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Genetic-fuzzy approach to model concrete shrinkage
Wilson Ricardo Leal da Silva,Petr Štemberka 사단법인 한국계산역학회 2013 Computers and Concrete, An International Journal Vol.12 No.2
This work presents an approach to model concrete shrinkage. The goal is to permit the concrete industry’s experts to develop independent prediction models based on a reduced number of experimental data. The proposed approach combines fuzzy logic and genetic algorithm to optimize the fuzzy decision-making, thereby reducing data collection time. Such an approach was implemented for an experimental data set related to self-compacting concrete. The obtained prediction model was compared against published experimental data (not used in model development) and well-known shrinkage prediction models. The predicted results were verified by statistical analysis, which confirmed the reliability of the developed model. Although the range of application of the developed model is limited, the genetic-fuzzy approach introduced in this work proved suitable for adjusting the prediction model once additional training data are provided. This can be highly inviting for the concrete industry’s experts, since they would be able to fine-tune their models depending on the boundary conditions of their production processes.
Free vibrations of circular arches with variable cross-section
Wilson, James F.,Lee, Byoung Koo,Oh, Sang Jin Techno-Press 1994 Structural Engineering and Mechanics, An Int'l Jou Vol.2 No.4
The differential equations governing free, in-plane vibrations of linearly elastic circular arches with variable cross-sections are derived and solve numerically for quadratic arches with three types of rectangular cross sections. Frequencies, mode shapes, cross-sectional load distributions, and the effects of rotatory inertia on frequencies are reported. Experimental measurements of frequencies and their corresponding mode shapes agree closely with those predicted by theory. The numerical methods presented here for computing frequencies and mode shapes are efficient and reliable.
In-plane free vibrations of catenary arches with unsymmetric axes
Wilson, James F.,Lee, Byoung Koo Techno-Press 1995 Structural Engineering and Mechanics, An Int'l Jou Vol.3 No.5
The differential equations governing in-plane free vibrations of the elastic, catenary arch with rotatory inertia are derived in Cartesian coordinates. Frequencies and mode shapes are computed numerically for such arches with unsymmetric axes, for both clamped-clamped and hinged-hinged end constraints. The lowest four natural frequency parameters are reported, with and without rotatory inertia, as a function of three nondimensional system parameters; the span to cord length ratio e, the slenderness ratio s, and the rise to cord length ratio f. Experimental measures of frequencies and mode shapes for several laboratory-scale catenary models serve to validate the theoretical results.
Drilling to Gabbro in Intact Ocean Crust
Wilson, Douglas S.,Teagle, Damon A. H.,Alt, Jeffrey C.,Banerjee, Neil R.,Umino, Susumu,Miyashita, Sumio,Acton, Gary D.,Anma, Ryo,Barr, Samantha R.,Belghoul, Akram,Carlut, Julie,Christie, David M.,Cogg American Association for the Advancement of Scienc 2006 Science Vol.312 No.5776
<P>Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D.</P>