Study and development of testing technology for in-situ X-ray CT mechanical testing observation system and combination with CAE data analysis technology

X-ray computer tomography (CT) is a technology that enables nondestructive observation of internal structures in objects. Utilizing that ability, we have developed a system that can capture tomographic images of objects as they are subjected to mechanical loading, such as during tensile, compression, bending, and puncture tests, simply by placing a small testing machine on the rotating stage inside an unmodified commercial X-ray CT system. This system enables observation of internal structures three-dimensionally, which was not possible with conventional video image correlation or other methods. Furthermore, 4D-CT data compiled from time series data of 3D images acquired while increasing the load in steps can be used to understand the status of structural changes, strain, changes in void shape or volume, and crack propagation from various angles. Applicable testing machines can be used to test large workpieces and parts, which was not possible with conventional testing machines for in-situ X-ray CT inspection. In addition to observing cracks, damage, and other microscopic phenomena, the 3D image correlation method can also be used to quantitatively determine 3D displacements and strain inside objects being tested. That has expanded the possibilities for new combinations of testing, measuring, and computer-aided engineering (CAE) analysis. This article describes the system, examples of image acquisition, test methods, and examples of combination with CAE analysis technology as a digital twin. (author)