玻璃钢化冷却过程预控模型与仿真

发布时间：2018-05-19 18:30

  本文选题：玻璃钢化 + 温度场　； 参考：《武汉科技大学》2015年硕士论文

【摘要】：钢化可以消除或减少玻璃表面的微裂纹，改善其机械性能，提高其热稳定性。冷却是钢化的最后一道工艺，由于冷却过程中板面冷却均匀性很难保证、各点冷却时间长短不一，易产生玻璃自爆或表面应力斑，降低玻璃钢化质量。为此，需预控冷却过程，稳定钢化质量，主要包括： 分析冷却过程中工艺控制需求，确定冷却速度和冷却时间为预控对象；根据傅里叶定律和玻璃应力松弛、结构弛豫特点，建立冷却速度与温度场之间关系模型、温度与玻璃粘弹性本构模型；推导冷却速度与残余应力之间变化关系，建立预控数学模型，通过冷却速度的调整，实现残余应力的预控。基于有限元分析方法，建立玻璃钢化冷却过程中温度、应力变化过程的仿真模型。 运行预控模型和进行多组仿真实验，获得相关结果：设定玻璃厚5mm及对流换热系数为190W/(m2K)，在前40s内应以0.375℃/s2匀减速加压急冷，，在40s到80s间以0.125℃/s2均减速冷却，从而可约在7s时于玻璃板中心线上获得高达151℃的温差，保证钢化程度；在10s内将玻璃温度降到转变温度区以下，基本定型玻璃结构；获得近似抛物线的残余应力分布，可提供玻璃受力时所需的预应力。证明所建立的预控数学模型具有一定的准确性和可靠性，可为实际生产提供一定的参考或指导。
[Abstract]:Toughening can eliminate or reduce the microcracks on glass surface, improve its mechanical properties and improve its thermal stability. Cooling is the last process of tempering. Because the uniformity of plate cooling is difficult to guarantee during the cooling process, the cooling time varies from point to point, so it is easy to produce glass self-explosion or surface stress spot, and reduce the quality of glass toughening. Therefore, it is necessary to pre-control the cooling process and stabilize the tempering quality, including: According to Fourier law, glass stress relaxation and structure relaxation, the relationship between cooling rate and temperature field is established. The relationship between cooling rate and residual stress is deduced and the mathematical model of pre-control is established. The residual stress is controlled by adjusting the cooling rate. Based on the finite element analysis method, the simulation model of temperature and stress change in the process of glass tempering and cooling is established. The results are as follows: set the glass thickness 5mm and convection heat transfer coefficient to be 190W / m ~ (2) K ~ (-1), 0.375 鈩

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