更新时间:05-09 上传会员:julu1004
分类:工业大学 论文字数:11823 需要金币:1000个
摘要:防弹玻璃是由玻璃(或有机玻璃)和优质工程塑料经特殊加工得到的一种复合型材料, 它通常是透明的材料,譬如聚碳酸酯纤维热塑性塑料。它具有普通玻璃的外观和传送光的 行为,对小型武器的射击提供一定的保护。随着现代汽车,高速铁路的迅猛发展,特别是 速度的大幅提高与安全性的需要,汽车也广泛应用了此类玻璃作为前挡风玻璃。汽车前挡 玻璃通常采用在两片玻璃间夹入树脂材料在高温高压下粘合而成的夹层玻璃。对于前档玻 璃冲击破坏强度的研究,过去主要依赖试验,近年来随着计算机性能的迅速提高和有限元 与 SPH 耦合方法不断完善,使前档玻璃冲击破坏强度的仿真研究成为可能。
本文以冲击破坏试验为基础,利用功能强大的前处理商用软件 HyperMesh 建立前档玻 璃冲击破坏分析用 SPH 单元与拉格朗日单元相耦合的仿真模型,并用在冲击破坏方面具有 良好应用业绩的非线性显式有限元动力分析软件 Ls-Dyna,研究该前档玻璃在时速 586 公 里、质量为 1 公斤铝弹撞击下的冲击破坏过程。针对玻璃冲击破坏后碎片的飞散不可避免, 通常的有限元方法难以描述这一现象的特 点。本文采用光滑粒子流体动力学法 (SPH-Smoothed Particle Hydrodynamic)与有限元法(FEM)耦合的计算方法,研究前档玻 璃冲击破坏过程,其中外侧玻璃使用 SPH 单元,内侧玻璃使用不共用节点的有限立体单元, 其它各层树脂等采用普通有限立体单元建模。SPH 层玻璃与普通有限单元之间的耦合使用 Ls-Dyna 的普通接触方法进行定义。综上所述,尽管通常的有限元方法难以描述脆性材料 的破坏过程和碎片飞散现象,但本文研究发现,上述模型化方法,对于解决此类问题是有 效的。
仿真计算结果表明,前档玻璃破坏过程(包括外侧玻璃的飞散状况)和内侧 PET 材料的 变形状况与实验基本一致,说明利用 SPH 和 FEM 耦合方法仿真分析高速列车前档玻璃冲击 破坏现象切实可行。
关键词:高速列车,前档玻璃,冲击破坏,SPH/FEM 耦合方法
Abstract:Bullet-proof glass is a composite material which made of glass (or plexiglass) and high-quality engineering plastic with a special processing, and usually it is transparent material, such as Polycarbonate Glass Fiber thermoplastic. It has appearance of ordinary glass and can transmitting light. And the firing of small arms cann’t breakdown it. With the rapid development of modern cars and high-speed train, in particular a substantial increase in speed and security needs, wider application of such cars as the front windshield glass, which is compressed by glasses and resin. And in the past, most researches depend on experiments. Recently, with the rapid improvement of computer performance and development of finite element analysis (FEA) software, numercial simulation has been becoming a important method to investigate the impact strength of the laminated glass.
Based on the experiment data, HyperMesh, a powerful pre-processing business software is used to describe the simulation model, which is made up of the SPH and Lagrangian coupling unit. In this paper,Ls-Dyna, a non-linear dynamic explicit finite element analysis software, is also used in this paper to study the process. In this process, a glass with special structure is impacted by an aluminum which is weighed 1 kg and with the speed of 586 km. We all know that the glass is a typical brittle material. Thus the flying debris is inevitable, which is beyond the touch of ordinary finite element analysis software. So the smooth particle hydrodynamics method and the finite element method are coupled in calculation. That is to say, the SPH simulation is used to describe the outer layer of glass, the FEM with unshared node is used to describe the inner layer of glass, and ordinarey FEM is used to describe other layers.
To sum up, the destruction process of the pre-stall glass and the deformation of PET materials are basically consistent with experimental, according to simulation results. That is to say, it is viable to use SPH and FEM coupling method to simulate and analyze the destruction of the phenomenon of the front windshield of high-speed train.
KEYWORDS: High-Speed train, The front windshield, Impact fracture, SPH/FEM coupling method