Research On Sublimation Of Composite Ice And Its Influence On The Mechanical Properties Of Ice Shell

As a new type of ice and snow structure developed in recent years,the large-span composite ice shell structure has expanded the boundaries of traditional ice and snow structures in terms of construction materials,architectural forms and construction techniques,and has the advantages of reasonable space stress and material saving as a thin shell structure.Therefore,it has great potential for development in the fields of ice and snow industry in cold regions and polar development that people are increasingly concerned about.In the outdoor low-temperature environment,the sublimation of the ice on the surface of the large-span composite ice shell structure will cause the thickness of the structure to become thinner and unevenly distributed,and even cause the structure to break through,which seriously affects the safety and long-term mechanical properties of the ice shell structure.As the composite ice shell structure gradually develops towards a larger span,the influence of this sublimation will become more prominent.In order to grasp the law and distribution of the sublimation on the surface of the large-span composite ice shell structure,so as to provide the necessary support for the design and maintenance of the large-span composite ice shell structure in the future,the theoretical analysis,experimental observation and numerical simulation are used in this paper,to study the simulation method and application of sublimation on the surface of ice shell structure.Mainly include the following aspects:(1)The sublimation performance test of composite ice was systematically carried out.Based on the HK equation of pure ice under vacuum conditions,the indoor singlefactor control experiment was conducted to study and establish the influence mode of atmospheric pressure,wind speed and admixture on ice sublimation.Through the sublimation experiment in the outdoor natural environment,the indoor experiment results were supplemented,verified and corrected.By means of numerical simulation,the influence mode of solar radiation intensity on ice sublimation was established.Finally,a sublimation rate calculation model suitable for 2% paper fiber composite ice is proposed.(2)A numerical simulation method for sublimation on the surface of the ice shell structure is established.Based on the proposed sublimation rate calculation model of 2% paper fiber composite ice,the existing solar radiation simulation technology and CFD simulation technology are integrated on a unified platform,and programming development is carried out,and finally established a numerical simulation method for the sublimation distribution of the composite ice shell surface.(3)The influence of sublimation on the mechanical properties of ice shell structure was studied.Based on the established sublimation numerical simulation method,corresponding sublimation simulation,finite element modeling and mechanical performance analysis were carried out on two typical composite ice shell structures,and the influence of sublimation on the static performance and stability performance of the structure was explored.