Journal articles: 'Warping deformation'

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Cao, Juan, Xiaoyi Zhang, Jiannan Huang, and Yongjie Jessica Zhang. "Polygonal finite element-based content-aware image warping." Computational Visual Media 9, no. 2 (January 3, 2023): 367–83. http://dx.doi.org/10.1007/s41095-022-0283-7.

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AbstractMesh-based image warping techniques typically represent image deformation using linear functions on triangular meshes or bilinear functions on rectangular meshes. This enables simple and efficient implementation, but in turn, restricts the representation capability of the deformation, often leading to unsatisfactory warping results. We present a novel, flexible polygonal finite element (poly-FEM) method for content-aware image warping. Image deformation is represented by high-order poly-FEMs on a content-aware polygonal mesh with a cell distribution adapted to saliency information in the source image. This allows highly adaptive meshes and smoother warping with fewer degrees of freedom, thus significantly extending the flexibility and capability of the warping representation. Benefiting from the continuous formulation of image deformation, our poly-FEM warping method is able to compute the optimal image deformation by minimizing existing or even newly designed warping energies consisting of penalty terms for specific transformations. We demonstrate the versatility of the proposed poly-FEM warping method in representing different deformations and its superiority by comparing it to other existing state-of-the-art methods.

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Zhou, Maoding, Yuanhai Zhang, Pengzhen Lin, Wei Ji, and Hongmeng Huang. "Study of Practical Analysis Method for Shear Warping Deformationof Composite Box Girder with Corrugated Steel Webs." Materials 16, no. 5 (February 23, 2023): 1845. http://dx.doi.org/10.3390/ma16051845.

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Shear warping deformation is an important part of the flexural and constrained torsion analysis of composite box girder with corrugated steel webs (CBG-CSWs), which is also the main reason for the complex force analysis of box girders. A new practical theory for analyzing shear warping deformations of CBG-CSWs is presented. By introducing shear warping deflection and corresponding internal forces, the flexural deformation of CBG-CSWs is decoupled to the Euler-Bernoulli beam (EBB) flexural deformation and the shear warping deflection. On this basis, a simplified method for solving shear warping deformation using the EBB theory is proposed. According to the similarity of the governing differential equations of constrained torsion and shear warping deflection, a convenient analysis method for the constrained torsion of CBG-CSWs is derived. Based on the decoupled deformation states, a beam segment element analytical model applicable to EBB flexural deformation, shear warping deflection, and constrained torsion deformation is proposed. A variable section beam segment analysis program considering the variation of section parameters is developed for CBG-CSWs. Numerical examples of constant and variable section continuous CBG-CSWs show that the stress and deformation results obtained by the proposed method are in good agreement with the 3D finite element results, verifying the effectiveness by the proposed method. Additionally, the shear warping deformation has a great influence on the cross-sections near the concentrated load and middle supports. This impact along the beam axis decays exponentially, and the decay rate is related to the shear warping coefficient of the cross-section.

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Chen, Chang Hong, and Ying Huang. "The Pre-Twisted Thin-Walled Beam Element Stiffness Matrix Considering the Saint-Venant Warping Deformation." Advanced Materials Research 871 (December 2013): 129–34. http://dx.doi.org/10.4028/www.scientific.net/amr.871.129.

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Based on the traditional mechanical model of thin-walled straight beam, the paper makes a systematic analysis and research on the pre-twisted thin-walled beam finite element numerical model. Firstly, based on the geometric deformation differential relationship, the paper deduces the pre-twisted thin-walled beam Saint-Venant warping strain. According to traditional thin-walled straight beam finite element mechanical model, the paper establishes its finite element stiffness matrix considering the Saint-Venant warping deformations. Finally, by calculating the pre-twisted elliptical section beam example, and contrasting three-dimensional solid finite element using ANSYS, the comparative analysis results show that pre-twisted thin-walled beam element stiffness matrix considering Saint-Venant warping deformation has good accuracy.

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Qin, Qin, Zu-huai Wu, Yong Zang, Ben Guan, and Jinxin Zhang. "Warping deformation of 316l/q345r stainless composite plate after removal strake." World Journal of Engineering 13, no. 3 (June 13, 2016): 206–9. http://dx.doi.org/10.1108/wje-06-2016-027.

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Purpose This study aims to reduce the warping deformation of the stainless composite plate after removal strake by using a finite element method. A three-dimensional thermo-mechanical coupled elastic-plastic finite element model has been suggested by using ABAQUS to simulate the multi-pass hot rolling of stainless composite plate. Design/methodology/approach A three-dimensional thermo-mechanical coupled elastic-plastic finite element model has been suggested by using ABAQUS to simulate the multi-pass hot rolling of stainless composite plate. Warping deformation rules of 316L/Q345R stainless composite plate after removal strake have been analyzed. Moreover, the influences of some different rolling parameters on this deformation have been discussed. Findings The warping deformation just varies in the range of cladding ratio from 0.1 to 0.25. Therefore, cladding ratio does not have a great influence on warping deformation. Originality/value The results show that higher heating temperature, larger final thickness and less rolling passes are beneficial for reducing the warping deformation.

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Siddiqui, A. H., and S. F. Ng. "Effect of diaphragms on stress reduction in box girder bridge sections." Canadian Journal of Civil Engineering 15, no. 1 (February 1, 1988): 127–35. http://dx.doi.org/10.1139/l88-014.

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The purpose of this study is to examine the effect of rigid diaphragms in reducing warping and distortion stresses developed in box girders due to deformation of the cross section. Tests were conducted for two Plexiglas box girder models to determine effect of diaphragms on the behaviour of box girder sections. The results of the tests were compared with values obtained from the so-called “beam on elastic foundation (BEF) analogy,” an analytical procedure that permits the calculation of warping and distortion stresses in box sections due to deformation of the cross section.Each box girder model was tested as a simply supported beam with a 1168.4 mm (46 in.) span. Six separate loading positions were used for each of the three predesigned diaphragm spacings. Thus, 18 separate loading tests were conducted for each model in order to obtain sufficient data to determine the amount of reduction in both warping and distortion stresses. Test measurements included the applied load, deflections, and strains at various locations on the webs and bottom flanges.The results indicate that deformation of a box girder cross section due to eccentric loading may cause substantial warping and distortion stresses, and that these stresses can be effectively controlled by judicious installation of rigid diaphragms along the span of the girder. Also, experimental warping and distortion stresses obtained from both tests compare reasonably well with those predicted by the BEF analogy. Key words: warping, torsional, stresses, deformations, box girder bridges, diaphragms.

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Kim, J. H., and Y. Y. Kim. "Thin-Walled Multicell Beam Analysis for Coupled Torsion, Distortion, and Warping Deformations." Journal of Applied Mechanics 68, no. 2 (October 4, 2000): 260–69. http://dx.doi.org/10.1115/1.1357166.

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Due to the complicated deformations occurring in thin-walled multicell beams, no satisfactory one-dimensional beam theory useful for general quadrilateral multicells appears available. In this paper, we present a new systematic approach to analyze the coupled deformations of torsion, distortion, and the related warping. To develop a one-dimensional thin-walled multicell beam theory, the method to determine the section deformation functions associated with distortion and distortional warping is newly developed. In order to guarantee the singlevaluedness of the distortional warping function in multicells, distortional shear flows have been utilized. The superior result by the present one-dimensional theory is demonstrated with various examples.

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Xu, Hao, Qi Zhou, Lei Yang, Minjing Liu, Dongyue Gao, Zhanjun Wu, and Maosen Cao. "Reconstruction of full-field complex deformed shapes of thin-walled special-section beam structures based on in situ strain measurement." Advances in Structural Engineering 23, no. 15 (July 4, 2020): 3335–50. http://dx.doi.org/10.1177/1369433220937156.

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This study proposed a method capable of reconstructing complex deformations of thin-walled special-section beam structures subjected to highly coupled loading cases, in terms of the combination of tension/compression, biaxial bending, and warping torsion. The complex beam deformation was decoupled, depending on axial strain measurement strategy on beam surface, and leads to reconstructed full-field displacements (deformed shapes) as the linear superposition of deformations subject to individual loading types. Full-filed strain/stress distributions can then be derived based on the reconstructed displacements. Particular efforts were focused on reconstructing beam deformation subject to warping torsion, where both rotations angles and warping displacements across the beam cross-section and along the beam length were identified precisely. As a proof-of-concept validation, the effectiveness of the method was examined using finite element analysis, where the deformed shape of a thin-walled hat-section beam under the coupling between uniaxial bending and warping torsion was reconstructed., Experiments were conducted subsequently to reconstruct deformation of an aluminum hat-section beam using distributed optical fiber sensors for the measurement of axial strains on the beam surface. The reconstructed full-field deformed shapes of the beam were compared with the three-dimensional displacement signals captured using a non-contact digital image correlation system. The effectiveness of the proposed methodology for complex deformation reconstruction is possible to be extended to a variety of thin-walled beam-type structures which are typical in civil and aerospace engineering, showing potential contributions in fields such as on-line structural health monitoring and active structural control.

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Song, Donghwan, Adrian Matias Chung Baek, Jageon Koo, Moise Busogi, and Namhun Kim. "Forecasting Warping Deformation Using Multivariate Thermal Time Series and K-Nearest Neighbors in Fused Deposition Modeling." Applied Sciences 10, no. 24 (December 15, 2020): 8951. http://dx.doi.org/10.3390/app10248951.

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Over the past decades, additive manufacturing has rapidly advanced due to its advantages in enabling diverse material usage and complex design production. Nevertheless, the technology has limitations in terms of quality, as printed products are sometimes different from their desired designs or are inconsistent due to defects. Warping deformation, a defect involving layer shrinkage induced by the thermal residual stress generated during manufacturing processes, is a major factor in lowering the quality and raising the cost of printed products. This study utilized a variety of thermal time series data and the K-nearest neighbors (KNN) algorithm with dynamic time warping (DTW) to detect and predict the warping deformation in the printed parts using fused deposition modeling (FDM) printers. Multivariate thermal time series data extracted from thermocouples were trained using DTW-based KNN to classify warping deformation. The results showed that the proposed approach can predict warping deformation with an accuracy of over 80% by only using thermal time series data corresponding to 20% of the whole printing process. Additionally, the classification accuracy exhibited the promising potential of the proposed approach in warping prediction and in actual manufacturing processes, so the additional time and cost resulting from defective processes can be reduced.

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HASSIS, H. "A “WARPING-KIRCHHOFF” AND A “WARPING-MINDLIN” THEORY OF SHELL DEFORMATION." Journal of Sound and Vibration 225, no. 4 (August 1999): 633–53. http://dx.doi.org/10.1006/jsvi.1999.2269.

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Hassis, Hedi. "A ‘warping’ theory of plate deformation." European Journal of Mechanics - A/Solids 17, no. 5 (September 1998): 843–53. http://dx.doi.org/10.1016/s0997-7538(98)80008-9.

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11

Chen, Zui, Jieling Xiao, Xueyi Liu, Hongpei Qin, and Rongshan Yang. "Deformation behavior of slab warping for longitudinal continuous rigid slab under temperature effect." Advances in Structural Engineering 22, no. 13 (May 29, 2019): 2823–36. http://dx.doi.org/10.1177/1369433219852053.

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Longitudinally coupled prefabricated slab track is prone to slab warping under the non-uniform temperature field. Analytical expressions for the displacement field of the track slab during the warping process are developed hereby based on equilibrium differential equations, and the expressions are verified through a numerical model by finite element method in ANSYS package. Through analyzing the factors such as types of temperature distribution, slab gravity, and rail weight, regulations of warping deformation for the track slab are systematically analyzed. Research shows that the displacements in the x and z directions are linearly related to the respective components during the warping deformation. The displacement in y direction has a quadratic relationship with x and z components. Temperature gradient is the pivotal factor to lead the warping of the track slab, and the type of temperature distribution has less effect on the warping displacement. If track slab remains unwarped under the effect of slab gravity, temperature gradient should be maintained in the range of –18°C/m–13°C/m. Rail weight has less influence on slab warping.

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Lalin, Vladimir, Vladimir Rybakov, and Alexander Sergey. "The Finite Elements for Design of Frame of Thin-Walled Beams." Applied Mechanics and Materials 578-579 (July 2014): 858–63. http://dx.doi.org/10.4028/www.scientific.net/amm.578-579.858.

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Recent years there have been observed a wide application of a metalware in industrial and civil engineering. Special place in the building industry is belonged to light steel thin-walled constructions having a lot of technological advantages. In the article the first development cycle of a numerical method creating is considered – creating of the stiffness matrixes of thin-walled finite elements of various types using the semisheared theory (by V.I.Slivker) – depending on a way of approximation of functions of deformations (torsion and warping): 1. Linear approximation of torsional functions with a 2-central finite element having 4 transitions; 2. Quadratic approximation of torsional functions and linear approximation of warping function with a 3-central finite element having 5 transitions; 3. Cubical approximation of functions of torsional and warping functions with a 3-central finite element having 6 transitions. Thus deformation functions (torsional angle and warping) are approximated as mutually independent functions.

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13

Lee, CH, JP Park, CV Tyne, and YH Moon. "Analysis of warping during flat rolling of bimetallic slabs." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, no. 17 (January 16, 2015): 3153–61. http://dx.doi.org/10.1177/0954406214568820.

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The current study analyzes the warping behavior of bimetallic slabs during the flat rolling process. An analytical model that predicts the degree of warping during the rolling of bimetallic slabs is developed, based on differential bending, which occurs due to the mismatch in longitudinal elongation. The warping model focuses on the mismatch of the lengthwise elongation, due to differences in the deformation resistances of constituent materials in the bimetallic slab. With this analytical model, warping can be predicted for various processing parameters, such as initial thickness ratios and rolling reductions. To validate the model, flat rolling experiments using Al1050/Al6061 bimetallic slabs, produced by continuous clad casting, were conducted. The deformation characteristics of the bimetallic slabs during rolling were also assessed by a finite element analysis using the commercial code, FORGE™. The results from the current study show that the warping behavior of bimetallic slabs during flat rolling can be characterized with a high degree of reliability.

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Hao, Ying, and Junfeng Guan. "Parametric Study on the Influence of Warping Deformation upon Natural Frequencies of Die Springs." Shock and Vibration 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/6231676.

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The free vibrational characteristics of die springs are examined by Riccati transfer matrix method in this study. The warping deformation of spring’s cross section, as a new design factor, is incorporated into the differential equation of motion. Numerical simulations show that the warping deformation is a significant role of the behavior of natural frequencies of die springs and should be considered carefully. Approximately 40% of the errors may occur if warping is neglected. The change laws of warping effect with the parameter variations of springs are also explored, including the height-to-width ratio of the cross section, the cylinder diameter, the helix pitch angle, and the number of coils. The warping effect exhibits the most remarkable changes with the variation in the height-to-width ratio of the cross section. However, this effect is not fairly sensitive to the changes in other parameters, and it is particularly significant when the cross section is relatively narrow regardless of the changes in other parameters. This study evidently answers the key scientific question: “under what working condition should the warping effect be considered or ignored?” The analysis results can be used to guide spring designers in engineering.

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Ontaneda, Pedro. "On the Farrell and Jones warping deformation." Journal of the London Mathematical Society 92, no. 3 (November 20, 2015): 566–82. http://dx.doi.org/10.1112/jlms/jdv049.

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Liang, Siming, Ya Wei, Zehong Wu, and Will Hansen. "Performance Evaluation of Concrete Pavement Slab Considering Creep Effect by Finite Element Analysis." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 27 (May 14, 2018): 65–77. http://dx.doi.org/10.1177/0361198118772951.

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Creep, as an intrinsic property of concrete material, will inevitably affect the performance of concrete pavement slabs in the field. However, the creep effect on the performances of concrete pavement slabs is far from being fully investigated. In this study, a test set-up is designed to measure the flexural creep of concrete beams exposed to both sealed and drying conditions. The measured flexural creep results are then modeled by the microprestress–solidification theory-based creep model which is incorporated into finite element analysis to evaluate numerically the creep effect on the moisture warping deformation, warping stress, and the total stress under traffic load in concrete slabs. Parameters including slab size, slab thickness, and subgrade modulus are considered. It is found that concrete creep has a significant effect on slab performance. Based on the measured creep properties in this study, the warping deformation of slabs can be reduced by 8–62%, and the warping stress and the total stress can be relaxed by at least 50%. Therefore, it is of importance to incorporate creep effect in analyzing warping deformation and stress generated in concrete pavement slabs. This study also provides a numerical methodology to the current performance evaluation of concrete slabs in the field.

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Hao, Ying, Wei He, and Yanke Shi. "Differential Equations of Motion for Naturally Curved and Twisted Composite Space Beams." Shock and Vibration 2018 (2018): 1–12. http://dx.doi.org/10.1155/2018/5015807.

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The differential equations of motion for naturally curved and twisted elastic space beams made of anisotropic materials with noncircular cross sections, being a coupled system consisting of 14 second-order partial differential equations with variable coefficients, are derived theoretically. The warping deformation of beam’s cross section, as a new design factor, is incorporated into the differential equations in addition to the anisotropy of material, the curvatures of the rod axis, the initial twist of the cross section, the rotary inertia, and the shear and axial deformations. Numerical examples show that the effect of warping deformation on the natural frequencies of the beam is significant under certain geometric and boundary conditions. This study focuses on improving and consummating the traditional theories to build a general curve beam theory, thereby providing new scientific research reference and design principle for curve beam designers.

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Li, Zai-Wei, Xiao-Zhou Liu, and Yue-Lei He. "Identification of Temperature-Induced Deformation for HSR Slab Track Using Track Geometry Measurement Data." Sensors 19, no. 24 (December 10, 2019): 5446. http://dx.doi.org/10.3390/s19245446.

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Slab track is widely used in many newly built high-speed rail (HSR) lines as it offers many advantages over ballasted tracks. However, in actual operation, slab tracks are subjected to operational and environmental factors, and structural damages are frequently reported. One of the most critical problems is temperature-induced slab-warping deformation (SWD) which can jeopardize the safety of train operation. This paper proposes an automatic slab deformation detection method in light of the track geometry measurement data, which are collected by high-speed track geometry car (HSTGC). The characteristic of track vertical irregularity is first analyzed in both time and frequency domain, and the feature of slab-warping phenomenon is observed. To quantify the severity of SWD, a slab-warping index (SWI) is established based on warping-sensitive feature extraction using discrete wavelet transform (DWT). The performance of the proposed algorithm is verified against visual inspection recorded on four sections of China HSR line, which are constructed with the China Railway Track System II (CRTSII) slab track. The results show that among the 24,806 slabs being assessed, over 94% of the slabs with warping deformation can be successfully identified by the proposed detection method. This study is expected to provide guidance for efficiently detecting and locating slab track defects, taking advantage of the massive track inspection data.

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Veress, Alexander I., Jeffrey A. Weiss, Grant T. Gullberg, D. Geoffrey Vince, and Richard D. Rabbitt. "Strain Measurement in Coronary Arteries Using Intravascular Ultrasound and Deformable Images." Journal of Biomechanical Engineering 124, no. 6 (December 1, 2002): 734–41. http://dx.doi.org/10.1115/1.1519279.

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Atherosclerotic plaque rupture is responsible for the majority of myocardial infarctions and acute coronary syndromes. Rupture is initiated by mechanical failure of the plaque cap, and thus study of the deformation of the plaque in the artery can elucidate the events that lead to myocardial infarction. Intravascular ultrasound (IVUS) provides high resolution in vitro and in vivo cross-sectional images of blood vessels. To extract the deformation field from sequences of IVUS images, a registration process must be performed to correlate material points between image pairs. The objective of this study was to determine the efficacy of an image registration technique termed Warping to determine strains in plaques and coronary arteries from paired IVUS images representing two different states of deformation. The Warping technique uses pointwise differences in pixel intensities between image pairs to generate a distributed body force that acts to deform a finite element model. The strain distribution estimated by image-based Warping showed excellent agreement with a known forward finite element solution, representing the gold standard, from which the displaced image was created. The Warping technique had a low sensitivity to changes in material parameters or material model and had a low dependency on the noise present in the images. The Warping analysis was also able to produce accurate strain distributions when the constitutive model used for the Warping analysis and the forward analysis was different. The results of this study demonstrate that Warping in conjunction with in vivo IVUS imaging will determine the change in the strain distribution resulting from physiological loading and may be useful as a diagnostic tool for predicting the likelihood of plaque rupture through the determination of the relative stiffness of the plaque constituents.

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Hao, Ying, and Jun Feng Guan. "Variation Rules of Warping Effect with Respect to Parameters of Cylindrical Helical Spring." Applied Mechanics and Materials 238 (November 2012): 236–39. http://dx.doi.org/10.4028/www.scientific.net/amm.238.236.

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The effect of warping deformation on the natural frequencies of the cylindrical helical spring with non-circle cross section, based on naturally curved and twisted beam theory, is analytically investigated in this paper. The purpose of this article is to discuss the variation rules of the warping effect with respect to the parameters of springs. The numerical simulations show that the results of the present model demonstrate a good agreement with those of ANSYS when the warping effect is included. Additionally, the effect of warping on the natural frequencies is more obvious as the parameters of the spring increase.

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Sapountzakis, Evangelos, and Amalia Argyridi. "Influence of in-Plane Deformation in Higher Order Beam Theories." Strojnícky casopis – Journal of Mechanical Engineering 68, no. 3 (November 1, 2018): 77–94. http://dx.doi.org/10.2478/scjme-2018-0028.

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AbstractComparing Euler-Bernoulli or Tismoshenko beam theory to higher order beam theories, an essential difference can be depicted: the additional degrees of freedom accounting for out-of plane (warping) and in-plane (distortional) phenomena leading to the appearance of respective higher order geometric constants. In this paper, after briefly overviewing literature of the major beam theories taking account warping and distortional deformation, the influence of distortion in the response of beams evaluated by higher order beam theories is examined via a numerical example of buckling drawn from the literature.

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Hjaji, Mohammed A., Hasan M. Nagiar, Moftah M. Krar, and Ezedine G. Allaboudi. "Exact finite beam element for open thin walled doubly symmetric members under torsional and warping moments." Journal of Structural Engineering & Applied Mechanics 4, no. 4 (December 31, 2021): 267–81. http://dx.doi.org/10.31462/jseam.2021.04267281.

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Starting with total potential energy variational principle, the governing equilibrium coupled equations for the torsional-warping static analysis of open thin-walled beams under various torsional and warping moments are derived. The formulation captures shear deformation effects due to warping. The exact closed form solutions for torsional rotation and warping deformation functions are then developed for the coupled system of two equations. The exact solutions are subsequently used to develop a family of shape functions which exactly satisfy the homogeneous form of the governing coupled equations. A super-convergent finite beam element is then formulated based on the exact shape functions. Key features of the beam element developed include its ability to (a) eliminate spatial discretization arising in commonly used finite elements, and (e) eliminate the need for time discretization. The results based on the present finite element solution are found to be in excellent agreement with those based on exact solution and ABAQUS finite beam element solution at a small fraction of the computational and modelling cost involved.

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Wang, Zhao Qiang, Jin Cheng Zhao, and Jing Hai Gong. "A New Torsion Element of Thin-Walled Beams Including Shear Deformation." Applied Mechanics and Materials 94-96 (September 2011): 1642–45. http://dx.doi.org/10.4028/www.scientific.net/amm.94-96.1642.

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Restrained torsion analysis of open thin-walled beam is presented in this paper. A finite element model is developed. The element is based on the first-order torsion theory, which accounts for the warping deformation and shear deformation due to restrained torsion. The interpolation functions of total rotation and twist rate of free warping rotation of cross section are constructed respectively by using the relationship between these two rotations. Numerical example is illustrated to validate the current approach and the results of the current theory are compared with those obtained from classical Vlasov theory and first-order torsion theory.

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Xu, Nan Nan, Zhuang Ya Zhang, Hai Guang Zhang, Tian Lv, Yuan Yuan Liu, and Qing Xi Hu. "The Optimization of Vacuum Casting Filling Velocity Based on Numerical Simulation." Key Engineering Materials 522 (August 2012): 221–26. http://dx.doi.org/10.4028/www.scientific.net/kem.522.221.

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In the process of vacuum casting, non-uniform flow front velocity about pouring material will lead to casting non-uniform shrinkage and warping deformation. Ideal filling pattern should make pouring material fill into the mold cavity with uniform flow front velocity. Give an optimization method of vacuum casting process, optimize the filling velocity in the filling process by combining numerical simulation and optimization method, and make the flow front velocity of pouring material uniform in the filling process, further reduce the warping deformation of casting. The example shows that the optimal model and the given solution algorithm is feasible.

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Liu, Yali, Jun Dong, Guohua Li, Xi Chen, and Yunkai Zhang. "Mechanical Mechanism Analysis of Warping and Bulging Of Track Slab of High-Speed Railway in Service." Journal of Physics: Conference Series 2148, no. 1 (January 1, 2022): 012035. http://dx.doi.org/10.1088/1742-6596/2148/1/012035.

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Abstract Due to warpage and ballooning of high-speed rail track slab caused by debonding and environmental temperature changes during the deterioration of CA mortar layer being extremely concerned in practical engineering, it is based on numerical simulation of typical working conditions and analysis of test model that the deformation dynamics mechanism of track slab of high-speed rail in service is studied in this paper. Firstly, three kinds of damage conditions of CA mortar layer are designed to simulate the partial stress state of track slab under normal, warping and bulging conditions, and the results of model test are compared with those of finite element analysis so that the accuracy and credibility of the numerical simulation method and results are verified. Then, through finite element numerical simulation, the dynamical mechanism of actual full-scale high-speed rail track slab under vibration load is studied. The results show that the warping deformation around the track slab and the bulging deformation in the middle part under the action of positive and negative temperature gradient load caused by environmental temperature change will have a great impact on the structural performance of itself and CA mortar layer; Bulging deformation of track slab is more destructive to its structure than warping deformation. It is of great practical significance to further study the critical position of track plate warpage and bulging deformation, and to optimize and strengthen the structure of this part; The research results are of great significance to further study the deterioration.

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Zhang, Ya Ting, Chun Xiu Zhou, Zhi Yi Huang, Jin Chang Wang, Gang Bing Wu, and Shan Jiang. "Research on the Behavior of Rigid Pavement of Basalt Fiber Reinforced Dowel Bar under the Condition of Variable Temperature." Applied Mechanics and Materials 587-589 (July 2014): 1209–15. http://dx.doi.org/10.4028/www.scientific.net/amm.587-589.1209.

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This paper analyzed temperature field and temperature stress of cement concrete pavement under periodic variable low temperature using finite element method modeling technique in ABAQUS. And discussed the effect of wind speed, surface thermal conductivity coefficient on temperature field. Cracking and warping at the joint of concrete panel was simulated to analyze pavement deformation and mechanical characteristics. Results show that at lower temperature, concrete face will appear horizontal longitudinal displacement, causing the appearance of cracking; and warping effect will appear at the concrete panel, leading to concrete pavement void. It is revealed that dowel bar has not occurred plastic deformation, that is, bending strength meets the requirements.

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Veress, Alexander I., Gregory Klein, and Grant T. Gullberg. "A Comparison of Hyperelastic Warping of PET Images with Tagged MRI for the Analysis of Cardiac Deformation." International Journal of Biomedical Imaging 2013 (2013): 1–14. http://dx.doi.org/10.1155/2013/728624.

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The objectives of the following research were to evaluate the utility of a deformable image registration technique known as hyperelastic warping for the measurement of local strains in the left ventricle through the analysis of clinical, gated PET image datasets. Two normal human male subjects were sequentially imaged with PET and tagged MRI imaging. Strain predictions were made for systolic contraction using warping analyses of the PET images and HARP based strain analyses of the MRI images. Coefficient of determinationR2values were computed for the comparison of circumferential and radial strain predictions produced by each methodology. There was good correspondence between the methodologies, withR2values of 0.78 for the radial strains of both hearts and from anR2=0.81andR2=0.83for the circumferential strains. The strain predictions were not statistically different(P≤0.01). A series of sensitivity results indicated that the methodology was relatively insensitive to alterations in image intensity, random image noise, and alterations in fiber structure. This study demonstrated that warping was able to provide strain predictions of systolic contraction of the LV consistent with those provided by tagged MRI Warping.

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Alexandru, Ioana, Constantin Nicula, Cristian Prodan, Răzvan-Paul Rotaru, Mihai-Lucian Voncilă, Nicolae Tarbă, and Costin-Anton Boiangiu. "Image Style Transfer via Multi-Style Geometry Warping." Applied Sciences 12, no. 12 (June 14, 2022): 6055. http://dx.doi.org/10.3390/app12126055.

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Style transfer of an image has been receiving attention from the scientific community since its inception in 2015. This topic is characterized by an accelerated process of innovation; it has been defined by techniques that blend content and style, first covering only textural details, and subsequently incorporating compositional features. The results of such techniques has had a significant impact on our understanding of the inner workings of Convolutional Neural Networks. Recent research has shown an increasing interest in the geometric deformation of images, since it is a defining trait for different artists, and in various art styles, that previous methods failed to account for. However, current approaches are limited to matching class deformations in order to obtain adequate outputs. This paper solves these limitations by combining previous works in a framework that can perform geometric deformation on images using different styles from multiple artists by building an architecture that uses multiple style images and one content image as input. The proposed framework uses a combination of various other existing frameworks in order to obtain a more intriguing artistic result. The framework first detects objects of interest from various classes inside the image and assigns them a bounding box, before matching each detected object image found in a bounding box with a similar style image and performing warping on each of them on the basis of these similarities. Next, the algorithm blends back together all the warped images so they are placed in a similar position as the initial image, and style transfer is finally applied between the merged warped images and a different chosen image. We manage to obtain stylistically pleasing results that were possible to generate in a reasonable amount of time, compared to other existing methods.

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ZHANG, Boyang. "Analysis of Complex Warping Deformation for Cold-rolled Strip." Journal of Mechanical Engineering 54, no. 12 (2018): 184. http://dx.doi.org/10.3901/jme.2018.12.184.

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Liu, Shutian, Xiaomin An, and Haipeng Jia. "Topology optimization of beam cross-section considering warping deformation." Structural and Multidisciplinary Optimization 35, no. 5 (June 2, 2007): 403–11. http://dx.doi.org/10.1007/s00158-007-0138-y.

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Le Coz, Camille, Arnold Heemink, Martin Verlaan, and Nick van de Giesen. "Spatial and Time Warping for Gauge Adjustment of Rainfall Estimates." Atmosphere 12, no. 11 (November 16, 2021): 1510. http://dx.doi.org/10.3390/atmos12111510.

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Many satellite-based estimates use gauge information for bias correction. In general, bias-correction methods are focused on the intensity error and do not explicitly correct possible position or timing errors. However, position and timing errors in rainfall estimates can also lead to errors in the rainfall occurrence or the intensity. This is especially true for localized rainfall events such as the convective rainstorms occurring during the rainy season in sub-Saharan Africa. We investigated the use of warping to correct such errors. The goal was to gauge-adjust satellite-based estimates with respect to the position and the timing of the rain event, instead of its intensity. Warping is a field-deformation method that transforms an image into another one. We compared two methods, spatial warping focusing on the position errors and time warping for the timing errors. They were evaluated on two case studies: a synthetic rainfall event represented by an ellipse and a rain event in southern Ghana during the monsoon season. In both cases, the two warping methods reduced significantly the respective targeted (position or timing) errors. In the southern Ghana case, the average position error was decreased by about 45 km by the spatial warping and the average timing error was decreased from more than 1 h to 0.2 h by the time warping. Both warping methods also improved the continuous statistics on the intensity: the correlation went from 0.18 to at least 0.62 after warping in the southern Ghana case. The spatial warping seems more interesting because of its positive impact on both position and timing errors.

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Li, Xiayuan, Shui Wan, Kongjian Shen, Peng Zhou, and Xiao Wang. "Prediction of Shear Lag Effect in Thin-Walled Single-Box Multicell Box Girder Based on the Modified Warping Displacement Function." Advances in Civil Engineering 2020 (May 15, 2020): 1–19. http://dx.doi.org/10.1155/2020/6815092.

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In this study, an effective and accurate theoretical analysis method for predicting the shear lag effect in the thin-walled single-box multicell box girder is presented. The modifications of longitudinal warping displacement functions at the flanges are fully investigated, including the shear lag width (bij) of flanges, the coefficients (αij) of shear lag warping functions, the deformation compatibility conditions in flanges, and the internal force balance (D). The initial shear deformation (γ03) in the top lateral cantilever flanges is innovatively introduced in multicell box girders and obtained by the designed procedure. In addition, the transverse distribution function for describing the longitudinal warping displacement is deduced and expressed in the form of the cosine function. Based on the principle of minimum potential energy, the governing differential equations are derived and solved with the associated boundary and load conditions. The accuracy and applicability of the proposed method (SL-THY2) are validated for four thin-walled single-box multicell (two- and three-cell) box girders with the results derived from the solid finite element method.

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Jin-gang, Jiang, Ma Xue-Feng, Zhang Yong-De, Liu Yi, and Huo Biao. "Springback mechanism analysis and experimentation of orthodontic archwire bending considering slip warping phenomenon." International Journal of Advanced Robotic Systems 15, no. 3 (May 1, 2018): 172988141877422. http://dx.doi.org/10.1177/1729881418774221.

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Malocclusion is a common oral disease. Fixed appliance technology is the most common and effective malocclusion orthodontic treatment method, and the key step of fixed appliance technology is the bending of orthodontic archwire. Because the slip warping phenomenon exists in the process of orthodontic archwire bending, it is difficult to realize rapid and accurate bending of the customized orthodontic archwires. A bending springback mechanism model considering the slip warping of the archwire in the process of bending is established. The influence of the slip warping phenomenon of the archwire between the fixed mold and the rotation mold is considered in the analysis of the springback mechanism. The bending process of archwire is divided into two stages: elastic deformation and plastic deformation, based on the variety of the bending radius in the bending process. A springback mechanism model of the orthodontic archwire is established. The springback mechanism model of the orthodontic archwire is analyzed and compensated based on the characteristics of the robot structure. An archwire bending experiment is carried out to verify the correctness of the springback mechanism model of the orthodontic archwire.

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Li, Na, Hong Bin Liu, and Hai Tao Wu. "The Deformation Analysis and Optimization of the Injection Molded Parts Based on the Moldflow and Minitab Software." Advanced Materials Research 753-755 (August 2013): 1180–83. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.1180.

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The deformation seriously affects the quality of the products, which is one of the common defects of plastic parts in the injection molding. Factorial design and CAE technology was used to study the product's warping rate influence in this paper. The minimum warping rate was obtained through the Minitab software and the optimized process parameters are verified with the Moldflow software. Experimental results show that the optimization design is effective and the warpage of the product is reduced.

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Feng, Chong You, Jin Mei Zhang, Zheng Yu Zhang, and Li Ping Li. "Rapid Development Technology of Mobile Phone Shell Basing on the Selective Laser Sintering." Applied Mechanics and Materials 198-199 (September 2012): 123–27. http://dx.doi.org/10.4028/www.scientific.net/amm.198-199.123.

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According to the characteristics of mobile phone shell, the mobile phone products model provided by Pro/E software, analyzed the technological parameters of warpage deformation influence, and designed the orthogonal experiment plan, Verified the plan on SINTERSTATION HIQ + HS selective laser sintering system, carried out optimum processing parameters of the minimum warping deformation.

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Zhou, Ju, Chang Jun Qiu, and Xi Yang Cheng. "Finite Element Simulation on Micro-Forging Process Inhibiting Warping of the Thin-Walled Components Treated by Laser Cladding." Advanced Materials Research 591-593 (November 2012): 1038–41. http://dx.doi.org/10.4028/www.scientific.net/amr.591-593.1038.

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During the process of laser cladding thin-walled components, warping deformation generated on the thin-walled components due to the difference between the change of temperature field and thermal expansion coefficient of materials. Through the micro-forging regulation, the internal stress of laser cladding layers changed, reaching the purpose of suppressing the warping plastic deformation generating on the thin-walled components. This paper utilized Ansys software to calculate the temperature field and stress field of the process of laser cladding 304 stainless steel regulated by micro-forging, and compared to the measurement result of the warp deflection and stress. The results indicated that reasonable effective micro-forging can effectively restrain the warp occurring on the thin-walled components treated by laser cladding.

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Yanze, Long, Zhang Ke, Shi Huaitao, Li Songhua, and Zhang Xiaochen. "Theoretical and Experimental Analysis of Thin-Walled Curved Rectangular Box Beam under In-Plane Bending." Scanning 2021 (April 30, 2021): 1–19. http://dx.doi.org/10.1155/2021/8867142.

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Thin-walled curved box beam structures especially rectangular members are widely used in mechanical and architectural structures and other engineering fields because of their high strength-to-weight ratios. In this paper, we present experimental and theoretical analysis methods for the static analysis of thin-walled curved rectangular-box beams under in-plane bending based on 11 feature deformation modes. As to the numerical investigations, we explored the convergence and accuracy analysis by normal finite element analysis, higher-order assumed strain plane element, deep collocation method element, and inverse finite element method, respectively. The out-of-plane and in-plane characteristic deformation vector modes derived by the theoretical formula are superimposed by transforming the axial, tangential, and the normal deformation values into scalar tensile and compression amounts. A one-dimensional deformation experimental test theory is first proposed, formulating the specific contributions of various deformation modes. In this way, the magnitude and trend of the influence of each low-order deformation mode on the distortion and warping in the actual deformation are determined, and the significance of distortion and warping in the actual curved beams subjected to the in-plane loads is verified. This study strengthens the deformation theory of rectangular box-type thin-walled curved beams under in-plane bending, thus providing a reference for analyzing the mechanical properties of curved-beam structures.

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Lin, Pengcheng, Meng Wang, Vyacheslav A. Trofimov, Yongqiang Yang, and Changhui Song. "Research on the Warping and Dross Formation of an Overhang Structure Manufactured by Laser Powder Bed Fusion." Applied Sciences 13, no. 6 (March 8, 2023): 3460. http://dx.doi.org/10.3390/app13063460.

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Warping and dross formation are the main defects of an overhang structure formed by laser powder bed fusion. In order to study these defects, a seven−shaped overhang structure with different lengths and heights of the overhang was printed. The influence of the temperature and stress field on the overhang structure was investigated using a 3D finite element (FE) model. The results of the simulation showed that the molten pool in the powder support zone was much larger than the molten pool in the solid support zone. The molten pool sank due to the actions of gravity and the capillary force. This led to the powder melting, which then formed a droplet−like dross formation on the lower surface. The temperature difference between the regions led to a large residual stress. When the residual stress exceeded the material strength, warping deformation occurred in the top area, affecting the subsequent powder−laying process. The warping zone was remelted when the next layer was processed. As the number of forming layers increased, the thermal conductivity and stiffness increased continuously, and the deformation of the top area gradually decreased. The experiment results showed that the longer the overhanging length was, the more serious the warpage was. When the overhanging length was below 3 mm, the warping of the top area continued to decrease to zero as the building process proceeded. Meanwhile, the dross formation appeared at the bottom of the overhanging area in all experimental groups. Studying the process of warping and dross formation was helpful to understand the defect change process in the manufacturing process of an overhang structure.

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Liu, Heng, Liandong Wang, Xiaodi Wang, and Qiying Tan. "Analysis and Control of Cracking and Wrinkling at the End of Seamless Steel Tube with Multi-Pass Large Deformation Diameter-Reducing." Metals 11, no. 9 (September 11, 2021): 1438. http://dx.doi.org/10.3390/met11091438.

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Axial cracking and circumferential wrinkling are found at the end of seamless steel tubes during multi-pass large deformations pushing diameter-reducing (PDR), which seriously affects product quality. However, the cracking and wrinkling mechanism of PDR has not been elucidated yet. In this paper, the Equation of circumferential residual stress at the end was deduced from the warping deformation and shear stress. It is revealed that the circumferential residual stress in the end warping area from the inner to outer surface is tensile, and the generation mechanism of circumferential wrinkling on the inner wall at the end was revealed through the deformation analysis of PDR. The geometric model of the tube with periodic alternating variation of wall thickness was established to reveal the generation and development of circumferential wrinkling. In addition, the four-pass PDR experiments and simulations were developed to reveal the influence of reducing pass and wall thickness deviation on the end warpage, unevenness and circumferential residual tensile stress. The pushing-pulling diameter-reducing (PPDR) method was proposed to control the wrinkling and cracking. The simulation and experimental results showed that the end warpage, unevenness and circumferential residual tensile stress are all greatly decreased, and the risk of axial cracking and circumferential wrinkling is eliminated.

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SAIKI, Isao, Xun ZHENG, and Takeki YAMAMOTO. "SHEAR DEFORMABLE BEAM THEORY WITH WARPING INDEPENDENT OF SHEAR DEFORMATION." Journal of Japan Society of Civil Engineers, Ser. A2 (Applied Mechanics (AM)) 75, no. 2 (2019): I_3—I_12. http://dx.doi.org/10.2208/jscejam.75.2_i_3.

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Brock, K. "280 speaker IMAGE REGISTRATION AND DOSE WARPING FOR INTERFRACTION DEFORMATION." Radiotherapy and Oncology 99 (May 2011): S111. http://dx.doi.org/10.1016/s0167-8140(11)70402-9.

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42

Hassis, Hedi. "A modified first-order-warping theory for shear deformation analysis." European Journal of Mechanics - A/Solids 19, no. 5 (September 2000): 911–23. http://dx.doi.org/10.1016/s0997-7538(00)00188-1.

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Seif, M. A., F. A. Moslehy, and S. L. Rice. "Deformation and Warping in Magnetic Tapes by Laser Speckle Technique." Journal of Elastomers & Plastics 25, no. 3 (July 1993): 216–23. http://dx.doi.org/10.1177/009524439302500303.

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Caruso, Valeria C., and Evan Balaban. "Auditory Perceptual Category Formation Does Not Require Perceptual Warping." Journal of Cognitive Neuroscience 27, no. 8 (August 2015): 1659–73. http://dx.doi.org/10.1162/jocn_a_00806.

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Categorical perception occurs when a perceiver's stimulus classifications affect their ability to make fine perceptual discriminations and is the most intensively studied form of category learning. On the basis of categorical perception studies, it has been proposed that category learning proceeds by the deformation of an initially homogeneous perceptual space (“perceptual warping”), so that stimuli within the same category are perceived as more similar to each other (more difficult to tell apart) than stimuli that are the same physical distance apart but that belong to different categories. Here, we present a significant counterexample in which robust category learning occurs without these differential perceptual space deformations. Two artificial categories were defined along the dimension of pitch for a perceptually unfamiliar, multidimensional class of sounds. A group of participants (selected on the basis of their listening abilities) were trained to sort sounds into these two arbitrary categories. Category formation, verified empirically, was accompanied by a heightened sensitivity along the entire pitch range, as indicated by changes in an EEG index of implicit perceptual distance (mismatch negativity), with no significant resemblance to the local perceptual deformations predicted by categorical perception. This demonstrates that robust categories can be initially formed within a continuous perceptual dimension without perceptual warping. We suggest that perceptual category formation is a flexible, multistage process sequentially combining different types of learning mechanisms rather than a single process with a universal set of behavioral and neural correlates.

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Kim, J. H., and Y. Y. Kim. "Analysis of Thin-Walled Closed Beams With General Quadrilateral Cross Sections." Journal of Applied Mechanics 66, no. 4 (December 1, 1999): 904–12. http://dx.doi.org/10.1115/1.2791796.

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This paper deals with the one-dimensional static and dynamic analysis of thin-walled closed beams with general quadrilateral cross sections. The coupled deformations of distortion as well as torsion and warping are investigated in this work. A new approach to determine the functions describing section deformations is proposed. In particular, the present distortion function satisfies all the necessary continuity conditions unlike Vlasov's distortion function. Based on these section deformation functions, a one-dimensional theory dealing with the coupled deformations is presented. The actual numerical work is carried out using two-node C0 finite element formulation. The present one-dimensional results for some static and free-vibration problems are compared with the existing and the plate finite element results.

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Bai, Hua, and Yi Du Zhang. "Research on Thermally Induced Deformation of Reinforcing Plate Based on Finite Element Simulation." Applied Mechanics and Materials 197 (September 2012): 139–43. http://dx.doi.org/10.4028/www.scientific.net/amm.197.139.

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The change of ambient temperature will cause deformation during the machining process of large-scale aerospace monolithic component. Based on finite element simulation, thermally induced deformation of reinforcing plate is studied in such aspects as reinforcement structure, clamping method and temperature change, and contact function in finite element software is used to simulate the unilateral constraint between workpiece and worktable. The results indicate that reinforcing plate will produce warping deformation due to the change of ambient temperature. Different reinforcement structures and clamping methods have important influence on the deformation positions and degrees, and the deformation is proportional to the temperature change.

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Pedersen, P. Terndrup. "Beam Theories for Torsional-Bending Response of Ship Hulls." Journal of Ship Research 35, no. 03 (September 1, 1991): 254–65. http://dx.doi.org/10.5957/jsr.1991.35.3.254.

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A consistent one-dimensional finite-element procedure for analysis of the coupled torsional-bending response of thin-walled beam structures such as ship hulls is presented. At each element end there are three translations, three rotations and one classical Vlasov warping degree of freedom plus possibly N degrees of freedom associated with higher order generalized warping deformation modes. These higher order warping modes are generated from an eigenvalue problem associated with the homogeneous plane stress equilibrium condition for the individual beam cross sections. The assembly of the beam elements to the global model is performed by use of transition matrices which assure compatibility between the elements in the sense of least squares. Numerical examples are included which demonstrate the accuracy of the mathematical model and the applicability of the proposed analysis procedure for calculation of torsion-horizontal bending response of a containership hull. Even if the higher order warping modes are not included in the finite element formulation it is found that the mathematical model is quite accurate for overall response analysis of hull structures.

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Jonker, J. B. "Three-dimensional beam element for pre- and post-buckling analysis of thin-walled beams in multibody systems." Multibody System Dynamics 52, no. 1 (January 21, 2021): 59–93. http://dx.doi.org/10.1007/s11044-021-09777-x.

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AbstractThis paper presents a three-dimensional beam element for stability analysis of elastic thin-walled open-section beams in multibody systems. The beam model is based on the generalized strain beam formulation. In this formulation, a set of independent deformation modes is defined which are related to dual stress resultants in a co-rotational frame. The deformation modes are characterized by generalized strains or deformations, expressed as analytical functions of the nodal coordinates referred to the global coordinate system. A nonlinear theory of non-uniform torsion of open-section beams is adopted for the derivation of the elastic and geometric stiffness matrices. Both torsional-related warping and Wagner’s stiffening torques are taken into account. Second order approximations for the axial elongation and bending curvatures are included by additional second order terms in the expressions for the deformations. The model allows to study the buckling and post-buckling behaviour of asymmetric thin-walled beams with open cross-section that can undergo moderately large twist rotations. The inertia properties of the beam are described using both consistent and lumped mass formulations. The latter is used to model rotary and warping inertias of the beam cross-section. Some validation examples illustrate the accuracy and computational efficiency of the new beam element in the analysis of the buckling and post-buckling behaviour of thin-walled beams under various loads and (quasi)static boundary conditions. Finally, applications to multibody problems are presented, including the stability analysis of an elementary two-flexure cross-hinge mechanism.

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Chu, Jian Zhong, and Rong Song. "Thin-Wall Plastic Parts’ Warpage Analysis Based on Taguchi Method." Applied Mechanics and Materials 80-81 (July 2011): 375–78. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.375.

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Warping deformation is an important indicator to evaluate the performance of thin-wall Plastic. In this paper, using the CAE（computer aided engineering）technology and DOE（Design of experiment）in the thin-wall injection molding field, take a box-shaped thin-wall plastic parts for example, using the moldflow software to simulation analyze of the process parameters of injection molding. By analyzing the causes of plastic parts’ warpage, learn the holding pressure is a leading role in warping. Optimization of process parameters under the guidance of the orthogonal test, it can reduce the warpage of plastic parts effectively.

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Cowin, S. C. "Modeling Shrinkage Mechanisms in Porous Elastic Solids." Journal of Applied Mechanics 52, no. 2 (June 1, 1985): 351–55. http://dx.doi.org/10.1115/1.3169052.

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This paper concerns the applications of a method of modeling the mechanism of shrinkage in porous elastic materials. Examples of the effects of shrinkage in porous elastic materials include the cracks that appear in the sun-dried gumbo at the bottom of a former mud puddle or in concrete, and the warping and cracking of drying lumber. The model for shrinkage is applied here for drying wood, but with an emphasis on the method and the generality of the results with regard to shrinkage in other materials. The model is able to predict the stresses, strains, deformation, and warping associated with wood drying.

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Journal articles on the topic 'Warping deformation'

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