Maps of deformations in a cantilever beam using particle image velocimetry (PIV) and speckle patterns

Abstract

PIV (particle image velocimetry) has been spreading in studies that use the movement of particles to monitor the displacement of an object or the flow of a fluid by means of velocity vectors using optical techniques and second order statistics. PIV is also known as laser speckle velocimetry when associated with speckle patterns. This technique has been used in works involving fluids, in general, building a map of velocity vectors representing the flow under analysis. This paper presents an approach by using PIV associated to speckle patterns for deformation measurements in a cantilever beam (ASTM A36 steel), one of the most common examples used in civil engineering, without the introduction of external particles. Results showed that the difference between PIV associated to speckle patterns and the analytic displacement values is increased along the beam length for a load of 1.96 N as an evidence of sensitivity of the proposed measurement method. This indicates that PIV is also capable for detecting displacement fields associated with laser speckle patterns in solid mechanics generating a map of deformation as an additional option for non-destructive tests.

Displacement Measurement in Sawn Wood and Wood Panel Beams Using Particle Image Velocimetry

“…Considering the values of the dial indicators as the base a. since in previous studies (Braga Jr. et al, 2015, Pereira, 2014, Souza et al, 2014 it was verified that the accuracy of this technique was restricted to small deformations. It is noteworthy that these materials present different mechanical behaviors.…”

“…This is an optical technique that generates results from sequential image analysis. The PIV technique was originally used in the field of fluids and gases (Bangalee et al, 2013;Xu et al, 2017) and in recent years it has also been applied to measurements of solid bodies (Baba and Peth, 2012;Braga Jr. et al, 2015;Magalhães et al, 2015;Pereira, 2014;Souza et al, 2014;Pereira et al, 2018).…”

Particle image velocimetry technique for analysis of retractibility in woods of Pinus elliottii

“…Using the equations, it is possible to estimate the reduction in the area of Pinus elliottii wood during drying. Research has shown satisfactory results of the PIV technique compared to conventional methods, with respect to physical and mechanical parameters in wood (Braga Jr et al 2015, Pereira et al 2018, Guedes et al 2019). In the literature, a value of 3,85 % and 3,44 % was found for the radial contraction of Pinus elliotttii wood in a natural drying process until equilibrium moisture content, measured with a pachymeter (Acosta et al 2019, Juizo et al 2015.…”

“…These images are processed in a computational algorithm that calculates the displacements that occurred on the surface of the object studied. This technique was originally developed in the field of fluids and gases, but authors have studied its application for solid materials (Braga Jr et al 2015, Souza et al 2014, Pereira et al 2018, Guedes et al 2019. It is a technique capable of measuring deformations in situations where there is a variation between the final and initial position of the object and obtaining the mechanical properties.…”

The Use of Particle Image Velocimetry for Displacement Measurements in Steel Columns Subjected to Buckling

“…The use of PIV and other optical measurement techniques as a contactless measurement test based on the structure mechanics has being proposed (Braga Jr. et al 2015;Lei et al 2016;Magalhaes et al 2015;Zhang et al 2012). Assuming that PIV technique can also be used for displacement measurements of steel columns, the aim of this paper is to evaluate PIV technique in rectangular tubular metal profile columns subject to buckling during compression tests.…”