Stress and Strain Concentrations in Perforated Structures Under Steady Creep Conditions

1980 ◽  
Vol 102 (4) ◽  
pp. 419-429 ◽  
Author(s):  
J. S. Porowski ◽  
W. J. O’Donnell ◽  
T. Tanaka ◽  
M. Badlani
Keyword(s):  
Creep Strain ◽  
Power Law ◽  
Plane Stress ◽  
Stress And Strain ◽  
Steady Creep ◽  
Strain Concentration ◽  
Local Stresses ◽  
Plane Stress Problem ◽  
Circular Holes ◽  
Concentration Factors

Steady creep solutions are obtained for perforated materials under various loading conditions. Norton’s creep power law is used and the plane stress problem is analyzed for both the triangular and square penetration patterns of circular holes. Maximum local stresses at the hole boundaries are obtained for calculating creep rupture damage. Local creep strain concentration factors are also obtained. The interrelations between the elastic, plastic and creep solutions are investigated.

ASME 1993 Nadai Lecture—Elastoplastic Stress and Strain Concentrations

1995 ◽  
Vol 117 (1) ◽  
pp. 1-7 ◽  
Author(s):  
William N. Sharpe
Keyword(s):  
Plane Strain ◽  
Plane Stress ◽  
Stress And Strain ◽  
Predictive Capability ◽  
Element Analysis ◽  
Elastoplastic Behavior ◽  
Local Stresses ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Elastic Constraint

Elastic stress concentration factors are familiar and easily incorporated into the design of components or structures through charts or finite element analysis. However when the material at the most concentrated location no longer behaves elastically, computation of the local stresses and strains is not so easy. Local elastoplastic behavior is an especially important consideration when the loading is cyclic. This paper summarizes the predictive capability of the Neuber and the Glinka models that relate gross loading to the local stresses and strains. The author and his students have used a unique laser-based technique capable of measuring biaxial strains over very short gage lengths to evaluate the two models. Their results, as well as those from earlier studies by other researchers using foil gages, lead to the general conclusion that the Neuber model works best when the local region is in a state of plane stress and the Glinka model is best for plane strain. There are intermediate levels of constraint that are neither plane stress nor plane strain. This paper presents a recommended practice for predicting the local elastoplastic stresses and strains for any constraint. First, one computes or estimates the initial elastic strains. Then, based on the amount of elastic constraint, one selects the appropriate model to compute the local elastoplastic stresses and strains.

On the Relation Between Stress and Strain-Concentration Factors in Notched Members in Plane Stress

1970 ◽  
Vol 37 (1) ◽  
pp. 77-84 ◽  
Author(s):  
C. V. Byre Gowda ◽  
T. H. Topper
Keyword(s):  
Plane Stress ◽  
Elastic Stress ◽  
Geometric Mean ◽  
Infinite Plate ◽  
Stress And Strain ◽  
Strain Concentration ◽  
Linear Elastic ◽  
Nonlinear Plane ◽  
Concentration Factors ◽  
The Relationship

The validity of the relationship between stress and strain-concentration factors proposed by Neuber, i.e., the geometric mean of the stress and strain-concentration factors is equal to the linear elastic-stress-concentration factor, is investigated for plane-stress problems. The physically nonlinear plane-stress problem of an infinite plate with a circular hole is solved by a perturbation method. Applicability of the solution and the restrictions on the relationship are discussed with reference to theoretical and experimental results.

Application of the Deformation Theory of Plasticity for Determining Elastoplastic Stress and Strain Concentration Factors

1976 ◽  
Vol 98 (4) ◽  
pp. 1152-1156 ◽  
Author(s):  
J. P. Eimermacher ◽  
I.-Chih Wang ◽  
M. L. Brown
Keyword(s):  
Deformation Theory ◽  
Analytical Data ◽  
Local Stress ◽  
Failure Criteria ◽  
Constitutive Law ◽  
Stress And Strain ◽  
Strain Concentration ◽  
Theory Of Plasticity ◽  
Concentration Factors ◽  
Von Mises

The deformation theory of plasticity is considered as a means for obtaining a solution to the problem of calculating stress and strain concentration factors at geometric discontinuities where the local stress state exceeds the yield strength of the material. Through the use of the Hencky-Nadai constitutive law and the Von Mises failure criteria, the elastoplastic element stiffness matrix is derived for a plane stress triangular plate element. An elastoplastic solution is arrived at by considering direct-iterative and finite element techniques. Verification of the analytical results is obtained by considering a numerical example and comparing the calculated results with published experimental and analytical data.

scholarly journals Stress and Strain Concentration Factors in Orthotropic Composites with Hole under Uniaxial Tension

2018 ◽  
Vol 5 (1) ◽  
pp. 213-231
Author(s):  
Samit Ray-Chaudhuri ◽  
Komal Chawla
Keyword(s):  
Uniaxial Tension ◽  
Fiber Orientation ◽  
Composite Plates ◽  
Systematic Investigation ◽  
Stress And Strain ◽  
Governing Parameter ◽  
Strain Concentration ◽  
Wide Range ◽  
Orthotropic Composites ◽  
Concentration Factors

Abstract A systematic investigation is carried out on how different parameters influence stress and strain concentration factors (SCF and SNCF) in a composite plate with a hole under uniaxial tension. Flat and singly curved composite plates have been modelled in ANSYS 15.0. The governing parameter includes: (i) size, shape and eccentricity of hole, (ii) number of plies, (v) fiber orientation and (vi) plate curvature. It is observed that different parameters influence the SCF and SNCF with varying degrees. For example, SCF may be as high as 7.16 for a square shaped hole. Also, SCF and SNCF are found to be approximately same in most of the cases. Finally, simplified design formulas are developed for evaluation of SCF for a wide range of hole size, eccentricity and fiber orientation.

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