Experimental And Numerical Study On Crack Propagation And Fragmentation Of Architectural Glass Subject To Impact Load

Glass windows are widely used for architectural purposes in modern society.However,due to the relatively weak strength and brittleness of glass material,glass windows are vulnerable parts in buildings under impact load and the associated glass fragments can also impose a huge threat to citizens.Therefore,it is necessary to systematically study the breaking process and impact resistance of architectural glass under impact load.However,there is still a lack of experimental study on crack propagation,energy absorption and impact resistance of impacted building glass under different boundary conditions.The accurate simulation of cracks and fragments of building glass under impact load has always been a difficult problem,and the applicability of various numerical methods in simulating related problems needs to be studied.In this dissertation,the crack propagation and breakage of architectural glass under impact load are studied by means of experiment and numerical simulation,and the failure mode as well as impact resistance are summarized.The specific research contents are as follows:Firstly,dynamic impact test was carried out on flat and PVB laminated glass specimens under two kinds of boundary conditions by a high-speed servo-hydraulic testing machine(INSTRON VHS 160/100-20).The crack propagation and failure process of glass under different impact velocities were studied.The results show that radial cracks and circumferential cracks appeared on glass specimens under impact;the specimens showed local failure characteristic under high-speed impact,and the number of cracks as well as the broken area were smaller than that under low-speed impact;under impact sharp dagger-like fragments were formed in the case of framed flat glass,and scaly fragments were formed in addition to dagger-like fragments in the case of four point-supporting flat glass.In this dissertation,energy absorption was also compared between glass specimens,and the results show that in general the energy absorption effect of the four point-supporting glass is stronger than that of the framed glass.At last,through regression analysis of the peak resistance of architectural glass under different impact velocities,the empirical formula of the resistance of architectural glass under 0.1m/s-10m/s impact is obtained.At the same time,based on the impact test,finite element method and meshless method are used to simulate the crack propagation,failure mode and splash of fragments of framed flat glass under impact load.The applicability of different simulation methods in simulating the crack propagation,failure mode as well as splash of fragments of impacted building glass is studied.The results show that the node-split method and the material point method are effective in simulating the crack growth of building glass specimens under high-speed impact,and the former is superior to the latter in simulating debris splash and computing efficiency.