Numerical modelling of sandwich panels with a non-continuous soft core

The paper presents the problem of static analysis of sandwich structures with a non-continuous soft core. In the numerical 3D FE models, the core is divided into separated parts. The contact between these parts has the form of unilateral constraints. The model also allows for local debonding of the facing and local imperfections of sandwich panel geometry. Particular attention is paid to the problem of local instability of the facing that is compressed during bending. The phenomenon of progressive damage and the influence of non-continuity of the core on the structural behavior of the sandwich panel is also discussed

Thermomechanical buckling of laminated composite plates using mixed, higher-order analytical formulation

A novel analytical mixed theory based on the potential energy principle has been presented in this paper to investigate backling response of laminated composite plates subjected to mechanical and hygrothermal loads. Two sets of higher-order mixed models have been proposed on the basis of an individual layer as well as equivalent single layer theories by selectively incorporating nonlinear components of Green's strain tensor Displacements, as well as transverse stress continuities, have been enforced in the formulation of models by incorporating displacements and transverse stresses as the degrees-of-freedom. The modal transverse stresses have been obtained as eigenvectors and thus their separate calculations have been advantageously avoided. Solutions from the models have been shown to be in excellent agreement with the available three-dimensional elasticity solutions. Few benchmark solutions have also been presented for the bi-axial compression-tension loading

Stability of composite and sandwich struts by mixed formulation

A unified mixed, higher-order analytical formulation is presented to evaluate the buckling of laminated composite struts. The formulation can also be used to evaluate the overall buckling and wrinkling loads of a general multilayer, multicore sandwich strut having any arbitrary sequence of stiff layers and cores. The usual assumptions of thin stiff layers and antiplane core are advantageously eliminated. Displacements as well as transverse stress continuities are enforced in the formulation by incorporating them as the degrees of freedom, thus avoiding separate calculations of the modal transverse stresses. Two sets of mixed models are proposed, based on individual layer and equivalent single layer,theories, by selectively incorporating, nonlinear components of Green's strain tensor. Limitations of the equivalent single-layer theories and typical,, simplifying assumptions are highlighted. A parametric investigation is presented, concerning the influence of the material and geometric Properties on the buckling behavior of a sandwich strut. A few recommendations are also made for the stability analysis of laminated composite struts

Stability of sandwich plates by mixed, higher-order analytical formulation

A unified mixed, higher-order analytical formulation has been presented in this paper to predict general buckling as well as wrinkling of a general multi-layer, multi-core sandwich plate having any arbitrary sequence of stiff layers and cores. Assumptions of thin stiff layers and anti-plane core, which are usually made in the analysis of sandwiches, have been eliminated in the present formulation. Displacements as well as the transverse stress continuities have been enforced in the formulation by incorporating them as the degrees-of-freedom. The modal transverse stresses have been obtained directly as eigen vectors and thus their separate calculations have been advantageously avoided. Two sets of mixed models have been proposed on the basis of individual layer as well as equivalent single layer (ESL) theories by selectively incorporating non-linear components of Green's strain tensor. Solutions from the models have been shown to be in excellent agreement with the available three-dimensional elasticity solutions as well as with the available experimental results. It has been demonstrated that the ESL theories cannot accurately evaluate the overall buckling as well as the wrinkling loads of sandwiches. Limitations of the typical simplifying assumptions have also been highlighted. (C) 2003 Elsevier Ltd

Modeling Domestic Architecture at Late Minoan IIIC Vronda, Kavousi, Crete

Glowacki, K.T., and S.K. Dafedar. “Modeling Domestic Architecture at Late Minoan IIIC Vronda, Kavousi, Crete.” Poster presented at the 111th Annual Meeting of the Archaeological Institute of America, Anaheim, CA, January 6–9, 2010. DOI: 10.13140/RG.2.1.4712.1444.Excavations at the archaeological site of Kavousi Vronda in eastern Crete brought to light a small rural settlement dating to the LM IIIC period (12th-early 11th centuries B.C.). At the time of abandonment, the settlement consisted of 15-20 houses, a large building with storerooms that may be the ruler's dwelling, a communal temple, and a kiln. While abandonment and post-abandonment processes have resulted in much disturbance, Vronda has provided a wealth of data for understanding LM IIIC domestic architecture, household activities and society at the end of the Bronze Age. This poster presents a digital reconstruction of the Vronda settlement, based upon the data (hand-drawn plans, section and elevations) recorded at the time of excavation, and evaluates the potential contribution of various graphics software for modeling the vernacular architecture of LM IIIC Crete. AutoCAD tracings of the original data were imported into Autodesk 3ds Max to render the topographic contours of the hill and extrude walls and features of individual buildings. Proposed reconstructions of no longer preserved details such as roof construction, door lintels, and chimneys were added directly in 3ds Max. Panoramic photos taken from the summit were mapped onto a cylinder to provide a photorealistic representation of the surrounding landscape. The project suggests several ways in which models of this type enhance archaeological research and provide new insights into the built environment of an ancient community

What happens between the taq and the Old City of Srinagar in Kashmir?

This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Thesis: S.M., Massachusetts Institute of Technology, Department of Architecture, 2019Cataloged from PDF version of thesis.Includes bibliographical references (pages 93-96).This thesis explores the importance of the traditional building crafts as integral and inextricable parts of traditional architecture, known as the 'taq', in the Old City of Srinagar and delves into the question, 'How does architecture become a platform for the different building crafts and a medium to facilitate their development, and vice versa?' The study shows the interrelation of Architecture and Craft through five scales of spatial configuration in the old city: 1) the urban context of the city; 2) the streetscapes in it; 3) the Dargahs amidst neighbourhoods; 4) traditional houses in the city; and 5) finally the crafts as they have been practiced individually in incorporated within interior architecture. This approach seeks to understand the relation of Architecture and Craft in Srinagar at different levels and to explore in detail, where the two meet and where they diverge. It is important to explore the intricate interdependency of these systems of spatial expressions and building functions to study their growth and diversification that we see in the old city of Srinagar today. There is ample research on both Traditional Crafts and Architecture in Kashmir as individual and separate topics of study, but this thesis study helps to look at them as cohesive and mutually supportive elements of the traditional built environment in the urban context of the Old City of Srinagar. It explores those relationship through fieldwork and visual methods of studying and enquiring at different spatial scales (e.g. maps at the urban scale and photography and drawing at the architectural scale). The results of the study encourage a new and different way of looking at, and studying, the relationship between architecture and craft in the old city of Srinagar. It synthesizes a framework that can have a broader application to study areas with similar circumstances in other regions of India.by Sharmeen Sayed Dafedar.S.M.S.M. Massachusetts Institute of Technology, Department of Architectur

Vronda Reconstruction - Preliminary (Nov. 2009)

YouTube video (00:55) with partial fly-through of the digital reconstruction of the Late Minoan IIIC settlement, beginning with Building I-O-N on the western slope and circling the communal shrine (Building G).Preliminary virtual reconstruction of the archaeological site of Kavousi Vronda in eastern Crete, Greece. This video segment tours part of the Late Minoan IIIC settlement, beginning with Building I-O-N on the western slope and circling the communal shrine (Building G). 3D modeling by Sayed Kashif Dafedar (M.Arch 2009, Texas A&M University) under the direction of Profs. Kevin T. Glowacki and Nancy L. Klein, Department of Architecture, Texas A&M University. Background music: “Alli agapi” from the CD Erotokritos (2000), featuring Charilaos Papadakis on the lyra. Used with permission