Surface Deformation Research Articles

Three-dimensional analysis using a dental model scanner: Morphological changes of occlusal appliances used for sleep bruxism under dry and wet conditions.

This study used a dental model scanner and best-fit alignment to analyze the deformation patterns of stabilized occlusal appliances (OcAs) used to treat sleep bruxism when stored in wet or dry conditions. Eight OcAs were prepared using polymethyl methacrylate, stored in water at room temperature for 4 weeks (wet storage), and then in air for 4 weeks (dry storage). After being stored in water for one month for hydration, they were 3D-scanned and digitized on days 0, 28, and 56. 3D-deformation patterns were obtained by comparing the storage-D group data using a best-fit alignment program that aligns the nearest points of the corresponding images in a virtual space and calculates the difference between the two images. The maximum deviation and deformed area in the ± direction, and the volume of the wet (W) and the dry (D) condition groups were compared using Wilcoxon's signed rank test. OcA showed no obvious deformities in the W group at 4 weeks. However, in the D Group, a typical deformation pattern was detected at 4 weeks, with the posterior margin of the molars shrinking anteriorly, the palatal side of the molars lifted, and the buccal side retracted inward. The Ⅾ group was significantly larger than the W groups in terms of maximum deviation in the ± direction, deformed area, and volume. After 4 weeks of storage under dry conditions, OcA showed a typical deformation pattern of shrinkage toward the center, with in-center lifting toward the palatal side. Significantly greater surface deviations, deformation areas, and deformation volumes were observed under dry conditions than in wet conditions.

Pressure tuning of intrinsic and extrinsic sources to the anomalous Hall effect in CrGeTe3

The integrated Berry curvature is a geometric property that has dramatic implications for material properties. This study investigates the integrated Berry curvature and other contributions to the anomalous Hall effect in CrGeTe3 as a function of pressure. The anomalous Hall effect is absent in the insulating phase of CrGeTe3 and evolves with pressure in a domelike fashion as pressure is applied. The dome's edges are characterized by Fermi surface deformations, manifested as mixed electron and hole transport. We corroborate the presence of bipolar transport using calculations, which also predict a nonmonotonic behavior of the Berry curvature as a function of pressure. Quantitative discrepancies between our calculations and experimental results indicate that additional scattering mechanisms, which are also strongly tuned by pressure, contribute to the anomalous Hall effect in CrGeTe3. Published by the American Physical Society 2025

Decoding physical sensor signals to reveal chip formation and surface deformation: An example in machining nickel-based superalloys

Decoding physical sensor signals to reveal chip formation and surface deformation: An example in machining nickel-based superalloys

Effect on surface deformation due to interacting fault in fractional standard linear solid

Effect on surface deformation due to interacting fault in fractional standard linear solid

Impact of Geometric Forms on the Effectiveness and Physical Features of POD-based Geometric Parameterization

Effective geometric parameterization is crucial in aerodynamic shape optimization for enabling flexible surface deformation while maximizing design space coverage. This paper studies the impact of different geometric forms (closed and open curves) on the effectiveness of Proper Orthogonal Decomposition (POD) geometric parameterization and explores the information of physical features contained in the POD bases. The efficiency and design space coverage which are the main indicators of effectiveness. These indicators of two POD-based parameterization methods are tested on a hybrid database and four typical airfoils. The convergence of aerodynamic properties is also investigated in typical airfoils. In addition, a modified application criterion for POD bases is established by the recursive feature elimination method. A feature importance-based explainable AI (xAI) method is also developed, combining Shapley additive explanations (SHAP) and modified application criterion to explore the physical information contained in POD bases. The results indicate that the POD-based parameterization method constructed from open curves can reconstruct database with better efficiency and design space coverage. Additionally, compared to geometric errors, more POD bases may be required to cover the airfoil design space in order to achieve superior aerodynamic accuracy. Significant differences exist in the importance and correlation of POD bases derived from different geometric forms, with those from closed curves providing better reconstruction efficiency for geometric parameters.

Study on subsidence evolution induced by coal mining under highway based on finite element simulation

Accurate estimation of overlying strata subsidence and surface deformation caused by coal extraction is crucial for assessing the impact of mining activities on surface infrastructure. In this study, we investigated the subsidence evolution of overlying strata and ground surface induced by underground mining using finite element simulation and focus on a mining district in the Yu-Heng mining area of the central Ordos Basin and then, the influence of underground longwall mining on the surface roads was evaluated. A three-dimensional geological model of the mining district was constructed, considering the actual stratum structures and the deterioration effect of water on rock mechanical properties. The whole coal mining process was simulated to predict the evolution of the subsidence basin at different mining stages, and the surface deformation characteristics caused by coal mining were calculated. Results showed that the subsidence characteristics by numerical simulation were highly consistent with the records of surface subsidence in the adjacent areas, indicating that the constructed geological model can accurately reflect the actual geological conditions and the deformation behaviors of overlying strata. A comparative study revealed that the mechanical properties of the generalized layers determined by processing the mechanical parameters of dry core samples will be much higher than those of the natural strata under the in situ water-saturated condition, and then the subsidence caused by coal mining will be significantly underestimated. Thus, the water-induced mechanical property deterioration of overlying strata must be fully considered when constructing geological models.

Kinematic characteristics of elastic screen surface and screening performance of material groupsunder different additional excitation conditions

ABSTRACT Screening is indispensable process, which is extensively used in coal separation on a global scale. In traditional screening, material stratification is difficult to achieve, which leads to a poor screening effect. In this study, balls are added under the elastic screen surface to increase the screen amplitude and promote the loose stratification of materials. The screen surface motion characteristics, the changes of the material layer on the screen, the material distribution characteristics under the screen, and the screening efficiency are studied by means of vibration tests, high-speed dynamic recording, and screening tests. The experimental results show that when 2-ball additional excitation is applied, the highest screening efficiency of 79.45% is reached, the elastic screen surface can produce a large amplitude of up to 24.77 mm, the screen surface deformation is larger, the material layer is looser, material migration is faster, and the screening effect is better. The main screening area of the material is the second sections of the screening surface, and the screening efficiency of fine particles is mainly affected by the screening efficiency of complex excitation screening. With the increase of the screening surface length, the screening effect of complex excitation elastic screening becomes better.

Investigating Plastic Anisotropy of Single and Two-Phase (α2-Ti3Al + γ-TiAl) PST-TiAl Through Computational Yield Surface Analysis

The anisotropic mechanical behaviour of multi-phase TiAl alloys is intrinsically governed by the anisotropic crystal properties and morphology of their constituent phases, which control the initiation of local plasticity. To advance the understanding of macroscopic plastic anisotropy in multi-phase alloys, this study presents a comprehensive numerical investigation of a two-phase (α2-Ti3Al + γ-TiAl) lamellar TiAl alloy, with a focus on the evolution of plasticity across multiple structural scales. Utilizing the crystal plasticity finite element method (CPFEM), the influence of lamellar orientation (φ) and applied loading angles (θ) on plastic deformation and yield surface evolution was analysed in both the individual phases and in the combined two-phase system. The findings reveal that phase-specific anisotropy stems from the activation of distinct slip systems in the α2 and γ phases, with the activation closely tied to the type of loading (e.g., proportional biaxial loading) and the direction of the load path. Furthermore, the anisotropy of the two-phase system is significantly influenced by the alignment between the lamellar interface orientation and the load-path direction. Analysis with varying load-path directions across different stress planes clarifies how local deformation constraints within the embedded phases modulate slip system activation, leading to either the enhancement or suppression of specific deformation mechanisms. This, in turn, alters the overall yield behaviour of the material. Based on these simulation results, this study provides a detailed understanding of the internal constraints within embedded phases and their role in the evolution of plasticity. It elucidates how anisotropy develops under diverse loading conditions and underscores the importance of hierarchical plasticity in shaping the global anisotropic response of TiAl alloys.

Combining InSAR and Time-Series Clustering to Reveal Deformation Patterns of the Heifangtai Loess Terrace

The Heifangtai Loess terrace in northwest China is frequently affected by landslides due to hydrological factors, establishing it as a significant research area for loess landslides. Advanced time-series InSAR technology facilitates the retrieval of surface deformation information, thereby aiding in the monitoring of landslide deformation status. However, existing methods that analyze deformation patterns do not fully exploit the displacement time series derived from InSAR, which hampers the exploration of potentially coexisting deformation patterns within the area. This study integrates InSAR with time-series clustering methods to reveal the surface deformation patterns and their spatial distribution characteristics in Heifangtai. Initially, utilizing the Sentinel-1 ascending and descending SAR data stack from January 2020 to June 2023, we optimize the interferometric phase based on distributed scatterer characteristics to reduce noise levels and obtain higher spatial density of measurement points. Subsequently, by combining the differential interferometric datasets from both ascending and descending orbits, the multidimensional small baseline subsets technique is employed to calculate the two-dimensional deformation time series. Finally, time-series clustering methods are utilized to extract the deformation patterns present and their spatial distribution from all measurement point time series. The results indicate that the deformation of the Heifangtai is primarily distributed around the surrounding area of the platform, with subsidence deformation being more intense than horizontal deformation. The entire terrace exhibits five deformation patterns: eastward subsidence, westward subsidence, vertical subsidence, westward movement, and eastward movement. The spatial distribution of these patterns suggests that the areas beneath the platform, namely Yanguoxia Town and Dangchuan Village, may be more susceptible to landslide threats in the future. Furthermore, wavelet analysis reveals the response relationship between rainfall and various deformation patterns, further enhancing the interpretability of these patterns. These findings hold significant implications for subsequent landslide monitoring, early warning, and risk prevention.

Bubble coalescence principle in saline water

Bubbles present in saline water typically exhibit a prolonged lifetime, making them attractive for various engineering processes. Herein, we unveil a transition from delayed bubble coalescence to rapid bursting within about one millisecond in salty solutions. The key aspect in understanding this transition lies in the combined influences of surface deformation and ion surface excess instead of characterizing the ions alone. Only with a sufficiently deformed region trapped between the colliding bubble and fluid surfaces can the coalescence inhibition effect be maintained to cause the bouncing behavior. Thus, we quantify a consistent upper limit of ion transfer content required for instant coalescence under different salty conditions. Furthermore, we present numerical ranges associated with different bubble behaviors in terms of [Formula: see text], [Formula: see text], and [Formula: see text] and determine the critical values to predict bubble dynamics. Our findings shed light on the bubble coalescence principle in saline water and allow access to the regulation of coalescence time based on the requirement of technological applications.

How Droplets Dry on Stretched Soft Substrates.

Droplet evaporation on solid substrates is a ubiquitous phenomenon and is relevant in many natural and industrial processes. Whereas it has been reported that the evaporation process is sped up on soft substrates compared with that on hard substrates, no attempt has been made in exploring how substrate stretching affects droplet evaporation and evaporative deposition patterns. Here, we systematically investigate the contact line dynamics of droplets evaporating on substrates with different stiffnesses and stretching ratios and the structures of the evaporative deposition patterns of nanoparticles. We show that the shapes of the droplets and their contact line dynamics during evaporation are strongly affected by uniaxial stretching of the soft substrates. The droplet evaporates with an elongated noncircular contact line and switches the elongation direction during evaporation. The contact line recedes earlier and faster in the direction parallel to the stretching than in the perpendicular direction. This is rationalized by a direct visualization of the evolution of the surface deformation of the soft substrates, the so-called wetting ridge underneath the contact line. We show that this anisotropic contact line receding only occurs on stretched substrates that are sufficiently soft. The anisotropic contact line motion enables us to prepare diverse anisotropic noncircular patterns of nanoparticles, which are beyond the well-known coffee-ring, by evaporating colloidal suspension droplets on stretched soft substrates. Our results suggest that stretching soft substrates is a simple way to manipulate the evaporative wetting dynamics and particle deposition of droplets, which should be of great interest to a wide range of scientific and industrial applications.

Error analysis of blade milling considering surface features and deformation

Error analysis of blade milling considering surface features and deformation

On the conformal deformations of surfaces in Euclidean space

On the conformal deformations of surfaces in Euclidean space

A method for monitoring three dimensional surface deformation in mining areas combining SBAS-InSAR, GNSS and probability integral method

In the process of mineral resource extraction, monitoring surface deformation is crucial for ensuring the safety of engineering and ground infrastructure. Monitoring complete three-dimensional surface deformation is particularly significant. Traditional synthetic aperture radar (InSAR) technology provides deformation components only along the line of sight (LOS) and often lacks sufficient effective data in vegetation-covered mining areas and mining subsidence centers. To address this, this study proposes a method (SBAS-PIM) that combines SBAS-InSAR with the probabilistic integral method (PIM). This method leverages high-coherence points in mining areas and GNSS data from vegetation-covered regions to invert the parameters required by PIM, thus obtaining three-dimensional surface deformation results. The proposed method allows for the acquisition of three-dimensional deformation data with fewer InSAR points and GNSS data, significantly reducing labor costs and addressing the gap in InSAR monitoring of three-dimensional surface deformation in densely vegetated areas. Additionally, it accounts for the mutual influence of multiple adjacent working faces. Finally, through the application to a mining area in Heze, China, the maximum displacements in the vertical, east–west, and north–south directions were obtained as −2011, −418, and − 281 mm, respectively. The correlation coefficients between the vertical and east–west directions and GNSS data were both greater than or equal to 0.9, indicating that this method can effectively monitor the three-dimensional surface deformation of the mining area.

Numerical Simulation of Overburden Deformation Mechanism and Surface Settlement Characteristics Induced by Underground Coal Mining: A Case Study

ABSTRACTUnderground mining in mountainous regions presents a significant geological hazard, characterised by the occurrence of land subsidence and movement of overlying strata. To aggrandise the theory of mine rock mechanics, we conducted a systematic investigation into the deformation and failure mechanisms of overlying strata as well as the patterns of surface subsidence in mountainous regions. With the method of engineering mechanics and theoretical analysis, supplemented by the universal distinct element code (UDEC) numerical simulation, the mining status of Songzao mine was simulated effectively. Herein, the results revealed that the nonlinearity of the overlying strata failure field occurred during mining, as evidenced by an increase in the failure field when the coal approached the seam roof. The subsidence curve of the underlying lower strata exhibits an inverted trapezoid pattern, while that of the overlying upper overburden displays a funnel‐shaped trend. Additionally, the upward transmission displacement velocity was significantly attenuated due to the shielding effect exerted by the key stratum in the overburden, resulting in a greater spatial separation from the underlying strata. The critical stratum fractures as the working face advanced to 120 m, subsequently leading to an increase in vertical displacement and cessation of surface subsidence. The surface subsidence value and speed, however, exhibited a gradual increase as the coal seam mining progressed. Due to the influence of mountain surface landforms, the subsidence value of convex landforms surpasses that of concave landforms, thereby expediting the rate of subsidence and resulting in geological hazards.

Analyzis of optical techniques as non-destructive test to detect internal failure in materials

Biological materials are governed by a disordered growing which promotes nonlinear deformations and deflects cracks into configuration. Nondestructive methods applied to detect material failure is experiencing significant development in engineering. Optical techniques are known to be simple application when compared with conventional methods of stress-state analysis and literature emphasizes speckle interferometric and moiré optical techniques as full field stress-strain state. This research work aimed to analyze the use of optical techniques to be applied as nondestructive test to detect internal material failures. Specimens included material of 1020 steel. Traction tests followed the brazilian norms. The experimental set up to carry on the moiré method included a grid of 0.2 mm density and for the speckle method it was included a laser of 632 mm of wavelength with collimated lens. The differences between the loaded and unloaded specimen images patterns are closely related to the imposed deformation. Image processing generated maps of deformation and surface deformation. Results showed that moiré technique methods generated precise identification of the point on the specimen surface of internal failure occurrence while speckle interferometry showed was precise. Moiré method presented some advantages if compared to the speckle interferometric method. It can be concluded that both tested methods can be used as nondestructive method to detect internal failure on the object surface.

Simulation analysis of coupling mechanism between transient flow field characteristics of bubble collapse and metal deformation based on surface micromorphology

In the process of modifying titanium alloy oral implants using cavitation water jet, the collapse of bubbles releases significant energy. This phenomenon is accompanied by micro-jets and shock waves, which induce changes in the three-dimensional microscopic morphology of the implant surface. The loose and porous surface of the implant will increase the adhesion area of the cells, which is more conducive to the combination of the oral implant with the surrounding bone tissue. In order to explore the coupling mechanism between the instantaneous energy of bubble collapse and the surface deformation of titanium metal, based on different flow field and solid field model parameters, the numerical analysis software Ansys and the fluid-structure coupling simulation method are used to establish the numerical simulation model of single bubble collapse on the near curved wall. In order to explore the coupling mechanism between the instantaneous energy of bubble collapse and the surface deformation of titanium metal, the bubble growth process is ignored. Based on different flow field and solid field model parameters, this paper adopts the numerical analysis software Ansys and the fluid-structure coupling simulation method to establish the numerical simulation model of single bubble collapse on the near curved wall. The effects of flow field parameters and wall morphology on the transient flow field of bubble collapse and the effect of metal surface modification are revealed. The results show that when the initial bubble diameter is 180 μm, the instantaneous collapse high pressure reaches 7.24 GPa, and the maximum stress on the titanium surface is 689 MPa, which is 1.57 times higher than that under the bubble diameter of 60 μm. When the bubble collapses away from the wall, due to the weakened constraint of the wall, more intense energy is released, but the energy decays rapidly in the propagation process, and the energy loss when it reaches the wall is more serious. In this paper, the surface micromorphology is simplified into a near-curved shape. After the modification, the flow obstruction on the near-curved concave wall inhibits bubble collapse, resulting in an increase in bubble collapse time. The stress and deformation caused by a single bubble collapse are concentrated within a radius of 1mm and a depth of 5 μm.

Mapping of surface deformation associated with the 7.8 magnitude Turkey earthquake of 6 Feb 2023 using radar interferometry

The objective of this study was to assess the surface deformation caused by the earthquake that occurred on February 6, 2023, in Turkey, utilizing Sentinel-1 Synthetic Aperture Radar (SAR) photos and Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques to show how the 7.8-magnitude earthquake that struck Turkey caused surface deformation. For the analysis, it was necessary to compute the displacement in the vertical direction for both the deformation before and after removing low coherence (coherence of less than 0.23) in order to minimize misinterpretations caused by phase decorrelation. When the mask was removed, the displacement measured anywhere from − 420 mm to + 713 mm, but when the coherence was increased to 0.23, it measured anywhere from − 330 mm to 700 mm. The greatest positive surface deformation (uplift) regions are visible in the northern, central, and southern regions, while negative surface deformation (subsidence) is visible in the regions of the south-east and south-west of the image. The epicentre of the earthquake is most likely located west of Gaziantep in Gaziantep Province and Ekin Ozu District in Maraş Province, where the earthquake was devastating. InSAR technology is appealing for long-term measuring performance of deformations due to the rising accessibility of civilian radar satellites and the quick development of digital signal analysis, and InSAR has the potential to be used at the network level since it can monitor surface displacements at a millimetre scale over a huge geographical mass.

Frequent Glacial Hazard Deformation Detection Based on POT-SBAS InSAR in the Sedongpu Basin in the Himalayan Region

The Sedongpu Basin is characterized by frequent glacial debris movements and glacial hazards. To accurately monitor and research these glacier hazards, Sentinel-1 Synthetic Aperture Radar images observed between 2014 and 2022 were collected to extract surface motion using SBAS-POT technology. The acquired temporal surface deformation and multiple optical remote sensing images were then jointly used to analyze the characteristics of the long-term glacier movement in the Sedongpu Basin. Furthermore, historical meteorological and seismic data were collected to analyze the mechanisms of multiple ice avalanche chain hazards. It was found that abnormal deformation signals of glaciers SDP1 and SDP2 could be linked to the historical ice avalanche disaster that occurred around the Sedongpu Basin. The maximum deformation rate of SDP1 was 74 m/a and the slope cumulative deformation exceeded 500 m during the monitoring period from 2014 to 2022, which is still in active motion at present; for SDP2, a cumulative deformation of more than 300 m was also detected over the monitoring period. Glaciers SDP3, SDP4, and SDP5 have been relatively stable until now; however, ice cracks are well developed in SDP4 and SDP5, and ice avalanche events may occur if these ice cracks continue to expand under extreme natural conditions in the future. Therefore, this paper emphasizes the seriousness of the ice avalanche event in Sedongpu Basin and provides data support for local disaster management and disaster prevention and reduction.

Kinematics, kinetics, and muscle activations during human locomotion over compliant terrains

Walking on compliant terrains, like carpets, grass, and soil, presents a unique challenge, especially for individuals with mobility impairments. In contrast to rigid-ground walking, compliant surfaces alter movement dynamics and increase the risk of falls. Understanding and modeling gait control across such soft and deformable surfaces is thus crucial for maintaining daily mobility. However, access to the necessary equipment for modeling compliant surface walking is limited. Therefore, in this paper, we present the first publicly available biomechanics dataset of 20 individuals walking on terrains of varying compliance, using a unique robotic device, the Variable Stiffness Treadmill 2 (VST 2), designed to simulate walking on adjustable compliant terrain. VST 2 provides a consistent and reproducible environment for studying the biomechanics of walking on such surfaces within laboratory settings. The goal of this dataset is to provide insights into the muscular, kinematic, and kinetic adaptations that occur when humans walk on compliant terrain in order to design better controllers for prosthetic limbs, improve rehabilitation protocols, and develop adaptive assistive devices that can enhance mobility on compliant surfaces.