Buckling of a Circular Cylindrical Web-Stiffened Sandwich Shell Under Axial Compression

1974 ◽  
Vol 18 (01) ◽  
pp. 55-61
Author(s):  
Vincent Volpe ◽  
Youl-Nan Chen ◽  
Joseph Kempner
Keyword(s):  
Axial Compression ◽  
Large Deflection ◽  
Single Layer ◽  
Subsequent Development ◽  
Buckling Load ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell ◽  
Axisymmetric Mode ◽  
Shell Equations ◽  
The Mathematical Model

A stability analysis of an infinitely long web-stiffened, circular cylindrical sandwich shell under uniform axial compression is presented. The formulation begins with the establishment of a set of suitable large-deflection shell equations that forms the basis for the subsequent development of the buckling equations. The mathematical model corresponds to two face layers that are considered as thin shells and a thick core that is capable of resisting both transverse shear and circumferential extension. The associated eigenvalue problem is solved. Results show that the lowest buckling load is associated with the axisymmetric mode and is less than one half the buckling load of an equivalent single-layer shell.

scholarly journals Vibration analysis of a sandwich cylindrical shell in hygrothermal environment

2021 ◽  
Vol 10 (1) ◽  
pp. 414-430
Author(s):  
Chunwei Zhang ◽  
Qiao Jin ◽  
Yansheng Song ◽  
Jingli Wang ◽  
Li Sun ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequency ◽  
Equations Of Motion ◽  
Single Layer ◽  
Functionally Graded ◽  
Sandwich Shell ◽  
Continuous Change ◽  
Multilayered Structures ◽  
Cylindrical Sandwich Shell ◽  
Vibrational Behavior

Abstract The sandwich structures are three- or multilayered structures such that their mechanical properties are better than each single layer. In the current research, a three-layered cylindrical shell including a functionally graded porous core and two reinforced nanocomposite face sheets resting on the Pasternak foundation is used as model to provide a comprehensive understanding of vibrational behavior of such structures. The core is made of limestone, while the epoxy is utilized as the top and bottom layers’ matrix phase and also it is reinforced by the graphene nanoplatelets (GNPs). The pattern of the GNPs dispersion and the pores distribution play a crucial role at the continuous change of the layers’ properties. The sinusoidal shear deformation shells theory and the Hamilton’s principle are employed to derive the equations of motion for the mentioned cylindrical sandwich shell. Ultimately, the impacts of the model’s geometry, foundation moduli, mode number, and deviatory radius on the vibrational behavior are investigated and discussed. It is revealed that the natural frequency and rotation angle of the sandwich shell are directly related. Moreover, mid-radius to thickness ratio enhancement results in the natural frequency reduction. The results of this study can be helpful for the future investigations in such a broad context. Furthermore, for the pipe factories current study can be effective at their designing procedure.

RELIABILITY ASSESSMENT OF AXIALLY COMPRESSED COMPOSITE CYLINDRICAL SHELLS WITH RANDOM IMPERFECTIONS

2011 ◽  
Vol 11 (02) ◽  
pp. 215-236 ◽  
Author(s):  
MATTEO BROGGI ◽  
ADRIANO CALVI ◽  
GERHART I. SCHUËLLER
Keyword(s):  
Mathematical Models ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Reliability Assessment ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Experimental Results ◽  
Drastic Decrease ◽  
Different Types ◽  
Probability And Statistics

Cylindrical shells under axial compression are susceptible to buckling and hence require the development of enhanced underlying mathematical models in order to accurately predict the buckling load. Imperfections of the geometry of the cylinders may cause a drastic decrease of the buckling load and give rise to the need of advanced techniques in order to consider these imperfections in a buckling analysis. A deterministic buckling analysis is based on the use of the so-called knockdown factors, which specifies the reduction of the buckling load of the perfect shell in order to account for the inherent uncertainties in the geometry. In this paper, it is shown that these knockdown factors are overly conservative and that the fields of probability and statistics provide a mathematical vehicle for realistically modeling the imperfections. Furthermore, the influence of different types of imperfection on the buckling load are examined and validated with experimental results.

Sensitivity in Large Deflection of Bossed and Pre-Tensioned Layered Plate under Lateral Load

2008 ◽  
Vol 47-50 ◽  
pp. 33-36
Author(s):  
Chun Fu Chen ◽  
Yu Chou Wu
Keyword(s):  
Large Deflection ◽  
Plate Theory ◽  
Single Layer ◽  
Radial Force ◽  
Iteration Scheme ◽  
Layered Plate ◽  
Mechanical Sensitivity ◽  
Initial Tension ◽  
Numerical Iteration ◽  
Over The Top

Mechanical sensitivity of a bossed and clamped layered isotropic circular plate with pretension in large deflection is evaluated. The approach extends Von-Karman’s plate theory for large deflection to a symmetrically layered plate with a center boss. The derived nonlinear governing equations are solved using a finite difference method incorporating a numerical iteration scheme in finding the lateral slope and radial force resultant. The obtained geometrical responses are further manipulated to calculate the associated mechanical sensitivity. For a 3-layered plate with nearly the same layer moduli, the results correlate well with those following available formulation for a single-layer isotropic plate. The developed approach is then implemented for various initial tensions, lateral pressures as well as different boss sizes and ratios between the layer moduli. The obtained numerical results show that, initial tension appears to have the strongest influence upon the radial variation of mechanical sensitivity over the top surface of the bossed layered plate. While both the size of center boss and magnitude of lateral pressure can still have a significant effect, the mechanical sensitivity seems to be insensitive to the change of the ratio between layer moduli for a bossed and symmetrically layered plate.

Effect of Imperfections on Buckling of Thin Cylinders and Columns Under Axial Compression

1950 ◽  
Vol 17 (1) ◽  
pp. 73-83 ◽  
Author(s):  
L. H. Donnell ◽  
C. C. Wan
Keyword(s):  
Axial Compression ◽  
Shell Theory ◽  
Large Deflection ◽  
Strain Curve ◽  
Test Results ◽  
Average Strain ◽  
Lower Yield ◽  
Initial Imperfections ◽  
Buckling Failure ◽  
Type Of Failure

Abstract Von Kármán and Tsien have shown that under elastic conditions the resistance of perfect thin cylinders subjected to axial compression drops precipitously after buckling. It is considered that this indicates that this type of buckling is very sensitive to imperfections or disturbances. In this paper the effects of certain imperfections of shape (assumed to be equivalent to all the actual defects or disturbances combined) are studied by the large-deflection shell theory developed in a previous paper (2). It is found that two types of buckling failure may occur. One is of a purely elastic type which occurs when the peak of the average stress versus average strain curve is reached, while the other type is precipitated by yielding, which for thicker cylinders or lower-yield material may occur before such a peak is reached. Curves are derived giving the dependence of each type of failure upon the dimensions and elastic and yield properties of the specimen and also upon an “unevenness factor” U which determines the magnitude of the initial imperfections and is assumed to depend on the method of fabrication. The relations derived are in line with test results, and similar studies of the buckling of struts indicate that the magnitude of the initial imperfections which have to be assumed to explain test strengths are reasonable.

Critical Buckling Load of Triple-Walled Carbon Nanotube Based on Nonlocal Elasticity Theory

2020 ◽  
Vol 62 ◽  
pp. 108-119
Author(s):  
Tayeb Bensattalah ◽  
Ahmed Hamidi ◽  
Khaled Bouakkaz ◽  
Mohamed Zidour ◽  
Tahar Hassaine Daouadji
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Axial Compression ◽  
Buckling Load ◽  
Small Scale ◽  
Beam Model ◽  
Buckling Loads ◽  
Critical Buckling Load ◽  
Nonlocal Continuum Theory ◽  
Walled Carbon Nanotubes

The present paper investigates the nonlocal buckling of Zigzag Triple-walled carbon nanotubes (TWCNTs) under axial compression with both chirality and small scale effects. Based on the nonlocal continuum theory and the Timoshenko beam model, the governing equations are derived and the critical buckling loads under axial compression are obtained. The TWCNTs are considered as three nanotube shells coupled through the van der Waals interaction between them. The results show that the critical buckling load can be overestimated by the local beam model if the small-scale effect is overlooked for long nanotubes. In addition, a significant dependence of the critical buckling loads on the chirality of zigzag carbon nanotube is confirmed, and these are then compared with: A single-walled carbon nanotubes (SWCNTs); and Double-walled carbon nanotubes (DWCNTs). These findings are important in mechanical design considerations and reinforcement of devices that use carbon nanotubes.

Biomechanical analysis of cranial settling after transoral odontoidectomy

1999 ◽  
Vol 6 (6) ◽  
pp. E9 ◽  
Author(s):  
Sait Naderi ◽  
Neil R. Crawford ◽  
M. Stephen Melton ◽  
Volker K. H. Sonntag ◽  
Curtis A. Dickman
Keyword(s):  
Axial Compression ◽  
Compressive Load ◽  
Subsequent Development ◽  
Biomechanical Analysis ◽  
Vertical Separation ◽  
Anterior Arch ◽  
Transoral Odontoidectomy ◽  
Student’S T

The authors conducted a biomechancial study to determine whether C-1 ring integrity is important in maintaining normal occiput-C-2 separation, specifically when the anterior arch is transected to provide access to the dens during an odontoidectomy procedure. Six human cadaveric occiput-C3 specimens were loaded under axial compression, and the bilateral horizontal separation of the C-1 lateral masses and the vertical compression of the occiput relative to C-2 were recorded. Specimens were first studied after odontoidectomy without C-1 ring transection, then after C-1 anterior arch transection, and finally after C-1 lamina transection. With applied compressive load corresponding to three times the weight of the head, the C-1 ring spread horizontally 1.57 ± 0.30 mm more when the anterior arch of C-1 was transected than when left intact, resulting in 0.74 ± 0.44 mm collapse in the occiput-C-2 vertical separation. After laminar transection, the C-1 ring spread 6.55 ± 2.29 mm more than when it was intact. The resultant vertical separation was a 3.37 ± 1.89-mm collapse in the occiput-C-2. All changes in C-1 spreading and the occiput-C-2 collapse were statistically significant (p < 0.05, paired Student's t-tests). The C-1 ring continuity prevents horizontal spreading caused by the wedging of C-1 between the occiput and C-2 and thus prevents cranial settling. Therefore, to prevent the subsequent development of disease related to cranial settling, the authors recommend that the surgeon resect part of C-1 only if necessary during odontoidectomy.

Flexure of a cylindrical sandwich shell of variable thickness

1968 ◽  
Vol 4 (5) ◽  
pp. 36-39
Author(s):  
I. M. Pirogov ◽  
F. I. Selitskii
Keyword(s):  
Variable Thickness ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell

Experimental and finite element study on the single-layer reticulated composite joints

2020 ◽  
Vol 23 (10) ◽  
pp. 2174-2187
Author(s):  
Liang Zheng ◽  
Cheng Qin ◽  
Hong Guo ◽  
Dapeng Zhang ◽  
Mingtan Zhou ◽  
...  
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Axial Compression ◽  
Wall Thickness ◽  
Great Influence ◽  
Single Layer ◽  
Experimental Results ◽  
Steel Pipe ◽  
Cover Plate ◽  
Element Analysis

In this article, a new type of reticulated joint, named the steel–concrete composite reticulated shell joint, is proposed. The proposed reticulated shell joint consists of an inner circular steel pipe, an outer circular steel pipe, a steel cover plate, and internal concrete. Five test specimens were tested under axial compression. The variable study included the wall thickness of the inner and outer circular steel pipes and the radius of the inner circular steel pipe. The test specimens exhibited a high bearing capacity and good plastic deformation ability under axial compression. The test results show that the wall thickness of the outer circular steel pipe and the radius of the inner circular steel pipe have a great influence on the bearing capacity of the steel–concrete composite reticulated shell joint, while the wall thickness of the inner circular steel pipe has little influence on the bearing capacity of the steel–concrete composite reticulated shell joint. Based on the test of the steel–concrete composite reticulated shell joints under axial load, the three-dimensional nonlinear finite element model was used to analyze the mechanical properties of the steel–concrete composite reticulated shell joints under axial compression. The results of the finite element analysis showed good agreement with the experimental results. The formula for calculating the bearing capacity of the joint is derived. By comparing with the experimental results, the calculated results are basically consistent with the experimental results.

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