrix composites (FGTMCs) with a “hard outer, tough inner” gradient architecture are promising lightweight armor materials. The use of Abaqus/Explicit finite element simulation for FGTMCs under dynamic impact can capture transient deformation and damage evolution while enabling rapid evaluation of the impact resistance of different materials; however, research in this area remains scarce. This study conducts a systematic parametric analysis of key simulation parameters, including calibration of the Johnson–Cook constitutive and damage model parameters for TC4 titanium alloy, optimization of mesh partitioning strategies, hourglass control schemes, model dimensions, and boundary conditions to suppress “ghost mesh” numerical artifacts. Material property assignments for TC4 and three typical titanium matrix composites are designed, along with a methodology for constructing functionally graded material models. Two projectile–target matching configurations (small projectile/thin target vs. large projectile/thick target) are compared, and the optimal model of a 700 m/s small-caliber tungsten projectile impacting a 50 mm TC4 target is identified. Parametric analysis demonstrates that a damage parameter D4 = 0.1 significantly improves numerical stability, and a graded mesh strategy with further refinement along the penetration path balances computational accuracy and efficiency. Using the optimized material system, the simulation results reproduce the three-stage damage evolution of titanium alloys under impact—cratering, plastic penetration, and back-face spallation—providing reliable numerical support for the structural optimization of graded armor materials. Full article

Recycled glass fiber-reinforced polymer (GFRP) powder from decommissioned wind turbine blades offers sustainable reinforcement for wood–plastic composites (WPCs), but its efficiency is limited by poor interfacial adhesion with the polypropylene (PP) matrix caused by surface epoxy residues. In this study, GFRP/WPCs with a fixed formulation of 15 wt% GFRP, 10 wt% wood flour, and 75 wt% PP were used to compare two modification strategies: MAPP compatibilization (1–7 wt%) and H₂O₂ treatment (5–30%). MAPP modification improved the mechanical properties of GFRP/WPCs, with the optimal concentration varying by property: flexural strength reached its maximum (75.45 MPa, +24.7%) at 1 wt% MAPP, while tensile strength (+9.2%), flexural modulus (+20.7%), and impact strength (+18.9%) were maximized at 3 wt% MAPP. H₂O₂ at 10% achieved higher strength gains (tensile: +23.65%, i.e., 26.7 MPa; flexural: +27.93%, i.e., 77.4 MPa; impact: +35.29%, i.e., 16.98 kJ/m²) but moderately reduced flexural modulus. FTIR confirmed up to 71.7% epoxy removal by H₂O₂, exposing cleaner fibers. Both modifications slightly lowered thermal decomposition temperatures but increased char residues and PP crystallinity via enhanced nucleation. SEM showed that MAPP created a compatible interphase, while H₂O₂ enabled direct mechanical interlocking. Surface free energy analysis revealed that MAPP increased polar components, whereas H₂O₂ increased dispersive components. Overall, MAPP offers simpler processing and balanced properties, while H₂O₂ provides superior strength at the cost of some stiffness—providing practical guidance for tailoring recycled GFRP/WPCs for construction and sustainable applications. Full article

To address the challenge of surrounding rock control in deep gob-side entry driving, the return airway of the 20203 working face of the Dahaize Coal Mine was taken as the engineering background. The stress, deformation and plastic zone evolution characteristics of the surrounding rock of the gob-side entry were studied through theoretical analysis, numerical simulation and field tests, and the surrounding rock control mechanism and the double-layer flexible thick anchor control technology were proposed. The results show that under the influence of the adjacent gob, the peak compressive stress of the gob-side entry is transferred to the solid coal side, and tensile stress areas are generated on the roof; shear failure is the main failure pattern of the surrounding rock in the gob-side entry, which is characterized by significantly asymmetric deformation. Based on the displacement failure characteristics of the surrounding rock zones, a double-layer flexible thick anchorage structure was constructed. The anchorage depth of the first basic support exceeds the critical thickness of the shallow fractured surrounding rock zone, forming a thick load-bearing layer for the roadway surrounding rock; the anchorage depth of the secondary reinforced support extends into the stable rock mass, enhancing the bearing capacity of the anchored body and the roadway surrounding rock. The results of numerical simulation show that after adopting a double-layer flexible thick anchor support, the average deformation of the roof decreases by 48.81%, and the range of the tensile stress zone and plastic zone is significantly reduced. In engineering applications, the average deformation of the roadway roof was 42.58 mm, the two-end convergence was 0–2 mm, the roof separation value was controlled within 0–30 mm, and the rock strata within 0–5.0 m remained intact. This technology effectively suppresses the large deformation of the surrounding rock in deep gob-side entry, providing an innovative strategy for roadway stability control under comparable geological and mining conditions. Full article

As timber construction continues to expand toward taller and larger buildings, ensuring structural resilience under fire conditions requires advanced fire–structural performance assessment approaches. Such assessments generally integrate fire models to define thermal exposure, heat transfer models to predict temperature evolution within structural members, and structural models to evaluate fire-induced structural response. While substantial progress has been achieved in fire and thermal modelling, the structural modelling component, particularly constitutive representation of timber behaviour at elevated temperatures, remains comparatively less developed. This paper presents Wood^ST, a temperature-dependent plastic–damage constitutive modelling approach developed to advance the structural assessment of timber structures under fire conditions. The key modelling components of Wood^ST are briefly introduced, and its capabilities are demonstrated through applications to representative timber structural systems, including bending members (LVL, glulam w/o openings, OSB-web I-joists), axially loaded compression members considering stability effects, complex bolted timber connections and assemblies (light wood frame and hybrid timber–concrete floors) involving multiple interacting components and contact behaviour. The presented applications demonstrate the capability of Wood^ST to capture fire-induced material degradation, nonlinear response, instability, and structural interaction across multiple scales. These advances support performance-based fire design and contribute to the development and implementation of design codes and standards (e.g., CSA O86 and ISO TC92), while facilitating innovation in timber products and structural systems. Full article

This study develops a finite element analysis (FEA) framework to quantify hydrostatic consolidation of ultra-high-molecular-weight polyethylene (UHMWPE) fibril arrays containing interstitial voids. Hexagonal and stochastic representative volume elements (RVEs) were constructed from experimentally measured fibril diameters and embedded in a nearly incompressible Mooney–Rivlin medium to transfer hydrostatic pressure to irregular fibril surfaces. Molecular dynamics (MD)-derived fibril properties at 300 K and 400 K were used to evaluate the effects of temperature, elastic–plastic deformation, and stochastic microstructure on void collapse and effective fiber properties. The 300 K elastic model required pressures approaching 1.3 GPa to reach approximately 1–2% void content, whereas the combined effects of elevated temperature, elastic–plastic fibril behavior, and stochastic fibril packing reduced the corresponding pressure to approximately 160 MPa. The stochastic RVE exhibited a higher initial void content, earlier plastic dissipation, lower initial effective stiffness, and nonuniform fibril–fibril contact evolution compared to the idealized hexagonal RVE. As void content decreased, both models converged toward the dense fibril response. The framework establishes a processing–microstructure–property relationship linking consolidation pressure to the evolving void morphology, fibril shape and contact development, and the resulting effective plane-strain bulk modulus and the transverse compressive stress–strain response, including the Young’s modulus and Poisson’s ratio, of UHMWPE fibers. Full article

Carbon fiber reinforced plastic (CFRP) composites have been widely adopted in the aerospace industry due to their excellent mechanical and physical properties. However, their anisotropy and weak interlaminar bonding make them prone to defects such as delamination and fiber pull-out during conventional drilling (CD). Longitudinal-torsional coupled ultrasonic vibration-assisted drilling (LTC-UAD) integrates axial and circumferential vibrations to suppress hole defects and is considered a promising machining method for improving the quality of holes drilled in CFRP. Based on kinematic analysis, a model for the working rake angle of the main cutting edge is established to obtain the variation law of the maximum working rake angle along the cutting edge. Compared with CD and longitudinal ultrasonic vibration-assisted drilling (L-UAD), LTC-UAD significantly increases and homogenizes the maximum working rake angle of the main cutting edge, which helps optimize its cutting performance. A three-dimensional finite element model of CFRP is constructed to analyze the dynamic fiber removal process under typical fiber orientations. Finally, drilling experiments are performed to observe the hole wall micro-morphology at various fiber angles. The simulation results indicate that ultrasonic vibration causes periodic changes in the fiber cutting angle, subjecting the fibers to a directional shear state and making them more prone to shear fracture. Two-dimensional ultrasonic vibration cutting enhances the directional shear effect, promotes fiber fracture, accelerates chip removal, and improves the quality of the machined surface. Experimental observations confirm LTC-UAD alleviates fiber crushing, bare fibers, and surface cavities with uniform resin coverage. Furthermore, ultrasonic vibration suppresses thrust force. L-UAD and LTC-UAD yield 10.6% and 17.1% reductions via periodic cutting depth variation and facilitated carbon fiber shear fracture. Full article

Classic elastic–plastic models for concrete do not fully account for either the material properties of shotcrete or the influence of environmental factors, resulting in significant limitations in the research and application of shotcrete in tunnels. This paper comprehensively considers the early-age strength of tunnel shotcrete and the physical and chemical attack effects of a sulfate environment, to investigate the mechanical degradation mechanisms of tunnel shotcrete under sulfate conditions and establish a corresponding nonlinear elastoplastic model. This study carried out sulfate attack tests on tunnel shotcrete and systematically revealed the stress–strain evolution characteristics of shotcrete under sulfate attack. Based on experimental data on both chemical and physical attack, this paper improves the classical elastoplastic constitutive model and constructs an elastoplastic constitutive model applicable to both the early and hardening stages of shotcrete. Overall, the improved model can describe the stress–strain response of shotcrete reasonably well; however, due to the high inherent discreteness of the shotcrete material itself, some fitting deviations still exist near points of sudden change in strain or stress. Under sulfate chemical attack conditions, the cracking stress of shotcrete exhibits a nonlinear trend of first increasing and then decreasing as corrosion time progresses. Under physical attack conditions, the cracking stress shows a clear linear decrease. Furthermore, in high-concentration sulfate environments, the influence of sulfate concentration on cracking stress is moderately reduced. The results of this study provide theoretical support for the durability assessment and constitutive modeling of tunnel shotcrete in sulfate-corrosive environments. Full article

In aircraft assembly, riveting is a critical joining method that directly determines structural integrity, fatigue life, and overall airframe reliability. With the increasing adoption of human–machine collaborative systems for complex assembly tasks, the rational design of riveting process parameters has become essential for ensuring consistent assembly quality. However, traditional experimental parameter optimization is time-consuming and costly, and lacks generalizability across varying working conditions. To address this challenge, this paper proposes a simulation-based design method for rapidly constructing process parameter schemes in human–machine collaborative aircraft assembly riveting. A theoretical dynamic model of the pneumatic reciprocating riveting gun is established to derive the relationship between input air pressure and piston impact velocity, providing physically grounded loading conditions for numerical simulation. A sequentially coupled numerical simulation method is developed using Ansys LS-DYNA and its Restart function to accurately model the entire multiple reciprocating impact forming process, which incorporating preloading analysis to reflect actual clamping conditions and reset analysis with applied damping to eliminate post-impact oscillations. Taking the riveting assembly of Aluminum (AL) 2024T351 rivets and AL 7039 aluminum sheets as a case study, the simulation successfully reproduces the rivet forming evolution over twelve consecutive impacts, revealing a two-stage deformation mechanism consisting of elastic springback and superimposed elastic-plastic deformation. Experimental verification on a self-built human–machine collaborative riveting platform demonstrates excellent agreement with simulation results in impact counts and upset head height. The proposed method provides a reliable, efficient, and low-cost approach for assembly process parameter calibration, offering direct theoretical support for assembly quality control, process robustness, and reliability assurance in aircraft manufacturing. Full article

N-methyl-D-aspartate (NMDA) receptors (NMDARs) are Ca²⁺-permeable ionotropic glutamate receptors in the brain that have critical roles in learning, memory, neural development, and synaptic plasticity. NMDARs are heterotetrameric Ca²⁺ channels, which open upon binding to the neurotransmitters, glutamate and glycine. Channel opening causes Ca²⁺ influx that activates a range of Ca²⁺-dependent cellular processes, including activation of Ca²⁺-dependent enzymes, which mediates various forms of synaptic plasticity. Prolonged channel opening elevates the intracellular Ca²⁺ level to a cytotoxic concentration. To maintain Ca²⁺ homeostasis, NMDAR channel activity is finely regulated by α-actinin (ACTN), which promotes channel opening by reducing the closed time, and by calmodulin (CaM), which promotes Ca²⁺-dependent channel desensitization (CDD). Defects in the regulation of NMDAR function are associated with a spectrum of neurological diseases. In this review, we integrate cryo-EM structures of NMDARs, NMR structures of the NMDAR cytosolic C0 domain of the GluN1 and GluN2A subunits bound to Ca²⁺-bound CaM (Ca²⁺-CaM), and various structures of α-actinin-1 (ACTN1) to construct structural models of NMDAR in the open channel state bound to Ca²⁺-free ACTN1 and the agonist-bound, desensitized channel state bound to Ca²⁺-CaM. These structural models provide insights into the Ca²⁺-dependent conformational changes that promote CDD. Full article

A critical research gap persists in modular steel construction regarding the seismic behavior of inter-module connections between square steel tubular columns and H-shaped steel beams. While numerous connection systems have been proposed, two fundamental challenges remain unresolved: the inherent conflict between construction efficiency and mechanical performance, and the insufficiency of restoring force models that systematically describe hysteretic characteristics and stiffness degradation under cyclic loading. To address these issues, a novel box-type modular connection between square steel tubular columns and H-shaped steel beams is proposed. A finite element model was established using ABAQUS, and the modeling methodology was validated against experimental results from the literature. The seismic behavior was systematically investigated, and a restoring force model with theoretical saturation and linear degradation was developed. Results show that the novel joint is a semi-rigid connection that satisfies the “strong column–weak beam” design principle. The outer ring plate shifts the plastic hinge away from the vulnerable beam end region, preventing failure at the beam–column connection. Among the detrimental factors identified, the insert-to-column gap has the most severe impact, causing up to a 49.5% reduction in energy dissipation and a 6.5% reduction in initial stiffness; the outer ring plate thickness below the beam flange thickness causes a 44.6% drop in energy dissipation. The proposed restoring force model, validated against nine calibration specimens and one independent specimen, predicts peak load with a deviation of only 1.14% and the equivalent viscous damping coefficient with a relative error of 14.7%, confirming its reliability in capturing the cyclic behavior of the joint. This study provides both design recommendations for engineering practice and a theoretical foundation for elasto-plastic analysis of modular frames with this connection type. Full article

Polymer-modified asphalt has been widely used to improve pavement durability under increasing traffic loads and complex environmental conditions. Styrene–butadiene–styrene (SBS) is one of the most effective elastomer modifiers. It can form a polymer-rich network within asphalt. Styrene–methyl methacrylate copolymer-based modifier (SMC) can be produced from recycled rubber and plastic resources. It has attracted increasing attention because of its potential compatibility, processability, and environmental benefits. This paper reviews the modification mechanisms, rheological properties, fatigue performance, aging resistance, and engineering applications of SBS-, SMC-, and SMC–SBS-modified asphalt and mixtures. Particular attention is given to the synergistic effects between SBS and SMC, including polymer swelling, phase morphology, network formation, interfacial compatibility, and durability evolution. Existing studies indicate that SBS mainly improves elastic recovery and high-temperature deformation resistance. In contrast, SMC can enhance workability, low-temperature flexibility, and construction compatibility. Their composite modification shows strong potential for balancing high-temperature, low-temperature, fatigue, and aging performance. However, current studies are still limited by insufficient quantitative comparisons, unclear microstructural mechanisms, and the lack of unified evaluation methods. Future studies should establish multi-scale structure–property–durability models. The modifier dosage range should also be optimized. This review provides a systematic reference for the development of high-performance and sustainable polymer-modified asphalt materials. Full article

This study proposes a novel friction-based beam-to-column shear connection designed to behave as a nominally pinned joint while avoiding any perforation of the connected members. The connection relies on frictional resistance to transfer shear forces, enabling full reversibility and preserving the integrity of the structural elements for future reuse. A comprehensive design methodology is first introduced, addressing key parameters such as clamping force, friction coefficient, and slip resistance. Subsequently, an extensive numerical investigation is carried out using refined finite-element models, i.e., considering multiple geometric configurations and loading conditions. The local behaviour of the connection is hence assessed in terms of stiffness, strength, and slip capacity. Results show that—with proper sizing—plastic deformation localises in the beam while the joint remains elastic and slip is limited, confirming the conservativeness of the approach. The joints behave as nominally pinned in terms of resistance while showing moderate stiffness. Derived findings highlight the feasibility of adopting friction-based, non-invasive connections as a viable alternative for circular steel construction, contributing to the ongoing transition toward more sustainable structural systems. Full article

Resistance to apoptosis, metabolic plasticity, and redox adaptation are major contributors to cancer progression and treatment failure. Ferroptosis and cuproptosis have therefore emerged as metal-dependent forms of regulated cell-death programs with potential relevance for tumours that survive conventional therapy. Ferroptosis is driven by iron-dependent phospholipid peroxidation when glutathione peroxidase 4 (GPX4)-dependent and parallel antioxidant systems fail, whereas cuproptosis depends on mitochondrial copper engagement of lipoylated tricarboxylic-acid-cycle proteins, lipoylated-protein aggregation, iron–sulfur protein destabilization, and proteotoxic stress. This review integrates the molecular basis, genetic architecture, long non-coding RNA (lncRNA)-mediated regulation, mechanistic crosstalk, and therapeutic implications of ferroptosis and cuproptosis in cancer. It emphasizes a critical evidence hierarchy: expression association, computational signature construction, metal accumulation, reactive oxygen species (ROS) generation, or reduced viability should not be interpreted as pathway dependency without pathway-defining biochemical endpoints and rescue experiments. The most credible translational opportunities will depend on functional stratification, tumour-selective delivery, and pharmacodynamic confirmation that distinguishes pathway-defined ferroptosis or cuproptosis from nonspecific metal-induced and oxidative cytotoxicity. Full article

Accurate prediction of cutting forces remains a key challenge in metal machining due to the strong coupling between geometry, material behavior, friction, and thermal effects, which limits the generality of purely empirical models. In this study, physically interpretable models with predictive capability for cutting and thrust forces are developed for orthogonal cutting of AISI 1045 steel using a dimensional analysis framework based on the Buckingham $\mathsf{\Pi }$ theorem. Experimental data collected from the literature are used to construct dimensionless formulations incorporating geometrical, kinematic, mechanical, and thermal parameters. The proposed models are calibrated and evaluated using statistical performance metrics and residual analysis, and subsequently validated against independent experimental datasets not used during model development. A correction factor associated with the tool–chip contact length is optimized during validation to improve predictive accuracy. Results show that both force components can be consistently represented through a reduced set of governing dimensionless groups, providing physically meaningful scaling across a wide range of cutting conditions. The validation results confirm the robustness of the proposed formulation, while also revealing different sensitivities of cutting and thrust forces to contact, thermal, and geometrical effects. A physical interpretation of the dimensionless groups is presented, framing the machining process as a case of severe plastic deformation under high strain rates and strong thermomechanical coupling. The study demonstrates that dimensional analysis offers a physically consistent, scalable, and transferable approach for modeling cutting forces, with potential applicability to other materials and machining configurations. Full article