The Onset of Plastic Yielding in a Spherical Shell Compressed by a Rigid Flat

2010 ◽  
Vol 78 (1) ◽  
Author(s):  
Longqiu Li ◽  
Izhak Etsion ◽  
Andrey Ovcharenko ◽  
Frank E. Talke
Keyword(s):  
Spherical Shell ◽  
Normal Load ◽  
Empirical Relation ◽  
Solid Sphere ◽  
Plastic Yielding ◽  
Element Analysis ◽  
Shell Parameter ◽  
Shell Geometry ◽  
Limiting Value ◽  
Critical Contact

The onset of plastic yielding in a spherical shell loaded by a rigid flat is analyzed using finite element analysis. The effect of spherical shell geometry and material properties on the critical normal load, critical interference, and critical contact area, at the onset of plastic yielding, is investigated and the location where plastic yielding first occurs is determined. A universal dimensionless shell parameter, which controls the behavior of the spherical shell, is identified. An empirical relation is found for the load-interference behavior of the spherical shell prior to its plastic yielding. A limiting value of the dimensionless shell parameter is identified above which the shell behaves like a solid sphere.

Numerical Analysis of a Spherical Shell Compressed by a Rigid Flat

2009 ◽  
Author(s):  
Longqiu Li ◽  
Izhak Etsion ◽  
Andrey Ovcharenko ◽  
Frank Talke
Keyword(s):  
Plastic Deformation ◽  
Spherical Shell ◽  
Material Properties ◽  
Normal Load ◽  
Solid Sphere ◽  
Element Analysis ◽  
Strong Function ◽  
Classical Shell Theory ◽  
Shell Parameter ◽  
Shell Geometry

The elastic-plastic contact between a spherical shell and a rigid flat is analyzed using finite element analysis. The effect of spherical shell geometry and material properties on the onset of plastic deformation is determined by finding the critical normal load and the critical interference which correspond to the onset of plastic yielding. The location of initial plastic deformation is identified as a function of material properties and spherical shell geometry. This work provides the dimensionless critical load as a function of the shell parameter λ = (t/R)*(E/Y), where t, R, E and Y are the spherical shell thickness, radius, Young’s modulus and yield strength, respectively. The numerical results are compared with the solid sphere model based on Hertz’s contact theory and classical shell theory in the elastic regime. The behavior of a spherical shell contacting a rigid flat plate is a strong function of the shell parameter λ.

The Effect of Contact Conditions on the Onset of Plastic Yielding in a Spherical Shell Compressed by a Rigid Flat

2010 ◽  
Author(s):  
Longqiu Li ◽  
Lin Wang ◽  
Izhak Etsion ◽  
Frank Talke
Keyword(s):  
Spherical Shell ◽  
Poisson’S Ratio ◽  
Load Ratio ◽  
Contact Condition ◽  
Poisson's Ratio ◽  
Plastic Yielding ◽  
Element Analysis ◽  
Contact Conditions ◽  
Wide Range ◽  
Shell Parameter

The effect of contact conditions on yield inception of a spherical shell compressed by a rigid flat is studied using finite element analysis. A wide range of material properties and shell thickness values, corresponding to the dimensionless shell parameter, were studied. This work provides the critical load ratio as a function of the shell parameter for different values of the Poisson’s ratio under both slip and stick contact condition. At small values of the Poisson’s ratio the behavior in stick is very different from that in slip. At high values of the Poisson’s ratio the yield inception in stick and slip is similar.

Axisymmetric Thermal Stresses in a Spherical Shell of Arbitrary Thickness

1957 ◽  
Vol 24 (3) ◽  
pp. 376-380
Author(s):  
E. L. McDowell ◽  
E. Sternberg
Keyword(s):  
Steady State ◽  
Spherical Shell ◽  
Spherical Cavity ◽  
Series Solution ◽  
Thermal Stresses ◽  
Solid Sphere ◽  
Theory Of Elasticity ◽  
Infinite Medium ◽  
Series Solutions ◽  
Arbitrary Thickness

Abstract This paper contains an explicit series solution, exact within the classical theory of elasticity, for the steady-state thermal stresses and displacements induced in a spherical shell by an arbitrary axisymmetric distribution of surface temperatures. The corresponding solutions for a solid sphere and for a spherical cavity in an infinite medium are obtained as limiting cases. The convergence of the series solutions obtained is discussed. Numerical results are presented appropriate to a solid sphere if two hemispherical caps of its boundary are maintained at distinct uniform temperatures.

Finite Element Analysis on the Structure Strength of Air Cushion Vehicle

2014 ◽  
Vol 918 ◽  
pp. 95-100 ◽  
Author(s):  
Ning Liu ◽  
Hui Long Ren ◽  
Jian Zhang Li ◽  
Lian Hui Jia
Keyword(s):  
High Speed ◽  
Normal Load ◽  
Structural Response ◽  
Fem Analysis ◽  
Direct Calculation ◽  
Wave Loads ◽  
Loading Test ◽  
Element Analysis ◽  
Air Cushion ◽  
Air Cushion Vehicle

Air Cushion Vehicle is widely used in the field of military and civil ship in recent years for its characteristic high speed and amphibian. Since the yield strength of aluminum sheet with stiffeners is relative low after welding, to ensure air cushion vehicle has significant strength under normal load and to avoid severe damage under adverse sea conditions, model loading test and theoretical prediction is used to determines the design values of wave loads, and FEM analysis with direct calculation method under the different load cases including the total longitudinal strength, cross-strength, torsional strength and shear strength, and then getting the structural response results. This essay gives several suggestions for the design according to the calculated results of stress and its deformation characteristics.

Optical Absorption of Dye Molecules in a Spherical Shell Geometry

2018 ◽  
Vol 122 (33) ◽  
pp. 19110-19115 ◽  
Author(s):  
Baptiste Auguié ◽  
Eric C. Le Ru
Keyword(s):  
Optical Absorption ◽  
Spherical Shell ◽  
Dye Molecules ◽  
Shell Geometry

Buildings on the Slope Considering Effects of Uneven Settlement of Single Pile on the Structure Research

2011 ◽  
Vol 368-373 ◽  
pp. 1949-1954
Author(s):  
Li Ming Wu ◽  
Zi Jian Wang
Keyword(s):  
Finite Element Analysis ◽  
Pile Foundation ◽  
Normal Load ◽  
Single Pile ◽  
Analysis Software ◽  
Load Bearing Capacity ◽  
Element Analysis ◽  
Structural Impact ◽  
Different Parts ◽  
Structure Research

Buildings built on the slope and slope, in order to avoid a lot of digging embankment. According to the slope of potential changes in pile foundation of General unequal height. In the design of such buildings are generally the superstructure and Foundation when considered separately, under normal load bearing capacity and deformation is to meet to coordinal requirements.Changes in water level cause of slope sliding, so lead to individual settlement, the class meets the deformation of the structure of coordination of the Department of architecture and how the force is not known. Based on this, to a shore in 8 layers of pile foundation in the framework, for example, using finite element analysis software ANSYS in different parts of a single settlement on the basis of structural impact.

Acrylic Plastic Spherical Shell Windows Under Point Impact Loading

1976 ◽  
Vol 98 (2) ◽  
pp. 563-575 ◽  
Author(s):  
J. D. Stachiw ◽  
O. H. Burnside
Keyword(s):  
Hydrostatic Pressure ◽  
Spherical Shell ◽  
Impact Loading ◽  
External Hydrostatic Pressure ◽  
Element Analysis ◽  
Destructive Effect ◽  
Tensile Stresses ◽  
Acrylic Plastic ◽  
Degree Of Confidence ◽  
Ocean Environment

Acrylic plastic spherical shell sector windows with 117-deg included angle and outside radius of 24-in. (61 mm), have been impacted at their center, with a 12,500 lb (5662 kg) weight, in a simulated ocean environment. Velocities of impacts ranged from 0.205 to 10.702 ft (0.06 to 3.26 m) per second. It has been found that fracture of windows is initiated by tensile stresses on the concave surface of the window, directly below the point of impact. Compressive stresses, generated by external hydrostatic pressure, decrease the destructive effect of tensile stresses introduced by point impact loading. For 2.25 and 4.0-in. (57 and 101 mm) thick windows the critical impact velocities were found to fall into the 1.5 to 3 ft (0.45 to 0.91 m) per second range, the exact value being a function of window thickness and external hydrostatic pressure. A finite element analysis was found to agree rather well with the experimental. This analysis can be employed to predict, with a reasonable degree of confidence, the critical impact velocities for acrylic plastic spherical windows in the bows of submersibles.

Analyses of Contact Pressure and Stress Amplitude Effects on Fretting Fatigue Life

2000 ◽  
Vol 123 (1) ◽  
pp. 85-93 ◽  
Author(s):  
K. Iyer ◽  
S. Mall
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Contact Pressure ◽  
Stress Amplitude ◽  
Normal Load ◽  
Contact Region ◽  
Local Stress ◽  
Fretting Fatigue ◽  
Element Analysis ◽  
Stress Ratios

Elastic-plastic finite element analyses of a cylinder-on-plate configuration, studied experimentally, were performed to provide an explanation for the decrease in fretting fatigue life with increasing contact pressure. Three values of normal load, namely 1338 N, 2230 N, and 3567 N, and three stress ratios (0.1, 0.5, and 0.7) were considered. Based on a previously determined dependency between contact pressure and friction coefficient, the effect of coefficient of friction was also evaluated. The deformation remained elastic under all conditions examined. Cyclic, interfacial stresses, and slips were analyzed in detail. The amplification of remotely applied cyclic stress in the contact region is shown to provide a rationale for the effect of contact pressure and stress amplitude on life. Comparisons with previous experiments indicate that the local stress range computed from finite element analysis may be sufficient for predicting fretting fatigue life. Further, the results suggest that the slip amplitude and shear traction may be neglected for this purpose.

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