An expression of stress concentration factor for a circular hole eccentrically located in a tensile finite-width strip of orthotropic material

Abstract

An explicit expression of stress concentration factor (SCF) for a circular hole eccentrically located in a finite-width strip of orthotropic material subjected to remote tension is derived using an approximate and analytical method. The eccentricity of the hole and the ratio of the diameter to strip width are two governing geometric parameters, and their effect to the SCF is shown clearly in the expression. The formulation for the expression is consisted of two steps, first, the derivation is based on section method using balance of force and moment, respectively, second, improvement is done by empirical modification of the related coefficients based on asymptotic matching of good results obtained for some special cases. The accuracy of the final SCF expressions is adequate except the extreme case where the eccentricity of the circular hole is very large, i.e. when the hole is located very near to one side of the strip. On the other hand, when the eccentricity is taken as zero, i.e. for the simplified case of a central circular hole in a finite-width strip, the corresponding SCF expression has good accuracy. The present work is an extension of previous work for central circular hole of orthotropic material and an eccentric circular hole for isotropic material.

Howland’s isotropic Kts curve for plates with circular holes as a master curve for Kts in orthotropic plates with elliptical holes

“…[1][2][3][4] As a result, the general issue of determining the stress distributions and/or stress concentrations produced by geometric discontinuities of the type considered herein in the orthotropic context has been given significant attention over the years. [5][6][7][8][9][10][11][12][13][14][15] One of the most important determining components in designs or analyses of mechanical and structural members, in spite of known limitations, is still today the so-called stress concentration factor (SCF), usually labeled as K t (with two variants, K t n as net section K t , and K t g as gross section K t , respectively) and customarily extracted from various charts 16,17 for the most diverse geometries in the isotropic context and as stated in a variety of published papers in the anisotropic context. [5][6][7][8][9][10][11][12][13][14] In this work, we examine strategies to estimate in a predictive fashion as was done in Zappalorto and Carraro, 7 and in Mu and Wu, 15 K t s for finite width plates of uniform unit thickness with elliptic centered holes for both isotropic and orthotropic materials subjected to tension, and report the results of the estimates thus obtained; we present as well the measures of the corresponding accuracy with which the stated goal is achieved using finite element method (FEM) calculated values as reference values.…”

“…1-4 As a result, the general issue of determining the stress distributions and/or stress concentrations produced by geometric discontinuities of the type considered herein in the orthotropic context has been given significant attention over the years. 5-15…”

“…One of the most important determining components in designs or analyses of mechanical and structural members, in spite of known limitations, is still today the so-called stress concentration factor (SCF), usually labeled as K t (with two variants, K t n as net section K t , and K t g as gross section K t , respectively) and customarily extracted from various charts 16,17 for the most diverse geometries in the isotropic context and as stated in a variety of published papers in the anisotropic context. 5-14…”