Structural Deformation Research Articles

Simulation and Deformation Analysis of Construction Process of Large Eccentric Frame‐Core Tube Structure

ABSTRACTThe large eccentric frame‐core tube structure may generate nonnegligible horizontal deformation in the eccentric direction during the construction process, which should be given due attention. The construction process of a 388‐m‐high super high‐rise structure was simulated with the effects of concrete properties and construction processes. The reinforcement effect of steel bar in reinforced concrete shear wall and the hoop effect of steel tube in concrete filled steel tube (CFST) columns were considered by using the two‐cell simulation method, respectively. The accuracy of the finite element model was effectively verified based on the measured data under different construction process. The results show that the construction process has a large influence on both the vertical and horizontal deformation. The measures of construction leveling effectively reduce the vertical and horizontal deformation of super high‐rise structures, which is important for controlling the structural deformation. The proportion of creep‐shrinkage deformation in the total deformation is large. In this case, the proportion of creep‐shrinkage deformation in the shear wall is 45% to 50%, whereas it is about 30% in the frame columns. The eccentricity caused by floor slab gravity will be mitigated if the construction of the frame slab lags behind the construction of the steel frame, which is beneficial to the control of the horizontal structural deformation. After construction completion, the deformation caused by nonload factors is limited compared to the deformation caused by live loads.

Monitoring performance of a new smart geosynthetic under drawing test

Geosynthetics are widely used in civil engineering reinforcements owing to their high strength, acceptable toughness, and ease of transportation. However, traditional geosynthetics do not have the capability to monitor damage inside the soil. Therefore, in this paper, a new sensor-enabled piezoelectric geobelt (SPGB) is developed to measure the deformation of reinforced-soil structures. In-soil drawing tests are conducted to investigate the sensing performance of the SPGB. Variations in the voltage and impedance signals of the SPGB with the drawing displacement under different damage conditions are investigated. The results show that with the increase of drawing displacement, SPGB undergoes tensile deformation followed by pullout damage. In tensile deformation, the signal response of SPGB is related to strain. As the strain increases, the output voltage first increases and then decreases, and the impedance gradually decreases. In the pullout damage phase, the signal response of SPGB is related to the contact area between SPGB and soil. As the drawing displacement increases, the contact area between SPGB and soil gradually decreases, the output voltage gradually decreases, and the impedance gradually increases. Therefore, the SPGB, as a sensor-enabled geosynthetic, provides a reinforcing function to the soil body and simultaneously performs in-soil catastrophe identification.

Visualization of Structural Deformation of Polymer Additives in Oil Under High Shear Flow

Visualization of Structural Deformation of Polymer Additives in Oil Under High Shear Flow

Retrospective Analysis of Cerebrospinal Gushers in Cochlear Implant Surgery: Incidence, Risk Factors, and Outcomes-A Systematic Review and Meta-analysis.

Background: Cerebrospinal fluid (CSF) gusher is a common complication experienced during cochlear implantation in patients with structural deformities in the inner ear. Objectives: This study aimed to investigate the incidence of CSF gusher, risk factors, and outcomes in patients during cochlear implantation. Methods: This systematic review and meta-analysis were guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses model. Studies used in the analysis were identified through a comprehensive search in Google Scholar and PubMed. Results: The analysis was performed using 13 retrospective studies. The incidence of CSF gusher was 5% (95% CI: 3%-9%). CSF gusher was more prevalent among patients with inner-ear malformation (IEM) than without IEM odds ratio = 63.01 (95% CI: 9.85-403.11, P < .00001, I2 = 88%). For incomplete partition (IP), CSF gusher in the IP-I group was 48% (95% CI: 25%-71%, I2 = 0%), 19% in IP-II, 86% in IP-III, 40% in the common cavity, 26% in cochlear hypoplasia, and 27% in patients with enlarged vestibula aqueduct. Conclusion: The CSF gusher incidences were determined to be 5%. Patients with IEM are at increased risk of experiencing CSF gusher during cochlear implant surgery. Therefore, precise scanning reports should be produced in preoperational phase to inform proper management techniques to reduce the chances of intraoperative complications, including CSF gusher.

Numerical Study of Vortex-Induced Vibration Characteristics of a Long Flexible Marine Riser

In ocean engineering, interactions between ocean currents and risers lead to regular vortex shedding on both sides of the riser, causing structural deformation. When the frequency of vortex shedding approaches the natural frequency of the structure, resonance occurs, significantly increasing deformation. This phenomenon is a critical cause of riser failure. Therefore, the dynamic response of flexible risers to vortex-induced vibrations (VIV) is crucial for their structural safety. This paper employs the finite-volume method to integrate over control volumes to solve for forces, such as pressure and shear stress, on the surface of the riser, while the finite-element method discretizes the continuous structural body into elements and nodes to solve for structural displacements and stresses. A strongly coupled method is utilized at each timestep to iteratively transfer load-displacement data between the fluid and structural fields, updating the boundary conditions of the fluid domain to achieve a bidirectional fluid–structure interaction simulation of vortex-induced vibrations in a seawater environment for flexible risers. The study finds that the three-dimensional flexible riser exhibits multi-frequency vibration phenomena and broadband vibration response characteristics under high flow velocity conditions. As the flow velocity increases, the vortex-shedding mode is observed to transition from the simple two single (2S) mode to the more complex pair + single (P + S) and two pair (2P) modes. In addition, the stiffness at the ends is enhanced by the fixed boundary conditions, and the coupling between the natural frequency of the ends and the vortex-shedding frequency triggers complex vortex-shedding phenomena in these regions. At higher flow velocities, these boundary effects result in more complex vortex-shedding modes and stronger vibration responses at both ends of the riser.

Dinucleotide composition representation -based deep learning to predict scoliosis-associated Fibrillin-1 genotypes.

Scoliosis is a pathological spine structure deformation, predominantly classified as "idiopathic" due to its unknown etiology. However, it has been suggested that scoliosis may be linked to polygenic backgrounds. It is crucial to identify potential Adolescent Idiopathic Scoliosis (AIS)-related genetic backgrounds before scoliosis onset. The present study was designed to intelligently parse, decompose and predict AIS-related variants in ClinVar database. Possible AIS-related variant records downloaded from ClinVar were parsed for various labels, decomposed for Dinucleotide Compositional Representation (DCR) and other traits, screened for high-risk genes with statistical analysis, and then learned intelligently with deep learning to predict high-risk AIS genotypes. Results demonstrated that the present framework is composed of all technical sections of data parsing, scoliosis genotyping, genome encoding, machine learning (ML)/deep learning (DL) and scoliosis genotype predicting. 58,000 scoliosis-related records were automatically parsed and statistically analyzed for high-risk genes and genotypes, such as FBN1, LAMA2 and SPG11. All variant genes were decomposed for DCR and other traits. Unsupervised ML indicated marked inter-group separation and intra-group clustering of the DCR of FBN1, LAMA2 or SPG11 for the five types of variants (Pathogenic, Pathogeniclikely, Benign, Benignlikely and Uncertain). A FBN1 DCR-based Convolutional Neural Network (CNN) was trained for Pathogenic and Benign/ Benignlikely variants performed accurately on validation data and predicted 179 high-risk scoliosis variants. The trained predictor was interpretable for the similar distribution of variant types and variant locations within 2D structure units in the predicted 3D structure of FBN1. In summary, scoliosis risk is predictable by deep learning based on genomic decomposed features of DCR. DCR-based classifier has predicted more scoliosis risk FBN1 variants in ClinVar database. DCR-based models would be promising for genotype-to-phenotype prediction for more disease types.

Kirigami-Inspired Three-Dimensional Metamaterials with Programmable Isotropic and Orthotropic Thermal Expansion.

Mechanical metamaterials with specifically designed cells can provide unusual thermal expansion properties for diverse applications. Limited by very few available cell topologies and complicated non-linear structural deformation, most existing thermal expansion metamaterials can only achieve orthogonally isotropic negative/zero/positive thermal expansion (NTE/ZTE/PTE) within a mild range, especially the 3D ones. Here, based on one-degree-of-freedom kirigami polyhedrons proposed with a kinematic design strategy, a family of 3D isotropic and orthotropic metamaterials capable of programmable NTE, PTE, and even ZTE over ultra-wide range is developed. Incorporating bi-material strips as creases for isotropic polyhedrons, NTE and PTE metamaterials with coefficients of thermal expansion (CTEs) ranging from -2354.3 to 3006.7ppm/°C are designed and programmed by the theoretical model. Meanwhile, isotropic ZTE metamaterials are constructed by either homogeneous tessellation of ZTE cells or hybrid tessellation of NTE and PTE cells. Furthermore, by allowing distinct geometric parameters in the three orthogonal directions of the kirigami polyhedrons while preserving the kinematic motion, orthotropic metamaterials, in which each of the three directions can be assigned with an independently programmed NTE, ZTE, or PTE, are also achieved. This study paves a novel pathway for the development of thermal expansion metamaterials with potential applications for space optical systems, MEMS, and so on.

Active Fault Interpretation in the Northern Segment of the Red River Fault Based on Multisource Remote Sensing Data

High-resolution topographic and geomorphic data are important basic data for the study of active structures. Here, multisource remote sensing data were used to reinterpret the active faults in the northern segment of the Red River Fault (China). First, we obtained airborne light detection and ranging (LiDAR) data, high-resolution GaoFen-7 (GF-7) remote sensing image data, and historical aerial photographs, and a high-resolution digital elevation model (DEM) was generated based on the airborne LiDAR data and GF-7 data. According to the remote sensing interpretation, the main active faults were identified. We subsequently verified the faults in the field and constrained the geographic locations. The current activity was confirmed to be dominantly normal faulting, with some dextral strike-slip components, and the latest active age was the Late Holocene. It reflects the coordination of structural deformation between the rotation of the secondary block and the sliding of the boundary fault within the Sichuan–Yunnan Block. The results show that airborne LiDAR and GF-7 remote sensing data have a great application value in providing high-resolution topographic and geomorphologic data for the study of active structures. The comprehensive application of multisource remote sensing data can greatly improve the reliability of active fault interpretations and provide a reference for follow-up research within the study area.

Nonlinear Finite Element Simulation and Analysis of Steel Frame Structures Considering Nonlinear Behavior

This paper focuses on investigating the nonlinear behavior of steel frame structures in practical engineering applications. Utilizing finite element analysis, the study simulates the response of structures under extreme loads such as strong earthquakes. By incorporating nonlinear material properties and contact effects, the numerical simulation and analysis explore phenomena such as plastic deformation, yield, and instability in frame structures. The research outcomes contribute to a deeper understanding of the energy dissipation and safety performance of these structures.

Comparison of Actual Deformations of Historic Wooden Structures with Values Obtained from Static Calculations

In historic wooden structures, deformations can be influenced by factors that are negligible within the first 50 years of the building's existence. In attics where the roof covering is made of metal sheets, the air and structural elements heat up during the day and cool down rapidly at night. This phenomenon, over a long period, can cause micro-cracks and surface material degradation. For the study, historic buildings meeting the criteria for service class II according to PN-EN 1995-1-1 were selected. Measurements of deflections, humidity, and modulus of elasticity of the wood were conducted. The actual deflections of the examined structures were found to be 28% to 37% higher than those obtained from numerical calculations, indicating ongoing rheological processes in the wooden structures.

Stepwise warm rolling for synergistic strength and ductility enhancement in heterolamellar medium-Mn steel

Medium manganese steel represents a promising third-generation advanced high-strength steel. However, achieving excellent plasticity in high-yield-strength medium manganese steel remains challenging, particularly with lower alloying element contents. In this study, we employed an innovative stepwise warm rolling process on 5Mn medium manganese steel, developing a heterolamellar microstructure along the rolling direction. The resulting steel exhibited a yield strength exceeding 1.5 GPa while maintaining a uniform elongation of approximately 29%. The high yield strength is attributed to fine lamellar grains with high dislocation density, while the excellent uniform elongation is due to the synergistic effect of multiple plastic deformation mechanisms, which promoted prolonged strain hardening and delayed the onset of necking. These mechanisms include hetero-deformation induced (HDI) hardening generated during the early deformation of the heterolamellar structure, transformation induced plasticity (TRIP) effect-induced work hardening, and delamination cracking that alleviates interface strain concentration and delays material failure. Collectively, these mechanisms enabled the material to achieve an exceptionally high product of yield strength and uniform elongation of 45 GPa·%. This work provides new insights into the design of high-strength, ductile medium manganese steels, advancing the application of high-performance medium manganese steels.

3D printed polymeric stent design: Mechanical testing and computational modeling

Polymer-based bioresorbable scaffolds (BRS) aim to reduce the long-term issues associated with metal stents. Yet, first-generation BRS designs experienced a significantly higher rate of clinical failures compared to permanent implants. This prompted the development of alternative scaffolds, such as the poly(L-lactide-co-ε-caprolactone) (PLCL) solvent-casted stent, whose mechanical performance has yet to be addressed. This study examines the mechanical behavior of this novel scaffold across a wide range of parallel and radial compression diameters. The analysis highlights the scaffold’s varying responses under different loading conditions and provides insights into interpreting simulation model parameters to accurately reflect experimental results.Stents demonstrated a parallel crush resistance of 0.11 N/mm at maximum compression, whereas the radial forces were significantly higher, reaching up to 1.80 N/mm. Additionally, the parallel test keeps the stent in the elastic regime, with almost no regions exceeding 50 MPa of stress, while the radial test causes significant structural deformation, with localized plastic strain reaching up to 30 %. Results showed that underestimating yield strain in computational models leads to discrepancies with experimental results, being 5 % the most accurate value for matching computational and experimental results for PLCL solvent-casted stents.This comprehensive approach is vital for optimizing BRS design and predicting clinical performance.

How to Make the Skin Contact Area Controllable by Optical Calibration in Wearable Tactile Displays of Softness.

Virtual reality systems may benefit from wearable (fingertip-mounted) haptic displays capable of rendering the softness of virtual objects. According to neurophysiological evidence, the easiest reliable way to render a virtual softness is to generate purely tactile (as opposed to kinaesthetic) feedback to be delivered via a finger-pulp-interfaced deformable surface. Moreover, it is necessary to control not only the skin indentation depth by applying quasi-static (non-vibratory) contact pressures, but also the skin contact area. This is typically impossible with available devices, even with those that can vary the contact area, because the latter cannot be controlled due to the complexity of sensing it at high resolutions. This causes indetermination on an important tactile cue to render softness. Here, we present a technology that allows the contact area to be open-loop controlled via personalised optical calibrations. We demonstrate the solution on a modified, pneumatic wearable tactile display of softness previously described by us, consisting of a small chamber containing a transparent membrane inflated against the finger pulp. A window on the device allowed for monitoring the skin contact area with a camera from an external unit to generate a calibration curve by processing photos of the skin membrane interface at different pressures. The solution was validated by comparisons with an ink-stain-based method. Moreover, to avoid manual calibrations, a preliminary automated procedure was developed. This calibration strategy may be applied also to other kinds of displays where finger pulps are in contact with transparent deformable structures.

Inductive Frequency-Coded Sensor for Non-Destructive Structural Strain Monitoring of Composite Materials

Structural composite materials have gained significant appeal because of their ability to be customized for specific mechanical qualities for various applications, including avionics, wind turbines, transportation, and medical equipment. Therefore, there is a growing demand for effective and non-invasive structural health monitoring (SHM) devices to supervise the integrity of materials. This work introduces a novel sensor design, consisting of three spiral resonators optimized to operate at distinct frequencies and excited by a feeding strip line, capable of performing non-destructive structural strain monitoring via frequency coding. The initial discussion focuses on the analytical modeling of the sensor, which is based on a circuital approach. A numerical test case is developed to operate across the frequency range of 100 to 400 MHz, selected to achieve a balance between penetration depth and the sensitivity of the system. The encouraging findings from electromagnetic full-wave simulations have been confirmed by experimental measurements conducted on printed circuit board (PCB) prototypes embedded in a fiberglass-based composite sample. The sensor shows exceptional sensitivity and cost-effectiveness, and may be easily integrated into composite layers due to its minimal cabling requirements and extremely small profile. The particular frequency-coded configuration enables the suggested sensor to accurately detect and distinguish various structural deformations based on their severity and location.

Drone SAR Imaging for Monitoring an Active Landslide Adjacent to the M25 at Flint Hall Farm

Flint Hall Farm in Godstone, Surrey, UK, is situated adjacent to the London Orbital Motorway, or M25, and contains several landslide systems which pose a significant geohazard risk to this critical infrastructure. The site has been routinely monitored by geotechnical engineers following a landslide that encroached onto the hard shoulder in December 2000; current in situ instrumentation includes inclinometers and piezoelectric sensors. Interferometric Synthetic Aperture Radar (InSAR) is an active remote sensing technique that can quantify millimetric rates of Earth surface and structural deformation, typically utilising satellite data, and is ideal for monitoring landslide movements. We have developed the hardware and software for an Unmanned Aerial Vehicle (UAV), or drone radar system, for improved operational flexibility and spatial–temporal resolutions in the InSAR data. The hardware payload includes an industrial-grade DJI drone, a high-performance Ettus Software Defined Radar (SDR), and custom Copper Clad Laminate (CCL) radar horn antennas. The software utilises Frequency Modulated Continuous Wave (FMCW) radar at 5.4 GHz for raw data collection and a Range Migration Algorithm (RMA) for focusing the data into a Single Look Complex (SLC) Synthetic Aperture Radar (SAR) image. We present the first SAR image acquired using the drone radar system at Flint Hall Farm, which provides an improved spatial resolution compared to satellite SAR. Discrete targets on the landslide slope, such as corner reflectors and the in situ instrumentation, are visible as bright pixels, with their size and positioning as expected; the surrounding grass and vegetation appear as natural speckles. Drone SAR imaging is an emerging field of research, given the necessary and recent technological advancements in drones and SDR processing power; as such, this is a novel achievement, with few authors demonstrating similar systems. Ongoing and future work includes repeat-pass SAR data collection and developing the InSAR processing chain for drone SAR data to provide meaningful deformation outputs for the landslides and other geotechnical hazards and infrastructure.

Utilization of the Resonance Behavior of a Tendon-Driven Continuum Joint for Periodic Natural Motions in Soft Robotics

Continuum joints use structural elastic deformations to enable joint motion, and their intrinsic compliance and inherent mechanical robustness are envisioned for applications in which the robot, the human, and the environment need to be safe during interaction. In particular, the intrinsic compliance makes continuum joints a competitor to soft articulated joints, which require additional integrated spring elements. For soft articulated joints incorporating rigid and soft parts, natural motions have been investigated in robotics research to exploit this energy-efficient motion property for cyclic motions, e.g., locomotion. To the best of the author’s knowledge, there is no robotic system to date that utilizes the natural motion of a continuum joint under periodic excitation. In this paper, the resonant behavior of a tendon-driven continuum joint under periodic excitation of the torsional axis is experimentally investigated in a functional sense. In the experiments, periodic inputs are introduced on the joint side of a tendon driven continuum joint with four tendons. By modulating the pretension of the tendons, both the resonant frequency and the gain can be shifted, from 3 to 4.3 Hz and 2.8 to 1.4, respectively, in the present experimental setup. An application would be the rotation of a humanoid torso, where gait frequencies are synchronized with the resonant frequency of the continuum joint.

A Drone-Based Structure from Motion Survey, Topographic Data, and Terrestrial Laser Scanning Acquisitions for the Floodgate Gaps Deformation Monitoring of the Modulo Sperimentale Elettromeccanico System (Venice, Italy)

The structural deformation monitoring of civil infrastructures can be performed using different geomatic techniques: topographic measurements with total stations and levels, TLS (terrestrial laser scanning) acquisitions, and drone-based SfM (structure from motion) photogrammetric surveys, among others, can be applied. In this work, these techniques are used for the floodgate gaps and the rubber joints deformation monitoring of the MOSE system (Modulo Sperimentale Elettromeccanico), the civil infrastructure that protects Venice and its lagoon (Italy) from high waters. Since the floodgates are submerged most of the time and cannot be directly measured and monitored using high-precision data, topographic surveys were performed in accessible underwater tunnels. In this way, after the calculation of the coordinates of some reference points, the coordinates of the floodgate corners were estimated knowing the geometric characteristics of the system. A specific activity required the acquisition of the TLS scans of the stairwells in the shoulder structures of the Treporti barrier because many of the reference points fixed on the structures were lost during the placement of elements on the seabed. They were replaced with new points whose coordinates in the project/as-built reference system were calculated by applying the Procrustean algorithm by means of homologous points. The procedure allowed the estimation of the transformation parameters with maximum residuals of less than 2.5 cm, a value in agreement with the approximation of the real concrete structures built. Using the obtained parameters, the coordinates of the new reference points were calculated in the project reference system. Once the 3D orientation of all caissons in the barrier was reconstructed, the widths of the floodgate gaps were estimated and compared with the designed values and over time. The obtained values were validated in the Treporti barrier using a drone-based SfM photogrammetric survey of the eight raised floodgates, starting from the east shoulder caisson. The comparison between floodgate gaps estimated from topographic and TLS surveys, and those obtained from measurements on the 3D photogrammetric model, provided a maximum difference of 1.6 cm.

Chemo-mechanical instabilities in lithium cobalt oxide at higher state-of-charge in Li-Ion batteries

Transition metal oxide cathodes are widely used in commercial Li-ion batteries. However, their practical charge capacity is limited due to severe chemo-mechanical instabilities at higher charge voltage, and state-of-charge condition. Here, in situ stress and strain measurements were synchronized to probe mechanical deformations in the lithium cobalt oxide (LCO) cathode via a multi-beam stress sensor and digital image correlation, respectively. In situ mechanical measurements revealed how Li removal from the electrode structure induces deformations on the LCO composite cathodes during cycling. The structure and morphology of the LCO cathodes were further investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) studies. Two distinct electrochemical and mechanical behaviors were identified when the LCO was charged up to 4.65 V. The LCO undergoes a compressive stress generation when charged up to 4.2 V and surface fractures on the LCO particles were detected by SEM. LCO cathode experienced significantly large contractions (negative strains) when charged up to 4.65 V, where intergranular crack formation and phase transformation were detected on the LCO particles via SEM and XRD, respectively. Overall, the study bridges complicated structural deformations with in situ analysis of mechanical degradations in LCO cathodes charged at higher voltages. The correlation is vital to understanding instability mechanisms in transition metal oxides at high voltages for alkali metal ion batteries.

Investigation of printing turn angle effects on structural deformation and stress in selective laser melting

Additive manufacturing (AM) technology facilitates the creation of complex structures, where the printing path significantly impacts thermal distribution, subsequently influencing stress distribution and structural deformation. The primary challenge in path planning is to determine a printing turn angle that ensures uniform thermal distribution, thereby minimizing structural deformation while maintaining printing efficiency. To address this issue, we propose a composite function, which comprehensively characterizes the effects of the printing turn angle and the length of the printing path on the printing results. Combining a specific cubic porous structure, we calculate the maximum (Pmax) and minimum (Pmin) values of the composite function P, and compare the structural deformation and stress of the Pmax and Pmin paths with those of the typical Pzigzag path. Finite element method (FEM) simulation and experimental validation show that the Pmax path achieves significantly lower structural deformation and residual stress compared to the Pzigzag path and Pmin path.

Compressive Mechanical Properties and Energy Absorption of Cubic Spherical Hollow Cellular Material Based on the Rod and Curved Surface Structure

Cellular materials, such as lattices and honeycombs, were widely used for structural protection owing to their excellent mechanical properties. By combining the excellent characteristics of lattice and honeycomb curved surface structures, this study designed a cell called Cubic Spherical Hollow (CSH), which had the advantages of orthogonal isotropy and better spatial connectivity. Inspired by the micro-structural arrangement of bamboo fiber and conch shell, we designed the new CSH cellular materials through the interlayer offset strategy. Then, the effects of interlayer offset on the mechanical properties and compression deformation behavior were explored experimentally and simulatively. Compared with other cellular materials, CSH cellular materials exhibited excellent mechanical properties with higher specific strength and specific modulus. The arrangement offsets of the CSH cells between different layers led to a change in the deformation mechanism from a rod’s compressive mode to a combination of a rod’s compressive mode and curved surface’s bending mode. The initial peak stress and plateau stress decreased with the increased arrangement offsets of the CSH since the extruded protrusions of the structure filled the holes and reduced the lateral expansion behavior of the material in the pressurized environment. This phenomenon also reduced the transverse expansion and prevented the sudden change in stress in the constrained space, indicating that the structural deformation was stable and had excellent cushioning and energy absorption properties. In this study, the cellular material design strategy opens a new avenue for energy absorption.