Dynamic Deformation Research Articles

Structural Evolution, Exhumation Rates, and Rheology of the European Crust During Alpine Collision: Constraints From the Rotondo Granite—Gotthard Nappe

AbstractThe rheology of crystalline units controls the large‐scale deformation geometry and dynamics of collisional orogens. Defining a time‐constrained rheological evolution of such units may help unravel the details of collisional dynamics. Here, we integrate field analysis, pseudosection calculations and in situ garnet U–Pb and mica Rb–Sr geochronology to define the structural and rheological evolution of the Rotondo granite (Gotthard nappe, Central Alps). We identify a sequence of four (D1–D4) deformation stages. Pre‐collisional D1 brittle faults developed before Alpine peak metamorphism, which occurred at 34–20 Ma (U–Pb garnet ages) at 590 ± 25°C and 0.9 ± 0.1 GPa. The reactivation of D1 structures controlled the rheological evolution, from D2 reverse mylonitic shearing at amphibolite facies (520 ± 40°C and 0.8 ± 0.1 GPa) at 18–20 Ma (white mica Rb–Sr ages), to strike‐slip, brittle‐ductile shearing at greenschist‐facies D3 (395 ± 25°C and 0.4 ± 0.1 GPa) at 14–15 Ma (white mica and biotite Rb–Sr ages), and then to D4 strike‐slip faulting at shallow conditions. Although highly misoriented for the Alpine collisional stress orientation, D1 brittle structures controlled the localization of D2 ductile mylonites accommodating fast (∼3 mm/yr) exhumation rates due to their weak shear strength (<10 MPa). This structural and rheological evolution is common across External Crystalline Massifs (e.g., Aar, Mont Blanc), suggesting that the European upper crust was extremely weak during Alpine collision, its strength controlled by weak ductile shear zones localized on pre‐collisional deformation structures, that in turn controlled localized exhumation at the scale of the orogen.

Dynamic deformation characteristics and microscopic analysis of xanthan gum-treated silty soil during wetting process

The deformation characteristics of silty soils under vibrational loads can easily change due to the wetting process, leading to the failure of roadbed structures. Commonly used methods for improving silty soils in engineering often yield unsatisfactory economic and ecological outcomes. As an environment-friendly soil improvement material, Xanthan gum has broad application prospects and is therefore considered a solidifying agent for enhancing silty soil properties in the Yellow River Basin. In this study, a series of tests is conducted using a scanning electron microscope and a dynamic triaxial testing apparatus to investigate the microstructure and dynamic deformation characteristics of unsaturated silty soil with varying xanthan gum contents during the wetting process. The results show that xanthan gum effectively fills voids between soil particles and adheres to their surfaces, forming fibrous and network structures. This modification enhances the inherent properties of the silty soil and significantly improves its stability under dynamic loading. Specifically, with increasing xanthan gum content, the dynamic shear modulus increases while the damping ratio decreases. During the wetting process, as suction decreases, the dynamic shear modulus decreases while the damping ratio increases. Xanthan gum reduces the sensitivity of the dynamic deformation characteristics of the treated silty soil to changes in suction levels. Finally, based on the modified Hardin-Drnevich hyperbolic model, a predictive model for the dynamic shear modulus and damping ratio of treated silty soil is proposed, considering the xanthan gum content. These research findings provide a theoretical basis for the construction and maintenance of water conservancy, slope stabilization, and roadbed projects in the Yellow River Basin.

3D 프린팅 기술 기반 콘 타입의 신축성 경피약물전달 마이크로니들 패치 개발

This study explored the potential of microneedle technology in transdermal drug delivery application based on a one-step fabrication process using digital light-processing (DLP) printing. To fabricate high-resolution microneedles, DLP printing parameters which include the printing angle were optimized from 0°, 40° and 60° in x-axes. The microneedle substrate was optimized to maintain high stretchability and durability to adapt to dynamic deformations resulting from human movement. The fabricated microneedle demonstrated good ability to effectively penetrate the artificial skin, releasing Rhodamine B as the therapeutic drug molecule in this study. This one-step DLP fabrication process is efficient and versatile, enabling the rapid development of wearable devices for transdermal Drug Deliv. These results emphasize the potential of microneedle technology for creating wearable devices that facilitate convenient, pain-free, and effective delivery of various bioactive molecules for both self-administration and clinical applications.

Preliminary study on the dynamic deformation mechanism of CoCrFeNi high-entropy alloy and its application in the shaped charge liner

High-entropy alloys (HEAs) with a face-centered cubic structure offer numerous advantages, including high plasticity, good processability, and high-temperature resistance. They are also suitable for use as materials in shaped-charge liners, which can cause significant damage. In this study, CoCrFeNi HEAs were prepared, and their mechanical characteristics were examined. The results indicated that the alloy exhibited good plasticity and processability. After dynamic compression, the samples were analyzed using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). It was found that dislocation was the primary deformation mechanism at low strain rates. However, as the strain rate increased, the deformation mechanism shifted from dislocations to a combination of dislocations and twinning. The damage performance of the CoCrFeNi HEA was verified through a static penetration experiment using a conical charge. The results were then compared with simulation results obtained using the AUTODYN software. This study demonstrated that the CoCrFeNi HEA could form a condensed, stable-shaped charge jet, leading to efficient damage after penetrating the steel target plate. Therefore, after uniform treatment, the CoCrFeNi HEA can be utilized as a high-energy structural material to design shaped charge structures that achieve highly efficient damage.

Optimization Design of Semi-active Suspension for Vehicles Based on LQR Optimal Control

Abstract The suspension system is crucial for providing a comfortable ride and ensuring smooth driving. This article presents a random road surface model and a 1/4 vehicle two-degree-of-freedom semi-active suspension model. The optimal control performance index function was obtained by using the minimum principle, and the optimal controller for semi-active suspension was designed. Simulations were conducted in MATLAB/Simulink, using vehicle acceleration, suspension dynamic deflection, and tire dynamic deformation as evaluation indicators. The study found that the vehicle’s acceleration, suspension dynamic deflection, and tire dynamic deformation were reduced by 21.79%, 21.86%, and 9.88%, respectively, with the use of the designed semi-active suspension optimization controller. This resulted in improved driving smoothness and riding comfort.

MODELING THE DYNAMICS OF DEFORMABLE OBJECTS BASED ON VOLUMETRIC PATCHES OF FREE FORMS

A method for solving nonlinear implicit numerical integration problems based on volumetric patches of free forms for modeling deformable objects with high-speed dynamics is proposed. This method improves the accuracy, consistency and controllability of deformation modeling and animation. The method is characterized by speed, accuracy, stability and uses optimization with region decomposition. The method is well suited for modeling deformable bodies with a large time step, in a wide range of deformation dynamics. We propose decomposed optimization, an optimization method based on free-form patches with region decomposition to minimize incremental potentials at each time step. The method uses quadratic matrix decomposition to combine non-overlapping subregions. The Hessian is evaluated once at the beginning of the time step. The advantages of the method are as follows. Geometric primitives and their mathematical models are proposed, which allow the reasonable application of these primitives to solve problems of volume-oriented modeling. Such requirements are met by volumetric patches of free forms based on analytical perturbation functions relative to the base triangles. The decomposed Hessian is constructed for each subregion and calculated using a set of vertices taken from a complete non-decomposed grid. The weights add the missing second-order Hessian data to the vertices of the subregions from the neighbors along the decomposition boundaries. Thanks to this, the descent is performed along the grid coordinates. There is no need to add gradients. During the descent, the gradient is determined. The Hessians under the region are calculated and factorized in parallel once per time step. They are used as an initializer at each iteration. Then the results are mixed together. This ensures stable and continuous high-quality modeling. An automated and reliable optimization method adapted for modeling nonlinear materials, high-speed dynamics and large deformations is proposed.

Co-Assembly of Soft and Hard Nanoparticles into Macroscopic Colloidal Composites with Tailored Mechanical Property and Processability.

Colloidal composites, translating the great potential of nanoscale building bricks into macroscopic dimensions, have emerged as an appealing candidate for new materials with applications in optics, energy storage, and biomedicines. However, it remains a key challenge to bridge the size regimes from nanoscopic colloidal particles to macroscale composites possessing mechanical robustness. Herein, a bottom-up approach is demonstrated to manufacture colloidal composites with customized macroscopic forms by virtue of the co-assembly of nanosized soft polymeric micelles and hard inorganic nanoparticles. Upon association, the hairy micellar corona can bind with the hard nanoparticles, linking individual hard constituents together in a soft-hard alternating manner to form a collective entity. This permits the integration of block copolymer micelles with controlled amounts of hard nanoparticles into macroscopic colloidal composites featuring diverse internal microstructures. The resultant composites showed tunable microscale mechanical strength in a range of 90-270MPa and macroscale mechanical strength in a range of 7-42MPa for compression and 2-24MPa for bending. Notably, the incorporation of soft polymeric micelles also imparts time- and temperature-dependent dynamic deformability and versatile capacity to the resulting composites, allowing their application in the low-temperature plastic processing for functional fused silica glass.

Dynamic deformation behavior of single phase VNbTa medium-entropy alloys

In this study, the deformation behavior of body-centered-cubic (BCC) VNbTa medium-entropy alloy (MEA) was studied under different strain rates ranging from 10−3 s−1 to 5000 s−1 using screw-driven testing machine and split Hopkinson pressure bar (SHPB), respectively. The alloy presents an outstanding synergy of strength and plasticity without any adiabatic shear bands even at a strain rate of 5000 s−1. Moreover, the yield strength of the alloy displays an obvious strain rate dependence, increasing by ∼94.4% from 842 MPa at 10−3 s−1 to 1637 MPa at 5000 s−1. The strain rate sensitivity (SRS) factor m and highest temperature rise under dynamic loading is calculated to be 0.2991 and 182 K, respectively, which means a strong strain rate hardening and thermal softening resistance. Microstructure evolution analyses demonstrate a transition of deformation mechanism from single dislocation slip controlling in low strain rate to a synergy of mechanical twinning and dislocation slip in high strain rate. Therefore, the excellent dynamic mechanical properties could be attributed to the synergistic effects of the strong strain rate hardening and thermal softening resistance, the mechanical twins, and the cell structures and microbands derived from dislocation slip controlling. In addition, the dynamic deformation behavior of VNbTa could also be described by a classical Johnson-Cook model. Combining the excellent cryogenic temperature mechanical properties (tensile strength of ∼1930 MPa and fracture elongation ∼27%), the present work further indicates that the VNbTa MEA has great potential for engineering applications under some extreme circumstances.

Phenomenological Model for the Dynamic Superplastic Deformation Mechanism in a Zn-Al Eutectoid Alloy Modified with 2 wt% Cu

Phenomenological Model for the Dynamic Superplastic Deformation Mechanism in a Zn-Al Eutectoid Alloy Modified with 2 wt% Cu

Integrated Textile Supercapacitors Enhanced with Energy‐Absorbing Spacer Fabrics and Ti3C2Tx MXene

AbstractThe rapid development of wearable electronics requires energy storage devices capable of withstanding both static and dynamic deformations. The versatility of textile supercapacitors renders them promising candidates, but their low electrochemical performance especially under mechanical deformation, poses many limitations for practical use. In this study, MXene‐based textile supercapacitors are designed and fabricated using hierarchical spacer fabrics as the skeleton to provide robust mechanical support and stable performance. Ti3C2Tx MXene is adopted as the current collector and active material for the spacer fabric supercapacitor, resulting in an impressive areal capacitance of 415 mF cm−2 with a MXene loading of 4.2 mg cm−2. Remarkable stability and durability are achieved in the form of three‐dimensional (3D) textile supercapacitors, even under both static and dynamic deformations. The compressive behaviors of these supercapacitors can be easily adjusted (e.g., from 10 to 168 KPa at 50% compression) by altering the spacer fabric structure, demonstrating their energy‐absorption (damping of kinetic energy) capability and their potential to meet the requirements of various wearable applications.

Blast protection of vehicle underside through fireball extinction by water

The aim of this research is the study of blast mitigation using water within the context of underbelly vehicle protection. The interaction of a shock wave generated by an explosive charge, with a relatively small quantity of water, in a vehicle underside environment has been investigated. The simulant vehicle underside was almost a cube with open side faces and a volume of about 7 m3. The deformation of target plates bolted onto the vehicle simulant floor was assessed. These were either unprotected or protected by plastic bags filled with water. Three quantities of water were tested: 4, 10 and 15 kg. Both the residual deformation of the test plate and the maximum dynamic deformation were assessed. This latter was obtained by the squeezing of a hexagonal aluminum tube and by digital image correlation. The results showed that both deformations, residual and dynamic, of a 5 mm thick steel plate decreased when it was protected by water. Water was more effective in reducing deformation parameters than using an equivalent mass of steel. The protective effect of water was also tested with a 1 kg TNT equivalent charge in a steel-pot on a 5 mm thick armor plate. In this case as well, it could be shown that for both deformations – residual and dynamic - the armor plate was less deformed when protected by water.

Subway track foundation settlement deformation prediction based on the BiLSTM-AdaBoost model

The rapid economic expansion has spurred extensive construction near subway networks, impacting the stability of their track foundations. Consequently, it’s crucial to monitor and predict settlement in subway track foundations. However, the dynamic deformation patterns often exhibit nonlinearity and non-stationarity, posing challenges for traditional linear regression models. To tackle this, our study integrates the BiLSTM (bi-directional long short-term memory) network with the AdaBoost ensemble learning algorithm. Using settlement data from Shanghai metro monitoring points, the model is trained and evaluated employing R2 (coefficient of determination), MAE (mean absolute error), and RMSE (root mean square error). Results show that our proposed model displays superior predictive accuracy compared to the LSTM and the BiLSTM, with an average training set R2 of 0.99, test set R2 of 0.78, average MAE of 0.32 mm, and average RMSE of 0.4 mm. Consequently, for forecasting subway track foundation deformations, employing our network model ensures highly accurate predictive capabilities.

Coupled DEM/CFD analysis of impact of free water on the static and dynamic response of concrete in tension regime

In this paper, the quasi-static and dynamic behavior of partially fluid-saturated concrete under two-dimensional (2D) uniaxial tension at the mesoscale is investigated numerically. It was calculated what effect the free pore fluid content (gas and water) had on the fracture process and strength of concrete in a tension regime. An improved pore-scale hydro-mechanical model based on DEM/CFD was used to simulate the behavior of fully and partially fluid-saturated concrete in quasi-static and dynamic conditions. The foundation of the fluid flow idea was a network of channels in a continuous area between discrete elements. In very porous, partially saturated concrete, a two-phase laminar fluid flow was proposed. To track the liquid/gas content, the position and volumes of the pores and cracks were considered. Numerical simulations of bonded granular specimens of a simplified spherical mesostructure that resembled concrete were carried out under dry and wet circumstances for two different strain rates. Investigations were conducted on the effects of fluid pore pressures, fluid saturations, and fluid viscosities on the strength and fracture process of concrete. The quasi-static tensile strength dropped nonlinearly with increasing fluid saturation and fluid viscosity during fluid migration through pores and cracks which contributed to a promoted fracture process. However, during rapid dynamic tensile deformation, a fracture process attenuated due to a fluid migration constraint from insufficient time to exit the pores. It caused the dynamic tensile strength to rise nonlinearly as fluid saturation and fluid viscosity increased.

Mechanical response and phase transformation characteristics of R-phase NiTi shape memory alloy under high strain rate compression

R-phase NiTi shape memory alloy (R-NiTi SMA) has many excellent properties, but there are application problems such as simple structure and high price. High velocity impact welding can effectively solve these problems, but the research on the mechanical response and phase transformation (PT) characteristics of R-NiTi SMA under dynamic deformation is lacking. Therefore, the quasi-static (0.001 s-1) and dynamic (500 s-1, 1000 s-1, 1500 s-1, 2000 s-1) compression experiments were conducted on R-NiTi SMA in this research. The results showed that the true stress-strain curves of R-NiTi SMA during deformation were characterized by three stages, including the superelastic, elastic, and plastic segments. The critical stress of austenite to R (A-R) and R to martensite (R-M) phase transformation increased with the increase of strain rate, and the phase transformation process gradually disappeared when the strain rate exceeded 1000 s-1, which was related to the velocities of A-R and R-M phase transformation. With the increase of strain rate, defects such as dislocations increased and hindered the phase transformation process during unloading, resulting in the increase of A-phase content. In addition, the enthalpy of the deformed samples decreased significantly and the temperature ranges of phase transformation increased slightly. This work deepens the understanding of the dynamic response of R-NiTi SMA and helps to expand the application of high strain rate processing technology in R-NiTi SMA.

Influence of GGBFS and alkali activators on macro-mechanical performance and micro-fracture mechanisms of geopolymer concrete in split Hopkinson pressure bar tests

With superior low-carbon emission and low-resource consumption, geopolymer concrete (GPC) is receiving increasing attention as an optimal alternative to conventional building materials for cleaner and sustainable construction. However, the practical application of GPC poses great challenges since its dynamic mechanical performance remains far from well understood. In this study, via a split Hopkinson pressure bar (SHPB) system, a series of dynamic compression tests at strain rates of 45 s-1 to 150 s-1are conducted on GPC specimens with different alkaline activators (AAS)-binder mass ratios (i.e., 10%, 15%, 20%, and 25%) and ground granulated blast furnace slag (GGBFS)-binder mass ratios (i.e., 0%, 30%, 50%, 70%, and 100%). Our testing results comprehensively explored the influence of mix proportions and loading rates on the dynamic mechanical performance of GPC, including the dynamic strength and deformation characteristics, energy evolution and utilization, and progressive failure behavior. The permanent strain, energy dissipation density, and dynamic strength of GPC specimens generally increase with increasing strain rate, while the average fragment size decreases. Under higher loading rates, GPC specimens are featured by denser microcracks, shorter propagation paths, and more prominent stepwise fractures. In addition, GGBFS has a greater impact on dynamic strength, strain rate sensitivity, and energy utilization than AAS. Micro-fracture effect of GPC with different mix proportions is investigated. An appropriate content of alkaline activator (i.e., 20%) and higher GGBFS content (i.e., 100%) promotes the binder depolymerization-aggregation reaction, reduces initial defects inside concrete specimens, and facilitates a more compact block structure.

Grain refinement induced dynamic plasticity improvement in lightweight high entropy alloys

Lightweight high-entropy alloys (LHEAs) have gained significant attention due to their exceptional mechanical properties. Understanding the mechanical properties and microstructural evolution of LHEAs under dynamic loading is crucial for their development and utilization. Current studies have shown that severe local deformation occurs during dynamic deformation, leading to dynamic instability and low ductility. This work investigates the mechanical behavior of the non-equimolar Ti-Zr-Nb-based LHEA at high strain rates (2.8×103 s-1 - 4.5×103 s-1) by varying the grain size. The results indicate that grain refinement enhances the dynamic fracture ductility of LHEAs from ∼34% to ∼44%. The study of deformation microstructure reveals that grain refinement significantly increases the density of dislocations, promoting more regions to participate in deformation, and enhancing the interaction between dislocations, resulting in improved strain hardening ability (from negative to positive) and ultimately achieving a significant improvement in uniform deformation capability. These findings offer valuable insights into optimizing the strength and plasticity of LHEAs and other alloy systems under dynamic loading.

Dynamic Failure Characteristics of Sandstone Containing Different Angles of Pre-Existing Crack Defects

Fracture within the rock is one of the main factors leading to rock destabilization and has a significant effect on the stability of the project. In this study, sandstone is used as a research target, specimens with crack inclination angles of 0°, 30°, 45°, 60°, and 90° are prefabricated, and the split Hopkinson pressure bar (SHPB) impact test of sandstone with cracks is carried out based on digital image recognition technology to explore the dynamic damage characteristics of the specimens with five angles. The basic mechanical parameters of sandstone are tested to determine the RHT model intrinsic parameters, and the numerical computational RHT model of sandstone containing crack defects is established, which is verified in comparison with the test to analyze the validity of the model. Finally, the failure characteristics of the numerical model under initial stress were carried out. The study shows the following: with the increase in the fracture angle, the dynamic compressive strength and deformation modulus are distributed in a slanting V-shape, and the inclination angle of 45° is the smallest. The strain rate and energy dissipation rate are distributed in a slanting N-shape, and the inclination angle of 45° is the largest. The transmittance shows a decreasing trend, which is the opposite of the reflectivity pattern. The crack angle determines the location and direction of the initial crack, which affects the failure mode. In addition, the parameters of the RHT constitutive model suitable for sandstone are obtained, and the damage and strength patterns of the established RHT model are highly consistent with the laboratory test results. The damage range of numerical models for crack defects with different inclination angles is negatively correlated with confining pressure values and positively correlated with axial pressure values. The damage zones are symmetrically distributed approximately perpendicular to the direction of cracks, and the confining pressure has a contributing role in the peak of the element stresses; however, the axial compression has no contribution in the peak of the element stresses.

High-strain rate deformation of aluminum during the Taylor test

The aim of the study is to develop a methodology for assessing changes in the microstructure of aluminum under dynamic deformation in a rather wide range of the strain rate and strain degree. The distribution of the microstructure and the strength properties in the cross-section of pure aluminum samples (A99) after dynamic deformation according to the Taylor test were studied. The tests were carried out at room temperature using a PG-20 light-gas cannon, at sample throwing speeds of 127 and 165 m/sec. An interference microscope (Leica IM DRM) and a scanning electron microscope (Jeol JSM-6490) were used to study the aluminum microstructure; the microhardness measurements were carried out on an HVS-1000 device to study the uniformity of the strain distribution in samples. It is shown that three characteristic areas can be distinguished in aluminum samples after Taylor test: the elastic deformation zone, the plastic deformation zone, and the zone of severe plastic deformation, which is located in the area of collision of the sample with a steel barrier. It is shown that dynamic deformation reduced the grain structure from 1 – 1.1 mm to 2.5 – 3 μm at high impact velocities. An elongated grain shape is observed in the collision zone. The proposed method provided determination of the critical strain degree necessary for the onset of grain fragmentation and allowed us to explain the formation of zones of weak and severe plastic deformation. It is shown that the critical strain degree corresponding to the beginning of grain fragmentation increases from 0.18 to 0.21 with an increase in the throwing speed of the sample from 127 to 165 m/sec. In the zone of weak deformation, plastic deformation proceeds by intragrain riveting and the initial stages of grain fragmentation. In the zone of severe plastic deformation, a fine-grained microstructure is formed, which leads to an increase in the microhardness of aluminum in accordance with the Hall – Petch equation.

Elbow Flexor Release Combined With Selective Neurectomy of Musculocutaneous Nerve for Spastic Elbow Flexion Deformity in Children and Adolescents.

Spasticity of the elbow flexors causes a dynamic and/or static elbow flexion deformity. This position interferes with the functional use of the hand, is aesthetically unpleasant and can cause problems with hygiene and comfort. A lengthening procedure of elbow flexor muscles can improve elbow posture and range of motion. However, causal spasticity is not addressed directly. Selective neurectomy of the musculocutaneous nerve has a direct effect on underlying spasticity but is not sufficient when contracture is present. In this study, we examine the long-term results of a combined surgical approach: a release procedure of the elbow flexors and selective neurectomy of the musculocutaneous nerve. A retrospective study of 14 patients with spastic flexion deformity of the elbow was performed. After a mean follow-up of 52.6 months (SD 33, range 12 to 113), the results of the combined surgical approach were evaluated. Spontaneous position of the elbow and active and passive range of motion were assesses using goniometry. Spasticity was assessed using the Modified Ashworth Scale. Function of the affected upper limb before and after surgery was assessed by the House functional classification. Patient and caretaker's satisfaction were assessed using a visual analogue scale. The mean decrease of passive elbow extension deficit was 34 degrees (SD 21.3, P <0.05). Active elbow extension increased with a mean of 41 degrees (SD 16.5, P <0.05). Spontaneous position elbow flexion decreased by a mean of 40 degrees (SD 21.1, P <0.05).The Modified Ashworth score decreased significantly ( P <0.05) from 3.27 (range 1 to 4) preoperatively to 0.64 (range 0 to 4) postoperatively.The difference between the House score preoperatively and postoperatively was not significant ( P =0.180). Mean patient satisfaction was 8.2/10 (SD 2.7, range 2 to 10) and mean caregiver satisfaction was 7.1/10 (SD 2.7, range 1 to 10). A combined surgical approach to elbow flexion deformity in the form of a lengthening procedure and selective neurectomy of the elbow flexors result in a significant and sustained improvement of the spontaneous position, active and passive elbow extension and elbow flexor spasticity and high patient and caregiver satisfaction. Case series, level IV.

Experimental investigation on dynamic deformation characteristics of the overlying strata in backfilling strip mining at different time scales.

The dynamic subsidence disaster caused by underground mining of coal resources is a complex spatiotemporal process, which is a common disaster in mining areas. The backfilling strip mining technology is a green and sustainable coal mining method, which has been commonly used to reduce the subsidence disaster of the overlying strata and protect surface buildings. The transient deformation is the main reason of surface buildings damage; therefore, in this study, the similar material model was used to research dynamic deformation characteristics of the overlying strata in backfilling strip mining at different time scales, and the optical image method was employed to monitor and obtain the movement data of the overlying strata automatically. The data analysis shows that there is a time-scale effect in mining subsidence. The deformation of the overlying strata increases instantaneously at a certain time under the monitoring of small time scale, and this phenomenon gradually disappears as time scales increase. According to the subsidence velocity of small time scale, the subsidence state of the overlying strata can be further divided into the abrupt subsidence state and the gentle subsidence state. This is really significant for promoting the development of the backfilling strip mining technology and preventing the damage of surface buildings.