Research On The Mechanical Properties Of Toughened Vacuum Glass And Toughening Damage Evaluation Method

Vacuum glass is a kind of green building material with excellent thermal insulation performance,which can be widely used in external protective structures such as building doors,windows and curtain walls.At present,almost all of the existing vacuum glass is made of ordinary glass.The vacuum glass made of ordinary glass does not meet the requirements for safe use due to its low bending strength and low impact strength.The use of tempered glass to make tempered vacuum glass can significantly increase the strength of the product,which is the future development trend of vacuum glass.Tempered vacuum glass is a flat plate-like structure,so it can be simplified to a rectangular thin plate of equivalent thickness,establish a mechanical model,and use elastic mechanics and other related theories to analyze its uniform load under atmospheric pressure and concentrated load of the supporting column.The response of stress and strain provides a theoretical basis for the structural design and optimization of toughened vacuum glass.Based on the finite element analysis theory,using ANSYS Workbench software,a finite element model of tempered vacuum glass was established.The support stress and deformation analysis of the tempered vacuum glass model under different support column arrangement spacing,height and diameter conditions,the results show that the maximum support stress and deformation of the tempered vacuum glass is greatly affected by the support column spacing and diameter.The height of the support column is relatively small,and the support structure of the tempered vacuum glass has been optimized by considering multiple angles.The lack of support for tempered vacuum glass was analyzed,and the clearance for lack of support for tempered vacuum glass was defined.Annealing test was carried out on the tempered glass with a prestress of 120 MPa in a vacuum environment.The test showed that the surface stress of the tempered glass deteriorated significantly after heating above 350℃.After heating for 3 hours at 350℃,the residual stress dropped to near the national standard tempered glass The minimum prestress value is 90 MPa.In order to ensure that the tempered vacuum glass still has a certain pre-stress after being formed,the sealing time must be further compressed,or a low temperature solder with a sealing temperature of less than 350℃ must be used.Using Pb-Bi-B system glass frit,a tempered vacuum glass was prepared at a sealing temperature of 350℃,and its surface stress distribution was tested.It was found that the tensile stress on the outer surface of the support point of the tempered vacuum glass and the compressive stress on the surface of the tempered glass were superimposed.The stress on the surface of tempered glass drops,and the stress on the surface of tempered vacuum glass changes in a wavy shape.According to the test and evaluation of the parameters that affect the tempering performance of the tempered vacuum glass,the basic parameter matrix of the tempering performance of the tempered vacuum glass is obtained.Principal component analysis is used to reduce the dimensionality of the parameters,so as to avoid the influence of the linear correlation between the parameters on the comprehensive evaluation of tempered vacuum glass.Using hierarchical cluster analysis,the tempered vacuum glass samples were classified according to their index characteristics and according to the degree of intimacy in nature,and a tempering damage evaluation method was established.