Distortion of Rectangular Tubes in Stretch Bending

2002 ◽  
Vol 124 (4) ◽  
pp. 886-890 ◽  
Author(s):  
Hong Zhu ◽  
Kim A. Stelson
Keyword(s):  
Internal Pressure ◽  
Energy Minimization ◽  
Stretch Bending ◽  
Rectangular Tube ◽  
Side Walls ◽  
Thin Walled ◽  
Analytical Expressions ◽  
Rectangular Tubes ◽  
Good Agreement

During stretch bending, considerable in-plane distortion occurs when a thin-walled rectangular tube is plastically bent. To minimize the distortion, fixed walls are used to limit the bulging of the side walls of the tube. Internal pressure can also be used to compensate for distortion. In this paper, analytical expressions for the amount of distortion and the needed internal pressure are derived based on energy minimization. The theory is in fairly good agreement with experiments.

Modeling and Closed-Loop Control of Stretch Bending of Aluminum Rectangular Tubes

2003 ◽  
Vol 125 (1) ◽  
pp. 113-119 ◽  
Author(s):  
Hong Zhu ◽  
Kim A. Stelson
Keyword(s):  
Experimental Data ◽  
Real Time ◽  
Control Algorithm ◽  
Closed Loop ◽  
Strain History ◽  
Closed Loop Control ◽  
Loop Control ◽  
Stretch Bending ◽  
Rectangular Tube ◽  
Rectangular Tubes

During stretch bending, considerable springback will occur after a tube has been plastically bent. To predict the springback, a simplified two-flange model for stretch bending of a rectangular tube has been developed in which the strain history has been considered. A comparison has been made between the springback predicted by this model and experimental data, which shows rough agreement. Based on this model, a real time closed-loop control algorithm is developed.

Distortion of U-Channel Sections in Plastic Bending

1999 ◽  
Vol 121 (2) ◽  
pp. 208-213 ◽  
Author(s):  
K. A. Stelson ◽  
A. Kramer
Keyword(s):  
Material Properties ◽  
Energy Minimization ◽  
Plastic Bending ◽  
Circular Arc ◽  
Channel Section ◽  
Analytical Expression ◽  
Flat Base ◽  
Thin Walled ◽  
Good Agreement

When a thin-walled U-channel section is plastically bent, considerable in-plane distortion occurs. The initially flat base of the U is deformed into a circular arc. The sides remain perpendicular to the base so that an angle between the sides develops. In this paper, an analytical expression for the amount of distortion is derived based on energy minimization. The expression is purely geometrical indicating that distortion should not depend on material properties. The theory is compared with fourpoint bending experiments of thin-walled channels, with good agreement found.

Experimental and Numerical Analysis of Ratcheting Behavior of SS 316 L Thin-Walled Pipes Subjected to Cyclic Internal Pressure

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
R. Karimi ◽  
M. Shariati
Keyword(s):  
Internal Pressure ◽  
Kinematic Hardening ◽  
Pressure Amplitude ◽  
Steel Pipes ◽  
Ratcheting Strain ◽  
Mean Pressure ◽  
Thin Walled Pipe ◽  
Thin Walled ◽  
Hoop Direction ◽  
Good Agreement

Abstract This paper investigates ratcheting behavior of SS316 L thin-walled steel pipes subjected to cyclic internal pressure experimentally and numerically. Numerical simulations were performed using abaqus software, and nonlinear isotropic/kinematic hardening model. According to experimentations, it was found that the ratcheting strain is only significant in the hoop direction of a pipe subjected to cyclic internal pressure. The effects of pressure amplitude and mean pressure on ratcheting behavior of thin walled pipe in hoop direction were studied experimentally and numerically, and it was observed that increasing the pressure amplitude and mean pressure increased the percentage of ratcheting strain. Another important point about the results was the dominance of pressure amplitude on mean pressure. The results showed that at higher mean pressures the effect of pressure amplitude on increasing the percentage of ratcheting strain was greater. Finally, the experimental and numerical results were in good agreement.

A New Method to Accurately Describe Cross-Section Distortion in Rotary Draw Bending Process of Thin-Walled Rectangular Tube

2011 ◽  
Vol 117-119 ◽  
pp. 1839-1842
Author(s):  
Gang Yao Zhao ◽  
Rang Yang Zhang ◽  
Yu Li Liu ◽  
Zheng Hua Guo ◽  
Ping Fang
Keyword(s):  
Current Model ◽  
New Method ◽  
Rotary Draw Bending ◽  
Cross Sectional ◽  
Bending Process ◽  
Rectangular Tube ◽  
Side Walls ◽  
Thin Walled ◽  
The Cross ◽  
Draw Bending

To obtain the cross-sectional distortion of thin-walled rectangular tube in rotary draw bending process accurately, a new method to exactly describe the distortion has been proposed. The coupling between the convex of the tube side walls and the concave of the tube flanges is considered in the distortion modeling. Combined with the experiments, the cross-sectional distortion obtained using the new distortion model are compared with the previous ones obtained without considering the convex based on numerical simulations. The results show that cross-sectional distortion obtained by current model is closer to reality than the previous ones. The distortion by current model is more safety in the practical bending process.

Effect of design parameters on stresses occurring at the tooth root in a spur gear pressed on a shaft

2021 ◽  
pp. 095440892199529
Author(s):  
Fatih Güven
Keyword(s):  
Internal Pressure ◽  
Tangential Stress ◽  
Spur Gear ◽  
Design Parameters ◽  
Interference Fit ◽  
Gear Design ◽  
Compact Design ◽  
Fit Tolerance ◽  
Moderate Stress ◽  
Good Agreement

Gears are commonly used in transmission systems to adjust velocity and torque. An integral gear or an interference fit could be used in a gearbox. Integral gears are mostly preferred as driving gear for a compact design to reduce the weight of the system. Interference fit makes the replacement of damaged gear possible and re-use of the shaft compared to the integral shaft. However, internal pressure occurs between mating surfaces of the components mated. This internal pressure affects the stress distribution at the root and bottom land of the gear. In this case, gear parameters should be re-considered to assure gear life while reducing the size of the gear. In this study, interference fitted gear-shaft assembly was examined numerically. The effects of rim thickness, profile shifting, module and fit tolerance on bending stress occurring at the root of the gear were investigated to optimize gear design parameters. Finite element models were in good agreement with analytical solutions. Results showed that the rim thickness of the gear is the main parameter in terms of tangential stress occurring at the bottom land of the gear. Positive profile shifting reduces the tangential stress while the pitch diameter of the gear remains constant. Also, lower tolerance class could be selected to moderate stress for small rim thickness.

Elastic-plastic response of a sandwich cylinder subjected to internal pressure

1971 ◽  
Vol 6 (4) ◽  
pp. 273-278 ◽  
Author(s):  
H F Muensterer ◽  
F P J Rimrott
Keyword(s):  
Mild Steel ◽  
Internal Pressure ◽  
Plastic Flow ◽  
Plastic Response ◽  
Concentric Cylinders ◽  
Initial Stage ◽  
Sandwich Type ◽  
Plastic Zones ◽  
Thin Walled ◽  
Von Mises

The propagation of plastic zones in a thin-walled sandwich-type cylinder has been analysed theoretically. Boundary conditions are clamped-clamped at both ends, i.e. no rotation is permitted. The material was assumed to behave isotropically and to obey the yieid criterion of Huber-Hencky-von Mises. Deformation was computed on the assumption that the vector of rate of strain was normal to the plastic-interaction curve. The predicted result was verified experimentally. Four specimens were built by lamination of a hexcell core between two concentric cylinders. In the two mild-steel specimens, the initial stage of plastic flow conformed well with the prediction. This proved that plastic flow is not initiated at the mid-position between the end constraints. In two aluminium specimens, this phenomenon of incipient plastic flow could not be observed owing to the absence of a pronounced yield point. The overall agreement was, however, satisfactory.

Torsional Stiffness of a Thin-Walled Beam Braced by Pinned or Rigidly Fixed Transverse Diaphragms

1973 ◽  
Vol 15 (5) ◽  
pp. 351-356
Author(s):  
T. Harrison ◽  
J. M. Siddall
Keyword(s):  
Experimental Evidence ◽  
Theoretical Work ◽  
Torsional Stiffness ◽  
Cross Sectional ◽  
Cross Sectional Profile ◽  
Thin Walled ◽  
Sectional Profile ◽  
Good Agreement

The torsional stiffness of a thin-walled beam of open cross-sectional profile braced by evenly spaced transverse diaphragms is studied. Diaphragms rigidly fixed or attached by frictionless pins are treated and it is seen that, in either case, the only effect is to modify the St Venant torsional constant for the thin-walled beam. The theoretical work is supported by experimental evidence from two braced perspex channels which simulate the two assumed methods of attaching the diaphragms. Good agreement is demonstrated.

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