A finite element model for simulation of delaminations in laminated glass panels subjected to cyclic thermal loading

夹胶玻璃板由至少两个用聚合夹层材料粘接的玻璃组件组成。薄夹层（0.38 - 2.28 mm）通常由聚乙烯醇丁醛（或PVB）组成，而玻璃层的厚度为3-25 mm。如果玻璃板最终破碎，层压板可以保证剩余的承载能力。应用于结构和汽车工程，造船，飞机工业和光伏电站。特别是在室外应用，温度暴露增加，损伤演变，由于分层发生。经过多年的使用，玻璃与聚合物间层之间的结合可能会减少，从而影响可用性和剩余承载能力。该项目涉及一个模型的开发，以描述由于循环热负荷而导致夹层玻璃板分层的开始和传播。这需要一系列的基础研究任务。由于层压板结构中各成分的行为完全不同，导致现有的数值模型不能应用于复杂的应力场。二维模型是研究的基础，与完全三维离散化或所谓的fe2模型相比，二维模型只需要少量的计算时间。为此，必须发展描述分层扩展的热-力学边值问题和运动学及本构行为的耦合问题。为了解释几千个周期，时间多尺度模型是进一步工作的一部分。参数研究与几个量的变化（材料选择和中间层的材料参数，缺陷和初始曲率的影响）导致结构改进。夹层安全玻璃作为设计元素越来越多地应用于各个技术领域。该研究项目旨在为这一重要结构元素的力学理解提供基础贡献。

Laminated glass panels consist of at least two glass components glued with polymeric interlayer materials. Thin inter layers (0,38-2,28 mm) often consist of polyvinyl butyral (or PVB) whereas the glass layers are with 3-25 mm essentially thicker. The laminate ensures the residual carrying capacity if the glass plates are ultimately broken. Applications are given in structural and automotive engineering, naval architecture, aircraft industries and for photovoltaic plants. Especially in outdoor applications with temperature exposure increased, damage evolution due to delamination occurs. Decreasing bonding between glass and polymer interlayer may occur after years of usage and thus influences usability and residual carrying capacity.The project deals with the development of a model to describe initiation and propagation of delaminations in laminated glass panels due to cyclic thermal loading. This requires a series of basic research tasks. Due to the structure of the laminate with entire different behavior of the constituents and hence resulting complicated stress fields existing numerical models cannot be applied. A two-dimensional model, which requires only a fractional amount of computing time in comparison with fully three-dimensional discretizations or so-called FE2-models, is basis of the research. For it the coupled thermomechanical boundary value problem and the kinematics as well as constitutive behaviour to describe propagating delaminations have to be developed. To account for several thousand cycles a time-multiscale model is further part of the work. Parameter studies with a variation of several quantities (material choice and material parameters for the interlayers, influence of imperfections and initial curvatures) give rise to structural improvements. Laminated safety glass is increasingly used as design element in various technical fields. The research project is to provide fundamental contributions for the mechanical understanding of this important structural element.