scholarly journals Shape Prediction of the Sheet in Continuous Roll Forming Based on the Analysis of Exit Velocity

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5178
Author(s):  
Jia-Xin Gao ◽  
Qing-Min Chen ◽  
Li-Rong Sun ◽  
Zhong-Yi Cai
Keyword(s):  
New Technology ◽  
Three Dimensional ◽  
Sheet Thickness ◽  
Roll Forming ◽  
Curvature Radius ◽  
Continuous Forming ◽  
Exit Velocity ◽  
Shape Prediction ◽  
Sheet Width ◽  
Predicted Values

Continuous roll forming (CRF) is a new technology that combines continuous forming and multi-point forming to produce three-dimensional (3D) curved surfaces. Compared with other methods, the equipment of CRF is very simple, including only a pair of bendable work rolls and the corresponding shape adjustment and support assembly. By controlling the bending shapes of the upper and lower rolls and the size of the roll gap during forming, double curvature surfaces with different shapes can be produced. In this paper, a simplified expression of the exit velocity of the sheet is provided, and the formulas for the calculation of the longitudinal curvature radius are further derived. The reason for the discrepancy between the actual and predicted values of the longitudinal radius is deeply discussed from the perspective of the distribution of the exit velocity. By using the response surface methodology, the effects of the maximum compression ratio, the sheet width, the sheet thickness, and the transverse curvature radius on the longitudinal curvature radius are analyzed. Meanwhile, the correction coefficients of the predicted formulas for the positive and negative Gaussian curvature surfaces are obtained as 1.138 and 0.905, respectively. The validity and practicability of the modified formulas are verified by numerical simulations and forming experiments.

Numerical Investigation of Continuous Roll Forming for Three-Dimensional Surface Parts

2013 ◽  
Vol 849 ◽  
pp. 287-290
Author(s):  
Mi Wang ◽  
Zhong Yi Cai ◽  
Zhou Sui ◽  
Ming Zhe Li
Keyword(s):  
New Technology ◽  
Three Dimensional ◽  
Simplified Model ◽  
Roll Forming ◽  
Middle Region ◽  
Forming Process ◽  
Shaped Part ◽  
Roll Gap ◽  
Roll Forming Process ◽  
Dimensional Surface

Continuous roll forming is a new technology for manufacturing three-dimensional surface parts. Extensive numerical simulations of continuous roll forming process were carried out. The influence of the middle curve and the magnitude of the roll gap on the longitudinal curvature of formed parts is investigated. Wrinkling is one of the most important defects for the formed parts in continuous roll forming process. A simplified model was established for analyzing the wrinkling of saddle-shaped part and torus-shaped part. The simulated results show that the wrinkling of saddle-shaped part is located at the edges, and the wrinkling of torus-shaped part emerges in the vicinity of middle region.

scholarly journals Edge behaviour in the glass sheet redraw process

2015 ◽  
Vol 785 ◽  
pp. 248-269 ◽  
Author(s):  
D. O’Kiely ◽  
C. J. W. Breward ◽  
I. M. Griffiths ◽  
P. D. Howell ◽  
U. Lange
Keyword(s):  
Numerical Solutions ◽  
Three Dimensional ◽  
Sheet Thickness ◽  
Glass Block ◽  
Final Thickness ◽  
Thin Glass ◽  
Boundary Layer Problem ◽  
Sheet Width ◽  
Good Agreement ◽  
Layer Problem

Thin glass sheets may be manufactured using a two-part process in which a sheet is first cast and then subsequently reheated and drawn to a required thickness. The latter redrawing process typically results in a sheet with non-uniform thickness and with smaller width than the cast glass block. Experiments suggest that the loss of width can be minimized and the non-uniformities can be essentially confined to thickening at the sheet edges if the heater zone through which the glass is drawn is made very short. We present a three-dimensional mathematical model for the redraw process and consider the limits in which (i) the heater zone is short compared with the sheet width, and (ii) the sheet thickness is small compared with both of these length scales. We show that, in the majority of the sheet, the properties vary only in the direction of drawing and the sheet motion is one-dimensional, with two-dimensional behaviour and the corresponding thick edges confined to boundary layers at the sheet extremities. We present numerical solutions to this boundary-layer problem and demonstrate good agreement with experiment, as well as with numerical solutions to the full three-dimensional problem. We show that the final thickness at the sheet edge scales with the inverse square root of the draw ratio, and explore the effect of tapering of the ends to identify a shape for the initial preform that results in a uniform rectangular final product.

scholarly journals Prediction of Longitudinal Curvature Radius of 3D Surface Based on Quadratic Relationship between Strain and Coordinates in Continuous Roll Forming

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1249
Author(s):  
Jiaxin Gao ◽  
Dongye He ◽  
Lirong Sun ◽  
Xi Zhang ◽  
Zhongyi Cai
Keyword(s):  
Convex Surface ◽  
Design Method ◽  
Three Dimensional ◽  
Roll Forming ◽  
Curvature Radius ◽  
Forming Process ◽  
3D Surface ◽  
Quadratic Relationship ◽  
Relative Errors ◽  
Roll Gap

Continuous roll forming (CRF) is a new method for the rapid forming of three-dimensional (3D) surfaces developed in recent years, and the significant advantage of CRF compared with traditional die forming is that the longitudinal dimension of the sheet metal is not limited. By controlling the curvature radius and gap shape of upper and lower bending rolls, three-dimensional parts with different shapes and sizes can be precisely formed. When the elastic deformation is ignored during the forming process, the transversal curvature radius of the three-dimensional surface is consistent with the radius of the roll gap centerline. Therefore, the calculation of longitudinal curvature radius is the key to improve the accuracy of the 3D surface in CRF. In this paper, the basic principle of CRF is described. The modified formulas for calculating the longitudinal curvature radius of convex and saddle surfaces based on the quadratic relationship between the strain and coordinates are deduced in detail, and the corresponding design method of the roll gap is derived. Furthermore, the mathematical equations of convex and saddle surfaces are given. Through numerical simulation and theoretical analysis, it is found that the relative errors of the longitudinal centerline radius are reduced from 13.67% before modification to 4.35% after modification for a convex surface and 6.81% to 0.41% for a saddle surface when the transversal curvature radius is 800 mm and the compression ratio is 5%. The experimental and measured results indicate that the shapes of formed parts are more consistent with the target parts after modification, which further proves the applicability of the modified formulas.

Elongation Rule of the Longitudinal Fiber of the Continuous Roll Forming Part

2018 ◽  
Vol 921 ◽  
pp. 184-188
Author(s):  
Yue Li ◽  
Shu Chen Yang ◽  
Mi Wang ◽  
Guo Long Lu
Keyword(s):  
Sheet Metal ◽  
Low Cost ◽  
Three Dimensional ◽  
Roll Forming ◽  
Longitudinal Deformation ◽  
Forming Process ◽  
Continuous Forming ◽  
High Efficient ◽  
Flexible Roll ◽  
Longitudinal Fiber

Continuous roll forming is a novel technique for low-cost, high-efficient manufacturing of three-dimensional surface part. Comparing with conventional continuous forming (using at least three rolls), continuous roll forming employs an upper and a lower flexible rolls to shape the sheet metal. The desired forming shape can be obtained by controlling the profile of the flexible roll and the gap between upper and lower flexible rolls. Modeling and simulation of the continuous roll forming process based on finite element analyses is established to investigate the elongation rule of the longitudinal fiber of the continuous roll forming part. The length of the longitudinal fiber at different positions across the thickness direction is discussed, and the mechanism of the longitudinal deformation is clarified. The following conclusions are obtained. When the flexible roll profile and the roll gap distribution meet certain conditions and make length of the longitudinal fiber linearly distributed, the longitudinal deformation of the sheet metal can be generated.

Towards Predicting Relative Belt Edge Endurance With the Finite Element Method

1990 ◽  
Vol 18 (4) ◽  
pp. 216-235 ◽  
Author(s):  
J. De Eskinazi ◽  
K. Ishihara ◽  
H. Volk ◽  
T. C. Warholic
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Shear Deformations ◽  
Element Analysis ◽  
Vertical Loading ◽  
Predicted Values ◽  
Element Method

Abstract The paper describes the intention of the authors to determine whether it is possible to predict relative belt edge endurance for radial passenger car tires using the finite element method. Three groups of tires with different belt edge configurations were tested on a fleet test in an attempt to validate predictions from the finite element results. A two-dimensional, axisymmetric finite element analysis was first used to determine if the results from such an analysis, with emphasis on the shear deformations between the belts, could be used to predict a relative ranking for belt edge endurance. It is shown that such an analysis can lead to erroneous conclusions. A three-dimensional analysis in which tires are modeled under free rotation and static vertical loading was performed next. This approach resulted in an improvement in the quality of the correlations. The differences in the predicted values of various stress analysis parameters for the three belt edge configurations are studied and their implication on predicting belt edge endurance is discussed.

Clinical Value of Computer-Assisted Taylor Three-dimensional External Fixation in the Treatment of Tibiofibular Fracture (Preprint)

2020 ◽  
Author(s):  
Hongfeng Sheng ◽  
Weixing Xu ◽  
Bin Xu ◽  
Hongpu Song ◽  
Di Lu ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Internal Fixation ◽  
External Fixation ◽  
External Fixator ◽  
Theoretical Basis ◽  
New Technology ◽  
Three Dimensional ◽  
Computer Assisted ◽  
Clinical Value

UNSTRUCTURED The retrospective study of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures provides a theoretical basis for the application of this technology. The paper collected 28 patients with tibiofibular fractures from the Department of Orthopaedics in our hospital from March 2015 to June 2018. After the treatment, the follow-up evaluation of Taylor's three-dimensional external fixator for the treatment of tibiofibular fractures and concurrency the incidence of the disease, as well as the efficacy and occurrence of the internal fixation of the treatment of tibial fractures in our hospital. The results showed that Taylor's three-dimensional external fixator was superior to orthopaedics in the treatment of tibiofibular fractures in terms of efficacy and complications. To this end, the thesis research can be concluded as follows: Taylor three-dimensional external fixation in the treatment of tibiofibular fractures is more effective, and the incidence of occurrence is low, is a new technology for the treatment of tibiofibular fractures, it is worthy of clinical promotion.

scholarly journals 3D Reconstruction of Cultural Heritage Sites as an Educational Approach. The Sanctuary of Delphi

2021 ◽  
Vol 11 (8) ◽  
pp. 3635
Author(s):  
Ioannis Liritzis ◽  
Pantelis Volonakis ◽  
Spyros Vosinakis
Keyword(s):  
University Students ◽  
3D Reconstruction ◽  
Cultural Heritage ◽  
New Technology ◽  
Three Dimensional ◽  
Computer Gaming ◽  
Educational Approach ◽  
Heritage Sites ◽  
3D Environment ◽  
Almost All

In the field of cultural heritage, three-dimensional (3D) reconstruction of monuments is a usual activity for many professionals. The aim in this paper focuses on the new technology educational application combining science, history, and archaeology. Being involved in almost all stages of implementation steps and assessing the level of participation, university students use tools of computer gaming platform and participate in ways of planning the virtual environment which improves their education through e-Learning. The virtual 3D environment is made with different imaging methods (helium-filled balloon, Structure for motion, 3D repository models) and a developmental plan has been designed for use in many future applications. Digital tools were used with 3D reconstructed buildings from the museum archive to Unity 3D for the design. The pilot study of Information Technology work has been employed to introduce cultural heritage and archaeology to university syllabuses. It included students with a questionnaire which has been evaluated accordingly. As a result, the university students were inspired to immerse themselves into the virtual lab, aiming to increasing the level of interaction. The results show a satisfactory learning outcome by an easy to use and real 3D environment, a step forward to fill in needs of contemporary online sustainable learning demands.

scholarly journals 3DP Printing of Oral Solid Formulations: A Systematic Review

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 358 ◽  
Author(s):  
Chiara R. M. Brambilla ◽  
Ogochukwu Lilian Okafor-Muo ◽  
Hany Hassanin ◽  
Amr ElShaer
Keyword(s):  
Systematic Review ◽  
Data Extraction ◽  
New Technology ◽  
Three Dimensional ◽  
Extraction Process ◽  
Carcinogenic Risk ◽  
Drug Dissolution ◽  
Dissolution Profile ◽  
Disintegration Time ◽  
Advantages And Disadvantages

Three-dimensional (3D) printing is a recent technology, which gives the possibility to manufacture personalised dosage forms and it has a broad range of applications. One of the most developed, it is the manufacture of oral solid dosage and the four 3DP techniques which have been more used for their manufacture are FDM, inkjet 3DP, SLA and SLS. This systematic review is carried out to statistically analyze the current 3DP techniques employed in manufacturing oral solid formulations and assess the recent trends of this new technology. The work has been organised into four steps, (1) screening of the articles, definition of the inclusion and exclusion criteria and classification of the articles in the two main groups (included/excluded); (2) quantification and characterisation of the included articles; (3) evaluation of the validity of data and data extraction process; (4) data analysis, discussion, and conclusion to define which technique offers the best properties to be applied in the manufacture of oral solid formulations. It has been observed that with SLS 3DP technique, all the characterisation tests required by the BP (drug content, drug dissolution profile, hardness, friability, disintegration time and uniformity of weight) have been performed in the majority of articles, except for the friability test. However, it is not possible to define which of the four 3DP techniques is the most suitable for the manufacture of oral solid formulations, because the selection is affected by different parameters, such as the type of formulation, the physical-mechanical properties to achieve. Moreover, each technique has its specific advantages and disadvantages, such as for FDM the biggest challenge is the degradation of the drug, due to high printing temperature process or for SLA is the toxicity of the carcinogenic risk of the photopolymerising material.

scholarly journals Effect of Structural Differences on the Mechanical Properties of 3D Integrated Woven Spacer Sandwich Composites

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4284
Author(s):  
Lvtao Zhu ◽  
Mahfuz Bin Rahman ◽  
Zhenxing Wang
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Three Dimensional ◽  
Sheet Thickness ◽  
Physical And Mechanical Properties ◽  
Sandwich Composites ◽  
Computed Tomography Images ◽  
And Performance ◽  
Industrial Textiles ◽  
Load Conditions

Three-dimensional integrated woven spacer sandwich composites have been widely used as industrial textiles for many applications due to their superior physical and mechanical properties. In this research, 3D integrated woven spacer sandwich composites of five different specifications were produced, and the mechanical properties and performance were investigated under different load conditions. XR-CT (X-ray computed tomography) images were employed to visualize the microstructural details and analyze the fracture morphologies of fractured specimens under different load conditions. In addition, the effects of warp and weft direction, face sheet thickness, and core pile height on the mechanical properties and performance of the composite materials were analyzed. This investigation can provide significant guidance to help determine the structure of composite materials and design new products according to the required mechanical properties.

Preoperative Use of CT Angiography in Infants With Coarctation of the Aorta

2017 ◽  
Vol 8 (2) ◽  
pp. 196-202 ◽  
Author(s):  
Kirsten Rose-Felker ◽  
Joshua D. Robinson ◽  
Carl L. Backer ◽  
Cynthia K. Rigsby ◽  
Osama M. Eltayeb ◽  
...  
Keyword(s):  
Radiation Dose ◽  
Surgical Approach ◽  
New Technology ◽  
Three Dimensional ◽  
Coarctation Of The Aorta ◽  
Computed Tomographic Angiography ◽  
Great Vessel ◽  
Z Score ◽  
Computed Tomographic ◽  
Tomographic Angiography

Background: Computed tomographic angiography (CTA) and echocardiography (echo) are used preoperatively in coarctation of the aorta to define arch hypoplasia and great vessel branching. We sought to determine differences in quantitative measurements, as well as surgical utility, between modalities. Methods: Infants (less than six months) with both CTA and echo prior to coarctation repair from 2004 to 2013 were included. Measurements were compared and correlated with surgical approach. Three surgeons reviewed de-identified images to predict approach and characterize utility. Computed tomographic angiography radiation dose was calculated. Results: Thirty-three patients were included. No differences existed in arch measurements between echo and CTA ( z-score: −2.59 vs −2.43; P = .47). No differences between modalities were seen for thoracotomy ( z-score: −2.48 [echo] vs −2.31 [CTA]; P = .48) or sternotomy ( z-score: −3.13 [echo] vs −3.08 [CTA]; P = .84). Computed tomographic angiography delineated great vessel branching pattern in two patients with equivocal echo findings ( P = .60). Surgeons rated CTA as far more useful than echo in understanding arch hypoplasia and great vessel branching in cases where CTA was done to resolve anatomical questions that remain after echo evaluation. Two of three surgeons were more likely to choose the surgical approach taken based on CTA (surgeon A, P = .02; surgeon B, P = .01). Radiation dose averaged 2.5 (1.6) mSv and trended down from 2.9 mSv (1.8 mSv; n = 20) to 1.6 mSv (0.5 mSv; n = 7) ( P = .06) with new technology. Conclusion: Although CTA and echo measurements of the aorta do not differ, CTA better delineates branching and surgeons strongly prefer it for three-dimensional arch anatomy. We recommend CTA for patients with anomalous arch branching patterns, diffuse or complex hypoplasia, or unusual arch morphology not fully elucidated by echo.

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