Journal articles: 'Wrinking effect'

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TSAI, N., and S. KIRKHAM. "Fingertip Skin Wrinkling – the Effect of Varying Tonicity." Journal of Hand Surgery 30, no. 3 (June 2005): 273–75. http://dx.doi.org/10.1016/j.jhsb.2004.12.010.

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Fingertip skin wrinkling after prolonged immersion in water is a well-recognized phenomenon, whereas a denervated digit does not exhibit normal skin wrinkling while a finger with a regenerated or repaired nerve shows at least partial reappearance of wrinkling. This is the basis for the bedside immersion-wrinkling test of autonomic digital nerve function. The exact mechanism of fingertip skin wrinkling is still subject to controversy. The purpose of this study was to investigate the relationship between the tonicity of a solution and the time elapsed to skin wrinkling. Fourteen healthy volunteers (28 hands) were recruited for investigation. We submerged all 28 hands in solutions of varying tonicity while maintaining all other parameters constant. We found that increased tonicity significantly slowed the time to wrinkling (TTW). Hypotonic solutions such as water should be used when performing clinical bedside testing for autonomic digital nerve function.

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Chen, Lu, and Shankar Kalyanasundaram. "Effect of Fiber Orientation on the Wrinkling Behavior of Thermoplastic Composite." Materials Science Forum 893 (March 2017): 21–25. http://dx.doi.org/10.4028/www.scientific.net/msf.893.21.

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In this work, experiments were conducted to examine the impact of fiber orientation of self-reinforced polypropylene on wrinkling phenomenon. Defects due to wrinkling are major quality issues in rapid forming of sheet materials. This article examines the influence of two fiber orientations [0°/90° and 45°/-45°] on wrinkling initiation of a self-reinforced polypropylene composite (Curv®) material system. It was found that 45°/-45° specimen wrinkles at smaller axial displacement compared to 0°/90° specimen. In both specimens, there was an abrupt change in strain increment ratio that corresponded to the onset of wrinkling. This phenomenon validates the robustness of the wrinkling indictor based on strain increment ratio concept.

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Hematian, J., and P. M. Wild. "Initial imperfections and the initiation of wrinkling in finite element modelling of deep drawing." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering 214, no. 1 (February 1, 2000): 63–73. http://dx.doi.org/10.1243/0954408001530227.

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The effect of initial imperfections on the initiation of wrinkling in finite element models of deep drawing operations is assessed. Models of an annular plate are subjected to radial in-plane loading and the effects of different types, magnitudes and distributions of imperfections are investigated. A model of a circular plate subjected to out-of-plane loading from a punch and die is similarly investigated and the results are compared with experimental data. It is confirmed that initial imperfections are an essential requirement for the initiation of wrinkling for the case of in-plane loading. Initial imperfections are shown to be unimportant in the initiation of wrinkling for the case of out-of-plane loading.

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Alawiye, Hamza, Ellen Kuhl, and Alain Goriely. "Revisiting the wrinkling of elastic bilayers I: linear analysis." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 377, no. 2144 (March 13, 2019): 20180076. http://dx.doi.org/10.1098/rsta.2018.0076.

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Wrinkling is a universal instability occurring in a wide variety of engineering and biological materials. It has been studied extensively for many different systems but a full description is still lacking. Here, we provide a systematic analysis of the wrinkling of a thin hyperelastic film over a substrate in plane strain using stream functions. For comparison, we assume that wrinkling is generated either by the isotropic growth of the film or by the lateral compression of the entire system. We perform an exhaustive linear analysis of the wrinkling problem for all stiffness ratios and under a variety of additional boundary and material effects. Namely, we consider the effect of added pressure, surface tension, an upper substrate and fibres. We obtain analytical estimates of the instability in the two asymptotic regimes of long and short wavelengths. This article is part of the theme issue ‘Rivlin's legacy in continuum mechanics and applied mathematics’.

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Fagerberg, L. "The effect of local bending stiffness on the wrinkling of sandwich panels." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 217, no. 2 (June 1, 2003): 111–19. http://dx.doi.org/10.1243/147509003321921355.

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The use of the face sheet elastic modulus versus the face sheet local bending stiffness while designing against wrinkling is discussed in this paper. It shows that there are several ways to improve the critical wrinkling load of a sandwich panel without replacing the core. It is often possible to increase the wrinkling load by as much as 25 per cent without virtually any increase in weight or cost of the sandwich. This is achieved by improving the local bending stiffness of the sandwich face sheet by either optimizing the stacking sequence, lowering the fibre volume fraction or adding some extra layers of a cheap fibre material to the sandwich face, creating a minisandwich within the face sheet. Experiments are performed that clearly show the potential for increasing the critical wrinkling load by means of altering the face sheet.

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ZHANG, YONGJU, PINGGEN CAI, LI ZHANG, and SENJIANG YU. "MULTIMODE WRINKLING PATTERNS OF IRON FILMS SPUTTER DEPOSITED ON FLEXIBLE SUBSTRATES WITH GRADIENT MODULUS." Surface Review and Letters 28, no. 05 (February 27, 2021): 2150035. http://dx.doi.org/10.1142/s0218625x21500359.

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Wrinkling patterns are beneficial for a wide range of engineering applications including flexible electronics, tuned optics, sensoring, energy harvesting, surface wetting and biomedicine. Here we report on controllable multimode wrinkling patterns of metal (iron) films sputter deposited on flexible substrates with gradient modulus. It is found that disordered wrinkles (G1 wrinkling) form in the weakly crosslinking region at the early stage of film deposition. Disordered labyrinth wrinkles with larger wavelengths and ordered stripe wrinkles localized by cracks (both G2 wrinkling) appear in the strongly crosslinking region for the samples with small film thickness and large thickness, respectively. The coexistence of the labyrinth G1 wrinkling and labyrinth G2 wrinkling (or stripe G2 wrinkling) can be obtained by tuning the substrate modulus and film thickness. The morphologies, evolutions and mechanisms of such wrinkles are discussed in detail based on the stress theory. This study can promote better understanding of the substrate effect on the complex wrinkling patterns.

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Hall, S. M., and S. G. Haworth. "Effect of cold preservation on pulmonary arterial smooth muscle cells." American Journal of Physiology-Lung Cellular and Molecular Physiology 270, no. 3 (March 1, 1996): L435—L445. http://dx.doi.org/10.1152/ajplung.1996.270.3.l435.

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The efficacy of preservation fluids on the cytoskeleton and contractile function of porcine pulmonary arterial smooth muscle (SM) cells during cooling and rewarming was evaluated, using EuroCollins solution (EC), University of Wisconsin solution (UW), Marshall's solution (MS), and tissue culture growth medium (GM). Functional studies included passive distensibility and contraction to prostaglandin F2a (PGF2a) in arterial rings and wrinkling of silicone membranes by cooled-rewarmed cultured SM cells. Immunofluorescence measurements were made of actin brightness in cooled arterial rings. Cultured SM monolayers were stained with antibodies to SM alpha-actin, SM myosin, and tubulin. In cooling, all solutions resulted in increased arterial distensibility, whereas EC and MS reduced cell wrinkling. With the use of all solutions, actin cables thinned, myosin filaments dissociated, and microtubules depolymerized. During rewarming, resistance to imposed tension increased in all arterial rings. After GM,ED, and MS preservation, contraction to PGF2a increased. Wrinkling increased and actin-myosin cables shortened after GM and EC; after UW, wrinkling decreased and actin-myosin cables thinned. No recovery occurred after MS. Thus the type of preservation solution influenced contractility during preservation and after rewarming. The absence of spontaneous contraction in cells cooled in UW may be advantageous.

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Wang, Xiaofeng, Haoyue Chu, and Qingshan Yang. "Numerical Analysis of Wind-Induced Response of a Wrinkled Membrane." International Journal of Structural Stability and Dynamics 20, no. 05 (May 2020): 2050056. http://dx.doi.org/10.1142/s021945542050056x.

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Membranes have been popularly used in the fields of civil engineering and aerospace engineering. When wrinkled, a membrane loses its stiffness in the direction perpendicular to wrinkles and is more sensitive to wind loads. This paper numerically studied the wind-induced responses of a wrinkled membrane and their variations with respect to wind speed, wind direction and wrinkling deformation. Based on the stability theory of plates and shells, the wrinkling deformation of a rectangular membrane under shear was obtained by post-buckling analysis. Then, by using the wind load derived from a wind tunnel test, the dynamic responses of the wrinkled membrane were numerically analyzed for different wind speeds, wind directions and wrinkling deformations. The results indicate the following: (1) the displacement and extreme stresses of a membrane are gradually intensified with an increase in the wind speed; (2) the wind direction plays an important role in the displacement, but it has little effect on the stresses and (3) the displacement increases with the wrinkling deformation, and the extreme stresses are intensified with an increase in the pre-tension. This study on the wind-induced responses of a wrinkled membrane is helpful to the understanding of the complex behavior of a wrinkled membrane under wind loads while reducing the adverse effects of wrinkling deformation and ensuring the dynamic stability of membrane structures.

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Huang, Jianzhang, and Qiang Han. "A Molecular Dynamics Study on Wrinkles in Graphene with Simply Supported Boundary under In-Plane Shear." Journal of Nanomaterials 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/1326790.

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The formation and evolution mechanisms of wrinkling in a rectangular single layer graphene sheet (SLGS) with simply supported boundary subjected to in-plane shear displacements are investigated using molecular dynamics simulations. Through investigating the out-of-plane displacements of the key point atom, we clarify the wrinkling growth and propagation process. Our results show that the boundary condition plays important roles in the wrinkling deformation. And the dependence of wrinkling parameters on the applied shear displacements is captured. Based on the elasticity theory, the formation mechanism of graphene wrinkling is revealed from the viewpoint of elastic energy. The effects of aspect ratio of graphene, temperature, and loading velocity on graphene wrinkling parameters and patterns are also investigated.

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Balamurugan, G. Prasath, Rohan N. Pukadyil, Mahdy M. Malayery, Michael R. Thompson, John Vlachopoulos, Kent E. Nielsen, and Frank A. Brandys. "Thermal wrinkling behavior of formable decorative film laminates." Journal of Plastic Film & Sheeting 33, no. 3 (August 5, 2016): 290–308. http://dx.doi.org/10.1177/8756087916663031.

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This paper focuses on wrinkle development in decorative film laminates during heating operations with the goal to understand their driving factors and develop strategies to overcome such defects. The study looked at temperature and heating rate effects on the wrinkling behavior of a commercial black-out film laminated onto a metal substrate. The 135℃ threshold temperature identified for our film under which no wrinkles formed, related to the stiffness of its different construction layers. Heating rate was also noted by this study to be an important parameter in wrinkling; values between 1℃ and 350℃/min were tested. It was possible to exceed the threshold temperature stated above without wrinkling when the heating rate was sufficiently low (closer to 1℃/min, though less than 50℃/min was often sufficient depending on the final temperature). The heating rate effect is believed to be related to the time-dependent viscoelastic response of the compliant layer in relation to building thermal stresses.

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Zanjani, Nima A., and Shankar Kalyanasundaram. "Wrinkling Phenomenon during Uniaxial Extension of a Woven Thermoplastic Composite." Advanced Composites Letters 24, no. 5 (September 2015): 096369351502400. http://dx.doi.org/10.1177/096369351502400501.

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In the current research, wrinkling behaviour of a pre-consolidated woven self-reinforced polypropylene (SRPP) composite is investigated. Specimens possessing different aspect ratios were uniaxially extended at room temperature. Principal strains were recorded by a 3D optical photogrammetric system. Continuous measurement of out-of-plane displacements and induced in-plane strains elucidated the effect of specimens’ aspect ratios on wrinkling behaviour of SRPP composite. Investigating the evolution of meridian strains offered a valuable insight into development of principal strains before and after wrinkling onset. Plotting major and minor strains in a 2D strain space clarified the role of different deformation modes in the evolution of wrinkles. It was shown that common wrinkling predictors used on metals cannot effectively predict wrinkling initiation in this class of composites and a more reliable measure, based on evolution of local strains, should be employed. The current study investigates the wrinkling behaviour of a woven thermoplastic composite for the first time through a modified Yoshida buckling experiment. The outcomes illustrated effective parameters on the wrinkling evolution in SRPP specimens.

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Huang, Jianzhang, and Qiang Han. "Wrinkling in Graphene Subjected to Gradient Tension." Nano 10, no. 03 (April 2015): 1550037. http://dx.doi.org/10.1142/s179329201550037x.

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In the present study, the initiation and evolution mechanisms of wrinkles in a square single layer graphene sheet (SLGS) under gradient tensile displacements are investigated based on molecular dynamics (MD) simulations. The mechanism of wrinkling process is elucidated by studying the atomic out-of-plane displacements development of the key atoms in SLGS. It reveals that the loading and boundary conditions play dominant roles in the wrinkling deformation of graphene. The dependences of the wrinkling amplitude, wavelength, out-of-plane displacement, direction angle and wrinkling area ratio on the applied gradient tensile displacements are obtained. The effects of temperature, size of graphene and loading grads on graphene wrinkling are investigated.

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Wang, L., H. Long, D. Ashley, M. Roberts, and P. White. "Effects of the roller feed ratio on wrinkling failure in conventional spinning of a cylindrical cup." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 225, no. 11 (September 12, 2011): 1991–2006. http://dx.doi.org/10.1177/0954405410396024.

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In this study, wrinkling failure in conventional spinning of a cylindrical cup has been investigated by using both finite element (FE) analysis and experimental methods. FE simulation models of a spinning experiment have been developed using the explicit finite element solution method provided by the software Abaqus. The severity of wrinkles is quantified by calculating the standard deviation of the radial coordinates of element nodes on the edge of the workpiece obtained from the FE models. The results show that the severity of wrinkles tends to increase when increasing the roller feed ratio. A forming limit study for wrinkling has been carried out and shows that there is a feed ratio limit beyond which the wrinkling failure will take place. Provided that the feed ratio is kept below this limit, the wrinkling failure can be prevented. It is believed that high compressive tangential stresses in the local forming zone are the causes of the wrinkling failure. Furthermore, the computational performance of the solid and shell elements in simulating the spinning process are examined and the tool forces obtained from wrinkling and wrinkle-free models are compared. Finally, the effects of the feed ratio on variations of the wall thickness of the spun cylindrical cup are investigated.

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Donaldson, Laurie. "Wrinkling and crumpling graphene to good effect." Materials Today 19, no. 5 (June 2016): 247. http://dx.doi.org/10.1016/j.mattod.2016.04.014.

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Wang, Ruonan, Haosheng Pang, Minglin Li, and Lianfeng Lai. "Atomic Simulation of Nanoindentation on the Regular Wrinkled Graphene Sheet." Materials 13, no. 5 (March 3, 2020): 1127. http://dx.doi.org/10.3390/ma13051127.

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Surface landscapes have vague impact on the mechanical properties of graphene. In this paper, single-layered graphene sheets (SLGS) with regular wrinkles were first constructed by applying shear deformation using molecular dynamics (MD) simulations and then indented to extract their mechanical properties. The influence of the boundary condition of SLGS were considered. The wrinkle features and wrinkle formation processes of SLGS were found to be significantly related to the boundary conditions as well as the applied shear displacement and velocity. The wrinkling amplitude and degree of wrinkling increased with the increase in the applied shear displacements, and the trends of wrinkling wavelengths changed with the different boundary conditions. With the fixed boundary condition, the degree of graphene wrinkling was only affected when the velocity was greater than a certain value. The effect of wrinkles on the mechanical characterization of SLGS by atomic force microscopy (AFM) nanoindentation was finally investigated. The regular surface wrinkling of SLGS was found to weaken the Young’s modulus of graphene. The Young’s modulus of graphene deteriorates with the increase in the degree of regular wrinkling.

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Nardinocchi, P., and E. Puntel. "Swelling-induced wrinkling in layered gel beams." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 473, no. 2207 (November 2017): 20170454. http://dx.doi.org/10.1098/rspa.2017.0454.

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Gels are widely employed in smart mechanical devices and biomedical applications. Swelling-induced bending actuation can be obtained by means of a simple bilayer gel beam. We show that this system can also exhibit wrinkling patterns of potential interest for structural morphing and sensing. We study swelling-induced wrinkling at the extrados of a bilayer gel beam with the softer layer on top. The bent configuration at finite strain is recovered first and, starting from it, a linear perturbation analysis is performed. We delimit the zone corresponding to wrinkling modes in a parameter plane encompassing a mechanical stiffness ratio and a geometric top layer to total height ratio. Interestingly, we observe that surface instability precedes and envelopes wrinkling modes of finite wavelength. Finally, we discuss the effect of changes in stiffness and of the Flory–Huggins parameters χ on the size of the wrinkling domain.

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Liu, Hong, Hugh Gong, Pinghua Xu, Xuemei Ding, and Xiongying Wu. "The mechanism of wrinkling of cotton fabric in a front-loading washer: The effect of mechanical action." Textile Research Journal 89, no. 18 (January 2, 2019): 3802–10. http://dx.doi.org/10.1177/0040517518821909.

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In order to understand the impact of mechanical action on the wrinkling of cotton fabrics in a drum washer, fabric movement was observed and a movement index system was developed to characterize the textile motion. Results showed that spinning speed and wash load were the major factors influencing the smoothness of cotton fabrics, with p values of 0.000 and 0.032, respectively. The analysis of fabric movement illustrated that when the wash load increased, the free motion region decreased and the ratio of passive motion region increased, resulting in severe wrinkling of cotton fabric. A regression model was developed to characterize the relationship between fabric movement and smoothness. These findings help the understanding of the mechanism of wrinkling during a drum washer washing.

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Box, Finn, Doireann O’Kiely, Ousmane Kodio, Maxime Inizan, Alfonso A. Castrejón-Pita, and Dominic Vella. "Dynamics of wrinkling in ultrathin elastic sheets." Proceedings of the National Academy of Sciences 116, no. 42 (September 30, 2019): 20875–80. http://dx.doi.org/10.1073/pnas.1905755116.

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The wrinkling of thin elastic objects provides a means of generating regular patterning at small scales in applications ranging from photovoltaics to microfluidic devices. Static wrinkle patterns are known to be governed by an energetic balance between the object’s bending stiffness and an effective substrate stiffness, which may originate from a true substrate stiffness or from tension and curvature along the wrinkles. Here, we investigate dynamic wrinkling induced by the impact of a solid sphere onto an ultrathin polymer sheet floating on water. The vertical deflection of the sheet’s center induced by impact draws material radially inward, resulting in an azimuthal compression that is relieved by the wrinkling of the entire sheet. We show that this wrinkling is truly dynamic, exhibiting features that are qualitatively different to those seen in quasistatic wrinkling experiments. Moreover, we show that the wrinkles coarsen dynamically because of the inhibiting effect of the fluid inertia. This dynamic coarsening can be understood heuristically as the result of a dynamic stiffness, which dominates the static stiffnesses reported thus far, and allows control of wrinkle wavelength.

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Bamdad, AH, and R. Hashemi. "Analytical and numerical investigation of wrinkling limit diagram in deep drawing of two-layer sheets with experimental verification." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 235, no. 5 (January 11, 2021): 974–90. http://dx.doi.org/10.1177/1464420720985315.

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Wrinkling, which is primarily caused by insufficient blank holder force, is a significant issue that induces inconsistencies in forming parts, particularly in the deep drawing process. In this article, an investigation of the wrinkling in the deep drawing process of two-layer sheets is performed through an analytical approach, numerical method, and experimental tests. Increasing in the blank holder force, the process is under control by the proposed algorithm. Consequently, it aims to find the minimum required blank holder force to avoid wrinkling. The energy technique is utilized to predict the wrinkling in the analytical approach. Similarly, finite element simulations are implemented to investigate the effect of forming parameters on wrinkling. The experimental tests are performed to verify the analytical and numerical results. The impact of the material properties and stacking sequences (lay-up) on blank holder force and forming force are studied. Results show that the optimum blank holder force is dependent on the material properties, blank geometry, and layer stacking sequences. Also, a good agreement between analytical, numerical, and experimental results is achieved.

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Gdoutos, E. E., and M. S. Konsta-Gdoutos. "Load and Geometry Effect on Failure Mode Initiation of Composite Sandwich Beams." Applied Mechanics and Materials 3-4 (August 2006): 173–78. http://dx.doi.org/10.4028/www.scientific.net/amm.3-4.173.

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Facing compressive failure, facing wrinkling and core shear failure are the most commonly encountered failure modes in sandwich beams with facings made of composite materials. The occurrence and sequence of these failure modes depends on the geometrical dimensions, the form of loading and type of support of the beam. In this paper the above three failure modes in sandwich beams with facings made of carbon/epoxy composites and cores made of aluminum honeycomb and two types of foam have been investigated. Two types of beams, the simply supported and the cantilever have been considered. Loading included concentrated and uniform. It was found that in beams with foam core facing wrinkling and core shear failure occur, whereas in beams with honeycomb core facing compressive failure and core shear crimping take place. Results were obtained for the dependence of failure mode on the geometry of the beam and the type of loading. The critical beam spans for failure mode transition from core shear to wrinkling failure were established. It was found that initiation of a particular failure mode depends on the properties of the facing and core materials, the geometrical configuration and loading of composite sandwich beams.

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Sattar, Amer, Irfan Anjum Manarvi, and Manzar Masud. "Prediction of Wrinkling Initiation and Growth in Aluminum 5456-H116, Alloy Sheets by Finite Element Analysis of Yoshida Test." Applied Mechanics and Materials 197 (September 2012): 686–90. http://dx.doi.org/10.4028/www.scientific.net/amm.197.686.

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Wrinkling is one of the most undesirable effects during forming of thin sheet metal plates. It deforms the surfaces and either hampers further assembly or creates stress concentration regions which may fail during operations. Yoshida wrinkling test is considered as one good tool to analyse the wrinkling properties of sheet metals. Alluminium alloys are most commonly used in aviation industry where wrinkling initiation and its propagation is considered an even serious defect. Present research was therefore focussed on Finite Element simulations of Allumium Alloy-5456-H116 metal sheets specimens of the standard shape of Yoshida specimen. During simulations the applied load values were equal to Yield strength, yield strength +10%, and Yield strength -10%. Wrinkling initiation and propagation was observed as deformations along X,Y and Z axis on a predefined path of the specimen and stress values at this path were also evaluated. Findings have been established through an overview of deformation along each axis corresponding to stress values at that location on the path.

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Liu, Y. P., C. G. Wang, H. F. Tan, and M. K. Wadee. "The interactive bending wrinkling behaviour of inflated beams." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 472, no. 2193 (September 2016): 20160504. http://dx.doi.org/10.1098/rspa.2016.0504.

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A model is proposed based on a Fourier series method to analyse the interactive bending wrinkling behaviour of inflated beams. The whole wrinkling evolution is tracked and divided into three stages by identifying the bifurcations of the equilibrium path. The critical wrinkling and failure moments of the inflated beam can then be predicted. The global–local interactive buckling pattern is elucidated by the proposed theoretical model and also verified by non-contact experimental tests. The effects of geometric parameters, internal pressure and boundary conditions on the buckling of inflated beams are investigated finally. The results reveal that the interactive buckling characteristics of an inflated beam under bending are more sensitive to the dimensions of the structure and boundary conditions. We find that for beams which are simply supported at both ends or clamped and simply supported, boundary conditions may prevent the wrinkling formation. The results provide significant support for our understanding of the bending wrinkling behaviour of inflated beams.

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Shi, Yu Qing, and Ai Zhi Guan. "Numerical Simulation in Deep Drawing of Cylindrical Cup with Elliptical Shape Die Shoulder." Advanced Materials Research 148-149 (October 2010): 1355–59. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.1355.

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Wrinkling and tearing are the main failure modes in sheet-metal forming. The radius of die is important for deep-drawing because of an effective way to promote deep formability sheet metal .This paper presents an attempt to determine the effect of various elliptical shape die shoulder on the fracture and wrinkling and was investigated using 08Al sheet metal .The ellipse with minor axis of b=4.5mm and major axis of a=6.5mm,a=7mm,a=8mm ,a=10mm were analyzed to eliminate wrinkling and fracture in deep-drawing .The aim of this study is to investigate the effect of elliptical major axis and elliptical minor axis variables in elliptical shape die shoulder on formability in the deep-drawing process and to obtain useful date from the industrial field .The experiment show that limit formability promote with elliptical shape die shoulder in deep-drawing process.

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Jun, Hye-Ji, Soo-Yeon Lee, Jeung-Hoan Kim, Bong-Jeun An, and Jin-Young Lee. "Anti-wrinkling Effects of Juniperus rigida Sied." Korean Journal of Microbiology and Biotechnology 41, no. 4 (December 28, 2013): 449–55. http://dx.doi.org/10.4014/kjmb.1307.07004.

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Cales, Lorri, and Robert A. Weber. "Effects of water temperature on skin wrinkling." Journal of Hand Surgery 22, no. 4 (July 1997): 747–49. http://dx.doi.org/10.1016/s0363-5023(97)80141-4.

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Hematian, J., and P. M. Wild. "The Effects of Tooling Imperfections on the Initiation of Wrinkling in Finite Element Modeling of a Deep Drawing Process." Journal of Engineering Materials and Technology 123, no. 4 (July 24, 2000): 442–46. http://dx.doi.org/10.1115/1.1396351.

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A brief review of the literature on wrinkling in deep drawing processes is presented. It is noted that, while there is a large body of literature related to thin sheet, only one study related to thick sheet or plate has been identified. Finite element based models are used to investigate the effect of initial tooling imperfections on the initiation of wrinkling in deep drawing of thick sheet. Two sorts of tooling imperfections, punch displacement and blank tilting, are considered. The simulation results are compared qualitatively to the experimental forming operation. It is confirmed that tooling imperfections, in particular blank tilting, are an important type of imperfection governing the wrinkling behavior of the blank in deep drawing process.

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Hutchinson, John W. "The role of nonlinear substrate elasticity in the wrinkling of thin films." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 1993 (June 28, 2013): 20120422. http://dx.doi.org/10.1098/rsta.2012.0422.

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The role of substrate nonlinearity in the stability of wrinkling of thin films bonded to compliant substrates is investigated within the initial post-bifurcation range when wrinkling first emerges. A fully nonlinear neo-Hookean bilayer composed of a thin film on a deep substrate is analysed for a wide range of the film–substrate stiffness ratio, from films that are very stiff compared with the substrate to those only slightly stiffer. Substrate pre-stretch prior to film attachment is shown to have a significant effect on the nonlinearity relevant to wrinkling. Two dimensionless parameters are identified that control the stability and mode shape evolution of the bilayer: one specifying arbitrary uniform substrate pre-stretch and the other a stretch-modified modulus ratio. For systems with film stiffness greater than about five times that of the substrate the wrinkling bifurcation is stable, whereas for systems with smaller relative film stiffness bifurcation can be unstable, especially if substrate pre-stretch is not tensile.

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Zheng, Kai Lun, Lei Zhu, Denis J. Politis, Jian Guo Lin, and Trevor A. Dean. "An Analytical and Numerical Investigation on Flange Wrinkling Behavior in Warm Forming Process of AA5754 Using Macro-Textured Tool Design." Key Engineering Materials 716 (October 2016): 586–94. http://dx.doi.org/10.4028/www.scientific.net/kem.716.586.

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In this paper, an analytical buckling model is established to predict the flange wrinkling behavior of deep drawn cylindrical cups of aluminium alloy sheet in warm forming conditions using macro-textured blankholders for the first time. A continuum damage mechanism (CDM) based material model was utilized to reflect the visco-plastic feature of material at elevated temperatures. Forming speed and temperature effects were investigated, and texture ratio and draw ratio effects were also discussed. The developed analytical buckling model was validated by finite element simulations. The increase of forming temperature and forming speed is prone to cause wrinkling for AA5754, but the effects are not as significant as the texture geometry and draw ratio. The analytical model presented in this paper can be used as a design guide to determine tool texture geometry necessary to avoid wrinkling defects in the warm forming processes of aluminium alloy.

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Wang, Xiaofeng, Haoyue Chu, and Qingshan Yang. "Numerical analysis of dynamic properties of wrinkled thin membranes." Engineering Computations 37, no. 8 (April 8, 2020): 2871–94. http://dx.doi.org/10.1108/ec-10-2018-0459.

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Purpose This paper aims to numerically study the effects of boundary conditions, pre-stress, material constants and thickness on the dynamic performance of a wrinkled thin membrane. Design/methodology/approach Based on the stability theory of plates and shells, the dynamic equations of a wrinkled thin membrane were developed, and they were solved with the Lanczos method Findings The effects of wrinkle-influencing factors on the dynamic performance of a wrinkled membrane are determined by the wrinkling stage. The effects are prominent when wrinkling deformation is evolving, but they are very small and can hardly be observed when wrinkling deformation is stable. Mode shapes of a wrinkled membrane are sensitive to boundary conditions, pre-stress and Poisson’s ratio, but its natural frequencies are sensitive to all these five factors. Practical implications The research work in this paper is expected to help understand the dynamic behavior of a wrinkled membrane and present access to ensuring its dynamic stability by controlling the wrinkle-influencing factors. Originality/value Very few documents investigated the dynamic properties of wrinkled membranes. No attention has yet been paid by the present literature to the global dynamic performance of a wrinkled membrane under the influences of the factors that play a pivotal role in the wrinkling deformation. In view of this, this paper numerically studied the global modes and corresponding frequencies of a wrinkled membrane and their variation with the wrinkle-influencing factors. The results indicate that the global dynamic properties of a wrinkled membrane are sensitive to these factors at the stage of wrinkling evolution.

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Yin, Shui Ping, Ying She Luo, Zheng Cao, Shu Ling Luo, and Wen Bin Liu. "Research on the Effect of Entry Angle and Pressure-Pad Force on Deep-Draw Thermo-Rheological Forming of a TC1 Ti-Alloy Sheet." Key Engineering Materials 353-358 (September 2007): 635–38. http://dx.doi.org/10.4028/www.scientific.net/kem.353-358.635.

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Numerical simulation can be successfully applied to evaluate product manufacturability and predict, while material wrinkling and splitting are associated with entry angle and pressure-pad force during sheet metal stamping process. In this paper, the influence of entry angle and pressure-pad force on deep-drawing thermal forming of TC1 titanium alloy was analyzed by using explicit dynamic finite element software STAMPACK, two kinds of main invalidation, including wrinkling and splitting, and obtained that the entry angle is an important factor for deep-draw thermal forming. By analyzing the forming operation and optimizing the entry angle and the pressure-pad force of the die, the best range of the entry angle and the suitable pressure-pad force without wrinkling were obtained and splitting phenomena were controlled effectively. The researched results of numerical simulation provided some parameters for die design.

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Cui, Liu, Sanqiang Shi, Gaosheng Wei, and Xiaoze Du. "Shear deformation-induced anisotropic thermal conductivity of graphene." Physical Chemistry Chemical Physics 20, no. 2 (2018): 951–57. http://dx.doi.org/10.1039/c7cp06415b.

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Han, J. O., and S. S. Kim. "Effects of Swirl on High-Speed Combustion in a Single-Shot Optical SI Engine." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 206, no. 4 (October 1992): 237–47. http://dx.doi.org/10.1243/pime_proc_1992_206_184_02.

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Single-shot tests in a single-cylinder, optical SI engine operated by a rapid compression and expansion machine were performed in order to investigate the combined effects of engine speed, ignition position and swirl on early combustion and overall performance. For central ignition, swirl showed consistently favourable effects on combustion-related performance. However, at half-radius ignition the desirable swirl effect persisted at low engine speeds but faded away as the speed increased. This reversing of trends can be partially explained by differences in the maximum cylinder pressure, flame growth rate and flame front wrinkling.

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Fu, Y. Q., S. Sanjabi, Z. H. Barber, W. M. Huang, M. Cai, S. Zhang, J. K. Luo, A. J. Flewitt, and W. I. Milne. "In-Situ Observation of Transition Between Surface Relief and Wrinkling in Thin Film Shape Memory Alloys." Journal of Nanoscience and Nanotechnology 8, no. 5 (May 1, 2008): 2588–96. http://dx.doi.org/10.1166/jnn.2008.630.

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Significant surface morphology evolution between relief and wrinkling was observed on a 3.5 μm thick TiNiCu film sputter-deposited on a silicon substrate. At room temperature, variation in surface relief morphology (from separated martensite crystals embedded in amorphous matrix to fully inter-weaved martensite plates) was observed with slight change in film composition. The phenomenon was attributed to variations in crystallization temperatures of as-deposited amorphous films during annealing because of the compositional difference. During thermal cycling between room temperature and 100 °C, reversible surface morphology changes can be observed between surface relief and wrinkling patterns. The formation of the surface wrinkling is attributed to the large compressive stress in the film during high temperature post-annealing and crystallization, whereas surface relief is caused by the martensitic transformation to relieve the large tensile stress in the film. Compositional effect on this surface morphology evolution is discussed. Results also indicate that there is a critical dimension for the wrinkling to occur, and a small circular island can only relax by in-plane expansion.

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Taheri Kahnamouei, J., and Mohammad Sedighi. "Theoretical, Numerical and Experimental Investigation of the Effects of Manufacturing Process Parameters on Thin-Walled Tube Bending Defects." Advanced Materials Research 83-86 (December 2009): 1107–12. http://dx.doi.org/10.4028/www.scientific.net/amr.83-86.1107.

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The aim of this paper is to survey thin-walled tube bending process (without use of mandrel and booster). In tube bending process there are several effective parameters such as wall thickness, outer diameter-to-wall thickness ratio, and centerline bending radius-to-outer diameter ratio. Any mismatch in selecting these parameters would cause defects like wrinkling, variation in wall thickness, and cross section distortion. Firstly, the effects of these parameters on the initiation of the wrinkle, depth of wrinkling, change in wall thickness, and cross section distortion are studied. For this purpose, an FE commercial code has been used to simulate the process. Then, a series of experimental tests have been carried out to verify the results simulation. A comparison between analytical and experimental results shows a reasonable agreement with each other. Based on this comparison, it has been observed that there is a critical bending radius for any tube with a certain radius and thickness, in which the wrinkling begins to occur. For a certain bending angle and radius, it have been observed that the depth of wrinkling, change in wall thickness, and cross section distortion increase with reduction in wall thickness and outer diameter-to-wall thickness ratio

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Shi, Yu Qing. "Improving the Quality in Deep Drawing of Rectangle Parts Using Variable Blank Holder Force." Applied Mechanics and Materials 37-38 (November 2010): 521–24. http://dx.doi.org/10.4028/www.scientific.net/amm.37-38.521.

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Wrinkling and tearing are the main failure modes in sheet-metal forming. Wrinkle may occur at the start of a punch stroke if the blank-holder force (BHF) is too low, and tearing may occur at the end of a stroke if the BHF is too high. The BHF is important for deep-drawing because of an effective way to promote deep formability sheet metal. They can be reduced or eliminated by manipulating a suitable BHF during sheet-metal forming. This paper presented an attempt to determine the effect of variable BHF on the tearing and wrinkling and investigated using 08Al sheet metal. The experiment show that tearing and wrinkling can be eliminated and the quality of deep drawing of rectangle parts can be improved using variable BHF.

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Bao, Hongwei, Yuhong Huang, Zhi Yang, Yaping Miao, Yunjin Sun, Yu Bai, Kewei Xu, and Fei Ma. "Circular torsion induced fan-blade shaped wrinkling in two-dimensional nano-rings." Physical Chemistry Chemical Physics 19, no. 37 (2017): 25360–68. http://dx.doi.org/10.1039/c7cp04799a.

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SUN, L., Y. ZHAO, W. M. HUANG, H. PURNAWALI, and Y. Q. FU. "WRINKLING ATOP SHAPE MEMORY MATERIALS." Surface Review and Letters 19, no. 02 (April 2012): 1250010. http://dx.doi.org/10.1142/s0218625x12500102.

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Many surface related properties, such as surface roughness, surface tension and reflection etc are heavily dependent on the surface morphology of materials. Patterned surfaces may have significant effects on these properties. In this paper, we compare wrinkles produced atop three different types of shape memory materials, namely, shape memory alloy, shape memory polymer and shape memory hybrid. We show the advantages and disadvantages of them in terms of the processing techniques and the resultant wrinkle patterns.

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Wang, Ziheng, Pardis Rofouie, and Alejandro Rey. "Surface Anchoring Effects on the Formation of Two-Wavelength Surface Patterns in Chiral Liquid Crystals." Crystals 9, no. 4 (April 2, 2019): 190. http://dx.doi.org/10.3390/cryst9040190.

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We present a theoretical analysis and linear scaling of two-wavelength surface nanostructures formed at the free surface of cholesteric liquid crystals (CLC). An anchoring model based on the capillary shape equation with the high order interaction of anisotropic interfacial tension is derived to elucidate the formation of the surface wrinkling. We showed that the main pattern-formation mechanism is originated due to the interaction between lower and higher order anchoring modes. A general phase diagram of the surface morphologies is presented in a parametric space of anchoring coefficients, and a set of anchoring modes and critical lines are defined to categorize the different types of surface patterns. To analyze the origin of surface reliefs, the correlation between surface energy and surface nano-wrinkles is investigated, and the symmetry and similarity between the energy and surface profile are identified. It is found that the surface wrinkling is driven by the director pressure and is annihilated by two induced capillary pressures. Linear approximation for the cases with sufficient small values of anchoring coefficients is used to realize the intrinsic properties and relations between the surface curvature and the capillary pressures. The contributions of capillary pressures on surface nano-wrinkling and the relations between the capillary vectors are also systematically investigated. These new findings establish a new approach for characterizing two-length scale surface wrinkling in CLCs, and can inspire the design of novel functional surface structures with the potential optical, friction, and thermal applications.

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Aizen, Efraim, and Amos Gilhar. "Smoking effect on skin wrinkling in the aged population." International Journal of Dermatology 40, no. 7 (July 2001): 431–33. http://dx.doi.org/10.1046/j.1365-4362.2001.01238.x.

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Huang, Rui, Christopher M. Stafford, and Bryan D. Vogt. "Effect of Surface Properties on Wrinkling of Ultrathin Films." Journal of Aerospace Engineering 20, no. 1 (January 2007): 38–44. http://dx.doi.org/10.1061/(asce)0893-1321(2007)20:1(38).

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41

Roh, Jin-Ho, Eun-Jung Yoo, Jae-Hung Han, In Lee, Wang-Gu Kang, and Chan-Hong Yeom. "Nonlinear Analysis of Inflatable Membrane Structures with Wrinkling Effect." Journal of the Korean Society for Aeronautical & Space Sciences 33, no. 12 (December 31, 2005): 33–38. http://dx.doi.org/10.5139/jksas.2005.33.12.033.

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42

Kim, Young-Ah, and Kyeong-Sik Woo. "Effect of Wrinkling on Failure Behavior of Thin Membranes." Journal of the Korean Society for Aeronautical & Space Sciences 39, no. 11 (November 1, 2011): 1005–12. http://dx.doi.org/10.5139/jksas.2011.39.11.1005.

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43

Bažant, Zdeněk, and Peter Grassl. "Size Effect of Cohesive Delamination Fracture Triggered by Sandwich Skin Wrinkling." Journal of Applied Mechanics 74, no. 6 (January 24, 2007): 1134–41. http://dx.doi.org/10.1115/1.2722778.

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Because the observed size effect follows neither the strength theory nor the linear elastic fracture mechanics, the delamination fracture of laminate-foam sandwiches under uniform bending moment is treated by the cohesive crack model. Both two-dimensional geometrically nonlinear finite element analysis and one-dimensional representation of skin (or facesheet) as a beam on elastic-softening foundation are used. The use of the latter is made possible by realizing that the effective elastic foundation stiffness depends on the ratio of the critical wavelength of periodic skin wrinkles to the foam core thickness, and a simple description of the transition from shortwave to longwave wrinkling is obtained by asymptotic matching. Good agreement between both approaches is achieved. Skin imperfections (considered proportional to the the first eigenmode of wrinkling), are shown to lead to strong size dependence of the nominal strength. For large imperfections, the strength reduction due to size effect can reach 50%. Dents from impact, though not the same as imperfections, might be expected to cause as a similar size effect. Using proper dimensionless variables, numerical simulations of cohesive delamination fracture covering the entire practical range are performed. Their fitting, heeding the shortwave and longwave asymptotics, leads to an approximate imperfection-dependent size effect law of asymptotic matching type. Strong size effect on postpeak energy absorption, important for impact analysis, is also demonstrated. Finally, discrepancies among various existing formulas for critical stress at periodic elastic wrinkling are explained by their applicability to different special cases in the shortwave-longwave transition.

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44

Zhao, Gang Yao, Yu Li Liu, and He Yang. "Numerical Simulation on Influence of Clearance and Friction on Wrinkling in Bending of Aluminum Alloy Rectangular Tubes." Materials Science Forum 546-549 (May 2007): 833–38. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.833.

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The clearance and friction have large influence on wrinkling in rotary draw bending process of thin-walled rectangular tube. In this paper, a three-dimension Al FEM model of rotary draw bending of thin-walled rectangular tube is built under the ABAQUS/ Explicit environment. Based on the model, simulation and analysis of rotary draw bending for aluminum alloy 3A21 thin-walled rectangular tube have been carried out. The results show that the height of wrinkling wave decreases obviously with the decrease of the clearance between mandrel and tube or with the increase of the friction coefficient between wiper die and tube; however, the effect of friction coefficient on wrinkling becomes weaker while increasing the clearance between mandrel and tube. The achievements of this study provide a guideline for determining the process parameters for thin-walled rectangular tube in rotary draw bending process.

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Jenkins, C. H., and J. W. Leonard. "Dynamic Wrinkling of Viscoelastic Membranes." Journal of Applied Mechanics 60, no. 3 (September 1, 1993): 575–82. http://dx.doi.org/10.1115/1.2900841.

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Problems associated with viscoelastic membrane structures have been documented, e.g., dynamic wrinkling and its effects on fatigue analysis and on snap loading. In the proposed analysis method, the constitutive equation is approximated by a finite difference equation and embedded within a nonlinear finite element spatial discretization. Implicit temporal integration and a modified Newton-Raphson method are used within a time increment. The stress-strain hereditary relation is formally derived from thermodynamic considerations. Use of modified strain-energy and dissipation functions facilitates the description of wrinkling during the analysis. Applications are demonstrated on an inflated cylindrical cantilever and on a submerged cylindrical membrane excited by waves.

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Fang, Jun, Shi Qiang Lu, Ke Lu Wang, and Zheng Jun Yao. "Effect of Bending Speed on Forming Quality of 0Cr21Ni6Mn9N Stainless Steel Tube NC Bending." Advanced Materials Research 1015 (August 2014): 198–202. http://dx.doi.org/10.4028/www.scientific.net/amr.1015.198.

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Based on the nonlinear FE platform ABAQUS, an elastic plastic 3D-FE model of 0Cr21Ni6Mn9N stainless steel tube was established to simulate the whole process, and its reliability was validated by experiment. Using the model, the effect of bending speed on forming quality was studied and the influence laws of bending speed on wrinkling wave ratio, wall thinning, cross section deformation and springback angle were revealed. The results show that the wrinkling wave ratio and springback angle decrease with the increasing of bending speed, while the effect of bending speed on wall thinning and cross section deformation are not significant. The maximum cross section deformation degree presents in the vicinity of the bending angle 30° along the bending direction and its position is almost unchanged with the variation of bending speed.

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47

Huang, Qun, Jie Yang, Wei Huang, Gaetano Giunta, Salim Belouettar, and Heng Hu. "The boundary effects on stretch-induced membrane wrinkling." Thin-Walled Structures 154 (September 2020): 106838. http://dx.doi.org/10.1016/j.tws.2020.106838.

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48

Safdarian, R. "Experimental and numerical investigation of wrinkling and tube ovality in the rotary draw bending process." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 16 (May 19, 2019): 5568–84. http://dx.doi.org/10.1177/0954406219850857.

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The tube wrinkling, ovality, and fracture are the main defects in the rotary draw bending process, which happen by incorrect selection of process parameters. In the present study, the wrinkling, fracture, and ovality of BS 3059 steel tube in the rotary draw bending were investigated using the experimental tests and the finite element method. The numerical results were verified using the experimental tests for tube ovality prediction. The tube fracture was predicted using the Gurson–Tvergaard–Needleman damage model in the rotary draw bending numerical simulations. The design of experiment based on the response surface method and the finite element method was used to investigate the effects of rotary draw bending parameters such as boosting velocity of pressure die, mandrel position, number of balls, and pressure of pressure die on the wrinkling, fracture, and tube ovality. The experimental and numerical results indicated that the mandrel position was one of the main parameters, which influence the tube ovality. The tube ovality and wrinkling increased with the increase in the mandrel position.

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Shi, Yu Qing. "Numerical Simulation in Deep Drawing of Cylindrical Cup with Circular Diving Equally Small Holes on Edge of Circle Blank." Advanced Materials Research 148-149 (October 2010): 769–73. http://dx.doi.org/10.4028/www.scientific.net/amr.148-149.769.

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Deep-drawing is one of the most important methods to form sheet metal ,but wrinkling and fracture are the main failure modes in sheet-metal forming. Blank shape is important for deep-drawing because of an effective way to promote deep formability sheet metal .This paper presents an attempt to determine the effect of circle blank with circular diving equally small hole on edge of circle blank on the fracture and wrinkling and was investigated using 08Al sheet metal .The circular blank with small hole of diameter = was analyzed to eliminate wrinkling and fracture in deep-drawing .The aim of this study is to investigate the circular diving equally small hole on edge of circle blank on formability in the deep-drawing process and to obtain useful date from the industrial field .The experiment show that limit formability promote with punching small holes on circle blank in deep-drawing process.

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Negreiros, Fábio R., Germán J. Soldano, Sergio Fuentes, Trino Zepeda, Miguel José-Yacamán, and Marcelo M. Mariscal. "The unexpected effect of vacancies and wrinkling on the electronic properties of MoS2 layers." Physical Chemistry Chemical Physics 21, no. 44 (2019): 24731–39. http://dx.doi.org/10.1039/c9cp04347k.

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We report a combined experimental/theoretical approach to study the connection of S-vacancies and wrinkling on MoS₂ layers, and how this feature produces significant changes in the electronic structure and reactivity of this 2D material.

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Journal articles on the topic 'Wrinking effect'

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