Reduction of Free-Edge Stress Concentration

1985 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Stress Concentration ◽  
Free Edge ◽  
Edge Stress

scholarly journals The Green's Function BEM for Bimaterial Solids Applied to Edge Stress Concentration Problems

2007 ◽  
Vol 1 (2) ◽  
Author(s):  
M. Denda
Keyword(s):  
Stress Concentration ◽  
Green’S Function ◽  
Green's Function ◽  
Free Edge ◽  
Fundamental Solutions ◽  
Singular Stress ◽  
Thin Coatings ◽  
Edge Stress ◽  
Line Force ◽  
Isotropic Solids

A boundary element method (BEM) for bimaterial domains consisting of two isotropic solids bonded perfectly along the straight interface will be developed. We follow the physical interpretation of Somigliana’s identity to represent the displacement in the bimaterial domain by the continuous distributions of the line forces and dislocation dipoles over its boundary. The fundamental solutions used are the Green’s functions for the line force and the dislocation dipole that satisfy the traction and displacement continuity across the interface of two domains. There is no need to model the interface because the required continuity conditions there are automatically satisfied by the Green’s functions. The BEM will be applied to study the edge stress concentration of the bimaterial solids. We calculate the singular stress distribution at the free edge of the interface for various bimaterial configurations and loadings, in particular, for the domain consisting of thin coating over the substratum. Since the Green's function BEM does not require the boundary elements on the interface, it can handle the edge singularity on the interface accurately even for extremely thin coatings. The BEM developed here is not limited to the edge stress concentration problems and can be applied to a broad range of the bimaterial domain problems effectively.

Influence of free edge stress concentration on effectiveness of FRP confinement

2010 ◽  
Vol 41 (7) ◽  
pp. 523-532 ◽  
Author(s):  
A. Zinno ◽  
G.P. Lignola ◽  
A. Prota ◽  
G. Manfredi ◽  
E. Cosenza
Keyword(s):  
Stress Concentration ◽  
Free Edge ◽  
Edge Stress ◽  
Frp Confinement

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

An Optimum Design of Crowned Cylindrical Roller Bearings Using Genetic Algorithms

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
K. Sunil Kumar ◽  
Rajiv Tiwari ◽  
P. V. V. N. Prasad
Keyword(s):  
Genetic Algorithms ◽  
Fatigue Life ◽  
Stress Concentration ◽  
Stress Concentrations ◽  
Rolling Bearings ◽  
Design Constraint ◽  
Roller Bearings ◽  
Edge Stress ◽  
Heavy Loads ◽  
Cylindrical Roller

The long fatigue life is the one of the most important criterion for the design of rolling bearings, however, due to complex and diverse internal geometries, each type of rolling bearings require a different design formulation. To increase the life of cylindrical roller bearings, the profile (or the crowning) of the roller plays an important role. A flat profile of the rolling element results in the edge stress concentrations at roller ends. A circular crowning of roller eliminates the edge stress concentration at the lower and moderate loads only; however, it develops edge stress concentrations at heavy loads. The logarithmic profile of the roller results in no edge stress concentration at the low, medium, and heavy loads; distribution of contact stresses is also nearly uniform along the length of the roller. A design methodology for the optimum design of cylindrical roller bearings with the logarithmic profile has been outlined. A nonlinear constrained optimization problem has been formulated for the design of cylindrical roller bearings with logarithmic profiles and is optimized by using real-coded genetic algorithms. The change in roller profile has not been accounted for explicitly in the standard definition of the dynamic capacity; hence, for the present case directly the Lundberg–Palmgren life equation has been chosen as an objective function. Design variables include four bearing geometrical parameters and the two logarithmic profile generating parameters are considered. In addition to these, another five design constraint constants are also included, which indirectly affect the fatigue life of cylindrical roller bearings. The five design constraint constants have been given bounds based on the parametric studies through initial optimization runs. The effective length of the roller is taken corresponding to the standard roller diameter, which has standard discrete dimensions. Constraint violation study has been performed to have an assessment of the effectiveness of each of the constraints. A convergence study has been carried out to ensure the global optimum point in the design. A sensitivity analysis of various geometric design parameters has been performed using the Monte Carlo simulation technique, in order to see changes in the fatigue life of the bearing. Illustrations show that the multiplier of the logarithmic profile deviation parameter has more effect on the fatigue life as compared with other geometric parameters.

Free-edge stress fields in cylindrically curved symmetric and unsymmetric cross-ply laminates under bending load

2017 ◽  
Vol 180 ◽  
pp. 862-875 ◽  
Author(s):  
Jan Eike Schnabel ◽  
Mejdi Yousfi ◽  
Christian Mittelstedt
Keyword(s):  
Free Edge ◽  
Stress Fields ◽  
Bending Load ◽  
Edge Stress
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