钢化玻璃自爆机理与自爆准则及其影响因素

Mechanism and Criterion of Spontaneous Breakage of Tempered Glass

钢化玻璃应用广泛,但其自爆问题是一个被称为玻璃癌症的难题,其特征是突发性和灾难性,因此如何减少和预防预测玻璃自爆是钢化玻璃工程应用领域的关键问题。本文重点探讨了钢化玻璃的自爆机理,揭示了钢化玻璃为什么会自爆,什么条件下可能自爆和各种影响玻璃自爆的内在与外在因素。研究发现由于杂质和缺陷引起的应力集中是导致自爆的关键因素,证明钢化玻璃内部的残余应力和局部强度均是非线性分布,局部强度在玻璃表面最高,中间层最低,自爆的根本原因是内部的应力集中超过了局部强度,而传统认识的硫化镍或单质硅等各种杂质只是引起自爆的间接原因。提出的钢化玻璃自爆准则为玻璃破碎分析提供了有用的参考。

Tempered glass is widely used in building and furniture as a type of safety glass. However, spontaneous breakage of tempered glass is a serious problem known as ＂glass cancer＂ characterized by sudden and catastrophic. It is important to reduce, prevent and predict this phenomenon of spontaneous breakage of tempered glass through preparation and application. This study focused on the mechanism of spontaneous breakage of tempered glass and provided the answers on the reasons of spontaneous breakage. The critical conditions including internal and external influence factors on spontaneous breakage were discussed. It is demonstrated that the spontaneous breakage of tempered glass is caused by stress concentration in glass itself while the stress concentration may result from various particles or defects in the glass. Furthermore, local strength is defined for tempered glass which is non-linear distributed along thickness of the glass together with residual stress. The maximum of the local strength occurs at surface of tempered glass, while the lowest value is at neutral layer. The fundamental reason behind spontaneous breakage of tempered glass is that the stress concentration in the glass exceeds local strength, while impurities, such as nickel sulfide or monolithic silicon particles traditionally considered as the breakage causes, are actually indirect causes. A criterion for spontaneous breakage of tempered glass is also revealed which is useful for analysis of breakage of glass.