Centrosymmetric 3D Deformation Measurement using Grid Method with a Single-Camera

Abstract

This study proposes an effective method to measure centrosymmetric 3D static and dynamic deformations from the microscale to macroscale using grid method with a single camera. The camera was tilted at a particular angle and used to observe specimen grids in order to acquire coupling fields of both in-plane and out-of-plane displacement. This study also analyzes the decoupling methods of these two displacement types, and a systematic deduction of a theoretical equation for 3D deformation analysis was conducted based on the method. The sensitivity of morphology measurement was then evaluated and the elimination of noise and rotational errors was discussed. The efficiency and accuracy of this technique was verified through a microscale static feasibility test and a highspeed impact experiment that simulated an underwater explosion. The proposed approach uses minimal equipment, is simple and convenient, and can be used to measure centrosymmetric 3D deformation in multi-scale both statically and dynamically. In addition, this method avoids the nonsynchronization problem of a pair of high-speed cameras in high-speed 3D measurements.

Single-camera displacement field correlation method for centrosymmetric 3D dynamic deformation measurement

“…Thus, the axes Y c and Y are parallel to each other, and the planes O − XZ and O c − X c Z c are the same plane. It is notable that the effect of rotating the specimen or tilting the camera is always equivalent in the experiment [17]. Thus, tilting the camera in the world coordinate system can be regarded as rotating the specimen in the camera coordinate system.…”

“…For specific situations, such as centrosymmetric 3D deformation measurements, a single-lens stereovision system is employed because of the complexity of stereovision methods. Centrosymmetric deformation is significant and occurs in nearly all types of 3D deformation, such as that of a spherical pressure vessel caused by impact waves [16][17][18] and in bulge experiments [3,19]. Wen proposed an easy method for centrosymmetric 3D deformation measurements with a single camera [17].…”

“…Centrosymmetric deformation is significant and occurs in nearly all types of 3D deformation, such as that of a spherical pressure vessel caused by impact waves [16][17][18] and in bulge experiments [3,19]. Wen proposed an easy method for centrosymmetric 3D deformation measurements with a single camera [17].…”

“…The high-speed dynamic deformation process of a sample panel was investigated using this method, which could resemble impulsive loading for simulating underwater explosions. According to the light path used in this work, which was proposed by Wen [17], the horizontal component of the in-plane displacement was coupled with the out-of-plane displacement. Through the decoupling of the DFC method, 3D deformation can be calculated.…”

Strain Analysis on Electrochemical Failures of Nanoscale Silicon Electrode Based on Three-Dimensional In Situ Measurement

“…A key factor to comprehensively understand the failure mechanism of the Si anode is that the full field deformation and the three-dimensional (3D) shape can be characterized quantificationally in real time during the lithiation/delithiation processes. Traditional full field displacement/strain measurement techniques are mostly based on optical methods, such as DIC (digital image correlation) [33,34], Moiré methods [35][36][37][38] and grid methods [39,40]. However, in situ measurement of Si anode poses extra problems when the anodes are within the electrolyte when they are in service.…”