Reduction of Alternating Stress Range Around Holes in Flat Plates by Use of Inserts

Abstract

Airy stress functions are established herein for the solution of hollow annular interfering inserts in thin flat plates which extend to infinity. The equations presented are solved for the case of a non-circumferential-slip insert to plate interface in a uniaxial stress field. The solution assumes plane stress and yields the stress and displacement fields for both plate and insert. The interface friction coefficient necessary to enforce the nonslip condition is determined as a function of initial interference. The analysis is extended to the case of a biaxial stress field through the use of superposition. The results indicate that inserts can be used to significantly reduce the maximum alternating stress range induced by plate load fluctuations. Curves are presented which may be easily applied to the design of inserts for the most effective reduction of alternating stress ranges around holes that could otherwise be a potential cause of failure due to low-cycle fatigue.