scholarly journals Fatigue Strength of Thin-Walled Rectangular Elements in the State of Post-Critical Deformation

2019 ◽  
Vol 13 (2) ◽  
pp. 84-91
Author(s):  
Przemysław Mazurek
2012 ◽  
Vol 85 (4) ◽  
pp. 495-512 ◽  
Author(s):  
Marina Fernando ◽  
Wong Hon Fei ◽  
Colin Hull

ABSTRACT Curing rubber is a complex process that involves the insertion of cross-links to convert the rubber into a useful functional material. The estimation of the cure time needed for product manufacture of small or thin walled products is often arrived at by means of a rheometer trace. Although this has been recognized as adequate for thin walled products, the production of large rubber articles requires a more rigorous analysis of cure kinetics for an essentially non-isothermal process. Often finite element analysis is used to generate non-isothermal temperature histories in a thick component, and then an appropriate cure kinetic equation is solved to predict the state of cure. In addition to generating the capability for cure time prediction, there is a need in the industry to minimize cycle time, improving productivity and therefore costs involved in product manufacture. For large products, the viability of the use of extrusion molding, where the rubber is extruded into a heated mold at the same temperature as the mold, has been demonstrated in previous reported work in this laboratory. The present work explores, via simulation, the feasibility of using extrusion molding as a manufacturing method for large components. The cure simulation module of Autodesk Moldflow has been used to compare the state of cure of a laminated bearing manufactured by conventional compression molding and extrusion molding. Previous experimental data on the temperature histories of a large laminated bearing manufactured using compression molding are compared with simulation data. Simulation data are then presented on manufacturing the bearing using extrusion molding. The aim is to demonstrate the usefulness of extrusion molding for very large components and to illustrate the advantages of using simulation codes to assist in shortening the cycle time in product manufacture.


ce/papers ◽  
2021 ◽  
Vol 4 (2-4) ◽  
pp. 505-510
Author(s):  
Thorben Geers ◽  
Benno Hoffmeister ◽  
Christoph Heinemeyer

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987772
Author(s):  
Xue Wen ◽  
Jian-ping Tan ◽  
Su-qi Liu ◽  
Xin-he Li

In order to perceive the state of the process of reverse thinning spinning of the ultra-thin wall tube, a monitoring method based on drum shape is proposed. The method uses the non-uniform rational basis spline curve fitting method based on the moving least squares method to reconstruct the outer contour data of the spinning zone collected by the line laser displacement sensor and extracts the outer contour curve of the drum zone according to the spinning characteristics. Then, the dynamic time warping algorithm is used to analyze the similarity between the current and previous drum curves in order to judge whether the current spinning state is abrupt or not. At the same time, the current spinning state is judged by combining the curvature comb of the drum curve, the number of convex areas of the drum curve, the drum ratio, and the drum change trend. Finally, the drum shape detection and the spinning condition monitoring experiments are carried out. The experimental results show that this method can obtain the outer contour shape of the drum section at one time, and the accuracy is 0.05 mm with respect to the measured value of the three coordinates. The method can realize the visual monitoring of the abrupt change of the spinning process by judging the similarity of the drum curve at the adjacent time under different spinning states. In the state of instability, the curvature comb of the drum curve is discontinuous, the curve is G0 continuous, the drum ratio exceeds the critical drum ratio 2.0, and there is more than one convex region, which realizes the monitoring of spinning state more accurately. The experimental results verify the correctness of the proposed method and prove that the method can be used as a new method to judge the stability of the ultra-thin-walled cylinder spinning process.


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