3D Deformation Research Articles

Internal shear damage evolution of CFRP laminates ranging from −100 °C to 100 °C using in-situ X-ray computed tomography

Carbon Fiber Reinforced Polymer (CFRP) composites have been widely used in aerospace due to their high specific stiffness, strength, and fatigue properties. However, the ambient temperature significantly influences CFRP's mechanical properties and damage evolution, deriving from the temperature effect on the microstructural behavior and the mesoscopic damage evolution. In this study, the temperature-dependent in-plane shear failure behavior of CFRP composites was investigated. In-situ X-ray Computed tomography (CT) tensile experiments of laminates ([45°/-45°]2s) at RT, −100 °C, and 100 °C were carried out to study the in-plane shear failure mechanisms. The 3D fracture morphology was extracted with internal damage evolution process estimated and quantified. The in-situ 3D deformation fields of critical regions were acquired using the Digital Volume Correlation (DVC) method. The effect of temperature on strain field and the correlation between the high-strain region and the fracture location were analyzed. The results revealed the temperature correlations and failure mechanisms of CFRP's mechanical characteristics and internal damage evolution process. Compared to room temperature (RT), the delamination damage area of the sample increased by 80 % at 100 °C. Meanwhile, the shear modulus of CFRP decreases by 78.4 % from −100 °C to 100 °C, and the fracture strain increases by 95 % from RT to 100 °C. The DVC results indicated a dispersion of high-strain regions at −100 °C, reflecting the brittle damage characteristics, while an extensive ductile deformation region was captured at 100 °C. Fiber-matrix debonding is the dominant failure mode of composites under shear loading, whereas significant matrix cracking was observed at −100 °C and partial fiber pullout occurred at 100 °C.

A novel dimension reduction model based on POD and two-grid Crank–Nicolson mixed finite element methods for 3D nonlinear elastodynamic sine–Gordon problem

Earthquake, petroleum and gas extraction, and underground nuclear test all could cause nonlinear tectonic deformation. It is of great significance to effectively predict and evaluate the disasters and impacts of these geological structure deformation. In this end, a three-dimension (3D) nonlinear elastodynamic sine–Gordon model that can be used to describe nonlinear tectonic deformation including 3D displacement vector, 3 × 3 symmetric stress tensor matrix, nonlinear sin term, and singular initial value functions is first proposed. Then, a new time semi-discrete mixed Crank–Nicolson (TSDMCN) scheme for the 3D nonlinear elastodynamic sine–Gordon model is developed, and the existence, stability, and error estimates of the TSDMCN solutions are proved. Next, a new two-grid mixed finite element Crank–Nicolson (TGMFECN) method with unconditional stability for the 3D nonlinear elastodynamic sine–Gordon model is developed, and the existence, stability, and error estimates of the TGMFECN solutions are proved. Thenceforth, it is the most important thing is that a novel reduced-dimensional iterative TGMFECN (RDITGMFECN) method in matrix form is established by resorting to proper orthogonal decomposition only to lower the unknown TGMFECN solution coefficient vectors and keep TGMFECN basis functions unchanged, which can ensure that the RDITGMFECN method has the same accuracy as the usual TGMFECN method, but can greatly lower the dimension of the unknown TGMFECN solution coefficient vectors so as to mitigate calculated workload, save CPU operating-time, improve computing efficiency, and improve real-time calculating accuracy. In theory, the existence, stability, and error estimates of RDITGMFECN solutions are demonstrated by matrix analysis such that the theoretical analysis becomes very intuitive and easy to be understood by the public, which is a new attempt of theoretical analysis. In application, two numerical examples are used to simulate the 3D nonlinear tectonic deformation caused by earthquake and to verify the correctness of our theoretical results and the effectiveness of the RDITGMFECN method.

Free Vibration and Stability Analyses of Functionally Graded Plates Resting on Elastic Foundations Based on 2D and Quasi-3D Shear Deformation Theories Using the Finite Strip Method

Free Vibration and Stability Analyses of Functionally Graded Plates Resting on Elastic Foundations Based on 2D and Quasi-3D Shear Deformation Theories Using the Finite Strip Method

Accuracy of the Conventional Facial Impression Method and Three-Dimensional Auricular Shape Data Obtained Using Extra- and Intraoral Optical Scanners

Background: Facial impression methods have been used to fabricate auricular prostheses; however, deformation due to the weight of the impression material remains. This study aimed to investigate the accuracy of auricular three-dimensional (3D) data obtained using a 3D optical extraoral scanner and an intraoral scanner compared with that of a conventional facial impression method. Methods: Six auricles were digitized using an extraoral scanner with and without a reference board around the auricle and an intraoral scanner. Auricle casts fabricated using auricle impressions were scanned using a laboratory scanner. All obtained data were superimposed, and the 3D deformations of the different methods were evaluated using measurement mapping and root mean square (RMS) values. The length, width, and height of the auricular casts and scanned data were measured and compared with the sizes of the original auricles measured using a caliper. Results: Large displacements of the back and margins of the ears were observed, and the RMS values ranged from 0.5–2.4 mm. Larger widths and smaller heights of the scanned and impression data were observed compared to the anthropometric ear data. Conclusions: The study concluded that the fabrication of auricular prostheses using optical scanning is clinically acceptable. All examined scanning techniques demonstrated discrepancies within acceptable limits when compared to the conventional facial impression method.

Shrinkage and deformation of material extrusion 3D printed parts during sintering: Numerical simulation and experimental validation

Material extrusion 3D printing (ME3DP) combined with sintering is a low-cost additive manufacturing technique for fabricating components of difficult-to-print metals, such as copper, aluminum, and ceramics. However, the sintering process includes complex material science, such as volumetric shrinkage and free structural bending, to identify the relative density and deformation of a 3D printed sample. The prediction of the relative density and deformations during the sintering process provides information to the design engineer to optimize the design of the CAD model before sintering. In this study, a phenomenological model based on constitutive equations was developed to predict the density and structural deformation during the sintering process of pure copper components fabricated by ME3DP using metal injection molding feedstock. The densification rate was determined using shrinkage estimation with an isothermal stairway heating cycle in a vertical dilatometer. Furthermore, different sets of experiments were performed with a load on the probe with long isothermal heating cycles at 850, 900, 950, 1000, and 1050 °C in a vertical dilatometer to estimate the axial viscosity of the copper. The constitutive equations were solved using the solid mechanics module with user-defined creep in COMSOL Multiphysics by considering isotropic assumptions. Two types of geometries, cube and overhanging I section, were used to predict shrinkage and deformation during the sintering process. The developed model successfully predicted the relative density based on shrinkage and structural deformation owing to gravity during the sintering process.

Magneto-viscoelastic rod model for hard-magnetic soft rods under 3D large deformation: Theory and numerical implementation

The main purpose of this work is to develop a three-dimensional (3D) viscoelastic rod model for hard-magnetic soft (HMS) rods under large deformation which are widely used active structures in soft robotics. To do so, the Simo’s viscoelasticity theory has been rationally incorporated into the geometrically exact 3D curved rod model. The proposed model includes the deformation modes of axial tension, shear, bending, and torsion, which is applicable to the HMS rods with arbitrarily initial curved and twisted geometries under 3D large deformation. The viscoelastic constitutive equations of the HMS rod in the present formulation are formulated, which include the general relaxation functions. To obtain the expression for the magnetic load, the rotation-based magnetic free energy density is introduced, and the governing equations of the HMS rod with magnetic load and body force are presented. To obtain the numerical implementation, an implicit time integration algorithm that simply extends the generalized-α method for the rotation group, and the corresponding variational formulation and its linearization of the rod model are derived. To validate the model, five numerical examples, including 2D dynamic buckling, 3D static, and 3D dynamic problem are presented. The dynamic problems include the dynamic snap-through behavior of a bistable HMS arch and damped oscillation of a quarter arc cantilever under 3D deformation. The simulation results show good agreement with the results reported in the literature.

Three-dimensional deformation monitoring of San Francisco Bay based on GNSS-InSAR data

As a cutting-edge technology in the field of remote sensing, Synthetic Aperture Radar Interferometry (InSAR) plays a significant role in monitoring urban surface deformation. The traditional multi-temporal InSAR technique can only obtain surface deformation in the line-of-sight (LOS) direction, and there are fewer studies on three-dimensional(3D) deformation monitoring in coastal areas. At the same time, there is a lack of research on integrating GNSS-InSAR data to obtain the three-dimensional deformation field in the San Francisco Bay area. Using ascending and descending orbit InSAR images and GNSS data to monitor ground subsidence in the San Francisco Bay area, various schemes of integrating GNSS and InSAR data to invert the three-dimensional deformation field were analyzed and compared. An improved Robust-Helmert estimation method was proposed to calculate the 3D ground deformation velocity. The results showed that the Robust-Helmert estimation method performed best, with Root Mean Square Error (RMSE) values of 3.96 mm, 6.51 mm, and 2.75 mm in the East-West (E), North-South (N), and Up-Down (U) directions, respectively. It also exhibited more stable solution accuracy and good universality.

Automatic modeling of the current state components of ancient buildings based on 3D deformation algorithm

AbstractAncient buildings possess significant artistic and cultural value. The digitization of these structures is a crucial aspect of their restoration, providing foundational data for subsequent stress and health analyses. However, creating accurate models of ancient buildings is a challenging endeavor, even for experienced researchers, especially when dealing with a large number of structures. A pressing issue that needs addressing is how to quickly obtain accurate models of ancient buildings while ensuring both precision and efficiency. Currently, one of the more precise methods for reconstructing models of ancient buildings involves the use of scanned point clouds and manual reconstruction through modeling software. However, this method suffers from poor accuracy and low efficiency, making the modeling process complex and time-consuming. In this article, we will refer to the model generated from the point cloud of real components as the "current state model", and the unforced mesh model of the ancient building as the "standard model". An algorithm is proposed to construct the current state model of ancient buildings by guiding the deformation of the unforced standard model using the scanned point cloud model. First, this paper designs an automatic modeling method for ancient building components as the foundational data before deformation, addressing the issue of low modeling efficiency for ancient buildings. Second, it proposes a method for automatically calculating deformation control point pairs based on the characteristics of ancient buildings, solving the problem of manually locating control points. Finally, the proposed adaptive weight Laplacian deformation algorithm is applied to deform the standard model into the current state model.

Internal damage evolution of C/SiC composites in air at 1650 °C studied by in-situ synchrotron X-ray imaging

Carbon fibre reinforced silicon carbide (C/SiC) ceramic matrix composites have attracted considerable attention due to their exceptional properties and extensive potential applications as high-temperature structural materials. However, due to their complex structure and manufacturing defects, C/SiC composites exhibit intricate mechanical behaviour under thermal-mechanical-oxidative coupling environments. To date, systematic studies on the internal damage evolution and failure mechanisms of C/SiC composites under high-temperature oxidative environments are lacking. In this study, a combination of synchrotron X-ray micro-computed tomography (SR-μCT) and in-situ experiments under thermal-mechanical-oxidative coupling environments at room temperature and 1650 °C in air was used to characterize the internal microstructures and damage evolution processes of C/SiC composites at different loading levels. Additionally, the 3D strain fields during in-situ loading were quantitatively analysed using the Digital Volume Correlation (DVC) method. The findings underscore the substantial impact of oxidative damage on the mechanical response of C/SiC composites, particularly concerning tensile properties and fracture modes. At room temperature, severe delamination, fibre bundle pull-out and interfacial debonding occurred internally. Whereas, under high-temperature atmospheric conditions, severe fibre oxidation reactions occurred at the specimen edges, resulting in rapid porosity escalation. Crack initiation from surface defects followed by rapid inward propagation is observed. Moreover, while the strain distribution remains relatively uniform until fracture, a pronounced concentration of strain is evident near the fracture zones at room temperature, with an even greater concentration observed at 1650 °C. Notably, the region of concentrated strain within the 3D deformation field corresponds closely to the final fracture location, as revealed by quantitative DVC analysis.

Three-dimensional deformation monitoring of internal nodes of large-span suspended dome structure using videogrammetry under camera instability

Large-span suspended domes often serve as landmarks for cities or countries. This paper proposes a videogrammetric method for monitoring the 3D deformation of internal key nodes in such structures, even under conditions of camera instability. Utilizing circular targets strategically placed on the measurement area, a dynamic parameter calibration method is developed to estimate the instantaneous position and orientation of cameras relative to the world coordinate system, minimizing camera motion-induced errors. Combined with surface targets on the rigid structure and local coordinate frame transformation, the 3D displacement response of structural internal nodes can be precisely measured using the proposed tracking method. The effectiveness and accuracy of the proposed methods were validated through exhaustive experiments, improving positioning accuracy for the structural internal nodes from 47.24 mm to 1.62 mm after dynamic parameter correction. This methodology offers a low-cost, easily implemented, and non-destructive vision-based solution for the long-term monitoring of large-span suspended domes.

A 3D finite deformation constitutive model for anisotropic shape memory polymer composites integrating viscoelasticity and phase transition concept

The phase transition theory of shape memory polymers (SMPs) often involves a phenomenological assumption that the reference configuration of the newly transformed phase deviates from that of the initial phase. This distinction serves as a crucial mechanism in the manifestation of the shape memory effect. However, elucidating the precise definition of the reference configuration of the transformed phase poses a significant challenge in the formulation of the constitutive model. To tackle this challenge, a three-dimensional (3D) finite deformation constitutive model incorporating effective phase evolution for SMPs has been developed. This model merges insights from the classical viscoelastic framework with the phase transition theory. The anisotropic thermo-viscoelastic constitutive model is further developed by introducing hyperelastic fibers, which integrate the anisotropy of the fibers into a continuous thermodynamic framework through structure tensors. Implemented within the ABAQUS software via a user material (UMAT) subroutine, the proposed model has been meticulously validated against experimental data, showcasing its prowess in simulating stress-strain responses and shape memory characteristics of SMPs and their composites (SMPCs). This innovative model stands as an invaluable instrument for the design and of sophisticated SMP and SMPC structures.

Foams with 3D Spatially Programmed Mechanics Enabled by Autonomous Active Learning on Viscous Thread Printing.

Foams are versatile by nature and ubiquitous in a wide range of applications, including padding, insulation, and acoustic dampening. Previous work established that foams 3D printed via Viscous Thread Printing (VTP) can in principle combine the flexibility of 3D printing with the mechanical properties of conventional foams. However, the generality of prior work is limited due to the lack of predictable process-property relationships. In this work, a self-driving lab is utilized that combines automated experimentation with machine learning to identify a processing subspace in which dimensionally consistent materials are produced using VTP with spatially programmable mechanical properties. In carrying out this process, an underlying self-stabilizing characteristic of VTP layer thickness is discovered as an important feature for its extension to new materials and systems. Several complex exemplars are constructed to illustrate the newly enabled capabilities of foams produced via VTP, including 1D gradient rectangular slabs, 2D localized stiffness zones on an insole orthotic and living hinges, and programmed 3D deformation via a cable-driven humanoid hand. Predictive mapping models are developed and validated for both thermoplastic polyurethane (TPU) and polylactic acid (PLA) filaments, suggesting the ability to train a model for any material suitable for material extrusion (ME) 3D printing.

Photothermalprogramming of magnetic soft materials for complex and reconfigurable 3D deformations

Photothermalprogramming of magnetic soft materials for complex and reconfigurable 3D deformations

Aerodynamics of a three-dimensionally deformed rigid wing

A flexible wing with a large aspect ratio emerges in many modern engineering applications (e.g. solar planes and super large wind turbine blades) and its interaction with incident flow differs markedly from conventional fluid–structure interactions (FSI), exhibiting frequently a large three-dimensional (3D) deformation. Yet, there is little information on how such deformation may change wing aerodynamics. This work investigates the aerodynamic performance of deformed and cantilever-supported NACA0012 rigid wings with an aspect ratio of 9, using ANSYS Fluent with the SST-κ-ω turbulence model at a chord-length-based Reynolds number Rec of 1.5 × 105. Numerical simulation is validated experimentally. The wing tip bending displacement is up to 4.14c, and the maximum twisted angle is up to 7°. The angle α of attack varies from 0° to 20° at mid span of the wing. It has been found that the torsional deformation can significantly advance the local flow separation, reattachment, bubble length, and transition from laminar to turbulence, resulting in a drop in the critical angle αcr of attack, at which the separation bubble size reaches the maximum. Accordingly, the lift and drag coefficients increase, as well as the bending and pitching-up moments, though the stall is advanced due to a change in local α. The tip vortex is also enhanced, inducing strong downwash postponing the separation bubble on the wing and resulting in redistributed force near the wing tip that increases markedly the local bending moment but decrease the local pitching-up moment. On the other hand, the bending deformation tends to produce an effect opposite to the torsion on the flow structure and causing little change in the lift coefficient, though reducing the induced drag and moments appreciably. With both deformations in place, the torsion overwhelms the bending in general in terms of its impact upon aerodynamics and flow structures, the latter acting to cancel at least partially the effect of the former.

Individualized C1-2 intra-articular three-dimensional printed porous titanium alloy cage for craniovertebral deformity

BackgroundCongenital craniovertebral deformity, including basilar invagination (BI) and atlantoaxial instability (AAI), are often associated with three-dimensional (3D) deformity, such as C1-2 rotational deformity, craniocervical kyphosis, C1 lateral inclination, among other abnormalities. Effective management of these conditions requires the restoration of the 3D alignment to achieve optimal reduction. Recently, 3D printing technology has emerged as a valuable tool in spine surgery, offering the significant advantage of allowing surgeons to customize the prosthesis design. This innovation provides an ideal solution for precise 3D reduction in the treatment of craniovertebral deformities.ObjectiveThis study aims to describe our approach to individualized computer-simulated reduction and the design of C1-2 intra-articular 3D printed porous titanium alloy cages for the quantitative correction of craniovertebral junction deformities.MethodsA retrospective analysis was conducted on patients with craniovertebral deformities treated at our institution using individualized 3D-printed porous titanium alloy cages. Preoperative CT data were used to construct models for 3D realignment simulations. Cage designs were tailored to the simulated joint morphology following computer-assisted realignment. Preoperative and postoperative parameters were statistically analyzed.ResultsFourteen patients were included in the study, with a total of 28 3D-printed porous titanium alloy cages implanted. There were no cases of C2 nerve root resection or vertebral artery injury. All patients experienced symptom relief and stable implant fixation achieved in all cases. No implant-related complications were reported.ConclusionThe use of individualized computer-simulated reduction and the design of C1-2 intra-articular 3D printed porous titanium alloy cage facilitates precise 3D realignment in patients with craniovertebral deformities, demonstrating effectiveness in symptom relief and stability.

Accurate modeling and safety evaluation of dented pipeline with internal pressure based on reverse modeling technique

ABSTRACT As a common form for pipeline geometric defects, dents can induce the local stress concentration of the pipeline, which would result in the debilitation of the bearing capacity and bring huge safety hazards. In this paper, the accurate surface profiles of dented pipeline are acquired based on the 3D scanning technology and deformation detection technology, respectively. Then, the dented pipeline models are constructed by the reverse modeling technique, and the stress distribution characteristics of the dented pipeline in the operation condition are simulated using ABAQUS. The maximum von Mises stresses of a dented pipeline obtained from two proposed modeling techniques are basically consistent. However, the deformation detection technology can effectively avoid the excavation work for buried pipelines. Therefore, the reverse modeling technique based on the deformation detection technology has strong feasibility in practical projects and significant application value in the safety assessment of submarine pipelines, where excavation work is impractical.

Hierarchical Spherical Cross‐Parameterization for Deforming Characters

AbstractThe demand for immersive technology and realistic virtual environments has created a need for automated solutions to generate characters with morphological variations. However, existing approaches either rely on manual labour or oversimplify the problem by limiting it to static meshes or deformation transfers without shape morphing. In this paper, we propose a new cross‐parameterization approach that semi‐automates the generation of morphologically diverse characters with synthesized articulations and animations. The main contribution of this work is that our approach parameterizes deforming characters into a novel hierarchical multi‐sphere domain, while considering the attributes of mesh topology, deformation and animation. With such a multi‐sphere domain, our approach minimizes parametric distortion rates, enhances the bijectivity of parameterization and aligns deforming feature correspondences. The alignment process we propose allows users to focus only on major joint pairs, which is much simpler and more intuitive than the existing alignment solutions that involve a manual process of identifying feature points on mesh surfaces. Compared to recent works, our approach achieves high‐quality results in the applications of 3D morphing, texture transfer, character synthesis and deformation transfer.

Evaluation of a Rapid Diagnostic Tool to Estimate Geometry Evolution of Multiple Simultaneously Propagating Fractures from Crosswell Fiber-Optic Strain Measurements

Summary Crosswell low-frequency distributed acoustic sensing (LF-DAS) strain rate measurements generate data useful for hydraulic fracture (HF) diagnostics. These data contain information about HF geometry; however, interpreting the data has relied on time-consuming and computationally expensive numerical interpretation methods. This study aims to evaluate the applicability of a rapid diagnostic tool, known as the “zero strain rate location method” (ZSRLM), for characterizing the geometry of multiple fractures propagating simultaneously. Simulations of multiple fracture propagation are conducted using a planar 3D multifracture simulator that incorporates 3D rock deformation, fluid flow in the wellbore, fluid leakoff, and multiscale fracture propagation regimes. A supertimestepping algorithm is used to solve the nonlinear parabolic equations governing fluid-driven fractures. The far-field strain profile induced by multiple propagating fractures along a crosswell fiber-optic cable is computed using the displacement discontinuity method (DMM). Various scenarios are simulated by adjusting key completion parameters, including the number of clusters, cluster spacing, in-situ stress states, and geomechanical properties. The ZSRLM is then applied to the computed strain field to estimate fracture extents and propagation rates. The accuracy of the ZSRLM is assessed by comparing the estimated fracture geometry parameters with the known simulated values. Our observations indicate that the ZSRLM is not effective when two or more fractures approach the observation well at similar times, as it becomes challenging to discern unique strain-rate converging patterns on waterfall plots for each fracture. However, when fracture arrivals at the monitor well are offset, distinct strain rate patterns emerge, enabling the application of the ZSRLM. Errors between simulated and estimated fracture extent propagation rates are quantified. Finally, the ZSRLM is applied to a field case involving multicluster fracture propagation, and the interpretation of the results is discussed in light of these findings. This research demonstrates the applicability of the ZSRLM for diagnosing the velocities and final extents of multiple fractures propagating simultaneously. The method offers a rapid means of characterizing stimulations using crosswell LF-DAS measurements, which can inform decisions regarding completion design, well spacing, and landing zone. The study contributes to the advancement of efficient fracture diagnostics in the industry, reducing the reliance on numerical interpretation methods.

Buckling-inspired triboelectric sensor for multifunctional sensing of soft robotics and wearable devices

Amidst the rapid development of intelligent robotics and wearable health monitoring devices, there is an urgent demand for flexible sensor with high sensitivity and precise feedback. In this paper, a multifunctional triboelectric sensor inspired by the phenomenon of buckling is introduced, which integrates kirigami structures with triboelectric nanogenerator principles to accurately detect one-dimensional (1D) and two-dimensional (2D) deformations. The sensor employs a contact-separating structure, with its friction layers consisting of 2D laser-cut kirigami electrodes, which deform into three-dimensional (3D) structures through tensile or compressive buckling. The tensile buckling sensor (BS) developed is capable of sensing the bending angle of soft grippers, allowing the detection of the size of grasped objects with a high recognition rate of 93.75 %. Additionally, in its 1D compressive buckling form, the sensor can be used to recognize various human motion patterns effectively, while the 2D compressive version can be used to measure the expansion of curved surfaces with a sensitivity of 1.3307 V/mm. By combining the unique properties of buckling structures, the innovative triboelectric multifunctional sensor proposed offers a new solution for high-precision motion feedback control with potential application in soft robotics and health monitoring.

Structural detection study of mine blanket area based on dynamic 3D deformation prediction

Structural detection study of mine blanket area based on dynamic 3D deformation prediction