Keynote Speaker

Abstract: Generations of research students have been taught that the strength of brittle materials containing microcracks follows the Weibull distribution. The Weibull modulus M has a constant value which describes the strength scatter of large specimens. The characteristic strength σ_ch defines the strength at a failure probability of 63.2%, and has no further application. In this talk, we suggest that if the microcracks are suppressed or pre-existing defects are smaller than the average grain size G, a new micro-grain Weibull strength distribution can be obtained. In addition, the characteristic strength, σ_ch, determined from the micro-grain Weibull plot with a high M value (>10), and an average G could be used to evaluate the fracture toughness K_IC without testing specimens with long cracks. That is, K_IC ≈ 2 σ_ch √3G . This provides a new physical interpretation of the characteristic strength in the Weibull equation. But, is this a new concept in fracture mechanics of brittle materials? Available results in the published literature offer some support.

Biography: Prof. Mai Yiu Wing （米耀荣）received his PhD, DSc and DSc (honoris causa) from the University of Hong Kong in 1972, 1999 and 2013, respectively. He spent more than 4 decades as an academic at the University of Sydney where he rose through the ranks to a University Chair in 2004. He retired in May 2023 and returned to PolyU in HK in November 2023 as a Distinguished Chair Professor. His research interests are fracture mechanics and advanced composites. Prof. Mai was elected to fellowships of several prestigious academies, including the Chinese Academy of Engineering, the Royal Society of London and the Australian Academy of Science.