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SUMMARY:Rigid Blocks for Masonry with an application to open-well spiral s
 tairs - Prof. Maurizio Angelillo\,  Dipartimento di Ingegneria Civile\, Un
 iversity of Salerno
DTSTART:20190405T140000Z
DTEND:20190405T150000Z
UID:TALK122353@talks.cam.ac.uk
CONTACT:Karen Mitchell
DESCRIPTION:Anyone working at some depth in material engineering knows tha
 t fracture and friction are still the most difficult challenges of modern 
 Mechanics. The main strength of the simplified unilateral model of Heyman\
 , which assumes zero toughness and infinite friction\, is indeed its abili
 ty\, while excluding these two tough guys\, of being still able to make so
 und predictions on masonry behavior at the macro-scale.\nWith Heyman’s a
 ssumptions\, the equilibrium of a structure composed of this ideal masonry
  material\, can be studied with Limit Analysis. Displacement discontinuiti
 es and concentrated stresses are inherent to the unilateral behaviour\, th
 erefore\, analytical and numerical tools must be introduced  that can hand
 le the unilateral No-Tension model with singular stress and strain fields\
 , within the framework defined by the two theorems of Limit Analysis.\nIn 
 particular\, the present study is concerned with the analysis of masonry s
 tructures\, modeled as continua composed of Normal Rigid No-Tension (NRNT)
  material. The NRNT material represents an extension of the model material
  of Heyman to 2d/3d continua. The material is rigid in compression\, and e
 xtensional deformations\, allowed at zero energy price\, can arise and be 
 either regular or singular\; then extensional deformation can appear as ei
 ther diffuse (smeared cracks) or concentrated (macroscopic cracks)\, and t
 here is not any reason to prefer one upon another\, on an energy ground. T
 he fact that rigid block deformation seems to be the preferred failure mod
 e for real masonry structures stems from mechanical characteristics\, such
  as toughness\, interlocking and cohesion\, that are not inherent to the s
 implified NRNT continuum model. So\, in the present study\, we force rigid
  block mechanisms over diffuse cracking. The equilibrium problem is formul
 ated as an energy minimum search\, and a numerical method for approximatin
 g the solution is proposed. With this method the energy is minimized in th
 e set of piecewise-rigid (PR) displacements\, meaning that the structure i
 s partitioned into a finite number of blocks that can move one with respec
 t to the other under unilateral Heyman’s constraints at the interfaces\,
  and a possible equilibrium state is searched by minimizing the potential 
 energy. After formulating and discussing the method\, in this presentation
 \, such numerical approach is applied to explain the equilibrium of some b
 eautiful and puzzling structures\, such as open-well spiral stairs.\n\nMau
 rizio Angelillo\, currently a Professor of Structural Engineering at the S
 chool of Engineering and Architecture of the University of Salerno\, is an
  Architect who graduated at the University of Naples in 1977 and did his p
 ost-graduate studies at the Department of Aerospace Engineering and Mechan
 ics of the University of Minnesota\, from 1982 to 1984.\n\nHis research in
 terests range from Biomechanics (he has worked in respiratory muscle physi
 ology and brain mechanics and is still active in the modelling of the eye)
  to Masonry Mechanics. He started his research on masonry\, both from the 
 theoretical and experimental point of view\, since the early 80ties\, at t
 he University of Naples\, working in the research group of Professor Giova
 nni Castellano. Castellano\, with other Italian scientists (Di Pasquale\, 
 Como\, Baratta\, the Romano brothers and some Italian mathematicians such 
 as Giusti\, Giaquinta and Anzellotti) contributed to the advance\, general
 ization\, formalization and diffusion of the No-Tension model for masonry 
 put forward by Jacques Heyman in 1966.\n	\nMaurizio Angelillo\, has writte
 n several papers concerning masonry structures\, such as vaults\, domes\, 
 churches and stairs\, published in leading Mechanic Journals\, and has bee
 n the coordinator of intensive doctoral and post-doctoral courses on mason
 ry (such as the CISM course 551 (2011)\, Mechanics of Masonry Structures\,
  CISM Courses and Lectures\, Springer 2014). Currently is one of the organ
 izers of the International Summer School on Historic Masonry Structures\, 
 that last year was held in Subiaco (https://historicmasonrysubiaco.wordpre
 ss.com/course/) and this year will take place in Anagni ( https://historic
 masonryschool2019.wordpress.com  ).\n  \n
LOCATION: Cambridge University Engineering Department\, LT6
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