Strength Design Methods for Glass Structures

In this thesis, user friendly and efficient methods for the design of glass structures are developed. The glass structures comprise various boundary conditions. Several types of glass are considered: single layered glass as well as laminated and insulated glass units. Typical load cases for strength design of glass are applied. A recently developed finite element is suggested to be suitable for the modeling of laminated glass structures. It is shown that the new finite element is superior to standard solid elements for modeling of laminated glass. The results show that the element provides excellent capabilities for modeling of complex laminated glass structures with several bolted or adhesive joints. The new element is utilized in the development of a method to compute stress concentration factors for laminated glass balustrades with two horizontal rows with two bolt fixings. The stress concentration factors are represented graphically in design charts. The use of the design charts allow the maximum principal stresses of the balustrade to be determined without using finite element analysis or advanced mathematics. The shear-capacity of adhesive glass-joints is tested in a short-term load-case. Commonly used stiff and soft adhesives are considered. Finite element models of the test are developed to determine the material models of the adhesives. The material models are verified through large-scale tests. For the stiff adhesives and the main part of the soft adhesives, the material models are experimentally validated for both small-scale and large-scale tests. For a group of the soft adhesives, further research is necessary to validate the material models for a large-scale joint. A reduced model for determining the maximum principal stresses of a glass subjected to dynamic impact load is developed and validated. The developed model is general in the sense that it is applicable to arbitrary location of the impact as well as to structures of arbitrary boundary condition. The validation is made for a four-sided supported glass pane and centric applied impact as well as excentric applied impact. It is shown that the model is applicable to small and medium sized structures. Finally it is proven that the model performs very well for a laminated glass balustrade of standard dimensions and with clamped fixings. Finally, insulated glass subjected to soft body impact is analyzed be means of structureacoustic analysis. A parametric study is made with respect to in-plane dimensions, glass thickness and thickness of the gas layer. For quadratic panes, a larger glass has a larger center displacement but lower stresses than a smaller glass. A single layered glass is proven to have only marginally greater stresses than the corresponding double glass. The air layer thickness has almost no influence on the stresses of the insulated glass but the thickness of the glass has a large influence. Finally, there is almost nothing to be gained to add a third glass pane to the insulated unit

Strength Design Methods for Laminated Glass

In this thesis, methods for efficiently determining stresses in laminated glass structures are developed and tested. The laminated glass structures comprise both bolted and adhesive joints. A recently developed finite element is suggested to be suitable for the modeling of laminated glass structures. The element is implemented and tested. It is proven by means of a simple test example that the element can be used in finite element analysis of laminated glass structures and give a good accuracy with a small fraction of the corresponding model size using standard solid elements. As an illustration of how the element would perform when more complicated glass structures are concerned, a similar element is implemented in the commercial finite element software ABAQUS and is used to analyze a laminated glass structure comprising one bolt fixing. The element performs well both when it comes to accuracy and efficiency. It is indicated that the new finite element is well suited for modeling laminated glass structures. The new finite element is rigourously tested and compared to standard solid elements when it comes to the modeling of laminated glass structures. It is shown that the new finite element is superior to standard solid elements when it comes to modeling of laminated glass. The new element is applied to laminated glass structures comprising bolted and adhesive joints. Good results concerning accuracy and efficiency are obtained. The results show that the element may well be suited to model complex laminated glass structures with several bolted or adhesive joints. The new element is used in the development of a method to compute stress concentration factors for laminated glass balustrades with 2+2 bolt fixings. The stress concentration factors are represented graphically in design charts. The use of the design charts allow the maximum principal stresses of the balustrade to be determined without using finite element analysis or advanced mathematics. The stresses can be computed for an arbitrary combination of geometry parameters of the balustrade. It is illustrated how design charts for laminated glass balustrades with 3+3 bolt fixings are developed. Keywords: finite element, computational techniques, laminated glass, stres

Designing Bolt Fixed Laminated Glass with Stress Concentration Factors

Abstract in Undetermined general method for determining stress concentration factors for laminated glass balustrades with two plus two bolt fixings with variable positions is developed. It is demonstrated how the stress concentration factors can be presented graphically in design charts and representative charts are displayed for the case of a more specific bolt-fixed balustrade type. In general, the use of simple formulas and design charts allows the maximum principal stresses of the balustrade to be determined for any relevant combination of variable geometry parameters involved

Large-scale mortality shocks and the Great Irish Famine 1845-1852

This paper considers the consequences of a large scale mortality shock arising from a famine or epidemic for long run economic and demographic development. The Great Irish Famine of 1845-1852 is taken as a case-study and is incorporated as an exogenous mortality shock into the type of long-run unified growth theory pioneered by Galor and Weil (1999, 2000), and modelled by Lagerlof (2003a,b) among others. Through calibration, the impact of such a mortality shock occurring on the cusp of a country's transition from a Malthusian to a Modern Growth regime is then depicted. (C) 2010 Elsevier B.V. All rights reserved