Characterization of eccentric internal crack expansion in brittle materials at low temperature

Abstract

Crack expansion in brittle materials due to low temperatures is a prevalent issue in engineering practices, particularly in cold regions and mining engineering. Understanding the behavior of cracks in materials subjected to thermal stress is crucial. Current research on crack extension under thermal stress primarily focuses on surface or penetrating cracks in materials, with limited studies on the expansion of three-dimensional internal cracks. This study examined the impact of thermal stress on the expansion of eccentric internal cracks within glass material, which were fabricated using laser technology to prevent surface damage. The specimens were subjected to low temperatures to observe the expansion pattern of internal cracks. Furthermore, three-dimensional (3D) numerical simulations were performed to calculate stress intensity factors (SIFs) and illustrate the crack expansion paths, thereby elucidating the expansion mechanism of eccentric internal cracks. The results revealed that thermal stress at the crack tip influences the expansion of prefabricated eccentric cracks, resulting in distinct crack morphologies such as ’S’ and ’L’ shapes. Moreover, the crack expansion within the specimen exhibited a mixed mode I-II-III crack. These findings provide valuable insights into the expansion of internal cracks in brittle materials under thermal stress.