Structural Deformation Research Articles

Performance Analysis Using CNN for Detecting Wood Knots

This study proposes a Convolutional Neural Network (CNN) model to quickly and accurately detect wood deformations. The performance of the CNN was enhanced by extracting structural deformation features, optimizing training parameters, and improving datasets. Experimental analyses demonstrate that the CNN achieved high accuracy rates and is an effective method for deformation detection. The CNN model was designed to identify various wood deformations. Its layered architecture was optimized to analyze deformations at different scales and levels of detail. Minimal preprocessing was applied to the images used during training, and data augmentation techniques were employed to enhance dataset diversity. The model was trained on a training dataset and tested on a validation dataset. Metrics such as loss function and accuracy were monitored throughout the training process. The CNN achieved an accuracy rate of 99.90% on the training dataset. This study highlights that the CNN model is an effective method for non-destructive detection of wood deformations. The proposed CNN model has potential applications in wood deformation detection and quality control processes.

Land-to-sea indicators of the Zanclean megaflood

One debated scenario for the termination of the Messinian salinity crisis 5.33 million years ago is cataclysmic refilling of the Mediterranean Sea through the Zanclean megaflood. Here we present a clear line of onshore-to-offshore evidence for this megaflood spilling over a shallow-water marine corridor in south-east Sicily into the nearby subaqueous Noto Canyon: (i) >300 asymmetric and streamlined erosional ridges aligned with the megaflood direction, (ii) poorly-sorted breccia deposited between the Messinian and Lower Zanclean Trubi Formations, (iii) soft-sediment deformation structures and clastic injections in the breccia and underlying units, and (iv) a 20 kilometre wide erosional shelf channel connecting the ridges with Noto Canyon. Numerical modelling results support the modulation of flow velocity and direction by the excavation of the channel and Noto Canyon. Our findings demonstrate that the Messinian salinity crisis was terminated through a cataclysmic flood, which implies pronounced Mediterranean sea-level drawdown prior to the flooding.

METHODS OF ANALYSIS OF DYNAMIC PROCESSES IN DISCRETE-CONTINUUM SYSTEMS UNDER PULSE EXCITATIONS

This paper addresses the enhancement of methods for calculating vibration-impact machines, particularly concerning adjustments to prevent potential shock resonances. This design criterion for substantiating the parameters of vibration-impact machines had not been previously considered. However, the likelihood of shock resonance increases significantly with the mass of the process load, operating frequencies of vibration excitation, and overall dimensions of the thin-walled bodies of vibrating machines. Hence, prioritizing the criterion of tuning out resonant modes through the appropriate choice of housing parameters becomes crucial for modern, heavily loaded machines. This novel approach is proposed in this paper for calculating vibration-impact machines and armored vehicles. To analyze the conditions for the onset of resonant modes under periodic shock loading, single-mass, multi-mass, and continuum dynamic systems were sequentially considered. It was shown that, in the absence of friction, shock resonance occurs when any natural frequency of the machine body oscillations matches a multiple of the excitation frequency from the drive. Additionally, numerical integration of the system of differential equations of motion was used to confirm shock resonance conditions. The numerical results were consistent with the analytical ones. It was also determined that tuning away from the resonant frequency by 5% to 10% significantly alters the steady-state mode of the vibration machine, notably reducing oscillation amplitudes. Therefore, to substantiate the parameters of vibrating machines, it is essential to maximize the adjustment of the natural frequency spectrum of their bodies, considered as elastically deformable structures, away from frequencies that are multiples of the drive frequency. To implement this algorithm, we propose adopting a generalized parametric description. Variable parameters include the thickness of housing elements, their cross-sections, reinforcement schemes, and the number of stiffeners. It was found that varying these parameters diversely affects the migration of natural frequencies in the spectrum. Specific parameters with the greatest impact on detuning from shock resonance frequencies were identified. This set of parameters is used to determine the optimal set that satisfies the criterion of maximum detuning from shock resonance. Similar developments and studies have been conducted for the armor hulls of lightly armored vehicles.

The Crooked Nose—Surgical Algorithm in Post-Traumatic Patient—Evaluation of Surgical Sequence

Background: A crooked nose is a challenge for a surgeon performing rhinoplasty. When performed correctly, rhinoseptoplasty aligns the nasal framework, restores nasal patency, and achieves facial symmetry. The key to this procedure is to dissect all the structures of the nasal framework, mobilize, reposition, and stabilize them. Aim: This study aims to discuss the quality of life after the rhinoseptoplasty and principles of treating a post-traumatic crooked nose with a view to improving the predictability and reliability of rhinoplasty procedures involving this challenging problem. Methods: The study compared the results of the Rhinoplasty Outcome Evaluation (ROE) and the Standardized Cosmesis and Health Nasal Outcomes Survey (SCHNOS) through statistical analysis. Results: Considering the structural deformities that lead to a crooked nose, the open approach seems to be preferred during a rhinoseptoplasty of a post-traumatic, crooked nose. When reconstructing the nasal septum, it is always necessary to leave the required amount of cartilage to provide nasal support and to secure the septum to the nasal spine. Osteotomies are important for fixing a crooked nose. The preoperative values for ROE were significantly lower before surgery than after surgery (8.7 vs. 20.2), while for SCHNOS, the postoperative values were statistically significantly lower compared to the preoperative values (46.0 vs. 9.1). Conclusions: Properly planned and performed surgery improves the functional and aesthetic outcomes in patients after rhinoseptoplasty.

Study on the Influence and Deformation Control of Rich Water Foundation Excavation on Adjacent Buildings

Taking the foundation pit of the Suzhou Chunshenhu Road Expressway Reconstruction Project as an example, the excavation process of the foundation pit was numerically simulated using a three-dimensional finite element method. The measured data and simulated data of the lateral deformation of the enclosure structure, surface settlement deformation of the ground outside the pit, and settlement deformation of the building were compared to analyze the impact of foundation pit construction on adjacent buildings. The influence of foundation pit floor and diaphragm wall thickness on wall displacement, building settlement, and foundation pit uplift was also discussed. The results showed the following: (1) Adding a foundation pit floor has a significant effect on reducing the lateral displacement of the diaphragm wall, settlement of the building, and uplift of the foundation pit. Increasing the thickness of the foundation pit floor has a limited effect on reducing the displacement, while increasing the thickness of the diaphragm wall has a small effect. (2) The displacement curve of the underground diaphragm wall increases with depth. It reaches a maximum at the excavation surface and then decreases gradually. (3) The surface settlement increases first and then decreases with distance from the foundation pit, showing a concave shape. As the depth of excavation increases, the settlement value increases. (4) Through analysis of the monitoring data of vertical displacement of buildings, it can be seen that during foundation pit excavation, buildings undergo five stages: initial slow descent, steep descent, mid-term slow descent, late steep descent, and stable deformation. The buildings are dominated by settlement deformation.

Ribbed moraines formed during deglaciation of the Icelandic Ice Sheet: implications for ice‐stream dynamics

Investigations of the geomorphological fingerprints of palaeo‐ice streams are essential for enhancing our understanding of ice‐stream behaviour. Cross‐cutting flowsets of palaeo‐ice streams, during and following the Last Glacial Maximum, have been suggested in northeast Iceland based on the mapping of streamlined subglacial bedforms (SSBs). To increase our understanding of the dynamics of the Icelandic Ice Sheet (IIS) during deglaciation, we investigate transverse ridges, together with glacifluvial and ice‐marginal landforms, within the largest flowset. The main emphasis is on the transverse ridges, which are primarily interpreted as ribbed moraines – the first to be described in Iceland. Morphological data are combined with sedimentological analyses of the ribbed moraines. Our results show that the ribbed moraines are composed of pre‐existing material, often exhibiting a base of stratified glacifluvial sediments draped with subglacial till. Deformation and thrust structures within both units suggest compressional flow during the formation of the ridges. Our results suggest the ribbed moraines develop due to velocity gradients under the lateral shear margin of an ice stream based on their distribution and often oblique orientation in relation to SSBs. The ribbed moraines superimpose and thus post‐date the SSBs, signifying the waning stage of ice streaming. We suggest that the ridges formed during ice‐stream shutdown following the Younger Dryas and/or Preboreal re‐advances. Eskers and ice‐marginal landforms imply channelized water drainage during the final deglaciation interrupted by short‐lived re‐advances. This study has implications for the style of deglaciation associated with ice streaming in the northeastern part of the IIS. We characterize the role of ribbed moraines within the ice sheet and identify directions for future work.

Development of a multi-scale nanofiber scaffold platform for structurally and functionally replicated artificial perforating arteries.

Experimental models for exploring abnormal brain blood vessels, including ischemic stroke, are crucial in neuroscience; recently, significant attention has been paid to artificial tissues through tissue engineering. Nanofibers, although commonly used as tissue engineering scaffolds, undergo structural deformations easily, making it challenging to create uniform tissue, especially for the smallest-diameter ones such as perforating arteries. This study focused on the development of a platform capable of reconstructing structurally and functionally replicated perforating arteries. To ensure structural consistency, 3D-printed modules were developed to minimize the structural deformation of nanofibrous scaffolds when integrated into a 3D-printed vessel culture dish. Surface structures and physical characteristics of the nanofibers before and after installation were compared using scanning electron microscopy, contact angle analysis, surface area analysis, and universal testing machine (UTM) analysis. The results showed a uniform thickness distribution, topography, maximum load, tensile strain, tensile strength, surface area, pore size, and pore volume of the nanofibers. For consistency in tissue culture, smooth muscle, endothelial, and astrocyte cells were co-cultured by continuously measuring the pH of the medium and replenishing the depleted glucose using the Kalman filter control system. The functional efficacy and consistency of the artificial perforating vessels were confirmed under oxidative stress induced by exposure to hydrogen peroxide. Transcriptional mRNA expression trends were similar to those in vivo for antioxidant enzymes, neurotrophic factors, inflammatory factors, and endothelial cell activation factors, with very low variation between tissues. This study provides a research platform for studying the oxidative stress environments related to stroke by mass-producing perforating arteries with consistent structures and functions.

Advance in Shape Memory Polymers for Aerospace Applications

As humanity's exploration of cosmic space becomes more and more in-depth, aerospace technology, as a critical cornerstone supporting this endeavor, is constantly facing new challenges and opportunities. Aerospace engineering has extremely stringent requirements for materials, which require high strength and toughness to withstand extreme environmental conditions, such as high temperature, low temperature, high radiation, etc., and meet the complex needs of lightweight, high reliability, and multi-functional integration. Traditional materials often face many limitations in meeting these requirements, and the emergence of shape memory polymers (SMPs) has provided new ideas and possibilities for the design and application of aerospace materials. As an emerging class of intelligent materials, SMPs, due to their unique shape memory effect, lightweight and high strength, good designability, and other characteristics have gradually demonstrated excellent application potential in several aspects of the aerospace field. Application potential in many aspects of the aerospace field. Based on this, this paper first explains the shape memory effect (SME). Then, SMPs under different actuation conditions are explored, including light, heat, electricity, and magnetic field stimulation conditions. Finally, the paper highlights the application of SMPs in wing deformation structures, space deployable structures, thermal protection systems, etc. This will provide new solutions for the lightweight and multifunctional design of spacecraft.

Characteristics and Control of Subway Train-Induced Environmental Vibration: A Case Study

With the widespread construction of the subway in the Chinese mainland, the environmental vibration caused by subway operation has attracted increasing attention. Train-induced environmental vibrations can cause structural deformation, uneven settlement of line foundations, and tunnel leakage, affecting the structural safety of lines and foundations. This research focuses on a segment of the Nanchang Metro Line 3, which has been chosen as the subject of investigation. A numerical model was developed to analyze the subway train-induced environmental vibration, employing the finite element method (FEM). Utilizing a numerical model, an investigation was conducted to examine the impact of train speed on the subway train-induced environmental vibration, the train-induced environmental vibration transmission characteristics were analyzed, and the control effects of vibration reduction tracks on train-induced environmental vibration were discussed. Train-induced vibration tests were also conducted on Nanchang Metro Line 3 to verify the control effects of various vibration reduction tracks. The results indicate that the subway train-induced environmental vibration rises as the train speed goes up, and the vibration peaks always appear around 63 Hz. When the train speed doubles, the Z-vibration level increases from about 5.1 dB to 5.9 dB. Subway train-induced environmental vibration shows a fluctuating decreasing trend with increasing distance from the centerline of the tunnel. The Z-vibration level reaches its maximum 4 m away from the centerline of the tunnel. Compared with the embedded sleeper, the vibration-damping fastener exhibits a vibration reduction effect of about 9 dB to 18 dB, the rubber vibration-damping pad exhibits a better vibration reduction effect of about 16 dB to 24 dB, and the steel spring floating plate exhibits the best vibration-damping effect of about 18 dB to 28 dB. The calculated Z-vibration levels are basically consistent with the measured values, indicating the accuracy of the calculated results of the control effects of the vibration reduction tracks.

Direct Crystallographic Observation of Obvious Structural Deformation in a Lead Halide Framework Induced by Host–Guest Interactions

AbstractHost–guest chemistry represents a prominent field within many inorganic solids, where the host entity typically retains its original lattice. The hybrid composition and soft lattice of organolead halides make their structural changes and optical properties highly sensitive to host–guest interactions, distinguishing them from conventional inorganic solids. Herein, 3D electron diffraction tomography, an advanced crystallographic technique, is employed to observe the pronounced structural deformation of the lead bromide layers upon the cleavage of coordinated solvent molecules, which renders a coordination unsaturated side for the activated Pb2+ sites. Moreover, the structural transmutation induced by this process leads to a significant enhancement and red‐shift in self‐trapped emission, which is analyzed in‐depth using a variety of photophysical studies. More importantly, the activated Pb2+ centers are able to re‐coordinate with the environmental N,N‐dimethylformamide vapors in a selective and reversible manner, highlighting high application potentials in multilevel information encryption and anti‐counterfeiting.

The Effect of a Fully Asymmetric Discontinuity in the Elastic Layer of a Geometrically Nonlinear Double-Beam Coupled Mechanical System

This paper presents the effect of an antisymmetric discontinuity in a Winkler nonlinear elastic layer and compares it with the case of a double Timoshenko beam system without discontinuities. The effects of geometric nonlinearity are considered, and the obtained results represent a time-domain analysis. A modified p-version finite element method is applied to analyse the vibrations of mechanical systems with discontinuities. The main contribution of this work is a comparative analysis of a double beam system without discontinuities and a double beam system with an antisymmetric discontinuity in the Winkler elastic layer. The study demonstrates significant deviations in the beam response under a concentrated periodic external force when an antisymmetric discontinuity is present. Its qualitative and quantitative characteristics are illustrated through time histories, showing amplitude variations in the steady-state oscillation regime. Forced vibrations in the time domain are analysed using the Newmark direct integration method. The cases of deviations in the antisymmetric model are explained, highlighting their potential applications in technical practice as well as in the field of deformable bodies and structures.

Research on the Full Life Cycle Deformation, Stress Response, and Dynamic Fatigue Performance of Concrete Structures in Pump Stations

Research on the Full Life Cycle Deformation, Stress Response, and Dynamic Fatigue Performance of Concrete Structures in Pump Stations

Enhance the Concrete Crack Classification Based on a Novel Multi-Stage YOLOV10-ViT Framework.

Early identification of concrete cracks and multi-class detection can help to avoid future deformation or collapse in concrete structures. Available traditional detection and methodologies require enormous effort and time. To overcome such difficulties, current vision-based deep learning models can effectively detect and classify various concrete cracks. This study introduces a novel multi-stage deep learning framework for crack detection and type classification. First, the recently developed YOLOV10 model is trained to detect possible defective regions in concrete images. After that, a modified vision transformer (ViT) model is trained to classify concrete images into three main types: normal, simple cracks, and multi-branched cracks. The evaluation process includes feeding concrete test images into the trained YOLOV10 model, identifying the possible defect regions, and finally delivering the detected regions into the trained ViT model, which decides the appropriate crack type of those detected regions. Experiments are conducted using the individual ViT model and the proposed multi-stage framework. To improve the generation ability, multi-source datasets of concrete structures are used. For the classification part, a concrete crack dataset consisting of 12,000 images of three classes is utilized, while for the detection part, a dataset composed of various materials from historical buildings containing 1116 concrete images with their corresponding bounding boxes, is utilized. Results prove that the proposed multi-stage model accurately classifies crack types with 90.67% precision, 90.03% recall, and 90.34% F1-score. The results also show that the proposed model outperforms the individual classification model by 10.9%, 19.99%, and 19.2% for precision, recall, and F1-score, respectively. The proposed multi-stage YOLOV10-ViT model can be integrated into the construction systems which are based on crack materials to obtain early warning of possible future deformation in concrete structures.

Bacterial Cellulose/Graphene Oxide/Hydroxyapatite Biocomposite: A Scaffold from Sustainable Sources for Bone Tissue Engineering.

Bone tissue engineering demands advanced biomaterials with tailored properties. In this regard, composite scaffolds offer a strategy to integrate the desired functionalities. These scaffolds are expected to provide sufficient cellular activities while maintaining the required strength necessary for the bone repair for which they are intended. Hence, attempts to obtain efficient composites are growing. However, in most cases, the conventional production methods of scaffolds are energy-intensive and leave an impact on the environment. This work aims to develop a biocomposite scaffold integrating bacterial cellulose (BC), hydroxyapatite (HAp), and graphene oxide (GO), designated as "BC/HAp/GO". All components are sourced primarily from agricultural and food waste as alternative means. BC, known for its biocompatibility, fine fiber network, and high porosity, serves as an ideal scaffold material. HAp, a naturally occurring bone component, contributes osteoconductive properties, while GO provides mechanical strength and biofunctionalization capabilities. The biomaterials were analyzed and characterized using a scanning electron microscope, a X-ray diffractometer, and a Fourier transform infrared spectrometer. The produced biocomposite scaffolds were tested for thermal stability, mechanical strength, and biocompatibility. The results showed a nanofibrous, porous network of BC, highly crystalline HAp particles, and well-oxygenated GO flakes with slight structural deformities. The synthesized biocomposite demonstrated promising characteristics, such as increased tensile strength due to added GO particles and higher bioactivity through the introduction of HAp. These inexpensively synthesized materials, marked by suitable surface morphology and cell adhesion properties, open potential applications in bone repair and regeneration.

Research on the Thermal Safety of Ion-Doped Na3V2(PO4)3 for Sodium-Ion Batteries

Na3V2 (PO4)3 (NVP) is considered to be a promising cathode material for sodium-ion batteries (SIBs). Ion doping can effectively improve its structural deformation, poor conductivity, and electrochemical performance. However, the research on the effect of ion doping on the thermal stability of NVP is still limited. In this paper, Mg/Ti co-doped and Mn/Ti co-doped modified NVP with carbon nanotubes (CNTs) (MgTi@ CNTs and MnTi@CNTs) were prepared, respectively, and X-ray diffraction (XRD) results proved that MgTi@CNTs and MnTi@CNTs have good structural stability and crystallinity. The electrochemical performance indicates that the dual strategy of p-n-type co-doping and CNT coating provides superior sodium storage performance, enhancing both electronic conductivity and ion diffusion. Secondly, based on the safety point of view, the thermal stability of p-n-type ion-doped NVP and its mixed system with electrolyte in a charged state was studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and accelerated calorimeter (ARC). The results show that the optimized MgTi@CNTs and MnTi@CNTs electrodes exhibit excellent thermal stability in the absence of electrolytes, indicating their high intrinsic safety. However, it is worth noting that in the electrode/electrolyte system, p-n-type ion-doped NVP have higher reactivity with the electrolyte, and their comprehensive thermal safety is lower than that of NVP. Therefore, in practical applications, it is necessary to comprehensively consider the thermal stability of the material and the thermal safety of its mixed system with the electrolyte. This paper provides a data basis for the practical application of NVP in SIBs.

Synergistic Effect of Anchoring Transitional/Interstitial Sites on Boosting Structural and Electrochemical Stability of O3-Type Layered Sodium Oxides.

O3-type layered oxides are considered promising cathode materials for next-generation high-energy-density sodium-ion batteries (SIBs). However, they face challenges, such as low rate capacity and poor cycling stability, which arise from structural deformation, sluggish Na+ diffusion kinetics, and interfacial side reactions. Herein, a synergistic substitution strategy for transitional and interstitial sites was adopted to improve the structure stability and Na+ diffusion kinetics of the O3-type NaNi0.2Fe0.4Mn0.4O2. Simulation results indicate that Co3+/B3+ codoping effectively lowers the Na+ migration energy barrier. In addition, the synergistic effect of Co3+/B3+ codoping provides ultralow lattice strain during repeated Na+ deintercalation/intercalation. In situ characterization verified that the complex phase transformation during charge and discharge was suppressed, thereby significantly improving the structural stability. At 1 and 3 C, the capacity retention of the modified O3-Na(Ni0.2Fe0.4Mn0.4)0.96Co0.04B0.02O2 (NFMCB) improved from 29.6% and 1.7% to 86.7% and 88.6% after 200 cycles, respectively. Even at 10 C, it could still produce 107.2 mAh·g-1. Furthermore, full cells assembled with this material and commercial hard carbon exhibit a high energy density of 316.2 Wh·kg-1 and a capacity retention of 80.8% after 200 cycles at 1 C. It is expected that this strategy will facilitate the commercialization of O3-type layered oxides.

MiR-378 exaggerates angiogenesis and bone erosion in collagen-induced arthritis mice by regulating endoplasmic reticulum stress

Rheumatoid arthritis (RA) is a chronic autoimmune disorder marked by pain, inflammation, and discomfort in the synovial joints. It is critical to understand the pathological mechanisms of RA progression. MicroRNA-378 (miR-378) is highly expressed in the synovium of RA patients and positively correlated with disease severity, but its function and underlying mechanisms remain poorly understood. In this study, miR-378 transgenic (miR-378high) mice were used to construct the collagen-induced arthritis (CIA) model for exploring the role of miR-378 in RA development. miR-378high CIA mice showed accelerated RA development, as evidenced by exaggerated joint swelling and bone structural deformities. More severe endoplasmic reticulum (ER) stress and the consequent angiogenesis and osteoclastogenesis were also activated in the synovial tissue and calcaneus, respectively, in the miR-378high group, suggesting that ER plays a significant role in miR-378-mediated RA pathogenesis. Upon in vitro RA induction, fibroblast-like synoviocytes (FLSs) isolated from miR-378high mice showed a higher expression level of ER stress markers. The conditioned medium (CM) from RA-FLSs of miR-378high mice stimulated more intensive angiogenesis and osteoclastogenesis. The ER stress-related protein Crebrf was identified as a downstream target of miR-378. Crebrf knockdown diminished the promoting effect of miR-378 on ER stress, as well as its downstream angiogenesis and osteoclastogenesis activities. Tail vein injection of anti-miR-378 lentivirus in an established RA mouse model was shown to ameliorate RA progression. In conclusion, miR-378 amplified RA development by promoting ER stress and downstream angiogenesis and osteoclastogenesis, thus indicating that miR-378 may be a potential therapeutic target for RA treatment.

Reduced Order Modelling of Fully Coupled Electro‐Mechanical Systems Through Invariant Manifolds With Applications to Microstructures

ABSTRACTThis article presents the first application of the direct parametrisation method for invariant manifolds to a fully coupled multiphysics problem involving the nonlinear vibrations of deformable structures subjected to an electrostatic field. The formulation proposed is intended for model order reduction of electrostatically actuated resonating Micro‐Electro‐Mechanical Systems (MEMS). The continuous problem is first rewritten in a manner that can be directly handled by the parametrisation method, which relies upon automated asymptotic expansions. A new mixed fully Lagrangian formulation is thus proposed, which contains only explicit polynomial nonlinearities, which is then discretised in the framework of finite element procedures. Validation is performed on the classical parallel plate configuration, where different formulations using either the general framework or an approximation of the electrostatic field due to the geometric configuration selected are compared. Reduced‐order models along these formulations are also compared to full‐order simulations operated with a time integration approach. Numerical results show a remarkable performance both in terms of accuracy and the wealth of nonlinear effects that can be accounted for. In particular, the transition from hardening to softening behaviour of the primary resonance while increasing the constant voltage component of the electric actuation is recovered. Secondary resonances leading to superharmonic and parametric resonances are also investigated with the reduced‐order model.

Multi-scale monitoring and safety assessment of a prefabricated subway station integrating space-borne InSAR, ground-based machine vision and internal-distributed fiber optic sensors

ABSTRACT Safety monitoring of prefabricated subway stations is essential for early detection of potential damages to mitigate major accidents. This study developed an integrated multi-scale safety assessment and monitoring strategy for a prefabricated subway station by combining space-borne synthetic aperture radar interferometry (InSAR), ground-based machine vision, and internal-distributed fiber optic sensing (DFOS) technologies. Compared to the traditional single-data-source-monitoring method, the proposed space-ground-internal integration strategy is designed to monitor the multi-scale damages of prefabricated subaway stations. This includes the mm level of ground subsidence, submm level of structural surface deformation, and microstrain level of structural internal strain field. Taking the prefabricated Shapu Station in Shenzhen as the research site, the spatiotemporal evolution of land subsidence, the underground structural settlement and convergence deformation, as well as the structural internal strain changes were monitored. Then, a multi-scale data fusion methodology combining the space-borne InSAR, the ground-based machine vision, and the internal DFOS measurements was presented for effective safety assessment of the subway station. The monitoring results indicated that deformation occurred during the backfill period, and the settlement of the dangerous assembly ring increased (the seventh ring was at the lowest safety level) when the backfill of the assembly section was completed.

MODELING OF HIGH-RATE HARDENING OF A POLYMER COMPOSITE MATERIAL UNDER LOADING ALONG THE REINFORCEMENT DIRECTION

Modeling the high-rate deformation of composite structures is of great interest in the industry. Moreover, some processes such as accidents, explosions and possible impact issues require analysis of composite materials at significantly high deformation rates. The paper considers the possibility of developing a model of deformation of a composite material based on a polymer matrix and carbon fiber taking into account high-rate hardening. A feature of the study is the development of a model that takes into account a wide range of deformation rates from static to several thousand reverse seconds. Thus, tests were carried out with special equipment and samples that allow us to obtain data with such high loading speeds. The model is based on an approach considering the use of damage parameters, the so-called class of models with progressive degradation. The main innovative part of the chosen model is the formalization of the rate of deformation on the material through the damage parameter, that is, the rate of change in damage values is considered. This approach makes it possible to make constitutive relations based only on the damage parameters, which modify the stiffness and strength characteristics of composites, which greatly simplifies the modeling and analysis of material deformation.