Journal Published Online: 06 November 2023
Volume 12, Issue 1

Effect of Stress Ratio, Constraint, and Load History on the Intrinsic and Extrinsic Components of Threshold Stress Intensity

CODEN: MPCACD

Abstract

Threshold intensity range, ΔKth, was experimentally investigated as the sum of two components, both of which are sensitive to applied loading conditions. The intrinsic component, ΔKth,i, is characterized as a sole function of a near-tip stress parameter, σ*, in much the same way as fatigue limit depends on mean stress or stress ratio. The extrinsic component, ΔKcl, is the attenuated fraction of crack tip response because of crack wake contact, whose exact value is not readily measured at threshold. The ΔKth,i versus σ* relationship is established using a specially designed load shedding process under constant baseline maximum load, with σ* modulated through periodic overload-underload combinations whose periodicity is regulated to avoid undue crack extension at threshold. This relationship is then used to extract the ΔKcl component from ΔKth readouts obtained on the same batch of material using conventional load shedding procedure. The effect of constraint on ΔKth and its two components was studied using specimens with sharp side grooves to maximize constraint across the crack front. The study was performed on a medium strength low-alloy steel.

Author Information

Sunder, R.
BISS Labs, ITW India (P), Ltd., Bangalore, India
Koraddi, Ramesh
BISS Labs, ITW India (P), Ltd., Bangalore, India
Chandra, Vishwas
BISS Labs, ITW India (P), Ltd., Bangalore, India
Pages: 20
Price: $25.00
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Stock #: MPC20230078
ISSN: 2379-1365
DOI: 10.1520/MPC20230078