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Failure Mechanism And Vulnerability Of Single-layer Spherical Aluminum Alloy Reticulated Shells Under Severe Earthquakes

Posted on:2020-12-23Degree:MasterType:Thesis
Country:ChinaCandidate:H LiFull Text:PDF
GTID:2392330590457754Subject:Structural engineering
Abstract/Summary:PDF Full Text Request
In recent years,the spatial reticulated shell structure has gradually been favored by engineers and is widely used in large public buildings such as stadiums,convention centers and airport terminals.Its status as a region or even a country has very important political and economic significance.Earthquakes are a devastating and sudden natural disaster that can cause huge casualties and property damage.It can bring very serious social impacts.Due to its excellent seismic performance,the large-span reticulated shell structure often becomes a refuge for the masses after the earthquake disaster.However,some space reticulated shell structures have suffered various degrees of damage or even collapse under the influence of strong earthquakes.Even if the reticulated shell structure after the earthquake did not partially or completely collapse,the cost of repairing after the earthquake is quite large,and the indirect losses such as economic loss and social impact derived from structural failure are often more serious.With the application of aluminum alloy materials in space grid structures,the seismic performance and failure mechanism of aluminum alloy space grid structures are particularly important.Therefore,the study on the failure mechanism of strong earthquakes and seismic vulnerability of aluminum alloy reticulated shells to ensure the safety performance of aluminum alloy reticulated shell structures and reduce the economic loss of seismic damage of aluminum alloy reticulated shell structures has become an important work in the study of spatial structure theory.Based on this background system,this paper studies the failure mechanism and seismic vulnerability of single-layer spherical aluminum alloy reticulated shell structures.The main contents are as follows:(1)Failure characteristics of single-layer spherical aluminum alloy reticulated shells under severe earthquakesFirstly,this paper uses the large-scale general finite element software ABAQUS to establish a finite element analysis model of single-layer spherical aluminum alloy reticulated shell structure.A sub-program based on ABAQUS secondary development(UMAT)was used to compile a constitutive model of aluminum alloy material suitable for space structure.Secondly,the characteristics of strong earthquake failure are analyzed for typical aluminum alloy reticulated shell structures.The characteristic response of aluminum alloy reticulated shells under strong earthquakes is obtained.Finally,through large-scale parametric analysis,the variation characteristics of strong earthquake failure characteristics of single-layer spherical aluminum alloy reticulated shell structures with different parameters(vector span ratio,rod section,roof load,etc.)are investigated.The influence of structural parameters on the response of strong earthquake failure characteristics is obtained.(2)Failure Mechanism of Single-layer Spherical Aluminum Alloy Reticulated Shell Structure under Severe EarthquakeFirstly,through the large-scale statistical analysis of the data,according to the typical failure characteristics of the single-layer spherical aluminum alloy reticulated shell structure under strong earthquakes,the strong earthquake failure mode of the structure is obtained.Then,considering the characteristic response(1P rod ratio,8P rod ratio,relative maximum node displacement,etc.)affecting the failure mode of single-layer spherical aluminum alloy reticulated shell structure,a strong earthquake failure identification method based on structural characteristic response is proposed.Finally,the fuzzy comprehensive discriminant method in fuzzy mathematics is used to establish a mathematical model for the fuzzy identification of strong earthquake failure modes of single-layer spherical aluminum alloy reticulated shell structures.The criterion for determining the failure mode of single-spheroidal spherical aluminum alloy reticulated shells is proposed.(3)Study on seismic vulnerability of single-layer spherical aluminum alloy reticulated shellsFirstly,the analysis principle of seismic vulnerability of aluminum alloy reticulated shells is systematically described.Based on the statistics of the response characteristics of strong earthquakes in a large number of examples,the seismic damage model of single-layer spherical aluminum alloy reticulated shell structures is fitted by MATLAB software.Secondly,the seismic damage classification standard of single-layer spherical aluminum alloy reticulated shell structure is established,and the basic steps of seismic vulnerability analysis of aluminum alloy reticulated shell structure are given.Finally,through the established seismic damage model and failure level classification criteria,the typical single-layer spherical aluminum alloy reticulated shell structure is subjected to the vulnerability analysis under earthquake action.The seismic vulnerability curve and its influence law are obtained.The seismic design theory of the spherical spherical aluminum alloy shell structure provides the basis.
Keywords/Search Tags:aluminum alloy, single-layer spherical reticulated shell structure, vulnerability, strong earthquake, failure mechanism
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