Author(s)

D. Vavrik, J. Bryscejn, J. Jakubek & J. Valach

Abstract

The optical measurement of flat specimen deformation is a frequent task. In some applications it is necessary to measure both the in-plane and out-of-plane displacement or strain fields respectively. To achieve this goal a variety of methods have been developed in the past. This paper describes a novel technique based on the use of only one camera which employs a combination of two different optical methods to achieve 3D displacement measurements. The optical grid method for the measurement of the in-plane strain field and the proposed Coded Photometric Stereo method for the measurement of the out-of-plane displacement can be applied simultaneously. This approach reduces hardware part costs. The combined method is full field (all data acquired at once), non-contact and non-destructive. Keywords: full field strain measurement, optical method. 1 Introduction The finite element 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. Unfortunately, the feedback based on strain measurements in several points only can lead to accurate but an 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-plane or out-of-plane experimental method is usually chosen. One

Keywords

full field strain measurement, optical method.