Fracture and post-fracture behaviour of glass and laminated glass structures

夹层玻璃作为承重结构在建筑和工程建设中的应用日益重要。除了广泛使用的玻璃幕墙外，夹层玻璃结构还被用作防坠落、可行走的玻璃地板以及梁和柱形式的基本承重部件。新型结构玻璃的设计和优化需要材料和结构性能方面的知识。特别是，需要了解玻璃的断裂机理，并可靠地预测层状夹层玻璃的结构断裂后的行为。目前，结构玻璃的建造和设计是基于对已获批准的设计方法的保守处理。达姆施塔特理工大学结构力学与设计院在夹层玻璃结构的制造和试验研究方面拥有多年的经验。德累斯顿理工大学结构分析研究所专注于数值模型的开发和实施。将大量的实验知识和数值模型中的综合经验相结合，是开发预测夹层玻璃结构断裂和断裂后行为的一种有前途的方法。首先，研究了鞋底玻璃结构的断裂力学行为。对热预应力玻璃断裂特性的系统实验记录和主要影响参数的识别是研究的重点。在此基础上，建立了分析模型和数值模型，以描述和可靠地预测断裂过程。该分析模型建立在对整个结构进行能量分析的基础上，用于预测断裂模式。断裂形态和断裂过程的描述应采用新的相场模型。首先，为了理解和刻画玻璃中的基本断裂过程，建立了微碎屑产生的连续介质力学模型。随后，将公式转换为板单元，这样，能够在结构级别上模拟断裂过程。在记录和模拟了玻璃中的破裂过程之后，作为夹层玻璃中间层的聚合物膜的行为成为实验研究和数值模拟的焦点。最后，研究了玻璃与聚合物的结合对断裂的影响。该研究项目的最终目标是开发一个系统的夹层玻璃结构断裂和断裂后特征的实验数据库，并开发、实施和应用一个数字概念，通过结合裂纹演化和材料模拟来描述观察到的行为。

The use of laminated glass as load bearing structure in buildings and engineering constructions gains increasing importance. Next to the use for extensive glass facades, laminated glass structures are applied as fall protection, walkable glass floor as well as essential load bearing component in form of beams and columns.The design and optimisation of novel structural glazing requires knowledge in material and structural behaviour. Especially, the understanding of the fracture mechanism in glass and the reliable prediction of the structural post-fracture behaviour of layered laminated glass is required. The construction and design of structural glazing is currently based on a conservative handling of approved design approaches. The Institute of Structural Mechanics and Design of TU Darmstadt has experience in manufacturing and experimental investigation of laminated glass structures for many years. The Institute for Structural Analysis of TU Dresden is focused on the development and implementation of numerical models. The combination of large experimental expertise and comprehensive experience in numerical models is a promising approach to the development of models to predict the fracture and post-fracture behaviour of laminated glass structures.Initially, the fracture mechanical behaviour of sole glass structures is investigated. The systematic experimental documentation of the fracture characteristics of thermally pre-stressed glass and the identification of the main influence parameters are in the focus of the investigation. Based on this, analytical and numerical models are developed, in order to describe and reliably predict the fracture process. The analytical model is founded on an energetic analysis of the whole structure for the prediction of the fracture pattern. The novel phasefield model shall be adopted for the description of the fracture configuration and the fracture process. At first, a continuum mechanical model is developed for the genesis of a micro-fragment, in order to understand and depict the fundamental fracture processes in glass. Subsequently, the formulation is transferred into a plate element and, this way, the simulation of the fracture process on the structural level is enabled. After documentation and modelling of the fracture processes in glass, the behaviour of the polymeric membrane, which is used as interlayer in laminated glass, is in the focus of the experimental investigation and the numerical modelling. Concluding, the combination of glass and polymer with respect to fracture is investigated. The final goal of the research project is the development of a systematic experimental data base for fracture and post-fracture characteristics of laminated glass structures as well as the development, implementation and application of a numerical concept for the description of the observed behaviour via the combination of crack evolution and material modelling.