3D Measurement of the Strain Field Surrounding Crack Tip

Abstract

Finite elements method is widely used for numerical simulations of solid object behaviour in many applications questioning in some cases the necessity of physical experiments. Available databases of material behaviour are quite sufficient for simulations of linear systems. However for the simulations of nonlinear systems, it is still necessary to have experimental information’s. Unfortunately, the feedback based on strain measurement in several points only can lead to accurate but imaginary numerical solution. Full field strain measurement is routinely performed today. Let’s reduce the class of the analyzed object onto flat specimens only. Dependency on loading type and studied feature, either the in-plain or out-of plain experimental method is usually chosen. One of the highly non-linear problems is the failure of ductile specimen with stress concentrator especially when failure is accompanied by the developing of damage zone in the vicinity of the stress concentrator. Corresponding damage models have a number of parameters which is necessary to determine. The feedback based on in-plane strain measurement only can lead to a non-unique solution as well as without prior knowledge of material damage type. From this reason both in-plane and out-of plane displacement measurement is required. On the other hand monitoring the out-of plane displacement can detect the onset of intensive damage zone development [1].