Study On Dynamic Mechanical Properties Of Transparent Polyurea And Its Coated Glass

With the development of building wall decoration technology,more and more shopping malls,hotels,office buildings and other buildings adopt glass structure as envelope structure.Glass structure in the daily use process will inevitably appear loss,crack and even fall off the risk.At the same time,disasters and accidents occur frequently,among which the impact of flying objects such as typhoons and hurricanes is the main source of damage to glass structures,and the glass debris generated during damage causes secondary damage to people in buildings and structures.Therefore,improve building facades of the strength of the glass structure under impact load,reduce splinters secondary damage to the premises,it is necessary to improve building exterior wall protection performance.As a new type of protective coating with excellent performance and convenient construction,polyurea is widely used in a variety of protective engineering,and because of its good adhesion with the substrate,when the substrate is affected by impact load,polyurea material can effectively wrap the substrate debris,which can reduce personnel injury to a certain extent.Transparent polyurea coated float glass composite was prepared by semi-prepolymer method and coated on float glass surface.The static and dynamic mechanical properties of float glass and polyurea coated float glass composite were tested by Hopkinson pressure rod(SHPB)device.The failure modes of float glass and polyurea coated float glass composite were studied at different strain rates.This paper mainly carries out research from the following aspects:(1)The curing agent(referred to as component A),polyaspartic acid resin and polyether polyamine component(referred to as component B)were synthesized by semi-prepolymer,and the component proportion design and the basic performance test of polyurea were carried out.A transparent polyurea formula was determined when NCO% was 13%,and its brushing performance and curing time were relatively excellent.(2)The quasi-static and dynamic uniaxial compression mechanical properties of transparent polyurea material were obtained by quasi-static compression experiment and dynamic compression experiment under impact load,and the stress-strain curve of polyurea uniaxial compression was obtained,which showed that transparent polyurea material had strain rate effect,and provided a basis for the analysis of mechanical properties of transparent polyurea coated float glass composite structural parts.(3)The mechanical properties of float glass and its transparent polyurea coated float glass composite under quasi-static compression were studied by universal testing machine,and the stress-time graphs and failure patterns of float glass and transparent polyurea coated float glass composite with different coating thicknesses were obtained.The results show that the strength of the composite coated with 1mm polyurea coating and 2mm polyurea coating is reduced by 5.9% and 9.8%,but the failure time is extended by 174% and 211%,and the failure form of float glass specimen is improved after coated with transparent polyurea coating.(4)The dynamic compression experiments of float glass(transparent polyurea coated glass composite)were carried out on the SHPB experimental platform to reveal the mechanism of coating location and coating thickness on the dynamic compression characteristics,failure modes and energy consumption.The results show that transparent polyurea has good coating property and can effectively relieve the damage of float glass under impact load.At the same time,the method of transparent polyurea coating float glass is used to limit and restrain the generation and development of float glass cracks to a certain extent.