Thermal Physical Properites And GT Forming Simulation Of Automotive Rear Glass

Automotive glass is one of the most important accessories in automobile manufacturing.Its dimensional accuracy,mechanical properties and optical properties are related to the safety quality and driving experience of automobiles.Automotive glass faces unprecedented opportunities and challenges.With the difference of car brands,installation parts,and even different parts of the same car windshield,the geometric sizes and radius of curvature is also different.Currently,private order are increasing.In order to meet the needs of customers,the R&D departments and production departments usually determine the corresponding production process parameters through a large number of glass trial-and-error manufacture tests,which is rather time-consuming and cost-consuming,and cannot adapt to the fierce competition environment of the automobile market and the rapid response to private customer’s needs.So the intelligent manufacturing of automobile glass is the only way for the transformation and upgrading of automobile industry and adapt to the increase of personalized demand.In recent years,the simulation and process optimization of automotive glass forming process has been listed as one of the main research projects of China’s automotive glass intelligent manufacturing simulation platform.The research work of this thesis is based on the construction requirements of intelligent manufacturing simulation platform in Fuyao Glass Industry Group Ltd.Combined with on-site investigation,theoretical analysis,experimental research and simulation,the main research work and some important research results have been obtained and presented in the following.The thermal performance test of the original plane glass was carried out.The specific heat,thermal expansion and viscosity curves of the automotive glass were obtained.Based on the experimental test results,the mechanical properties of the automotive glass were analyzed with temperature,which provide a numerical simulation and production line analysis.Based on the in-depth analysis of the viscous and elastic mechanical behavior of automotive glass,the three-dimensional transient constitutive equation model of automotive glass GT forming process was established,which provided a theoretical basis for numerical simulation of automotive glass GT forming.The three-dimensional digital reconstruction of the GT production line and equipment of Fuyao Glass Industry Group was carried out.Using the case of Mercedes-Benz X156 glass that Fuyao has already put into production,the three-dimensional transient coupling model of "structure-temperature-flow field" in the whole process of "heating-forming-dropping-tempering" was established.The fine description and control of the point-by-point curvature of the glass surface were realized,and the geometric deviation analysis of the automobile glass caused by the springback after hot pressing of the mold was predicted.According to the results of temperature field,stress field and displacement field,the distribution of temperature field and the residual stress of automobile glass affected by temperature field under different process conditions were studied.The accuracy of glass constitutive model and simulation method is verified.The digital design method of the mold profile was established,that is,according to the target glass geometry after molding,the glass springback amount was compensated by treverse cyclical adjust,and the three-dimensional target molding die size was graduallygained on approach approximat And the concave and convex mold surface for the production of X156 glass was abtained finally.During the research process,based on the simulation results,the temperature field distribution,stress field distribution and strain field distribution of automotive glass GT forming were systematically studied,and the process parameters such as heating temperature,forming temperature and falling height of Punch-pin were established.The influence of process parameters such as heating temperature,forming temperature and Punch-pin height on the springback and residual stress of automobile windshield GT after forming is obtained,which provides valuable reference for the actual production line of automotive glass GT forming.