Deformation Analysis Research Articles

Reference intervals of two-dimensional speckle tracking–derived endocardial global longitudinal strain analysis in 132 healthy cats

IntroductionThe assessment of left ventricular myocardial deformation and function by two-dimensional speckle tracking–derived strain analysis is an established method in human cardiology. It also progressively gains recognition in veterinary cardiology in both dogs and cats. ObjectivesThe objectives of this study were to create reference intervals for two-dimensional speckle tracking echocardiography (STE)–derived endocardial global longitudinal strain (GLS) in a population of healthy adult cats of different breeds. Influences of heart rate, body weight, and age were investigated. AnimalsA total of 132 healthy, adult cats were included in this study. Materials and MethodsLeft apical two-, three-, and four-chamber views were obtained prospectively for GLS measurements using two-dimensional speckle tracking performed with cardiac performance analysis. Potential influence of body weight, heart rate, and age was analyzed, and the interobserver and intra-observer variability of the measurements was determined. ResultsEndocardial GLS values were not significantly influenced by body weight (P=0.102), heart rate (P=0.144), or age (P=0.075). A reference interval for GLS of −21.18% to −37.50% (±4.12) was determined. The interobserver and intra-observer variability showed excellent agreement. Discussion and ConclusionsTwo-dimensional STE is a feasible technique for the evaluation of cardiac myocardial deformation and systolic function in cats. Showing an excellent interobserver and intra-observer agreement, two-dimensional STE is a promising method for clinical analysis of cardiac deformation in cats.

Application and Effect Evaluation of Elastic Foundation Beam Method in Deformation Analysis of Underground Passage Underneath Excavated Tunnel

Tunneling under existing underground buildings has become a common issue in densely populated urban areas. The current elastic analysis for ground displacement from new tunnel construction focuses on circular tunnels. However, theoretical analysis for non-circular chamber excavations is lacking. This paper aims to develop an elastic analysis for ground deformation from non-circular chamber excavations using the ‘equivalent radius’ theory, Verruijt’s formula, and Park’s model. It adjusts the ellipticization parameter δ and uniform radial displacement ε in Verruijt’s formula. Additionally, equivalent stiffness values for diverse existing hollow structures are considered using various approaches. A comparison of the theoretical results from field measurements and simulations shows the modified equations predict ground deformation well. Finally, parametric analysis explores the impacts of non-circular cavern excavations on existing structures under different factors.

Study on mechanical properties and acoustic emission characteristics of composite rock mass with different thicknesses of weak interlayer

To study the influence of the thickness of a weak interlayer on the deformation and failure characteristics of composite rock mass. Based on the measured data of sand-mudstone interbedded floor rock mass in the Yima mining area, Henan Province, China. Using quartz sand, gypsum, and cement as similar materials make composite rock-like specimens with weak interlayers. The mechanical properties, deformation evolution process, failure characteristics, and acoustic emission laws of rock samples with different interlayer thicknesses under uniaxial compression were studied using the digital image correlation method and acoustic emission monitoring technology. The results show that: (1) With an increase in the thickness of the weak interlayer, there is a corresponding decrease in the compressive strength of the specimen. When the thickness of the weak interlayer exceeds 5 cm, the compressive strength of the composite rock specimen is even less than that of the single weak rock-like. (2) Under uniaxial compression conditions, the strain concentration zone first appears in the weak interlayer part of the composite rock-like specimen. As the pressure continues to increase, the specimen is the first to fail at the position of the maximum strain concentration zone. (3) The thickness of the weak interlayer is an important factor affecting the failure mode of composite rock-like specimens. With the increase of the thickness of the weak interlayer, the composite rock-like specimens change from overall failure to local failure. (4) With the increase of the thickness of the weak interlayer in the middle of the composite rock specimen, the maximum value of the energy released by the single acoustic emission event and the maximum value of the cumulative acoustic emission energy decrease during the compression failure process. The research results can provide a reference for the manufacture of composite rock mass with a weak interlayer and the deformation and failure analysis of composite rock mass.

Deformation Analysis and Reinforcement Effect Evaluation for the No. 65 Slope on the Shangsan Expressway Based on SBAS-InSAR

The deformation of the No. 65 slope on the Shangsan Expressway poses a potential threat to road safety. In July 2021, the deformation rate of this slope accelerated significantly, leading to the implementation of reinforcement measures in 2022. To comprehensively analyze the historical deformation characteristics of the slope and evaluate the effectiveness of the reinforcement measures, this study employs Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology to calculate and analyze the historical deformation characteristics of the slope and the adjacent hillside for two periods: from 10 January 2018 to 22 August 2021, and from 3 September 2021 to 22 December 2023. The SBAS-InSAR monitoring results were compared with in situ data from borehole inclinometers to verify the reliability of the calculations. The SBAS-InSAR results indicate that before reinforcement, the slope exhibited slow movement; however, after the implementation of the reinforcement measures, the displacement significantly decreased, demonstrating the success and effectiveness of the interventions. The consistency between the SBAS-InSAR results, borehole inclinometer data, and surface observations confirms the substantial potential of SBAS-InSAR technology for slope engineering monitoring.

Tunnel Cross-Section Deformation Monitoring Based on Mobile Laser Scanning Point Cloud.

Mobile laser scanning (MLS) has emerged as a pivotal tool for accurately collecting tunnel point cloud data and enabling the detection of tunnel deformation. This study introduces a novel approach for the precise monitoring of tunnel cross-section deformation, a critical factor in assessing stability and lining safety. The MLS system used in this study is the Self-mobile Intelligent Laser Scanning System (SILSS) for data acquisition. A comparison with corresponding data acquired by Leica P16 demonstrates that the data collected by SILSS are accurate. The methodology developed utilizes ellipticity parameters and deformation analysis indices based on the ellipse-fitting analysis of circular shield tunnel deformation. A key innovation is the robust denoising of data using the Random Sample Consensus (RANSAC) method, ensuring accurate ellipse fitting and extraction of tunnel lining. Subsequently, an algorithm segmented the tunnel cross-section lining into individual shield tunnels, enabling the calculation of ellipticity parameters for shield tunnels, which are the objects for deformation analysis. The experimental results underscore the novelty and effectiveness of this approach in monitoring deformation across different indices. The method proves to be a reliable tool for assessing tunnel health, providing a detailed evaluation of the cross-section's condition through statistical and graphical visualization. This study significantly advances shield tunnel monitoring, offering a practical and precise methodology for tunnel deformation analysis based on MLS point cloud data.

Solid-State NMR Analysis of the Dynamics of Cofactors: Comparison of Heliobacterial and Purple Bacterial Reaction Centers.

Photosynthetic reaction centers (RCs) serve as natural engines converting solar energy to chemical energy. Understanding the principles of efficient charge separation and light-induced electron transfer (ET) between the chlorophyll-type pigments might guide the synthesis for artificial photosynthetic systems. We present detailed insight into the dynamics at the atomic level using solid-state NMR techniques applied to the RCs of Heliobacillus (Hb.) mobilis (HbRCs) and the purple bacterium Rhodobacter (R.) sphaeroides (PbRCs). It is assumed that heliobacteria were among the first phototrophic organisms; therefore, their RC can be regarded as ancient. They are constructed homodimerically with perfect C2 symmetry, enabling ET over both branches of cofactors. Modern RCs of R. sphaeroides wild-type (WT) have higher redox power and are functionally highly asymmetric. The dynamics of the cofactors in both RCs has been explored using nuclear hyperpolarization, induced by the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect. Based on the individual incorporation of 13C positions of the cofactors (through supplementation by 13C-δ-aminolevulinic acid), photo-CIDNP magic-angle spinning (MAS) NMR experiments provide access to the local dynamics of the cofactors along the ET path over a broad range of time scales. Theoretical analysis of the dynamic deformation of these macrocycles is also discussed in terms of function. The dynamics observed in HbRCs appears to be correlated to ET. The cofactors in PbRC are significantly less dynamic than those in the HbRC. Relevance for efficiency and redox properties are discussed.

Monitoring and Analysis of Surface Deformation in the Buzhaoba Open-Pit Mine Based on SBAS-InSAR Technology

The Buzhaoba open-pit mine is an important lignite production base in Yunnan Province, China. As mining activities have continued to progress, varying degrees of deformation have occurred in different areas of the Buzhaoba open-pit mine, threatening normal coal production and mine safety. To comprehensively investigate the characteristics of surface deformation and its influencing factors at the Buzhaoba open-pit mine, this study employed the following methods: first, the SBAS-InSAR technique was used to process 86 Sentinel-1A ascending and descending orbit remote sensing images from 2020 to 2023, obtaining LOS surface deformation information for the mining area; second, leveling observation data were used to validate the accuracy of the SBAS-InSAR results, and based on the principle of two-dimensional deformation decomposition, the east–west and vertical surface deformation information of the mining area was obtained; finally, the temporal variation characteristics and influencing factors of the Buzhaoba open-pit mine were analyzed. The study results indicate that (1) the maximum LOS surface deformation rates in the ascending and descending orbits of the mining area were −42.1 mm/a and −114.0 mm/a, respectively; (2) the correlation coefficient between the SBAS-InSAR monitoring results and the leveling observation results was 0.938, confirming the reliability of the SBAS-InSAR monitoring results; (3) the maximum east–west and vertical deformation rates obtained from the two-dimensional deformation decomposition were −103.4 mm/a and −189.2 mm/a, respectively, with the surface deformation in the east–west direction being more pronounced; (4) internal factors such as stratigraphic lithology and geological structures, as well as atmospheric rainfall, have a certain degree of influence on the surface deformation of the Buzhaoba open-pit mine. Therefore, the research results of this study can provide important data support and theoretical references for safety management and disaster prevention in the mining area.

Automated cell tracking using 3D nnUnet and Light Sheet Microscopy to quantify regional deformation in zebrafish.

Light Sheet Microscopy (LSM) in conjunction with embryonic zebrafish, is rapidly advancing three-dimensional, in vivo characterization of myocardial contractility. Preclinical cardiac deformation imaging is predominantly restricted to a low-order dimensionality image space (2i) or suffers from poor reproducibility. In this regard, LSM has enabled high throughput, non-invasive 4i (3d+time) characterization of dynamic organogenesis within the transparent zebrafish model. More importantly, LSM offers cellular resolution across large imaging Field-of-Views at millisecond camera frame rates, enabling single cell localization for global cardiac deformation analysis. However, manual labeling of cells within multilayered tissue is a time-consuming task and requires substantial expertise. In this study, we applied the 3i nnU-Net with Linear Assignment Problem (LAP) framework for automated segmentation and tracking of myocardial cells. Using binarized labels from the neural network, we quantified myocardial deformation of the zebrafish ventricle across 4-6 days post fertilization (dpf). Our study offers tremendous promise for developing highly scalable and disease-specific biomechanical quantification of myocardial microstructures.

A novel Bayesian updating finite element model using enhanced unscented Kalman filter for time-dependent estimation of rockfill dam structure deformation

Due to the time-dependent effect of rockfill dams, the conventional time-invariant finite element method (FEM) can hardly meet practical engineering requirements. This paper proposes an updating Bayesian FEM method for accurate long-term deformation analysis. A combined FEM model is introduced accounting for both instantaneous and creep behaviors. The FEM model is then updated using a Bayesian algorithm, unscented Kalman filter (UKF). The UKF calibrates the prior FEM predictions by incorporating real-time measurement data, thus iteratively reducing discrepancies between model predictions and actual observations. To further enhance the algorithm accuracy, a power-law-based fading memory factor is proposed to mitigate measurement noise in standard UKF. For parameter identification, a slice approach of the high-dimensional covariance confidence ellipsoid is developed. The methodology is validated in Qingyuan rockfill dam, in Guangdong province, China. Results show that the updated FEM is more consistent with the actual monitoring data. The fading memory improves standard UKF performance with a lower relative root-mean-square error (RRMSE). Additionally, the slice method reveals that a specific three-parameter configuration behaves better than the others. The proposed approach can also be extended to other fields including slope and tunneling.

Process and mechanism analysis of typical permafrost area surface deformation at two sites along the Qinghai-Tibet highway based on long-term leveling observation

Surface deformation indicates permafrost changes and multi-year surveys can reflect its characteristics and causes. In this study, surface deformations in Wudaoliang (WDL) and Xidatan (XDT) were determined based on long-term leveling measurements, hydrothermal data, precipitation and soil sampling. In-situ observations can be used to study the influence of hydrothermal changes in the active layer on the surface. The amplitude and onset date of seasonal deformation are different due to the soil moisture (SM) and soil texture in the two permafrost regions. High SM and fine-grained soils can cause significant seasonal surface deformation. A good correlation existed between the freeze-thaw front migration rate and deformation in the active layer with a uniform distribution of SM. The inter-annual subsidence rate in the WDL was higher than in the XDT, owing to the different rates of ground ice thawing near the permafrost table. The long-term subsidence rate positively correlates with the increased seasonal deformation amplitude, especially in fine-grained soils.

Uncertainty analysis of hypersonic flight dynamics under elastic effects

Abstract In addressing the aerodynamic-elastic coupling issues of hypersonic vehicles, this study delves into the analysis of the elastic deformation of the aircraft based on mechanistic understanding. It employs the Interval Analysis Method based on Polynomial Approximations to conduct uncertainty analysis of the aerodynamic model under elasticity, delineating the range of uncertainty in the aerodynamic model influenced by elastic deformation. The aerodynamic force of the aircraft under elasticity is connected with the rigid body, and then the aerodynamic layout of the aircraft fuselage and control surface after elastic deformation is calculated to study the influence of the elastic effect on the aerodynamic force. The results show that the change caused by uncertainty has a relatively small effect on lift but a relatively large effect on drag and pitching moment.

Multi-Case Analysis and Prediction Formulas for Deformation of Underlying Tunnels Caused by Foundation Excavation

Multi-Case Analysis and Prediction Formulas for Deformation of Underlying Tunnels Caused by Foundation Excavation

Fluid-Structure Interactions of a Fin over a Compliant Panel in Supersonic Flow

The fluid-structure interactions of a blunt fin mounted over a compliant panel in Mach 2 flow were investigated. The test geometry consisted of a thin, flexible panel fixed on all edges with a blunt fin with a hemispherically rounded leading edge mounted in a manner that the leading edge of the fin overhung the panel. The blunt fin was also pivoted to several angles of attack with respect to the oncoming flow. This allowed for the study of the dynamic system created by the interactions between the compliant panel and the blunt fin geometries. Both rigid and compliant panel models were used in order to provide a comparison between the flow with and without the dynamics of the compliant panel. High-speed schlieren and surface oil flow visualizations showed that the time-averaged flow remained almost entirely unchanged between the rigid and compliant panels. The instantaneous flow fields, however, showed a highly dynamic system where the compliant panel induced oscillatory shock waves that were both stationary and freely moving. Simultaneous high-speed schlieren visualization and stereo digital-image correlation showed a strong linkage between the motion of the shock waves and the deformation of the panel. This was demonstrated through frequency analysis and modal decomposition of the panel deformation and shock motions.

Overview of discontinuous deformation analysis and its prospects for intelligent modelling

Since its proposal in 1985, the Discontinuous Deformation Analysis (DDA) has developed into a powerful tool for simulating the mechanical behaviour of rock masses and other discontinuous systems and has been widely applied in the field of geotechnical engineering. This paper systematically reviews the theoretical development of DDA, including the basic framework for solving two-dimensional and three-dimensional problems, improvements in contact detection algorithms, coupling with other numerical methods, and high-performance computing. In addition, the application of DDA in engineering problems such as wave propagation, rock blasting, slope instability, underground structures, and hydraulic structures is discussed in detail, demonstrating its wide applicability in solving complex geological and engineering problems. In the future, DDA deeply integrated with artificial intelligence (AI) may enhance its performance in simulation accuracy, computational efficiency, and engineering applications. Automated modelling, non-parametric simulation, and physical-numerical fusion in AI-based DDA may become new research directions.

Opto-mechanical-thermal integration design of the primary optical system for a tri-band aviation camera

This paper presents a tri-band aviation camera that integrates short-wave infrared (SWIR, 0.9–1.7 μm), mid-wave infrared (MWIR, 3.7–4.8 μm) and visible (VIS, 0.486–0.656 μm) bands into a primary optical system and three subsystems, to enhance optical remote sensing capabilities. The focus is on opto-mechanical-thermal integration to effectively manage thermal stress and minimise deformation. Finite Element Analysis is employed to extract Zernike coefficients for deformation analysis, facilitating a comprehensive assessment of the camera’s performance across a temperature range of −40 °C to 60 °C. An innovative flexible support system is integrated to maintain the optimal surface figure of the primary mirror, further reducing thermal effects. Extensive empirical testing, including resolution and wavefront error detection, has validated the system’s robustness under various thermal conditions.

Studying and analysis of deformation and stresses in horizontal-axis wind turbine using fluid-structure interaction method

Fluid-structure interaction (FSI) studies have become an important tool in the development of wind turbine blades as well as for analyzing and optimizing Horizontal Axis Wind Turbine (HAWT). The most essential elements for estimating the turbine blade strength to withstand extreme wind loads and aerodynamic performance are the blade deformation and the associated stresses. This study aims to compare the strength and analyze the deformation behavior of two models of HAWT blades. A three-dimensional model was created and loaded into a Finite Element (FE) model for analysis. The Computational Fluid Dynamics (CFD) investigation was coupled with the structural model using one-way FSI. In this article, the effect of the aerodynamics on the blade surface of a small HAWT has been studied numerically and experimentally. The airfoil used for the blade profile is S826 airfoil. To provide an appropriate displacement for static measurements, the blade in the experimental investigation is made of thermoplastic polyurethane material (TPU). It is noted that the current experimental findings verify the simulation results, and a comparison between the simulations and the experimental findings reveals a reasonable agreement. The numerical simulations are also implemented on a HAWT epoxy E-glass unidirectional (EEGUD) material. It can be concluded from this study that the blade deformation and stress on the blades are related to the wind speed. The deformation along the span length exhibits nonlinear variation that gradually increases from the blade root and reaches its maximum at the blade tip position. The tip deflection and equivalent stress were found to increase with an increase in wind speed. The dynamic analysis at different tip speed ratios shows the highest deformation at λ = 4, for wind speed of 20 m/s.

Prediction and Analysis of Borosilicate Glass Surface Deformation Induced by Flame Jet

To address the issues of low processing efficiency, poor forming accuracy, and internal damage in glass material processing, this study proposes the use of flame jet forming. However, the mechanism of flame jet processing requires further elucidation. This research investigates the relationship between the indentation morphology on the glass surface and the inlet velocity of the flame jet. A theoretical model was established through mathematical analysis to reflect this relationship. The model’s accuracy was validated using numerical simulation methods. By comparing experimental data with theoretical model results, surface tension was incorporated, and the model was iteratively optimized using MATLAB R2024a. The final optimized model demonstrated an absolute error range of 0.009 to 0.069 mm. This study confirms the feasibility of flame jet processing and enriches the understanding of its mechanism, providing a novel, efficient, and precise method for processing glass materials.

Bio-inspired Design and Performance Evaluation of Lawnmower Cutter Blade

This study presents a bio-inspired design approach for the engineering applications of agricultural implements, with practical implications for the field. The CAD modeling of bio-inspired serrated lawnmower cutter blades was followed by structural and fatigue analysis with a comparative evaluation of the performance of conventional plain cutter blades. This method involved the bionic transformation of a biological model of the serrated leg of the grasshopper, traced using MATLAB edge detection and image processing software. The solid modeling CAD software for the Bionic Blade lawnmower cutter blade converts this biological model into an engineering model. After designing the geometric shape of the bionic tooth profile's serrated cutting edge, the boundary conditions are evaluated for numerical simulation based on the machine specifications of the conventional lawnmower cutter. After analyzing the power of the motor, the rotational speed, and the torque, the static structural and fatigue analysis was carried out in numerical simulation software to synthesize the performance of the bionic lawnmower cutter blade for engineering analysis of deformation, shear stress, and fatigue life. The bionic design of the blade and conventional plain blades were manufactured using an Amada CO2 laser cutting machine and sheet metal bending processes for Stainless Steel (SS 304) material. The experimental validation of software simulation was carried out by field trials using the Bionic design of a lawnmower cutter blade to evaluate the performance improvement in cutting time and yield of grass cut in kg for 60 to 100 meters distance cutting. After comparing the performance of the plain blade and the design of the bionic blade, there was a reduction in abrasive wear, a 12.87% improvement in the cutting time, and a 14.8% increase in the yield of grass compared to the conventional blade. This performance improvement was attributed to the unique bionic design of serrated cutting-edge and ground clearance. The bio-inspired design approach has immense practical applications in designing agricultural implements, as confirmed by this performance evaluation of this case study of bio-inspired lawnmower cutter blades.

Research on the Stability of Lining Structures Under Different Fault Moments Based on FDM-DEM

Currently, research on employing finite difference method and discrete element method (FDM-DEM) coupling to assess the stability of tunnel lining structures is limited. This study utilized the FDM-DEM coupling approach, with the F2 fault of the East Tianshan Tunnel as a case study, to develop a numerical model in conjunction with PFC3D 6.0 and FLAC3D 6.0 software. We conducted a comprehensive analysis of the displacement deformation and crack progression of the tunnel lining structure under varying dislocation momentum conditions, unveiling the underlying mechanisms. The findings indicated that as the dislocation increased, the extent of damage to the vault intensified, and the particle contact force within the tunnel lining shifted from compression to tension, significantly contributing to the crack formation. Fault dislocation influenced the gradual expansion of cracks from the vault to the spandrel and arch waist, with the crack width increasing alongside the rising dislocation momentum. In particular, under substantial dislocation momentum, the overall stability of the tunnel lining was markedly diminished. The safety factor at the tunnel section declined progressively as the dislocation momentum escalated, with values of 2.53, 2.49, 2.43, 2.39, and 2.32 corresponding to dislocation momenta of 0.01 m, 0.05 m, 0.1 m, 0.15 m, and 0.2 m, respectively. This research offers valuable insights and a reference framework for investigating the stability of tunnel lining structures in proximity to fault dislocations, pinpointing potential failure points, and bolstering the structural integrity of tunnels.

Associations between heart rate, deformational echocardiographic parameters and clinical outcomes in patients with atrial fibrillation

Abstract Background The relationship between baseline heart rates and cardiac function in patients with atrial fibrillation (AF) remains unknown, as does its impact on long-term outcomes. Methods Patients with newly diagnosed AF and available echocardiography images were included. Conventional echocardiography measurement and myocardial deformation analyses using two-dimensional speckle-tracking echocardiography were performed during AF. Clinical endpoints included first-time hospitalization for ischemic stroke, heart failure (HF), all-cause mortality, and composite endpoint. Results Patients were categorized into groups according to baseline heart rates: 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 beats per minutes (bpm). As heart rates increased, there was a stepwise decrease of peak atrial longitudinal systolic strain (PALS: 14.6 ± 5.3%, 14.7 ± 5.5%, 14.1 ± 4.6%, 13.4 ± 4.7%,12.6 ± 4.9%, 12.1 ± 4.5%, 11.2 ± 5.2% and 10.8±4.1% in 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively; P < 0.001)) and LV strain (-13.8 ± 3.9%, -14.5 ± 4.0%, -13.4 ± 3.4%, -13.4 ± 3.6%, -12.5 ± 3.6%, -11.9 ± 3.8%, -10.3 ± 3.8%, and -10.2 ± 3.8%, in 40-59, 60-69, 70-79, 80-89, 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively; P < 0.001)(Figure). The lowest risk of composite endpoint was observed for patients whose heart rate between 60 to 69 bpm (Figure). Compared to the 60-69 heart rate group, faster heart rates were associated with increased risk of ischemic stroke (adjusted hazard ratios [aHR] 4.448 in the ≥120 bpm group), HF (aHR 1.909 in the ≥120 bpm group), mortality (aHRs 2.487, 2.810, 4.569, 4.760 in the 90-99, 100-109, 110-119, and ≥120 bpm groups, respectively), and composite endpoint (aHRs 2.034, 2.349, 3.492 in the 100-109, 110-119, and ≥120 bpm groups, respectively) (all P < 0.05). Conclusion In patients with AF, heart rate is closely linked to cardiac function and plays a pivotal role in long-term prognosis. Faster heart rates were associated with worse LA/LV functions and increased risk of clinical events. Favorable outcomes were found at heart rates below 100 bpm, with even better LA/LV function noted at heart rates below 80 bpm.