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Dislocation Density Function Dynamics DDFD

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Results Publications Pictures Movies 🆕 Simulations
DDFD code request
Results Publications
Pictures Movies 🆕 Simulations
DDFD code request

In dislocation density function dynamics (DDFD), developed by Alfonso H.W. Ngan of the University of Hong Kong, the evolution of “all-dislocation” is governed by a simple kinematic evolution equation [1,2]:

ρ̇ ( r,θ ) = - ( ρ v ) r θ̂ movement - ( ρ ω ) θ tilting
All-dislocation kinematic equation

DDFD Presentation Slides HKU Mech Engg

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[1] A.H.W. Ngan, MRS Commun. 7 (3), 583–590 (2017). (DOI: 10.1557/mrc.2017.66)
[2] Alireza Kalaei, Yang Xiang, and Alfonso H.W. Ngan, Int. J. Plast. 158, 103433 (2022). (DOI: 10.1016/j.ijplas.2022.103433)

About Professor Alfonso Ngan Hing Wan顏慶雲教授
 Professor Alfonso H.W. Ngan (顏慶雲教授) is currently Kingboard Professor in Materials Engineering, Chair Professor of Materials Science and Engineering, as well as Head of Department of Mechanical Engineering, at the University of Hong Kong. He obtained his BSc (Eng) degree from the University of Hong Kong (HKU) in 1989 as the Williamson Prizeman (top Engineering graduate), and PhD from the University of Birmingham in the U.K. in 1992. After a year of postdoctoral training at Oxford University in the U.K., he joined HKU in 1993, and was promoted through the ranks to Chair Professorship in 2011.
 Professor Alfonso Ngan is a leading authority in the microstructural basis of properties of engineering materials, in particular, crystalline defects and their modeling, and nanomechanics including applications to biological systems. He has published over 200 ISI papers, and co-authored two books. His main contributions include a method, the so-called “Feng-Ngan equation”, for correcting viscoelastic effects in nanoindentation measurements of soft materials, which has been used by peer researchers in their work as reported in more than 100 ISI publications by now. His research-related honours include the prestigious Rosenhain Medal and Prize from the Institute of Materials, Minerals and Mining, U.K., in 2007—he is the only non-British national so far to have received this award since its establishment in 1951. He was also awarded a higher doctorate (DSc) from his alma mater the University of Birmingham in 2008, the Croucher Senior Research Fellowship in 2009, Fellow of the Hong Kong Academy of Engineering Sciences (FHKEng) in 2014, Changjiang Professorship from the Chinese Ministry of Education in 2019, the Guanghua Engineering Science and Technology Prize of the Chinese Academy of Engineering in 2020, and in 2021 he was elected International Fellow of the Royal Academy of Engineering (FREng).
 Professor Ngan is an expert advisor to the Hong Kong Government's Water Supplies Department, solving problems including lead-leaching in potable-water systems and corrosion in Hong Kong's unique sea-water flushing system, and is a Trustee of the Croucher Foundation. He has played advisory roles in a number of government committees and tertiary institutions. He is serving on the Gordon Research Conference Board for Hong Kong Conferences. He served as one of five Meeting Chairs in the Materials Research Society (MRS) 2017 Spring Meeting held in Phoenix, Arizona, USA, in April 2017. 

Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China

Novel Thin-film Actuating Materials Group (Alfonso's Experimental Research)

Croucher Scholar Page: Alfonso Hing-wan Ngan - 顏慶雲 教授

2017 MRS Spring Meeting: Interview with Co-chairs Alfonso Ngan and Eli Sutter