Deformation Transfer Research Articles

Experimental Study on Deformation and Load Transfer Mechanisms of Symmetrical Batter Piles under Vertical Loading

Under the action of vertical loading, batter piles rarely appear individually, as they undergo horizontal and vertical displacements at the same time and produce a sizeable additional bending moment. However, previous studies have mainly focused on a single batter pile, which is inconsistent with engineering practices. Although single pile tests can easily reveal its working behavior, they also ignore two important factors, namely, the internal force redistribution caused by the deformation limitation of the mirror-like pile, and the interaction between the symmetrical piles and “clamped” soil (the soil between two symmetrical piles). Therefore, this paper took symmetrical batter piles as the test object to explore the influence of the two factors on the load transfer mechanism. Moreover, the deformation mode, distribution of inertial forces, and group effect of symmetrical batter piles were also discussed. The results showed that the “clamping effect” caused by the pile deformation had a significant impact on the load transfer. Under vertical loading, the flexible symmetrical floating batter piles were the only deformation mode. Under the constraint of the cap and mirror-like batter piles, the symmetrical conformation partially compensated for the disadvantage of the additional bending moment.

Real-time 3D Digital Image Correlation for Large Deformation and Rotation Measurements Based on a Deformation Transfer Scheme

With the recent increase in digital image correlation (DIC) applications, it is important to improve the computational efficiency of DIC and realize the closed loop control of systems. A real-time three-dimensional (3D) DIC method for large deformation and rotation measurements is proposed in this paper. To solve the problem of initial guess estimation under large deformation and rotation, the convergence radius of the inverse compositional Gauss-Newton (IC-GN) algorithm considering large rotation and deformation is analyzed. Then, a temporal-spatial deformation transfer scheme is proposed for efficient temporal and stereo matching in 3D-DIC. The highly efficient IC-GN algorithm with an improved interpolation look-up table is proposed to further improve the computational efficiency. The multipoint and full-field real-time 3D deformation measurements are performed by parallel CPU computation. The convergence radius of IC-GN are estimated to be below 3 pixels for rotation and below 5 pixels for tensile deformation. The accuracy of the initial guess estimation by deformation transfer is improved and can meet the requirements of large deformation and rotation measurements. Benefiting from the temporal-spatial deformation transfer scheme, the efficient IC-GN algorithm, the efficient temporal and stereo matching strategy and the parallel computation, real-time multipoint deformation measurements at 60 Hz with 50 points and full-field deformation measurements at 15 Hz with 5000 points are realized. Real-time multipoint and full-field 3D deformation measurements for large deformations and rotations are realized. High-accuracy, real-time and fully automatic 3D deformation measurement sensors are expected.

The Influence of Longitudinal Force on the Internal Force Distribution and Deformation Coordination Mechanism for Segment Lining

A series of local prototype tests are conducted on the Sutong GIL (Gas-Insulated Line) and Shiziyang Tunnel. These tests investigate the redistribution law of segment deformation and the bending moment during construction. The results reveal that the transfer ability of deformation and the bending moment improve with an increase in the longitudinal force. Stage characteristics are observed for the effect of the longitudinal force on the opening of the circumferential joints. Segments are fully contacted for the circumferential joints when the joint opening is not observed. The frictions between the segments are the key factors for the bending moment and segment deformation control. The opening of the circumferential joint with an increase in the joint opening then becomes the primary control factor. The transfer ability becomes stable when the load continues increasing after mortise and tenon contact. Better transfer ability occurs with a general segment with four pairs of mortises and tenons. This was presented as a smaller value of an increasing rate and the stable magnitude of the joint opening. From the perspective of practical engineering, mortises and tenons can be added to the vault to increase the load and deformation transfer ability of the general segment after the loss of the longitudinal force.

ИССЛЕДОВАНИЕ ВОЗМОЖНОСТЕЙ УПРОЩЕНИЯ СОПРЯЖЕННОЙ ТЕРМОГИДРОМЕХАНИЧЕСКОЙ МОДЕЛИ ИСКУССТВЕННОГО ЗАМОРАЖИВАНИЯ ПОРОД ПРИ СТРОИТЕЛЬСТВЕ СТВОЛОВ ШАХТ

An important stage in the design of the artificial ground freezing during the construc-tion of mine shafts (and other underground structures) is the simulation of deformation and heat transfer in the media to be frozen. This is necessary to calculate the required thicknesses of frozen wall, the time of its formation and the parameters of freezing stations. The choice of an adequate mathematical model is impossible without analyzing the significance and coupling of various physical processes occurring during the freezing of soil. Such an analysis allows se-lecting a reasonable degree of detailing of physical processes in the model: take into account all important factors and neglect the rest. This article proposes a methodology for analyzing the significance and coupling of such physical processes. For this, a general thermo-hydro-mechanical model of soil freezing has been formulated, a set of dimensionless complexes has been identified and classified, which determine the relationship between various physical pro-cesses. The transition from the general thermo-hydro-mechanical model to simpler models is possible only if the corresponding dimensionless complexes are small.

Slip-twinning interdependent activation across phase boundaries: An in-situ investigation of a Ti-Al-V-Fe (α+β) alloy

Microstructural plastic strain distribution evolution is highly heterogeneous even in single-phase alloys. One of the important factors that govern this heterogeneity is slip/twinning transfer across grain/phase boundaries. In this regard, the fundamentals of transfer across grain boundaries have drawn significant attention in the literature, while the understanding of phase boundaries remains comparatively limited. (α+β) titanium alloys provide a profound platform to explore these phenomena, since: (i) both of the present phases can exhibit plastic deformation at similar microscopic strain levels; and (ii) both dislocation slip and mechanical twinning can be triggered to accommodate plastic strain. In the present work, we evidenced a deformation transfer unit involving dislocation slip in the β-phase and {101¯2}-mechanical twin in the α-phase. We revealed by crystallographic calculations that the combination of Schmid factor and the Luster-Morris compatibility factor enables a rational quantification for the inception propensity of the slip-twinning transfer event. Our in-situ strain mapping approach verified that this sort of transfer activity can plausibly alleviate strain incompatibility/localization, demonstrating the potential to facilitate deformation homogeneity.

Understanding partitioning of deformation in highly arcuate orogenic systems: Inferences from the evolution of the Serbian Carpathians

Highly curved orogens often demonstrate a complex poly-phase tectonic evolution and significant strain partitioning. While the oroclinal bending towards the outer arc is understood to be often driven by rapid slab roll-back, processes driving such bending towards the back-arc domain are less understood. The Serbian segment of the larger, highly bended Carpathians–Balkanides Mountains is one key example where we studied the kinematics of nappe stacking and the mechanics of oroclinal bending by the means of a field kinematic study correlated with available information in adjacent orogenic segments. Although not apparent in the large-scale structure of the Serbian Carpathians, our results demonstrate a poly-phase evolution, where the late Early Cretaceous nappe stacking was followed by Oligocene–middle Miocene ~40° of clockwise rotations. The superposition of Dinarides extension with the oroclinal bending in the Carpathians created overlapping stages of orogen-perpendicular extension and dextral strike-slip coupled with orogen-parallel extension, driven by the 100 km cumulated offset of the Cerna and Timok Faults. Extension was associated with the formation of Oligocene–Miocene basins, providing critical timing constraints for our kinematic study. These deformations were followed by the late Miocene E-ward thrusting of the Upper Getic sub-unit, which was driven by a transfer of deformation in the orocline and around the Moesian Platform during the last stages of Carpathians collision. These results show that the mechanics of oroclinal bending is associated with the activation of strike-slip faults and strain partitioning by bi-modal extension, enhanced by the overlap between different geodynamic processes.

Deformation transfer survey

Deformation transfer is a type of retargeting method that operates directly on the mesh and, by doing so, enables reuse of animation without setting up character rigs and a mapping between the source and target geometries. Deformation transfer can potentially reduce the costs of animation and give studios a competitive edge when keeping up with the latest computer animation technology. Unfortunately, deformation transfer has limitations and is yet to become standard practice in the industry. This survey starts by introducing Sumner and Popović’s [18] seminal work and highlights key issues for industry settings. We then review related work in sections, organized by these key issues. After surveying related work, we discuss how their advances open the door to several practical applications of deformation transfer. To conclude, we highlight areas of future work.

A mesh stiffness method using slice coupling for spur gear pairs with misalignment and lead crown relief

The misalignment and lead crown relief make the tooth partial contact along the tooth width direction, which greatly affects the mesh characteristics. In this paper, a mesh stiffness model of spur gear pairs with misalignment and lead crown relief is proposed based on the slice theory, in which the slice coupling effect is presented. The slice coupling is simulated as a spring and the corresponding model is developed. Then, the solving procedure of the mesh stiffness model is studied. The deformation transfer model is derived between the springs in contact state and non-contact state. An iterative computation method is designed to calculate the mesh deformation of tooth pairs. Finally, the mesh stiffness model is validated by the finite element method for a spur gear pair with ideal tooth profile, misalignment and lead crown relief. Effects of the misalignment and lead crown relief on mesh stiffness of gear pairs are also studied. The results reveal that the proposed model is accurate, effective and efficient for spur gear pairs with ideal tooth profile, misalignment and lead crown relief. It is suggested that the slice coupling should be considered in mesh stiffness calculation of gear pairs with misalignment and lead crown relief.

Plastic shrinkage cracking in 3D printed concrete

In concrete, early age pore water evaporation results in volumetric shrinkage that, if restrained, can cause plastic shrinkage cracking (PSC). 3D printed concrete (3DPC) is vulnerable to PSC due to a lack of formwork, minimal bleeding water, low aggregate to binder ratio and high quantities of fines in the mixture. A novel experimental method was developed to determine the PSC risk, evaluating the efficacy of PSC prevention measures and understanding the behaviour of PSC in early age 3DPC. This study evaluated the free shrinkage of 3DPC specimens as well as identified and systematically introduced sources of restraint to induce PSC. The free shrinkage results showed a rate of strain gain and peak strain significantly higher than commonly found in ordinary concrete. Severe cracking was observed when the shrinkage was restrained under a moderate evaporation rate. Cracks formed within the first 2 h after printing, earlier than in ordinary concrete. The proposed method was employed to study the fundamental behaviour of crack formation and propagation in 3DPC. The unique filament interlayer plane has a notable effect on the transfer of shrinkage deformation in the specimen. Differential horizontal deformation in consecutive layers and consequential interlayer slip was observed when the shrinkage was restrained. It is reasonable to conclude that interlayer slip caused by early age shrinkage has the potential to reduce the long-term interlayer bond strength and the durability of 3DPC.

Dynamic manipulation of piezotronic behaviors of composite multiferroic semiconductors through time-dependent magnetic field

A dynamic non-contact approach to tuning the semiconducting (SM) properties of multiferroic composite semiconductor (MCS) fibers by applying a time-dependent magnetic field is proposed and theoretically demonstrated in this paper. The considered fiber is symmetric with respect to its geometrical middle plane and made from two outer piezomagnetic (PM) layers, two piezoelectric (PE) layers, and a SM core. Through the interface strain or deformation transfer, the MCS fiber exhibits not only the conventional magnetoelectric (ME) coupling effect but also the comprehensive magneto-electro-semiconductive (MES) coupling effect. Based on a one-dimensional model for the MCS fibers, we present the analytical solutions for the physical fields of the MCS fiber with a pure longitudinal deformation under a time-dependent magnetic field. The electrons redistribute themselves in the MCS fiber under the driving of the induced piezoelectric field due to the MES coupling effect. Near the natural frequencies, the magnetic field has a remarkable tuning effect. The ME and MES coefficients achieve their local peak values at the natural frequencies. There is an optimal range for the volume fraction of the PM or PE layer for the MES coupling effects. We can manipulate the electrons to assemble in multiple local regions in the MCS fiber by setting the exciting frequency to a specific higher natural frequency. This provides a new way to explore multi-tunnel electronic devices through the dynamic contactless magnetic control approach.

The Ust’-Barguzin Transfer Zone (Central Baikal): Seismological Evidence on the Transtensive Stress Field of the Crust

According to seismological and geodetic data, the central part of the South Baikal basin is under an extension regime of the Earth’s crust. This study presents for the first time seismological evidence of a transtensive stress field in a local area adjacent to the eastern side of the Central Baikal subbasin. Two independent approaches to determining the orientation of the principal stress axes show a subhorizontal orientation of the axes of stresses of minimum and maximum compression, which results in a strike–slip component in the focal mechanisms of the earthquakes. The area under consideration is a part of the Ust’-Barguzin transfer zone, in which the transfer of deformations between South Baikal and the Barguzin basin takes place. The results obtained are in agreement with the geological and structural data and may indicate the contribution of horizontal displacements in the transfer of deformations between the segments of the rift zone.

Plastic deformation mechanisms of nanotwinned Mg with different twin boundary orientations: molecular dynamics simulations

ABSTRACT Molecular dynamics (MD) are employed to study the plastic deformation mechanisms of nanotwinned (NT) Mg with different twin boundary (TB) orientations under uniaxial tension. The orientation effect on the plastic deformation mechanisms of NT Mg is discussed. When the uniaxial tension is applied perpendicular to the TB plane, the emission of basal partial dislocations (BPDs) dominates the plastic deformation. The BPD-TB interaction and the gradual loss of coherence of TBs contribute to the ductility of NT Mg. With the increasing of the TB orientation angle (α), the twining dislocations (TDs) nucleate at the TB due to the shear component on the TB plane, the basal-dislocation-governed deformation transfers to the twinning-dislocation-governed deformation. The gliding of TDs along the TBs causes the migration of TBs and the subsequent detwinning. An obvious strain hardening is observed after the detwinning due to the disappearance of TBs.

Mechanism of Load and Deformation Transfer among Fibers in Composite Materials

The processes that occur during loading and destruction of composite materials (CMs) are studied by the full pull-out method. The mechanisms of load and deformation transfer in CM and the effects of the plasma activation of fibers and of the matrix properties on them are ascertained. It is established that the transfer and distribution of load and deformation among fibers in CM occur via two adhesive joints of fibers with the matrix layer. Reinforcing fibers activated by nonequilibrium low-temperature plasma increase the specific absorbed-in-fracture energy from 26 to 44 J/cm2, the shear strength from 7.1 to 10.4 MPa, and the strain from 1.8 to 2.33%. When the maximum load and strain are reached, the CM is destroyed and the fiber is fired from the matrix. In the case of nonactivated fiber reinforcement, destruction of the CM occurs in two stages: first, the strength and deformation reach the limiting values and the fiber then begins to shift in the matrix, which causes stress relaxation and a sharp drop in strength of the CM. Further deformation occurs as a result of pulling fibers out of the matrix at low load. Plasma activation of reinforcing fibers leads to an increase in properties of the CM.

Development of Sliding Regimes in Faults and Slow Strain Waves

The paper investigates a model simulating crustal fault dynamics and strain wave generation in a fault block geological medium, the parameters determining sliding regimes in faults, and the physics of transitions between different deformation regimes. The model comprises the most important mechanisms responsible for the interaction of fault walls: friction, geometric irregularities (roughness and asperities on the fault surface), and external load, which govern sliding along the fault. The results of field and laboratory studies of deformation migration on the macro/mesoscale are consistent with the concept of localized deformation propagation in the form of solitary waves (kinks, solitons) and autowaves. The conditions are defined which make possible the transition from the model simulating solitary waves in a conservative medium with low “friction” (soliton-like behavior of the system) toward the model of solitary waves in an active medium with diffusion (autowave-like behavior of the system). Two possible deformation regimes of the fault block structure in the high-friction limit are considered. The fault wall displacement is stopped due to this friction, but the adjacent blocks move relative to each other in the core of the fault. It is shown that in the high-friction limit a perturbed sine-Gordon equation applied for fault dynamics modeling is reduced to a reaction-diffusion equation, whereas the system goes from the soliton regime to the autowave regime. In the case of high friction and a lack of energy supply to the fault from an external source, the transfer of localized deformation is changed by a diffusive dissipation of stress.

Structural Health Monitoring of Adhesively Bonded Joints: Proposing a new Method by use of Polymer Optical Fibers

According to the current state of the art, adhesively bonded joints cannot be tested completely non-destructively. This is the main motivation to permanently monitor adhesively bonded joints in order to record their structural integrity and - as a result - to ensure safe load transmission. By the use of permanent non-destructive Structural Health Monitoring (SHM) methods, structural damages in the adhesive bond can be detected at an early stage.This paper presents a new method for monitoring the structural integrity of adhesively bonded joints by integrating a Polymer Optical Fiber (POF) into the adhesive layer. The sensor concept is based on a deformation transfer from the adhesive to the POF, which results in a change in the cross-sectional shape of the POF. The cross-sectional shape influences the optical light propagation in the POF, which can be detected by simple optical measuring devices. The paper describes the general principle and first results of investigations on a structural adhesive (3M Scotch-Weld DP 609). The sensor signal is in a good relation to the stress state of the adhesive layer.

Fully Automatic Facial Deformation Transfer

Facial Animation is a serious and ongoing challenge for the Computer Graphic industry. Because diverse and complex emotions need to be expressed by different facial deformation and animation, copying facial deformations from existing character to another is widely needed in both industry and academia, to reduce time-consuming and repetitive manual work of modeling to create the 3D shape sequences for every new character. But transfer of realistic facial animations between two 3D models is limited and inconvenient for general use. Modern deformation transfer methods require correspondences mapping, in most cases, which are tedious to get. In this paper, we present a fast and automatic approach to transfer the deformations of the facial mesh models by obtaining the 3D point-wise correspondences in the automatic manner. The key idea is that we could estimate the correspondences with different facial meshes using the robust facial landmark detection method by projecting the 3D model to the 2D image. Experiments show that without any manual labelling efforts, our method detects reliable correspondences faster and simpler compared with the state-of-the-art automatic deformation transfer method on the facial models.

Transfer of deformation during indentation: Inferences from the post- middle Miocene evolution of the Dinarides

Understanding the structural and kinematic effects of indentation is still debated due to the large number of competing mechanisms associated with the complex orogenic build-up. Among the many examples available worldwide, the evolution of the Adriatic continental microplate in the Mediterranean domain provides one of the best places to understand the mechanics of indentation. This understanding is hampered by the lack of structural and kinematic data in the Dinarides, an orogen situated at the critical transition between the Alps, Albanides and Hellenides, and across the Adriatic margin of the Apennines. We have studied the less known area of the central and south-eastern Dinarides by focussing on collecting a new kinematic dataset for structures formed during the Adriatic indentation, which postdates the main Late Jurassic – Paleogene orogenic structuration. Our results are in agreement with previous interpretations of an early-middle Miocene period of extension that affected the entire orogen across its strike and is incompatible with indentation effects in the studied parts of the Dinarides. More importantly, we demonstrate for the first time that the post- middle Miocene Dinarides deformation was characterized by a coherent regional system of large offset dextral strike-slip faults, which transfer gradually their offsets to thrusts and high-angle reverse faults. The overall deformation transfer mechanism can be described as a special class of continental restraining bends or stepovers, whose geometry is controlled by rheological distribution. The integration of our results in the larger geodynamic context shows that the post-middle Miocene Dinarides fault system accommodates the differential motion between the N- to NE-wards Adriatic indentation and the rapid S- to SW- ward movement of a Hellenides area situated SE of the Kefalonia Fault, driven by the Aegean slab-roll back.

Responses of deep soil layers to combined recharge in a leaky aquifer

Groundwater withdrawal during exploitation of underground space greatly affects the hydrogeological environment, causing severe land subsidence. Artificial recharge is considered to be an effective way to minimize dewatering-induced land subsidence. However, well clogging often affects the recharge efficiency. To avoid well clogging, it is necessary to periodically redevelop recharge wells. Field measurements show that well redevelopment can cause visible environmental settlements. To solve this problem, some researchers have proposed a method called combined recharge, which can successfully restrict redevelopment-induced settlement at the ground surface. However, if the protected area is located in deep soils, whether this method can still be applicable is unclear since the deformation response of the deep soil layers to combined recharge is unknown due to the current lack of investigations. In this study, a combined recharge test is simulated by a numerical model. The model is verified by field measurements and is used to study the response of deep soils during combined recharge. The results show that much greater amounts of soil heave can appear in deep soils (compared to those at surface) during combined recharge. The reason is that the soils between the ground surface and the recharged aquifer will show a strong restraining effect on the transfer of deformation from the recharged aquifer to the ground surface. If we use combined recharge to protect deeply buried targets, some measures should be taken to reduce the deep soil heave to within an acceptable range.

Compressing animated meshes with fine details using local spectral analysis and deformation transfer

Geometry-centric shape animation, usually represented as dynamic meshes with fixed connectivity and time-deforming geometry, is becoming ubiquitous in digital entertainment and other relevant graphics applications. However, digital animation with fine details, which requires more diversity of texture on meshed geometry, always consumes a significant amount of storage space, and compactly storing and efficiently transmitting these meshes still remain technically challenging. In this paper, we propose a novel key-frame-based dynamic meshes compression method, wherein we decompose the meshes into the low-frequency and high-frequency parts by applying piece-wise manifold harmonic bases to reduce spatial-temporal redundancy of primary poses and by using deformation transfer to recover high-frequency details. First of all, we partition the animated meshes into several clusters with similar poses, and the primary poses of meshes in each cluster can be characterized as a linear combination of manifold harmonic bases derived from the key-frame of that cluster. Second, we recover the geometric details on each primary pose using the deformation transfer technique which reconstructs the details from the key-frames. Thus, we only need to store a very small number of key-frames and a few harmonic coefficients for compressing time-varying meshes, which would reduce a significant amount of storage in contrast with traditional methods where bases were stored explicitly. Finally, we employ the state-of-the-art static mesh compression method to store the key-frames and apply a second-order linear prediction coding to the harmonics coefficients to further reduce the spatial-temporal redundancy. Our comprehensive experiments and thorough evaluations on various datasets have manifested that, our novel method could obtain a high compression ratio while preserving high-fidelity geometry details and guaranteeing limited human perceived distortion rate simultaneously, as quantitatively characterized by the popular Karni–Gotsman error and our newly devised local rigidity error metrics.

A synthesis of the first full-scale experiment in Central America

ABSTRACT The initial full-scale experiment in Costa Rica began in 2012 under a program that has been identified as PaveLab. The main purposes were to identify the effect of typical construction practices in the country: use of granular vs. cement-treated bases (CTB), and thin vs. thick HMA layers. The effect of moisture was also considered: sections under optimal moisture conditions were compared to sections where the water table was raised to approximately the middle of the subbase. The recorded information includes: stress and strain measurements for the top layers of the structure, vertical pressure in supporting layers, surface roughness and deflection data. Preliminary results show the importance of considering the effect of water on the stability of pavement structures. It was noted that even though the CTB layer showed higher initial stiffness as compared to a granular base, the loss of stiffness associated to load-induced damage occurred at a significantly higher rate than that observed at the other layers. Similarly, the results showed that an increase in HMA layer thickness results in higher overall structural capacity, independent of the supporting layers. The data is currently being used to calibrate fatigue, permanent deformation and surface roughness transfer functions.