On the planning of handling large arbitrarily curved glass sheets

Abstract

Architects and designers are increasingly using glass as a building material because of its adaptability and versatility. Glass is favored because it is visually versatile and structurally strong; it helps buildings open up to their environment while still protecting them from the elements. Glass can be cut, bent, laminated, tempered and chemically treated to give it desired properties, hence it is favored by many architects and manufacturers. Curved glass gives architects and designers the freedom to create aesthetically pleasing curved glazed facades where straightness, corners, and edges can be enhanced with soft curves. These high-strength sheets can be shaped by machines in specialized furnaces or on-site kilns without breaking and enabling architects to create sculptural glass buildings. Many glass facade panels are made of multiple (two or three) layers of tempered glass sandwiched by a polymer layer to form a single unit, framed by metal extrusions in the form of mullions and transoms. In this thesis, we aim to devise optimal configurations to manipulate these arbitrarily curved glass sheets using suction cups, an important during the fabrication of the panels.The stress in the sheet is calculated using Finite Element methods using SolidWorks and verified using Ansys. Since all the curved glass sheets are made by heating and bending a plane sheet in a kiln available onsite, the minimum edge bounding box (MEBB) is calculated for the curved sheet to find its initial orientation while lifting. A rigorous search for different configurations is done on two sheets to find the stress behavior for different cup configurations, which can be used to develop algorithms and tailor the parameters accordingly to enhance the efficiency of the algorithms. The algorithms such as cuckoo search and adaptive k-means are used and tested to find the optimal lifting configuration of the sheets. The objective function of the study is to minimize the maximum stress in the sheet while lifting it while keeping it well within industry standards since glass is a brittle material and it breaks without any prior warning. A modified Lloyd’s algorithm for k-means clustering is used to find an initial lifting configuration since it ensures a relatively better search point for the following optimization techniques. Heuristic algorithms like steepest descent search and the method of univariate gradient descent are used to calculate the near-optimal solutions and are modified to reduce the run-time of the algorithms. The main objective of this thesis is to provide the on-site construction workers with optimal configuration to manipulate arbitrarily curved glass sheets without breaking them.

Date of Award	2022
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology
Supervisor	Ajay JONEJA (Supervisor) & Pedro SANDER (Supervisor)