Bending Curvature Research Articles

Manufacturing of Hydraulically Steerable Actuator Using Closed Molding and Core Template for Vascular Intervention Guidewires

Abstract Active steering catheters and guidewires for vascular intervention, employing pressure-driven mechanisms, have been studied for their promise of safety, miniaturization capacity, and ease of operation. Manufacturing methods of pressure-driven catheters and guidewires at the microscale is challenging, and suffer from limitations such as low durability, restricted steering shape, cytotoxicity, and applicability. This paper proposes a novel manufacturing method of the hydraulically steerable actuator for micro guidewires utilizing closed molding and a laser-patterned core template. The cylindrical core template composed of stainless steel is employed to ensure biocompatibility and is patterned by femtosecond laser processing with relative errors of up to 15.04%. The proposed method enables a bonding-free manufacturing of the micro actuator which is an eccentric tube with integrated patterns on its inner surface. Trapezoidal patterns are designed to be symmetrically placed in the direction of the eccentricity on the proximal part. The steering shape of the micro actuator is designed by adjusting the geometry of the patterns engraved onto the core template. A steerable actuator of 600 μm diameter with a double bending curvature is manufactured, achieving a maximum bending angle of 132.93 degrees and a steering distance of 9.20 mm. Experiments of selective insertion with the steerable actuator are conducted using the model of cerebral vascular branching, which resembles the human blood flow. The experiment results show that the steerable actuator can navigate through the vascular bifurcations of 4.2 mm and 1.5 mm diameters with branching angles of 112 degrees.

Mechanical Reversal in the Catalytic Capability of Monolayer Transition Metal Dichalcogenides for Hydrogen Evolution Reaction: An Explicit First-Principles Study.

Pristine transition metal dichalcogenide (TMD) monolayers are generally regarded as exhibiting low chemical reactivity due to their inert surfaces. Our extensive first-principles calculations, which incorporate an explicit solvation model, reveal that the catalytic performance of pristine TMD MX2 (where M = Mo or W, and X = S, Se or Te) monolayers for hydrogen evolution reaction can be significantly altered and enhanced through mechanically bending deformation. For a WTe2 monolayer, its hydrogen adsorption Gibbs free energy decreases to 0.004 eV under a bending curvature of 0.15 Å-1. The notable reversal in the catalytic capability of curved TMD monolayers can be primarily ascribed to the interplay between elastic energy stimuli and hydrogen adsorption energy barrier, alongside charge transfer to metal atoms facilitated by the weakening of M-X bonds and the exposure of metal atoms. A theoretical model has been established to elucidate the relationship among hydrogen adsorption Gibbs free energy, bending elastic energy, and adsorption energy barrier.

Modeling and analysis of the bending curvature and mechanical properties of the bimetallic clad plate by the asynchronous rolling

Modeling and analysis of the bending curvature and mechanical properties of the bimetallic clad plate by the asynchronous rolling

Seismic performance of round-end hollow RC tall bridge piers considering to higher-order vibration mode effect

Round-end hollow reinforced concrete (RC) tall piers have been widespreadly utilized for railway bridges in river valleys and mountainous regions. The post-earthquake damage state of such bridge piers differs significantly from that of traditional short-to-medium piers. To investigate the seismic performance and failure mode of RC round-end hollow tall piers, a finite element model was developed using the OpenSees platform and calibrated against previous test results. Subsequently, incremental dynamic analysis (IDA) and modal pushover analysis (MPA) were conducted to obtain bending moment and curvature distributions as well as damage ranges for piers subjected to different intensities of ground motion. The results indicate that: The RC round-end hollow tall piers subjected to strong ground motions can crack up to 75% and 80% of its height according to IDA and MPA, respectively. The MPA incorporating mode coupling up to the third order is capable of predicting crack distribution of the pier as demonstrated in this study. Furthermore, it is recommended that the damage range of the pier be considered as a primary control indicator in seismic design.

Bending Moiré in Twisted Bilayer Graphene.

Moiré potentials caused by lattice mismatches significantly alter electrons in two-dimensional materials, inspiring the discovery of numerous unique physical properties. While strain modulates the structure and symmetry of the moiré potential, serving as a tuning mechanism for interactions, the impact of out-of-plane deformation, e.g., bending, on the moiré superlattice remains unknown. Here, we performed large-scale molecular dynamics simulations to study the evolution of the moiré superlattice of twisted bilayer graphene under out-of-plane bending deformation. Our findings indicated that curvature-dependent bending caused both global and local lattice structure modifications in the moiré superlattice. We revealed a linear relationship between lattice displacement and bending curvature across varying initial twist angles along with precise regulation of local interlayer rotation. Additionally, the atomic potential energy landscape revealed that the localized atomic stacks underwent a whirlpool-like transformation, becoming a relaxed superlattice. This work opens up new opportunities for tailoring moiré superlattices by using out-of-plane bending engineering.

Magnetic kirigami dome metasheet with high deformability and stiffness for adaptive dynamic shape-shifting and multimodal manipulation.

Soft shape-shifting materials offer enhanced adaptability in shape-governed properties and functionalities. However, once morphed, they struggle to reprogram their shapes and simultaneously bear loads for fulfilling multifunctionalities. Here, we report a dynamic spatiotemporal shape-shifting kirigami dome metasheet with high deformability and stiffness that responds rapidly to dynamically changing magnetic fields. The magnetic kirigami dome exhibits over twice higher doming height and 1.5 times larger bending curvature, as well as sevenfold enhanced structural stiffness compared to its continuous counterpart without cuts. The metasheet achieves omnidirectional doming and multimodal translational and rotational wave-like shape-shifting, quickly responding to changing magnetic fields within 2 milliseconds. Using the dynamic shape-shifting and adaptive interactions with objects, we demonstrate its applications in voxelated dynamic displays and remote magnetic multimodal directional and rotary manipulation of nonmagnetic objects without grasping. It shows high-load transportation ability of over 40 times its own weight, as well as versatility in handling objects of different materials (liquid and solid), sizes, shapes, and weights.

A Flexible Sensing Material with High Force and Thermal Sensitivity Based on GaInSn in Capillary Embedded in PDMS.

Flexible sensing materials have become a hot topic due to their sensitive electrical response to external force or temperature and their promising applications in flexible wear and human-machine interaction. In this study, a PDMS/capillary GaInSn flexible sensing material with high force and thermal sensitivity was prepared utilizing liquid metal (LM, GaInSn), flexible silicone capillary, and polydimethylsiloxane (PDMS). The resistance (R) of the flexible sensing materials under the action of different forces and temperatures was recorded in real-time. The electrical performance results confirmed that the R of the sensing material was responsive to temperature changes and increased with the increasing temperature, indicating its ability to transmit temperature signals into electrical signals. The R was also sensitive to the external force, such as cyclic stretching, cyclic compression, cyclic bending, impact and rolling. The ΔR/R0 changed periodically and stably with the cyclic stretching, cyclic compression and cyclic bending when the conductive pathway diameter was 0.5-1.0 mm, the cyclic tensile strain ≤ 20%, the cyclic tensile rate ≤ 2.0 mm/min, the compression ratio ≤ 0.5, and the relative bending curvature ≤ 0.16. Moreover, the material exhibited sensitivity in detecting biological signals, such as the joint movements of the finger, wrist, elbow and the stand up-crouch motion. In conclusion, this work provides a method for preparing a sensing material with the capillary structure, which was confirmed to be sensitive to force and heat, and it produced different types of R signals under different deformations and different temperatures.

Shape measurement using a multicore optical fiber sensor with asymmetric dual cores

Abstract Shape measurement using multicore optical fiber sensors has attracted more attention in many fields due to the good consistency of the fiber cores. Three symmetrically arranged cores in a multicore fiber are usually used to reconstruct shapes by calculating the bending vectors, which will not be achieved when one of the cores is damaged or occupied in actual application. A shape measurement method using a multicore optical fiber sensor with asymmetric dual cores is proposed in this paper. Based on the analysis of the principle of shape reconstruction and the geometric relationship of the asymmetric dual cores in the multicore fiber sensor, the bending vector is decomposed. The mathematical expressions for the bending curvature and orientation of the asymmetric dual cores are derived. The two-dimensional (2D) and three-dimensional (3D) shape reconstruction results in both finite element modeling simulation and shape measurement experiments based on optical frequency domain reflectometry have shown that the proposed method using a multicore fiber sensor with asymmetric dual cores is able to achieve shape measurement; its performance is comparable and even equivalent to the traditional method that uses three symmetrically arranged cores. In the experiment, the maximum relative errors of 2D and 3D reconstructed shapes are 2.653% and 5.139%, respectively. The proposed method, which only needs asymmetric dual cores in the multicore optical fiber sensor for shape reconstruction, will be conducive to solving the limitations of multicore optical fiber sensors in shape measurement applications.

Phase Diagrams for Anticlastic and Synclastic Bending Curvatures of Hexagonal and Reentrant Honeycombs

Abstract Transformation between saddle- and dome-like bending shapes of regular and reentrant hexagonal honeycomb panels are explored. An analytical model is proposed to uncover the underlying mechanisms and identify the controlling parameter when the cell walls are slender beams. Then, 3D finite element simulations are performed to examine the architecture dependence of bending shape and construct the phase diagrams of anticlastic and synclastic curvatures when the cell walls have a general geometry. The results are believed helpful to the design and application of related honeycomb structures.

Flexible and Stretchable Li Ion Battery Using Origami Scale Structure for Untethered Soft Robot

In recent years, technology of soft robotics has emerged as an important issue for the robot industry. Compared to conventional industrial metallic robots in controlled environments, soft robots are highly expandable in responding to non-standardized environments. Due to these characteristics, it is expected to be used not only in daily life, but also in specific applications such as treatment of disease and disaster relief. The development of a structure that is free to deformation with energy source is also essential to improve the technology. Among several energy sources, Lithium ion batteries (LIBs) are the prime choices for these applications due to light weight, high energy density and long cycle life. The integration of flexible structure and LIBs is very important to reduce the waste of space and weight of soft robots for versatility and portability. However, there are many difficulties due to the absence of batteries with high reliability under deformation. LIBs usually have little flexibility due to the high stack cells and stiff nature of cell components. It is required to have a new design of LIBs. Geometrically designed structures incorporating bioinspiration are promising solutions for integrating components of soft robots. In this study, we propose a novel geometric structure for stretchable devices, created by folding well-defined two-dimensional patterns with cutouts to produce an extremely stretchable structure with superior reliability and bi-axial deformability. The structure is designed to mimic the hinge of a snakeskin so that its unit cells do not interfere with each mutual movement enabling stable deformations without mechanical damage. In addition, to maximize areal density and stretchability, the optimal shape of unit is determined. The unit-based geometric structure is applied to a stretchable Li-ion battery and constructed of hexagonal pouch cells and parallelogram interconnections. In situ electrochemical characterization confirms that the performance of the battery is maintained under dynamic deformation with a stretching ratio of 90% and a 10-mm-radius bending curvature, guaranteeing a long-lasting cycle life. To confirm the mechanical reliability of the scale battery, the strain distribution at the flexible hinge is obtained by FEA(Finite element analysis). The strain is mainly localized in the folding parts of the interconnection, and it is found that the unit cell experiences on deformation during the unfolding process. This is the main reason that the electrochemical performance is maintained during the mechanical deformation of the scale battery. Finally, the geometrically designed structure-based battery is applied to movable robots, crawling and slithering, with dynamic bi-axial deformations and can be pivotal role in the development of flexible electronics including human-friendly wearable electronics and soft robots.

Parallel Farby-Perot Interferometers in an Etched Multicore Fiber for Vector Bending Measurements.

Vector bending sensors can be utilized to detect the bending curvature and direction, which is essential for various applications such as structural health monitoring, mechanical deformation measurement, and shape sensing. In this work, we demonstrate a temperature-insensitive vector bending sensor via parallel Farby-Perot interferometers (FPIs) fabricated by etching and splicing a multicore fiber (MCF). The parallel FPIs made in this simple and effective way exhibit significant interferometric visibility with a fringe contrast over 20 dB in the reflection spectra, which is 6 dB larger than the previous MCF-based FPIs. And such a device exhibits a curvature sensitivity of 0.207 nm/m-1 with strong bending-direction discrimination. The curvature magnitude and orientation angle can be reconstructed through the dip wavelength shifts in two off-diagonal outer-core FPIs. The reconstruction results of nine randomly selected pairs of bending magnitudes and directions show that the average relative error of magnitude is ~4.5%, and the average absolute error of orientation angle is less than 2.0°. Furthermore, the proposed bending sensor is temperature-insensitive, with temperature at a lower sensitivity than 10 pm/°C. The fabrication simplicity, high interferometric visibility, compactness, and temperature insensitivity of the device may accelerate MCF-based FPI applications.

Machine learning-Assisted spiral fiber Bragg Grating-Based flexible dual-parameter sensing

The ability of flexible sensors to bend or fold freely offers great advantages in sensing ability and adaptability to harsh environments. Moreover, compared with typical electrical effect based flexible sensors, optical based fiber Bragg grating (FBG) flexible sensors offer much greater ease of networking and resistance to electromagnetic interference, making them suitable for distributed multi-point strain measurements in complex environments. In this paper, two FBGs with no overlapping reflective spectra are shallowly embedded in the surface layer of a flexible thin-cylinder substrate to form a dual-parameter flexible strain sensor. However, it is crucial for the changes in direction and curvature parameters of FBG strain sensors under deformation to be accurately understood to characterize the current deformation state of the flexible sensor. Moreover, conventional peak tracking demodulation methods often fail to account for distortion in the reflected spectrum of a spiral FBG under stress. Hence, a multi-output convolutional neural network learning model is constructed to simultaneously identify the bending direction and curvature radius of the flexible sensor using machine learning methods. Experimental results show that the flexible dual-parameter FBG sensor has precisely recognize angles to within 2° across a 360° range, with a curvature recognition accuracy of 99.1%, offering precision sensing performance suitable for highly demanding application scenarios such as bionic robots and flexible medical devices.

Experimental and parametric study on seismic performance study of column mid-height uplift steel rocking frame

Structural overturning due to second-order effects presents a significant challenge in the design of uplift rocking frames, particularly in high-seismic regions. Existing configurations, which typically locate the uplift joint at the base of the column, exacerbate this issue by increasing rocking demands. While various solutions have been proposed to address this limitation, a design that effectively mitigates these risks while maintaining energy dissipation(ED) and self-centering capabilities remains underexplored. In response to this challenge, this study introduces a novel column mid-height uplift steel rocking frame (CMURF) that relocates the uplift joint to the mid-height of the first-story columns, restoring the column foot to a fixed condition. This design induces reverse curvature bending in the upper and lower segments of the columns, effectively reducing rocking demands and the associated risk of structural overturning. To validate this concept, a half-scale, single-span, three-story CMURF specimen was subjected to cyclic loading tests. Subsequently, 20 detailed full-scale finite element models (FEMs) were developed in ABAQUS to assess the effects of varying key parameters, such as height, span, initial prestress of steel strands, and the quantity and arrangement of LYP225 steel web hourglass-shaped pin dampers (LYP-WHP), on the seismic performance of the frame. The results demonstrate that the CMURF exhibits a characteristic double-flag hysteresis shape, indicating strong self-centering performance. Additionally, the specimen demonstrated sufficient lateral stiffness, bearing capacity, and effective control of residual deformation, with the LYP-WHP providing stable ED capabilities. The findings indicated that CMURF offers a promising solution for mitigating structural overturning risks in rocking frames while preserving critical seismic performance features. Key parameters, such as height and span, significantly influence performance, with taller structures experiencing reduced self-centering ability and seismic resilience, while larger spans improve both. The initial prestress of the steel strands primarily affects self-centering, while the configuration of LYP-WHP impacts ED. Optimal design recommendations include a self-centering coefficient between 1.52 and 2.45 and a height-to-span ratio between 1.13 and 3.63.

Hole-assisted three-core fiber directional coupler operated in reflection mode for vector bending measurement

We demonstrate a vector bending sensor operated in reflection mode based on a hole-assisted three-core fiber (HATCF) coupler. The sensor is built by splicing a piece of HATCF with a gold film-coated end to a single-mode fiber (SMF). The gold film on the center core end is etched with femtosecond laser and only the lights transmitted in the two suspended cores of the HATCF are reflected. The center core couples with the two suspended cores at different wavelengths, respectively. The bending direction and curvature are identified by monitoring the wavelength of the two coupled peaks. The maximum curvature sensitivity of the sensor is 15.146 nm/m−1. The temperature sensitivity is less than −58.8 pm/°C. The vector bending sensor operated in reflection mode has the advantages of a compact structure and simple transmission line, which is conducive to the miniaturization and integration of optical fiber bending sensors.

A numerical investigation on rheological turbulent flow through a 90° mixing elbow

Mixing elbows are widely used in various industrial processes to mix two different Newtonian or non-Newtonian fluids under turbulent flow conditions. This study numerically investigates the fluid flow and mixing characteristics in 90-degree elbows with different bend curvatures (curvature ratios of 3, 6, and 9) and Reynolds numbers ranging from 1 × 104 to 5 × 105 for both fluid types. The Reynolds-Averaged Navier–Stokes equations are solved using the turbulent k-epsilon model in ANSYS Fluent. Results show that the bend curvature creates an adverse pressure gradient that drives secondary flows, which become more pronounced with higher Reynolds numbers and lower curvature ratios. Higher Reynolds numbers improve mixing quality, as indicated by velocity and temperature variations quantified using standard deviations. For Reynolds numbers in the range of 104, velocity fluctuations initially increase, but at higher values (~ 105), they decrease, even by up to 64% as the Reynolds number rises from 1 × 105 to 5 × 105. Similarly, increasing the curvature ratio enhances mixing efficiency, with a 32% reduction in velocity fluctuations when the curvature ratio increases from 6 to 9. Furthermore, shear-thinning fluids (n=0.6\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n = 0.6$$\\end{document}) exhibit superior mixing performance, with a standard deviation of velocity fluctuations at the outlet of 0.32, compared to 0.54 for shear-thickening fluids (n=1.4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n = 1.4$$\\end{document}). In terms of temperature fluctuations also, a similar trend is observed. These findings are valuable for optimizing mixing and fluid transport in industries such as chemical processing and food production, where effective mixing of complex fluids is critical. This study provides insights for improving the design of mixing systems that handle fluids with various rheological characteristics.

Evaluating the impact of the membrane thickness on the function of the intramembrane protease GlpG

Cellular membranes exhibit a huge diversity of lipids and membrane proteins that differ in their properties and chemical structure. Cells organize these molecules into distinct membrane compartments characterized by specific lipid profiles and hydrophobic thicknesses of the respective domains. If a hydrophobic mismatch occurs between a membrane protein and the surrounding lipids, there can be functional consequences such as reduced protein activity. This phenomenon has been extensively studied for single-pass transmembrane proteins, rhodopsin, and small polypeptides such as gramicidin. Here, we investigate the E. coli rhomboid intramembrane protease GlpG as a model to systematically explore the impact of membrane thickness on GlpG activity. We used fully saturated 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine(DMPC) model lipids and altered membrane thickness by varying the cholesterol content. Physical membrane parameters were determined by 2H and 31P NMR spectroscopy and correlated with GlpG activity measurements in the respective host membranes. Differences in bulk and annular lipids as well as alterations in protein structure in the respective host membranes were determined using molecular dynamics simulations. Our findings indicate that GlpG can influence the membrane thickness in DLPC/cholesterol membranes but not in DMPC/cholesterol membranes. Moreover, we observe that GlpG protease activity is reduced in DLPC membranes at low cholesterol content, which was not observed for DMPC. While a change in GlpG activity can already be due to smallest differences in the lipid environment, potentially enabling allosteric regulation of intramembrane proteolysis, there is no overall correlation to cholesterol-mediated lipid bilayer organization and phase behavior. Additional factors such as the influence of cholesterol on membrane bending rigidity and curvature energy need to be considered. In conclusion, the functionality of α-helical membrane proteins such as GlpG relies not only on hydrophobic matching but also on other membrane properties, specific lipid interaction, and the composition of the annular layer.

Human interventions alter meandering channels evolution: Insights from the inner bank scouring and outer bank deposition in the Jingjiang Reach after the operation of the Three Gorges Dam

Geomorphic abnormal responses of consecutive river bends to human activities, such as reservoir constructions and bank protection projects, have not been understood sufficiently. Based on the measured hydrological and topographic data, and remote sensing data, we investigated the morphological adjustments of 17 typical consecutive bends with different curvatures (the ratio of bend width B and bend radius R at the bend apex ranging from 0.22 to 1.96) in the Jingjiang Reach after the Three Gorges Dam (TGD) (2004–2021). The results show that these bends generally experienced inner bank scouring (IBS) and outer bank deposition (OBD). The distance to the dam affects the mechanism of IBS, from being primarily controlled by the water scouring intensity near the dam to the bend curvature and the regime adjustment of the upstream bend. Our results also show that the locations of IBS and OBD in the bends are related to the bend curvature. In sharp bends (B/R > 0.5), IBS occurs in the upper half of the bend, accompanied by OBD near the bend apex. In moderate bends (B/R ≤ 0.5), IBS occurs throughout the whole bend, with OBD near the bend entrance. A higher curvature bend tends to experience greater scouring of the inner bank near the bend apex. Moreover, the effect of upstream bends on downstream bends is revealed. In response to IBS and OBD in the upstream bend, the thalweg at the entrance shifts towards the inner bank, further promoting IBS in the downstream bend. OBD in the downstream bend is intensified by the residual reverse circulation of upstream bend. The results of this study can enhance the understanding of the evolution of meandering rivers in response to human activities, and may serve as a rational reference for managing the meandering rivers downstream of cascade reservoirs.

Multi-Beam Surveying Ocean Exploration Model and Applications

With the development of artificial intelligence, fiber Bragg grating (FBG) sensing technology has garnered increasing attention. This paper first proposes a surface reconstruction algorithm based on curvature information, which is applicable to two different sensor structures: implanted FBG sensors and whisker array sensors. The design and analysis of these sensors are based on a pure bending model, where the corresponding bending curvature is obtained by measuring the wavelength shift of the fiber Bragg grating at the measurement points. Next, the paper elaborates on the surface reconstruction algorithm for the implanted FBG sensor. This sensor contains FBG sensing points that are evenly distributed. Curvature information corresponding to the position can be obtained based on the direction and magnitude of the wavelength shift. The fiber bending is considered as a connection of multiple arc segments, and the coordinates of the sensing points are calculated in the Cartesian coordinate system using the properties of the tangents. The fiber bending curve is then reconstructed by connecting the arc segments in MATLAB. Finally, the paper provides a detailed introduction to the surface reconstruction algorithm for the whisker array sensor. When the whiskers bend, the FBGs fixed on them act as curvature sensors. The curvature is determined by the FBG wavelength shift, and the three-dimensional coordinates of the whisker tip relative to the base are calculated based on a geometric model. MATLAB is then used to connect the whisker tip coordinates, completing the construction of the surface.

Responsive integration performed by laser-induced Er3+ structural doping and graphene nanoplatelets

Laser-induced preparation method has the advantages of high efficiency, high yield, no ionic diffusion restriction and competitive side reaction, which can prepare diversified composite materials based on small-scale and distributed characteristics. Besides, integrating multiple performance and conducting inductive feedback are helpful for the reliability and calibration of laser-induced materials in the precision field. Herein, responsive integration is designed based on graphene nanoplatelets/ZnSe:Er3+ composite with optical, electrical, thermal and visual properties for real-time feedback. Er3+ ions doped ZnSe is obtained by fast laser-induced method, combined with two-dimensional graphene nanoplatelets and assembled into temperature-sensitive polyimide and cellulose paper, realizing the characteristics of photoelectric conversion and photothermal conversion. Besides, red fluorescence guiding perceptual behavior can also be produced under the radiation of NIR laser. Based on the proposed composite, bionic flower is constructed, and exhibits good motion features in blooming. Meanwhile, large curvature bending, high thermal sensitivity and strong fluorescence emission are also revealed. Such performance combination design provides a convenient approach for multi signals cross feedback in soft actuator, which strengthens the monitoring and guidance of motion perceptions, and can be potentially applied in diversified fields.

Multiscale Damage Identification Method of Beam-Type Structures Based on Node Curvature

This paper proposes a multiscale damage identification method for beam-type structures based on node curvature. Firstly, based on the assumption that micro-damage has little effect on stress redistribution and the basic relationship between structural bending moment and curvature, combined with the denoising function of wavelet analysis, the linear matrix equation before and after node curvature damage is solved using the singular value decomposition (SVD) method. Then, the theoretical feasibility of this method is verified with laboratory tests of a simply supported beam. Finally, the damage sensitivity and noise resistance of this method are verified using field measurements of a beam bridge. The results show that the nodal curvature serves as an indicator parameter for damage identification in beam-type structures, enabling the precise localization of damage within these structures. When utilizing a multiscale finite element model for analysis, the nodal curvature enhances the ability to identify both the location and severity of damage within small-scale elements. Furthermore, this method can provide a reference for the damage identification and health monitoring of other types of bridges.