General Instability of Swedge-Stiffened Circular Cylinders Under Uniform External Pressure

1993 ◽  
Vol 37 (01) ◽  
pp. 77-85
Author(s):  
C. T. F. Ross ◽  
A. Palmer
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Finite Element ◽  
Theoretical Analysis ◽  
External Pressure ◽  
Reduction Factor ◽  
Circular Cylinders ◽  
The Finite Element Method ◽  
Uniform External Pressure ◽  
Thinness Ratio

A theoretical and experimental investigation into the general instability of nine swedge-stiffened circularcylinders under uniform external pressure is described. The investigation found that most of the vesselssuffered plastic general instability, and that initial out-of-roundness played a significant role in the magnitude of the elastic knockdown. The theoretical analysis was based on the finite-element method, and a thinness ratio is proposed from which one can determine a plastic reduction factor when more experimental results are available.

scholarly journals Study on calculation method of stability for embedded penstocks with stiffener ring under external pressure

2021 ◽  
Vol 272 ◽  
pp. 02010
Author(s):  
Bifei Wang ◽  
Yuewei Li ◽  
Wenqiang Qi ◽  
Qihang Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
External Pressure ◽  
Reduction Factor ◽  
Surrounding Rock ◽  
The Finite Element Method ◽  
Initial Defect ◽  
Critical External Pressure ◽  
Element Method

A three-dimensional FEM(finite element model)is established, including penstocks with initial defect (ovality), backfill concrete, drainage cushion and surrounding rock. The nonlinear static calculation of the model is carried out. The stability of penstocks with backfill concrete, drainage cushion and surrounding rock under external pressure is studied. The sensibility of the embedded penstocks to initial defect, initial gap and elastic modulus of drainage cushion is analyzed. The results of finite element method, Jacobsen method and strength formula in SL281 are compared and analyzed. The results indicate that the FEM of penstocks, backfill concrete and surrounding rock with initial defects is easy to converge by nonlinear calculation; the ovality and gap have little influence on the critical external pressure of the embedded penstocks with stiffener ring, while the drainage cushion has a certain influence on the critical external pressure; the critical external pressure calculated by SL281 is low and safe; compared with Jacobsen method, the critical external pressure of the finite element method is increased by about 14%; for the embedded penstocks with drainage cushion, the finite element method can be used to calculate the influence of the drainage cushion on the critical external pressure, and the appropriate reduction factor can be obtained, and then the Jacobsen result can be modified by the reduction factor.

Design of Dome Ends to Withstand Uniform External Pressure

1987 ◽  
Vol 31 (02) ◽  
pp. 139-143
Author(s):  
C. T. F. Ross
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
External Pressure ◽  
Efficient Design ◽  
The Finite Element Method ◽  
Qualitative Design ◽  
Uniform External Pressure ◽  
Element Method

A radical proposal is suggested for a more efficient design of dome ends to withstand uniform external pressure. A qualitative design of a cylinder/dome combination is considered, together with a stress investigation, using the finite-element method. These have shown that this design is feasible.

Research and Simulation on Drawing Force of the Tripod Type Universal Coupling

2012 ◽  
Vol 482-484 ◽  
pp. 792-795
Author(s):  
Ye Qiang Lu ◽  
Wen Feng Wei ◽  
Yi Long Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Theoretical Analysis ◽  
Cross Section ◽  
The Finite Element Method ◽  
Drawing Force ◽  
Simulation Results ◽  
Universal Coupling ◽  
Castigliano’S Theorem ◽  
Static Simulation

Analyzing the strain expression referring to Castigliano’s Theorem after analysis of the tripod type universal coupling under drawing force comes to the simplified mode of tripod type universal coupling. And with the help of simplified mode, it concludes that the minimum strain occurs when the radius of cross-section of the circlip equals to the depth of groove. After setting material attributes, boundary conditions, contacts of the tripod type universal coupling, and static simulation with the finite element method in SolidWorks, the strain of the universal couplings is carried out. Theoretical analysis and simulation results show that when the radius of cross-section of the coupling equals to the depth of groove, the strain is minimum.

The vibration of ring-stiffened prolate domes under external water pressure

2003 ◽  
Vol 217 (2) ◽  
pp. 173-185
Author(s):  
C T F Ross ◽  
A P F Little ◽  
L Chasapides ◽  
J Banks ◽  
D Attanasio
Keyword(s):  
Finite Element Method ◽  
Experimental Investigation ◽  
Finite Element ◽  
Water Pressure ◽  
The Finite Element Method ◽  
Resonant Frequencies ◽  
External Water Pressure ◽  
External Water ◽  
Theory And Experiment ◽  
Good Agreement

The paper presents a theoretical and an experimental investigation into the free vibration of three ring-stiffened prolate domes in air and under external water pressure. The theoretical investigation was via the finite element method where a solid fluid mesh was used to model the water surrounding each dome. Good agreement was found between theory and experiment. Both the theory and the experiment found that, as the external water pressure was increased, the resonant frequencies decreased.

Strength of Reinforced Concrete Chambers Under External Pressure

1975 ◽  
Vol 97 (4) ◽  
pp. 309-314 ◽  
Author(s):  
O. Buyukozturk ◽  
P. V. Marcal
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Special Reference ◽  
External Pressure ◽  
General Purpose ◽  
The Finite Element Method ◽  
Cylindrical Tank ◽  
Geometric Imperfection ◽  
Cylindrical Tanks

A study was made to establish the strength of concrete chambers subjected to external pressure with special reference to the reinforced concrete cylindrical tanks. The finite element method as implemented in a nonlinear general purpose program produced analytical results which agreed with the experiment. The study concluded that the cylindrical tank was weakened in buckling by 20 percent due to geometric imperfection, 10 percent due to creep and 6 percent due to reinforcements. The main failure mode of the shell was compression shear.

The vibration of ring-reinforced circular cylinders under external water pressure

1998 ◽  
Vol 212 (4) ◽  
pp. 299-306 ◽  
Author(s):  
C T F Ross ◽  
W D Richards
Keyword(s):  
Finite Element Method ◽  
Water Pressure ◽  
External Pressure ◽  
Circular Cylinders ◽  
The Finite Element Method ◽  
Similar Form ◽  
Surrounding Water ◽  
Resonant Frequencies ◽  
External Water Pressure ◽  
External Water

The paper reports on an experimental and a theoretical investigation into the vibration of three ring-stiffened circular cylinders under external water pressure. The theoretical analysis was via the finite element method, where both the structure and the surrounding water were modelled using finite elements. Comparison between experiment and theory was good, and showed that the resonant frequencies decreased with increasing external pressure. The results also showed that there was a possibility of a form of dynamic buckling, when the vibration eigenmodes became of similar form to the static buckling eigenmodes.

Vibration of Hemi-Ellipsoidal Axisymmetric Domes Submerged in Water

1986 ◽  
Vol 200 (6) ◽  
pp. 389-398 ◽  
Author(s):  
C T F Ross ◽  
T Johns
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Aspect Ratio ◽  
Theoretical Analysis ◽  
Shell Structure ◽  
The Finite Element Method ◽  
Axisymmetric Form ◽  
Different Types ◽  
Thin Walled ◽  
Theory And Experiment

Ten thin-walled domes, of hemi-ellipsoidal form, were vibrated in air and while partially and fully submerged in water. The domes varied in shape from oblate ones of aspect ratio (AR) 0.25 to prolate ones of aspect ratio 4. The fundamental modal patterns for the oblate domes tended to be of axisymmetric form, while the fundamental modal patterns of the hemispherical and prolate domes tended to be of asymmetric or lobar form. The theoretical analysis was carried out by the finite element method, where the motion of the shell structure was represented by three different types of element and the motion of the water was represented by a solid annular element. Comparison between theory and experiment was found to be good.

Study of the Torsional Effect of a Rectangular Quartz Disc

2011 ◽  
Vol 474-476 ◽  
pp. 2286-2289
Author(s):  
Chang Yin Gao ◽  
Wan Quan Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Field ◽  
Theoretical Analysis ◽  
Anisotropic Elasticity ◽  
Electromagnetic Theory ◽  
The Finite Element Method ◽  
Piezoelectric Body ◽  
Quartz Disc ◽  
Piezoelectric Wafers

The torsional effect of a rectangular piezoelectric quartz is studied in the article. Using the anisotropic elasticity and Maxwell electromagnetic theory, the stress field and electrostatic field is founded, and then by the Finite Element Method the distribution of the electric field in the piezoelectric body is obtained. Based on theoretical analysis of the bound charge distribution, the measuring electrodes are effectively disposed on the surfaces of the piezoelectric wafers. The theoretical and experimental results show that the measurement charge is linear with the torque. The research will provide the basis for the torque measuring technique.

Deformation and stability studies of thin-walled domes under uniform external pressure

1983 ◽  
Vol 18 (3) ◽  
pp. 167-172 ◽  
Author(s):  
C T F Ross ◽  
M D A Mackney
Keyword(s):  
Finite Element Method ◽  
External Pressure ◽  
Axisymmetric Deformation ◽  
Hydraulic Pressure ◽  
Elastic Instability ◽  
Stability Studies ◽  
The Finite Element Method ◽  
Uniform External Pressure ◽  
Stiffness Matrices ◽  
Thin Walled

Fifty hemiellipsoidal domes were cast in solid urethane plastic, with profiles which varied from oblate to prolate shapes. The domes were subjected to external hydraulic pressure in a test tank and tested to failure. All the domes appeared to fail through elastic instability, the oblate shapes failing axisymmetrically, and the prolate shapes failing asymmetrically in a lobar manner. The theoretical analysis was carried out via the finite element method, and stiffness matrices were developed for an axisymmetric element of constant meridional curvature. The element was capable of being applied to axisymmetric deformation or axisymmetric and asymmetric instability, and it was generated numerically.

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