Optimization and Antioptimization of Buckling Load for Composite Cylindrical Shells Under Uncertainties

AIAA Journal ◽  
2012 ◽  
Vol 50 (7) ◽  
pp. 1513-1524 ◽  
Author(s):  
Isaac Elishakoff ◽  
Benedikt Kriegesmann ◽  
Raimund Rolfes ◽  
Christian Hühne ◽  
Alexander Kling
Keyword(s):  
Cylindrical Shells ◽  
Buckling Load ◽  
Composite Cylindrical Shells

scholarly journals Buckling Test of Composite Cylindrical Shells with Large Radius Thickness Ratio

2021 ◽  
Vol 11 (2) ◽  
pp. 854
Author(s):  
Atsushi Takano ◽  
Ryuta Kitamura ◽  
Takuma Masai ◽  
Jingxuan Bao
Keyword(s):  
Cylindrical Shells ◽  
Design Criterion ◽  
Thickness Ratio ◽  
Buckling Load ◽  
Large Radius ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Buckling Test ◽  
Composite Cylinders ◽  
Composite Cylindrical Shells

A buckling test of composite cylindrical shells with a radius–thickness ratio (r/t) = 893 under axial compression was conducted to investigate the effects of the radius–thickness ratio (r/t). It is known that the buckling load of cylinders shows large differences and scatter between theory and experiment. The ratio of the experimental buckling load and theoretical buckling load is called the knockdown factor (KDF). Many investigations have been conducted to find the cause of the degradation and scatter in the KDF, but as yet, no cause has been found. In 1968, NASA’s buckling design criterion, NASA SP-8007, gave an empirical KDF curve that decreased with the increasing r/t (up to 2000) for metal cylinders. The same curve has been applied to composite cylinders. Recently, Takano derived a flat lower-bound KDF in terms of A- and B-basis values (99% and 90% probability with a 95% confidence level) through a statistical analysis of experimental buckling loads. The result, however, based on experimental results up to r/t = 500 and, thus, the dependency on a large range of r/t, is not clear. Thus, the authors focused on a larger range of r/t. Cylindrical shells made from carbon fiber-reinforced plastic (CFRP) were tested. The nominal radius, thickness, and length were r = 100.118 mm, t = 0.118 mm, and L = 200 mm and, thus, the r/t = 848 and length-to-radius ratio (L/r) = 2.0. Shape imperfections were also measured by using in-house laser displacement equipment. The buckling load was slightly affected by the r/t, but the reduction in the KDF was insignificant.

Buckling of the Composite Cracked Cylindrical Shells Subjected to Axial Load

2003 ◽  
Author(s):  
A. Vaziri ◽  
H. Nayeb-Hashemi ◽  
H. E. Estekanchi
Keyword(s):  
Crack Length ◽  
Cylindrical Shells ◽  
Critical Length ◽  
Pressure Vessels ◽  
Buckling Load ◽  
Mode Shapes ◽  
Buckling Mode ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Composite Cylindrical Shells

Cylindrical shells constitute the main structural components in pressure vessels and pipelines. Cylindrical shells made of fiber-reinforced composites are now being considered in the design of many components due to their high specific strength and stiffness. Buckling is one of the main failure considerations, when designing the cylindrical shells. The buckling behavior of the composite cylindrical shells can severely the compromised by introducing defect in the structure, due to high stress field generated around these defects. Defects could be generated during service due to cyclic loading or during manufacturing. A reliable operation of these structures require to understand the effects of these defects on the bucking of cylindrical shells. Finite Element Analyses are performed to study the buckling behaviour of composite cylindrical shells with and without a crack, under an axial compressive loading. The effects of the plies angle on the buckling loads and buckling mode shapes of the composite cylindrical shells are studied. Furthermore, the effects of the crack length and its orientation on the buckling loads of the composite cylindrical shells are investigated. The results indicate that the global buckling loads and mode shapes of the cracked composite shells are not significantly sensitive to the presence of the defect, for shells with a crack length less than a critical length. This critical crack length depends on the crack orientation, composite ply angles, ply sequence and the cylinder geometry. For shells with a crack longer than the critical length, the buckling load reduces and the local buckling mode at the crack tip prevail the buckling behavior of the composite cylindrical shell. The optimum ply angle for attaining the maximum buckling load is specified.

Finite Element Analysis of Composite Cylindrical Shells with and without Cutouts

2012 ◽  
Vol 1 (1) ◽  
pp. 34-38
Author(s):  
B. Siva Konda Reddy ◽  
◽  
CH. Srikanth ◽  
G. Sandeep Kumar ◽  
◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cylindrical Shells ◽  
Element Analysis ◽  
Composite Cylindrical Shells
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