Yiu-Wing Mai

Professor
Fellowships of Australian Academy of Science, UK Royal Society, and Chinese Academy of Engineering
The Hong Kong Polytechnic University, Kowloon, Hong Kong, China

Biography: Professor Yiu-Wing Mai received his PhD, DSc and DSc (honoris causa) degrees from the University of Hong Kong in 1972, 1999 and 2013, respectively. In 1976, he joined the University of Sydney, where he obtained his DEng degree in 1999. His major research interests are on fracture mechanics and advanced composites. Prof. Mai is the recipient of the Scala Award of the International Committee on Composite Materials in 2015, the AA Griffith Medal of the UK Institute of Materials, Minerals and Mining, and the AGM Michell Medal of Engineers Australia in 2016. He was also awarded the 2023 Warner T. Koiter Medal of ASME. He was elected to the Fellowships of the Australian Academy of Technological Sciences and Engineering in 1992, the Australian Academy of Science in 2001, the UK Royal Society in 2008, the UK Royal Academy of Engineering in 2011, and the Chinese Academy of Engineering in 2017.

Invited Lecture: Weibull strength distributions of brittle ceramics and fracture toughness evaluation without long cracks: controversy or reality?

Abstract: The classic Weibull strength distribution has been re-interpretated by a new concept of micro-grain distributions which we conceptualized over the past two years. We proposed that the new micro-grain Weibull strength distribution is intrinsic and pertinent to micro-grain structures after the micro -defects are sufficiently suppressed. We also proposed that the commonly-known Weibull strength distribution linked to micro-defects is extrinsic, depending on the micro-cracks produced owing to material processing and sample preparation. The micro-grain Weibull strength distributions display negligible size effect; and the median strength in combination with the average micro-grain size can be used to determine the fracture toughness KIC. This means that KIC can be evaluated from polished samples without the need for artificial long cracks. We finally confirm this new micro-grain Weibull strength distribution concept using results of brittle polycrystalline ceramics with microstructures varying from nano-, micro- and to macro-scales.