Elastic and Elastic-Plastic Buckling of Internally Pressurized 2:1 Ellipsoidal Shells

1978 ◽  
Vol 100 (4) ◽  
pp. 335-343 ◽  
Author(s):  
G. D. Galletly
Keyword(s):  
Strain Hardening ◽  
Linear Strain ◽  
Plastic Buckling ◽  
Elastic Plastic

Elastic and elastic-plastic buckling pressures for internally-pressurized 2:1 ellipsoidal shells with diameter-thickness ratios in the range 750 < D/t < 1500 are given in the paper. The effects of σyp, E and linear strain hardening on the buckling pressures were investigated and both flow and deformation theories utilized. Some experimental/theoretical correlations are also given. The elastic pcr’s differ from some which have been published recently and the elastic-plastic pcr’s are believed to be new. For steel shells, flow and deformation theories sometimes gave contradictory buckling predictions but this was not the case with the aluminum shells which were investigated.

ELASTO-PLASTIC BUCKLING OF PRESTRESSED ARCHES

2002 ◽  
Vol 02 (03) ◽  
pp. 295-313
Author(s):  
AMIR MIRMIRAN ◽  
AMDE M. AMDE ◽  
ZEFANG XU
Keyword(s):  
Yield Strength ◽  
Strain Hardening ◽  
Beam Element ◽  
Fabrication Technique ◽  
Linear Strain ◽  
Plastic Buckling ◽  
Buckling Mode ◽  
Hardening Material ◽  
Straight Beam ◽  
Support Conditions

Intentional buckling as a fabrication technique for arch frameworks results in prestrains at every section of the arch, which in turn affect its strength and stability. A nonlinear corotational straight beam element with elastic, linear strain hardening material has been developed to study the elasto-plastic buckling of prestressed arches. The study indicates that for prestressed arches there is an interdependence between the slenderness and steepness ratios of the arch with the ratio of prestresses to the yield strength of the material, all of which control the magnitude and shape of buckling mode. While steeper arches are generally more stable in their elastic range, the effect of steepness ratio is reduced as the prestress exceeds 55% of the yield strength. Effects of loading and support conditions have also been considered. Although fixed supports result in more stable arches, their effectiveness depends on the steepness ratio and the level of prestresses. Finally, the effect of strain hardening on the plastic buckling of the arch is more pronounced for lower values of the plastic tangent modulus.

scholarly journals Numerical solution of thermal elastic-plastic functionally graded thin rotating disk with exponentially variable thickness and variable density

2019 ◽  
Vol 23 (1) ◽  
pp. 125-136 ◽  
Author(s):  
Sanjeev Sharma ◽  
Sanehlata Yadav
Keyword(s):  
Strain Hardening ◽  
Functionally Graded Material ◽  
Circumferential Stress ◽  
Rotating Disk ◽  
Functionally Graded ◽  
Linear Strain ◽  
Annular Disk ◽  
Elastic Plastic ◽  
Non Linear ◽  
Graded Material

Thermal elastic-plastic stresses and strains have been obtained for rotating annular disk by using finite difference method with Von-Mises? yield criterion and non-linear strain hardening measure. The compressibility of the disk is assumed to be varying in the radial direction. From the numerical results, we can conclude that thermal rotating disk made of functionally graded material whose thickness decreases exponentially and density increases exponentially with non-linear strain hardening measure (m = 0.2) is on the safe side of the design as compared to disk made of homogenous material. This is because of the reason that circumferential stress is less for functionally graded disk as compared to homogenous disk. Also, plastic strains are high for functionally graded disk as compared to homogenous disk. It means that disk made of functionally graded material reduces the possibility of fracture at the bore as compared to the disk made of homogeneous material which leads to the idea of stress saving.

Elastic-Plastic Buckling of Internally Pressurized Thin Torispherical Shells

1979 ◽  
Vol 101 (3) ◽  
pp. 216-225 ◽  
Author(s):  
G. D. Galletly ◽  
S. K. Radhamohan
Keyword(s):  
Strain Hardening ◽  
Material Properties ◽  
Parametric Study ◽  
Geometric Parameters ◽  
Plastic Buckling ◽  
Elastic Plastic ◽  
Hardening Coefficient ◽  
Approximate Formulas

The elastic-plastic buckling of internally pressurized torispherical shells is considered in some detail in the paper. The effects of geometric parameters (r/D, RS/D and D/t) and material properties (σyp, E and the strain-hardening coefficient) on the elastic-plastic internal buckling pressures were investigated using the BOSOR 5 program. Based on the results of the parametric study, approximate formulas for predicting the elastic-plastic internal buckling pressures are suggested. These should be useful to designers.

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