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Journal articles on the topic 'Preforming'

Author: Grafiati

Published: 4 June 2021

Last updated: 9 February 2022

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1

Nuss, Dominik, Quang Pham, Gerald Hoffmann, and Chokri Cherif. "Neue Technologie zur direkten Fertigung sphärisch gekrümmter Gewebe." Technische Textilien 64, no. 1 (2021): 14–17. http://dx.doi.org/10.51202/0323-3243-2021-1-014.

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Preformen für komplex gekrümmte Schalenstrukturen für den Einsatz in faserverstärkten Kunstoffen werden aktuell meist mittels sequentiellem Preforming gefertigt, wodurch zeit- und materialaufwändige Prozessschritte notwendig sind. Um diese Arbeitsschritte zu minimieren und den hohen Bedarf seitens der Industrie an dreidimensionalen, schalenförmigen Preformen zu decken, wurde im Rahmen des IGF-Projekts 19805 BR die neuartige Technologie des abzugsfreien Webens entwickelt. Diese ermöglicht das direkte Weben sphärisch gekrümmter Strukturen komplexer Geometrie. Dominik Nuss, Quang Pham, Gerald Hoffmann, Chokri Cherif Institut für Textilmaschinen und Textile Hochleistungswerkstofftechnik (ITM), Technische Universität Dresden, Dresden

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2

Schnabel, Andreas, Tim Grundmann, Frank Felix Kruse, and Thomas Gries. "Automatisiertes textiles Preforming." Lightweight Design 2, no. 3 (June 2009): 44–47. http://dx.doi.org/10.1007/bf03223573.

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3

Xu, Hui Yuan, Rong Xia Zhang, Yuan Song Zeng, and Jia Jia Liu. "Improving Thickness Uniformity of Ti₃Al Sheet Metal SPF by Preforming." Materials Science Forum 735 (December 2012): 130–35. http://dx.doi.org/10.4028/www.scientific.net/msf.735.130.

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Ti3Al intermetallic alloy is a hard formed material with many advantages for aviation and aerospace applications. Superplastic forming (SPF) is an ideal process for Ti3Al alloy to form sheet metal component. The thickness distribution of U cross-section circular parts, which were superplastically formed in two different female die cavity, were predicted by FEM software. According to female die forming thickness distribution, preforming die cavity was designed and was optimized by FEM software. Superplastic bugling tests with and without preforming were carried out. The thickness of parts were measured and compared with predictions by FEM software. The results showed that preforming can promote thickness uniformity efficiently in female die forming. In this experiment, the thickness difference range of the part formed with preforming reduced 75.8% compared with part formed without preforming.

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4

Fong, Lihwa, and L. James Lee. "Preforming Analysis of Thermoformable Fiber Mats — Preforming Effects on Mold Filling." Journal of Reinforced Plastics and Composites 13, no. 7 (July 1994): 637–63. http://dx.doi.org/10.1177/073168449401300703.

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5

Chiu, Hsuan-Hao, and Wen-Bin Young. "Characteristic study of bamboo fibers in preforming." Journal of Composite Materials 54, no. 25 (May 1, 2020): 3871–82. http://dx.doi.org/10.1177/0021998320923144.

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The bamboo fiber preforming is an important process in the liquid composite molding for fabricating fiber reinforced composites with non-planar geometric shapes. This study investigated the deformation and spring back behaviors of the single bamboo fiber and bamboo fiber mat under a simple bending preforming test. The effects of the heating temperature and moisture content of bamboo fibers were studied during the tests. The result showed that the [0/90] bamboo fiber mats could be perfectly preformed without spring back after bending under the conditions of a wet and high temperature conditions. The internal structure of bamboo fiber with moisture tends to expand and soften, which makes the fibers to deform plastically under external stresses. The single bamboo fiber preforming test and stress relaxation test were conducted to study its formability. Higher heating temperature and moisture content for the bamboo fibers during preforming process can reduce the spring back effect after preforming.

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6

Hopmann, Christian. "Preforming — das ungeliebte Kind." Lightweight Design 8, no. 6 (December 2015): 3. http://dx.doi.org/10.1007/s35725-015-0057-6.

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7

Liu, Gang, Ke Huan Wang, Yi Xu, Bin Wang, and Shi Jian Yuan. "An Approach to Improve Thickness Uniformity of TA15 Tubular Part Formed by Gas Bulging Process." Advanced Materials Research 712-715 (June 2013): 651–57. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.651.

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Gas bulging with local-stretching preforming is presented to form titanium alloy tubular part with small radius. In ordinary gas bulging process, local thinning occurs at the corners with small radius and produces dangerous position of the component. In the paper, a preforming process so-called local-stretching is applied before gas bulging. Finite element simulation and experiments were carried out to verify the effectiveness of the preforming and gas bulging process for the tubular component of titanium alloy TA15. During the local-stretching preforming, the material near the corner was kept almost rigid, but the material far away from the corner experienced stretching deformation and thickness thinning. Then, during gas bulging, the material near the corner experienced thinning deformation. So, the thickness uniformity of the final component was improved effectively.

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8

Lin, F. C., and Shen Yung Lin. "Predictions of the Minimum Amounts of Preforming in the Radial Extrusion of Tubular Components." Materials Science Forum 505-507 (January 2006): 769–74. http://dx.doi.org/10.4028/www.scientific.net/msf.505-507.769.

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Both the minimum relative depth of die cavity and the minimum amount required in preforming are determined to produce a defect-free product of tubular component in the preforming technique of radial extrusion in this study. This scheme is based on the least amount of material dissipation in radial extrusion of tubular component. A finite element based code is utilized to investigate the effects of various relative depths of die cavity, different percentage of preforming and relative height reduction on the material flow characteristics resulting in the movements of the defects locations. The abductive network is also applied to synthesize the data sets obtained from the numerical simulations. Consequently, a prediction model is established for organizing the minimum relative depth of die cavity and the related minimum amount required in preforming of the tubular component for different end strokes of deformation.

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9

Fauster, Ewald, Christian Schillfahrt, Christian Hueber, and Ralf Schledjewski. "Automated profile preforming for structural components." Science and Engineering of Composite Materials 24, no. 5 (September 26, 2017): 631–50. http://dx.doi.org/10.1515/secm-2015-0377.

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AbstractThe work presented in this paper addresses various techniques for automated preforming of profiles for structural components made from fiber-reinforced polymer composites. After reviewing the existing preforming techniques, a quantitative comparison with respect to two different application scenarios is presented. The technology comparison is conducted individually for the two application scenarios by means of a weighted decision matrix approach incorporating a list of technical and economic criteria. The preforming costs are derived by means of a bottom-up cost estimation model and are incorporated in the technology comparison.

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10

Mojarad Farimani, Saeed, Javad Gholipour Baradari, Henri Champliaud, Jean Savoie, and Priti Wanjara. "Numerical and Experimental Study of Preforming Stage in Tube Hydroforming." Key Engineering Materials 611-612 (May 2014): 1132–38. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.1132.

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The preforming stage in hydroforming of an aerospace generic shape was investigated using a combination of experimentation and numerical modeling. The preform die was manufactured using a rapid prototyping method, namely the selective laser sintering (SLS) process. The preforming experiments were conducted on 0.9 mm and 1.2 mm thick stainless steel 321 (SS321) tubes. To evaluate the preforming process, an automated deformation measurement system, ARGUS®, was used to measure the 3-dimensional (3D) strains on the deformed tubes. Data collected from the experiments were used to validate the simulation of the preforming stage. The simulation and experimental results were found to be in good agreement, indicating that the preform model can be used as a starting point for simulating the tube hydroforming (THF) process. In addition, the SLS approach was found to be very promising, as it reduced greatly the lead time and cost of process development for THF.

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11

Wang, Yilei, and Chunlan Jiang. "Influence of Molding Parameters on Quasi-Static Mechanical Properties of Al-Rich Al/PTFE/TiH2 Active Materials." Materials 14, no. 11 (May 22, 2021): 2750. http://dx.doi.org/10.3390/ma14112750.

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Preforming pressure and the pressure holding time are important parameters of the molding process, which directly affect the mechanical properties of materials. In order to obtain the best molding parameters of Al-rich Al/PTFE/TiH2 composites, based on the quasi-static compression test, the influence of molding parameters on the mechanical properties of Al-rich Al/PTFE/TiH2 composites was analyzed, and the microstructure characteristics of Al-rich Al/PTFE/TiH2 specimens were analyzed by SEM. An X-ray diffractometer was used to analyze the phase of the residue after quasi-static compression experiment. The results show that: (1) With the increase in molding parameters (preforming pressure and the pressure holding time), the compressive strength, failure strain and toughness of Al-rich Al/PTFE/TiH2 specimens first increase and then decrease. The best molding process parameters of Al-rich Al/PTFE/TiH2 materials are preforming pressure 240 MPa and the pressure holding time 100 s. (2) For unsintering specimens, when the preforming pressure is less than 150 MPa, the porosity of the specimen increases slowly at first and then decreases. When the preforming pressure is greater than 150 MPa, the porosity of the specimen increases first and then decreases. When the pressure holding time is no more than 100 s, the porosity of the specimen decreases gradually. When the pressure holding time is more than 100 s, the porosity of the specimen increases first and then decreases. For sintered specimens, when the preforming pressure is less than 100 MPa, the porosity of the specimen decreases gradually. When the preforming pressure is greater than 100 MPa, the porosity of the specimen first increases and then decreases. With the increase in the pressure holding time, the porosity first increases and then decreases. For each preforming pressure specimen, compared with that before sintering, the porosity after sintering either decreases or increases. For each the pressure holding time specimen, the porosity increases after sintering compared with that before sintering. The microstructure of PTFE crystal inside the specimen is mainly planar PTFE crystal. The size and number of planar PTFE crystals are significantly affected by the molding parameters, which further affects the mechanical properties of Al-rich Al/PTFE/TiH2 specimens. When the preforming pressure is less than 100 MPa, the planar PTFE crystals are small and few, which results in the worst mechanical properties of the specimens. When the preforming pressure is more than 100 MPa and does not contain 240 Mpa, the planar PTFE crystals are small and there are more of them, which results in better mechanical properties of the specimens. When the preforming pressure is 240 MPa, the planar PTFE crystals are large and numerous, which results in the best mechanical properties of the specimen. When the pressure holding time is 100 s, the planar PTFE crystals are large and there are more of them, which results in the best mechanical properties of the specimen. (3) The reactivity of Al-rich Al/PTFE/TiH2 specimens with TiH2 the content of 10% under quasi-static compression is not significantly affected by the molding parameters.

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12

Grieser, Timo, and Peter Mitschang. "Kontinuierliches Profil-Preforming für Versteifungsstrukturen." Lightweight Design 7, no. 4 (August 2014): 24–29. http://dx.doi.org/10.1365/s35725-014-0395-9.

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13

Ariawan, A. B., S. Ebnesajjad, and S. G. Hatzikiriakos. "Preforming behavior of polytetrafluoroethylene paste." Powder Technology 121, no. 2-3 (November 2001): 249–58. http://dx.doi.org/10.1016/s0032-5910(01)00385-0.

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14

Orliac, Jean Guillaume, Adrien Charmetant, Fabrice Morestin, Philippe Boisse, and Stephane Otin. "3D Interlock Composite Preforming Simulation." Key Engineering Materials 504-506 (February 2012): 261–66. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.261.

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In order to simulate 3D interlock composite reinforcement behavior in forming processes like Resin Transfer Molding (RTM), it is necessary to predict yarns positions in the fabric during the preforming stage of the process. The present paper deals about thick 3D interlock fabric forming simulation using a specific hexahedral semi-discrete finite elements simulation tool : Plast4. Using the virtual work principle, we distinguish the virtual internal work due to tensions in yarns from other internal virtual works. The part of material stiffness relative to yarns tension is described as "first order stiffness" by a 3D discrete beam model. The rest of the rigidities - like transverse compression, shear strains or friction between yarns - are depicted by a continuous quad-based discretization designated in our work as "second order stiffness". A combination of this "first order" discrete model and a continuous orthotropic hyperelastic "second order" material formulation will enables us to simulate interlock preforming process. Jointly to the simulation work, we also had to specify and perform experimental testing identification of material's parameters. Thoses parameters concern both parts of the model. A bilinear tension approach for the yarns discrete modelization and an orthotropic continuous material for the "second order" part.

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15

Bel, Sylvain, Nahiene Hamila, and Philippe Boisse. "Analysis of Non-Crimp Fabric Composite Reinforcements Forming." Key Engineering Materials 504-506 (February 2012): 219–24. http://dx.doi.org/10.4028/www.scientific.net/kem.504-506.219.

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Abstract Two experimental devices are used for the analysis of the deformation mechanisms of biaxial non-crimp fabric composite reinforcements during preforming. The bias extension test, commonly use for the shear behaviour characterisation of woven fabrics, allows to highlight the sliding between the two plies of the reinforcement. This sliding is localized in areas of high gradient of shearing. This questions the use of bias extension test in determining the shear stiffness of the studied reinforcement. Then a hemispherical stamping experiment, representative of a preforming process, allows to quantify this sliding. The slippage is defined as the distance, projected onto the middle surface, of two points initially opposed on both sides of the reinforcement. For both experiments, the characteristic behavior of the non-crimp fabric reinforcement is highlighted by comparison with a woven textile reinforcement. This woven fabric presents only a very little sliding between warp and weft yarns during preforming. This aspect of the deformation kinematics of the non-crimp fabric reinforcement must be considered when simulating the preforming.

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16

Wu, Wang Qing, Bin Yan Jiang, Lei Xie, and Gerhard Ziegmann. "Experiment and Modeling Study on the Compaction Behavior of Bindered Textile Preforms." Applied Mechanics and Materials 268-270 (December 2012): 148–54. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.148.

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The effect of compaction and preforming parameters on the fiber volume content of bindered textile preforms during a compaction experiment was investigated by using Taguchi method. Four compaction and preforming parameters of compaction temperature, binder activation temperature, binder content and binder activation time were selected and optimized with respect to the fiber volume content at specified compaction pressure (0.2 MPa). The results reveal that the compaction behavior of bindered textile preforms has significantly influenced due to the presence of binder. The fiber volume content during compaction was correlated with the compaction and preforming parameters using a modified four-parameter-compaction-model which has been proposed for describing the compaction behavior of bindered textile preforms.

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17

De Luycker, E., F. Morestin, P. Boisse, and D. Marsal. "Simulation of 3D interlock composite preforming." Composite Structures 88, no. 4 (May 2009): 615–23. http://dx.doi.org/10.1016/j.compstruct.2008.06.005.

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18

Krieger, Helga, Dorit Kaufmann, and Thomas Gries. "Kinematic Drape Algorithm and Experimental Approach for the Design of Tailored Non-Crimp Fabrics." Key Engineering Materials 651-653 (July 2015): 393–98. http://dx.doi.org/10.4028/www.scientific.net/kem.651-653.393.

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In the preforming process, the textile is draped into the geometry of the structural part and afterwards consolidated with resin via injection. For preforming processes non-crimp fabrics (NCFs) have become increasingly popular for cost effective applications. For the realization of automated draping of two-dimensional textiles into three-dimensional complex geometries during the preforming process there is a high advantage for the use of tailored textiles compared to textiles with uniform material properties. Large flat surfaces require a high bending stiffness and low shear stiffness due to high structural stability of the textile and small radii of curvature require a low bending stiffness due to good drapeability of the textile. The bending and the shear stiffness of NCFs with a given layup can be influenced by the manufacturing parameters of the knitting yarn. With tailored NCFs it is possible to adapt the manufacturing parameters of the knitting yarn locally in the production direction to improve drapeability and handling of the textile in the preforming process. To use the high potential of tailored NCFs, the development of the new textile structure has to go hand in hand with the characterization and with the simulation of the draping process. An experimental approach and a modelling approach using a kinematic drape algorithm have been developed to define the local stitching parameters for tailored NCFs dependent on the geometry of the component part.

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19

Mitschang, P., A. Ogale, J. Schlimbach, F. Weyrauch, and C. Weimer. "Preform Technology: A Necessary Requirement for Quality Controlled LCM-Processes." Polymers and Polymer Composites 11, no. 8 (November 2003): 605–22. http://dx.doi.org/10.1177/096739110301100801.

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A considerable number of process versions of Liquid Composite Moulding (LCM) technologies have been commercialised during the last few years. Only recently there have been attempts to reduce costs and to implement more complex components by the application of preform technology. This article indicates the most appropriate application fields for LCM techniques for the manufacture of fibre reinforced polymers. Different LCM methods are described and summarised. The preforming techniques and particularly the sew -and -cut philosophy for developing a tailored reinforcement is explained. Investigations designed to elucidate the influence of sewing parameters and thread properties have led to an understanding of the requirements and preform characteristics needed to operate the quality controlled LCM process. Some concepts related to the control of the resin injection are described, and a realization of a decision-tree-concept is shown. Finally, a comparison of cost effects for different preforming methods shows a need to define a “critical preforming effort” to manufacture quality components as well as economically optimised parts.

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20

Cheng, Lian Jun, Tie Zhu Zhang, and Hong Xin Zhang. "The New Preforging Method of Closed-Die Forging with Controlled-Flash for Steering Knuckles." Advanced Materials Research 482-484 (February 2012): 2409–13. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.2409.

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In this paper, the new forging process for forming the steering knuckle of the truck is proposed, which includes preforming, preforging and finish-forging. The key technology of new forging process is focused on the preforging design. The closed-die forging with controlled-flash process for the preforging is proposed, by which the material utilization rate is enhanced greatly. The proper preforming includes three steps: rod extrusion, fork flatting and cleaving. The 3D finite element method (FEM) for simulation the forging process is also presented. The new and the traditional forging processes of producing the steering knuckle are compared too.

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21

Reinhold, Raphael, and Torsten Mehlenhoff. "Continuous Preforming System for Curved Composite Profiles." SAE International Journal of Aerospace 4, no. 2 (October 18, 2011): 681–89. http://dx.doi.org/10.4271/2011-01-2515.

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22

Matveev, Mikhail, Vivek Koncherry, Sree Shankhachur Roy, Prasad Potluri, and Andrew Long. "Novel textile preforming for optimised fibre architectures." IOP Conference Series: Materials Science and Engineering 406 (September 21, 2018): 012050. http://dx.doi.org/10.1088/1757-899x/406/1/012050.

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23

Cherouat, Abel, and Houman Bourouchaki. "Numerical Tools for Composite Woven Fabric Preforming." Advances in Materials Science and Engineering 2013 (2013): 1–18. http://dx.doi.org/10.1155/2013/709495.

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An important step in the manufacturing processes of thin composite components is the layingup of the reinforcement onto the mould surface. The prediction of the angular distortion of the reinforcement during draping and the changes in fibre orientation are essential for the understanding of the manufacture process and the evaluation of the mechanical properties of the composite structures. This paper presents an optimization-based method for the simulation of the forming processes of woven fabric reinforced composites. Two different approaches are proposed for the simulation of the draping of woven fabric onto complex geometries: geometrical and mechanical approaches. The geometrical approach is based on a fishnet model. It is well adapted to predimensioning fabrics and to give a suitable quantification of the resulting flat patterns. The mechanical approach is based on a mesostructural model. It allows us to take into account the mechanical properties of fibres and resin and the various dominating mode of deformation of woven fabrics during the forming process. Some numerical simulations of the forming process are proposed and compared with the experimental results in order to demonstrate the efficiency of our approaches.

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24

Hsia, Shao-Yi. "Optimization of Microextrusion Preforming Using Taguchi Method." Mathematical Problems in Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/305797.

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Micropin head geometry significantly influences surface contact and electrical conductivity. In this paper, the preforming process of extrusion is investigated to establish it as a viable process for microforming. Here, the numerical simulations using DEFORM-3D software are used to examine the effect of preformance and pin shape on the extrusion of microbrass pins with a minimum diameter of 0.88 mm under several design parameters. These parameters are planned with the Taguchi method and help to discover better conditions for the minimum extrusion loads. For obtaining the required parameters to enable the finite element software, a compression test is first performed to determine the true stress and true strain curve of the materials. The result acquired from the experiment is compared with the simulation outcome and verified the accuracy. The consequences show that the optimal microextrusion forming conditions appear on stage rod length 0.015 mm, extruding angle 60°, upper front-end taper 60°, and bottom stage angle 60° to minimalize the forming load, and the dimensions of the deformed micropin reveal a good identification with the simulation. The study hence shows a potential tool for the combination of Taguchi method and finite element software to analyze the microforming process in the fastener industry.

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25

Colla, D., S. B. Petersen, and P. A. F. Martins. "An investigation into the preforming of tubes." International Journal of Mechanical Sciences 39, no. 5 (May 1997): 507–21. http://dx.doi.org/10.1016/s0020-7403(96)00045-8.

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26

Lai, Chyi-lang, and Wen-bin Young. "Modeling fiber slippage during the preforming process." Polymer Composites 20, no. 4 (August 1999): 594–603. http://dx.doi.org/10.1002/pc.10382.

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27

Mostaghel, N., K. C. Fu, and Qiulin Yu. "Shifting natural frequencies of plates through preforming." Earthquake Engineering & Structural Dynamics 24, no. 3 (March 1995): 411–18. http://dx.doi.org/10.1002/eqe.4290240308.

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28

De Luycker, E., F. Morestin, P. Boisse, and D. Marsal. "Numerical Analysis of 3D Interlock Composite Preforming." International Journal of Material Forming 1, S1 (April 2008): 843–46. http://dx.doi.org/10.1007/s12289-008-0267-x.

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29

Wait, J. R., and K. A. Nabulsi. "Preforming an electromagnetic pulse in lossy medium." Electronics Letters 28, no. 6 (1992): 542. http://dx.doi.org/10.1049/el:19920342.

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30

Wang, Guang Chun, Bin Hai Hao, Chao Feng, and Tao Wang. "Study on Microstructure of a Gear Shaft during Hot Forging Process." Advanced Materials Research 712-715 (June 2013): 705–8. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.705.

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The microstructure revolution of a spur gear shaft during hot forging was numerically simulated with FEM using Yada Model. The grain size distribution of the gear shaft after hot forged using initial billets with different dimensions was obtained through microstructure simulation and relative metallographic experiment show a good agreement with the simulation result. Effect laws of different forging parameters including the initial forging temperature and the punch speed, on grain size of the gear shaft after forged were given. A preforming process was proposed and the microstructure simulation shows that the preforming process can significantly improve the grain size refinement and distribution uniformity of the gear shaft by hot forging.

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31

Mathieu, Sylvain, Philippe Boisse, Nahiene Hamila, and Florent Bouillon. "Locking and Stability of 3D Woven Composite Reinforcements." Key Engineering Materials 611-612 (May 2014): 292–99. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.292.

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3D woven composite reinforcements preforming simulations are an unavoidable step of composite part processing. The present paper deals with thick composite fabric behavior modelling and issues arising during the numerical simulation of preforming. After the description of the independent deformation modes of initially orthotropic reinforcements, a physically motivated and invariant based hyperelastic strain energy density is introduced. This constitutive law is used to show the limitations of a classical finite element formulation in 3D fabric simulations. Tension locking is highlighted in bias extension tests and a reduced integration hexahedral finite element with specific physical hourglass stabilization is proposed. Instabilities due to the highly anisotropic behavior law, witnessed in bending dominated situations, are exposed and a stabilization procedure is initiated.

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32

Shen, Ni, Shi-Jing Zhai, Chi Wai Cheung, and Jun-An Ma. "Direct N-formylation of nitroarenes with CO2." Chemical Communications 56, no. 67 (2020): 9620–23. http://dx.doi.org/10.1039/d0cc03098h.

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33

M.N, Abdullah, and . "Numerical and Experimental Investigation on the Effect of Billet Preforming in the Flange Forming." International Journal of Engineering & Technology 7, no. 4.7 (September 27, 2018): 188. http://dx.doi.org/10.14419/ijet.v7i4.7.20541.

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Finite element method and experiments have been used to study a cold forming method for fabrication of a flange using the effect of billet preforming. Three dimensional finite element methods carried out to obtain the forming load, die filling, material flow, effective stress, effective strain with DEFORM-3D software, and a series of experimental works has been performed using lead metal with four types of billet preforming in the first stage. Pressing process has been done using computerized hydraulic press machine with 100 tons. The forming sequence is carried out in two stages. In the first stage, the cylindrical billet is preformed by upsetting and in the second stage forming it in a die. Results indicate that the process of formation is influenced by preforming of billet with fixed volume in the final stage of pressing, improve the mechanical properties of the metal and thus facilitates the final deformation process with less stress and better flow of the metal inside the die. Simulation results show that the effective stress, maximum principal stress, effective strain, velocity and damage are maximum at locations where flange open out and rib growth begins across the geometrical interlocking between the two halves of die-set and the component surface.

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34

Yang, Yu Juan, Jian Pin Lin, and Bin Wang. "Analysis of Preform Annealing Process for the Aluminum Automotive Door Inner Panel." Materials Science Forum 850 (March 2016): 618–24. http://dx.doi.org/10.4028/www.scientific.net/msf.850.618.

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To improve the formability of aluminum alloy, a new forming technique-the preform annealing process is proposed. Based on the mechanical properties of the original aluminum alloy AA5182-O with two experienced preforming annealing treatment, and preforming annealing process of a complex geometric shape aluminum door inner panel was numerical simulated by using LS-DYNA software. As a result, the effects of annealing time at 365°C on stamping height of the panel and the optimum annealing time were obtained. The results showed that the preform annealing process was feasible in the door inner panel. At 365°C, the smooth forming of the door inner panel was achieved after annealing for 20s with the pre-deformation amount 97mm, Which are the most suitable parameters.

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35

Du, Zhihao, Guofeng Wang, and Hailun Wang. "The Process Design and Rapid Superplastic Forming of Industrial AA5083 for a Fender with a Negative Angle in a Small Batch." Metals 11, no. 3 (March 17, 2021): 497. http://dx.doi.org/10.3390/met11030497.

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A front automobile fender with a negative angle was trial produced via rapid superplastic forming (SPF) technology. The tensile test of industrial AA5083 was carried out at elevated temperatures, and the results showed that the maximum elongation was 242% at 480 °C/0.001 s−1. A rigid-plastic constitutive model of the SPF process was established. Initial dies of preforming and final forming were designed. The finite element method (FEM) was used to simulate the forming process and predict the thickness distribution of different areas. Furthermore, the dies were optimized to make the thickness distribution uniform. In the final structure, the maximum thinning ratio decreased from 83.2% to 63% due to the optimized design of the forming dies. The front automobile fender was then successfully fabricated by the preforming process and final forming process at 480 °C. A thickness measurement was carried out, and the minimum thickness of the preforming structure was 2.17 mm at the transverse tank, while that of the final structure was 2.49 mm near the edge of the lamp orifice. The average grain size grew from 20 to 35 μm. The grain growth led to the reduction of mechanical properties. Compared with the mechanical properties of the initial material, the maximum decrease in tensile strength for the material after superplastic forming was 5.78%, and that of elongation was 18.5%.

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Ochoa, Isaias, and Savvas G. Hatzikiriakos. "Polytetrafluoroethylene paste preforming: viscosity and surface tension effects." Powder Technology 146, no. 1-2 (August 2004): 73–83. http://dx.doi.org/10.1016/j.powtec.2004.06.003.

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Cherouat, Abel, and Houman Borouchaki. "Advanced numerical tool for composite woven fabric preforming." Advances in aircraft and spacecraft science 2, no. 1 (January 25, 2015): 1–16. http://dx.doi.org/10.12989/aas.2015.2.1.001.

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Wait, J. R., and K. A. Nabulsi. "Erratum: Preforming an electromagnetic pulse in lossy medium." Electronics Letters 28, no. 22 (1992): 2112. http://dx.doi.org/10.1049/el:19921354.

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Chestney, J. A., S. J. Moore, and M. Sarhadi. "A Methodology for Preforming Three-Dimensional Aerospace Components." Advanced Composites Letters 4, no. 5 (September 1995): 096369359500400. http://dx.doi.org/10.1177/096369359500400501.

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Alagirusamy, R., R. Fangueiro, V. Ogale, and N. Padaki. "Hybrid Yarns and Textile Preforming for Thermoplastic Composites." Textile Progress 38, no. 4 (January 2006): 1–71. http://dx.doi.org/10.1533/tepr.2006.0004.

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Wang, Lidong, Xiongqi Peng, and Mingrui Liu. "Development and application of hyperelastic model for diaphragm considering the influence of temperature." International Journal of Computational Materials Science and Engineering 08, no. 03 (September 2019): 1950010. http://dx.doi.org/10.1142/s2047684119500106.

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The basic mechanical properties of a diaphragm under various temperatures in hot diaphragm preforming of composites are obtained by uniaxial tensile tests. A constitutive model considering the influence of temperature is accordingly developed to characterize its large deformation behavior. Model parameters are obtained by nonlinear fitting experiment data. The constitutive model is implemented in ABAQUS through the user material subroutine UHYPER. The developed constitutive model is verified by simulating the covering deformation of the diaphragm over a C-type mold. Finally, as an application of the developed hyperelastic model, an optimal design of a support bar in the hot diaphragm preforming process is implemented. The constitutive model lays a solid foundation for the finite element simulation and process optimization of the hot diaphragm forming (HDF) of carbon composites.

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Tonejc, Maximilian, Martin Pletz, Ewald Fauster, and Ralf Schledjewski. "Permeability Customisation through Preform Manipulation Utilising 3D-Printing Technology." Polymers and Polymer Composites 25, no. 9 (November 2017): 651–60. http://dx.doi.org/10.1177/096739111702500902.

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The importance of preforming techniques is constantly increasing due to the fast development of liquid composite moulding processes. Besides traditional preforming methods such as tufting and stitching, tackifier based methods have developed rapidly. This paper presents a new methodology utilising 3D-printer technology for fabrics, through preform manipulation and thus enabling in-plane permeability property customisation. Two patterns of 45° and 90° with respect to the predominant permeability direction were printed onto the fabric consisting of parallel thermoplastic polymer melt strands. After a hot pressing stage the resulting preforms were characterised in terms of their in-plane permeabilities with an optical permeameter and compared to the original material's permeabilities. Furthermore a parameterised model is proposed describing the phenomena causing the manipulation by introducing a scale matrix for translating the original material's permeabilities into the permeabilities of the manipulated preforms.

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Ma, Xin Wu, Guo Qun Zhao, and Wen Juan Li. "The Coning Designs for the Micro Forming of a Surgical Slit Knife Using FE Simulations." Applied Mechanics and Materials 197 (September 2012): 745–49. http://dx.doi.org/10.4028/www.scientific.net/amm.197.745.

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This paper deals with problems in the coining process for manufacturing surgical slit knife using two-dimensional (2D) and three-dimensional (3D) finite element (FE) simulations. The FE simulations are performed to investigate the material flow, and especially stress distribution on the coining dies. The main objective of this paper is to study the feasibility of a coining process for manufacturing a given geometry of surgical slit knife without forming defects and die failure. Very high stress distribution on the coining dies is found by 2D simulations of the coining process that exceeds the strength limit of the die material. The optimum preform and preforming die geometry are determined by FE simulations in order to reduce the die stress. 3D simulations of the preforming and coining processes are conducted with the optimal design to show that the geometry of the product can be achieved without defects by the coining process.

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Zhao, G. H., Z. Liang, J. L. Tian, F. G. Jiang, and L. Zhang. "Large deflection plastic studying on preforming of multilateral tool." Materials Research Innovations 15, sup1 (February 2011): s49—s52. http://dx.doi.org/10.1179/143307511x12858956846878.

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De Luycker, E., J. G. Orliac, F. Morestin, P. Boisse, D. Marsal, and S. Otin. "Experimental and Numerical Analyses of 3D Interlock Composite Preforming." International Journal of Material Forming 3, S1 (April 2010): 719–22. http://dx.doi.org/10.1007/s12289-010-0871-4.

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Härtel, Frank, Farbod Nezami, and Nicolas Schur. "Innovative Preforming-Routen für die Herstellung von CFK-Bauteilen." Lightweight Design 8, no. 2 (April 2015): 54–61. http://dx.doi.org/10.1007/s35725-015-0018-0.

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Tsubaki, Takayuki, Kazuya Aono, Masao Hiratsuka, Tsunenori Murata, Hidetaka Himuro, Takahisa Nakajima, and Akira Tamesue. "Preforming of a nasal endotracheal tube to avoid obstruction." Journal of Anesthesia 4, no. 2 (April 1990): 194–95. http://dx.doi.org/10.1007/s0054000040194.

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Liu, Jie Min, Wei Nan Wang, and Shuang Liu. "Linear Analysis of the Constitutive Relation of Concrete Elastoplastic Disturbance." Applied Mechanics and Materials 580-583 (July 2014): 2894–97. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.2894.

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A linearization method of the uniaxial non-fitting nonlinear stress-strain curve given by the author of the paper is presented. The evolution equation between disturbances variable and plastic strain is derived based on Theory of Duality Disturbance. A simple method for concrete structures preforming elastoplastic analysis is presented (including softening analysis).

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Zimmermann, Bastian, and Marion Merklein. "Influence of the Preforming Material State in Common Tribological Tests." Advanced Materials Research 1140 (August 2016): 75–82. http://dx.doi.org/10.4028/www.scientific.net/amr.1140.75.

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Different tests to determine friction factors for cold forging processes are given in the literature. The double cup extrusion test, the ring compression test and the T-shape compression test are three of the common tests, which are compared in this investigation. From former investigations it is known that there is an influence of the work-hardening of the test sample on the friction factor, which is determined by the test. At this study, the influence of the work-hardening of the material on the three named tests is investigated by using a wire drawing process. In addition, the drawn wire from the originally thermo mechanical rolled wire is also annealed to have a second material state without any work-hardening. The used material and its numerical modelling as well as the analyzed tribological conditions of the real specimens are described. Afterwards the three test setups are explained for the numerical as well as for the real experiments. In the end, the influence of the drawing respectively the work-hardening for the three tests is presented and discussed.

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Kunz, Holger, Christian Löchte, Franz Dietrich, Annika Raatz, Fabian Fischer, Klaus Dröder, and Klaus Dilger. "Novel form-flexible handling and joining tool for automated preforming." Science and Engineering of Composite Materials 22, no. 2 (March 1, 2015): 199–213. http://dx.doi.org/10.1515/secm-2013-0326.

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AbstractThe production rates of carbon fiber reinforced plastic (CFRP) parts are rising constantly which in turn drives research to bring a higher level of automation to the manufacturing processes of CFRP. Resin transfer molding (RTM), which is seen as a production method for high volumes, has been accelerated to a high degree. However, complex net-shape preforms are necessary for this process, which are widely manually manufactured. To face these challenges a new concept for the manufacturing of carbon fiber preforms with a form-flexible gripping, draping and joining end-effector is presented and discussed. Furthermore, this paper investigates the application of this concept, describes the initial build-up of a demonstrator, focusing on material selection and heating technology, and discusses test results with the prototype. This prototype already validates the feasibility of the proposed concept on the basis of a generic preform geometry. After a summary, this paper discusses future in-depth research concerning the concept and its application in more complex geometries.

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