Static And Impact Performance Of Rigid Polyurethane Foam Filled Circular Steel Tube

In recent years,construction structure may subject to accidental loads such as explosions and shocks due to the frequent occurrence of terrorist attacks during normal use.In addition,under the action of earthquake and strong wind,the problem of collision damage between adjacent buildings and the limit collision of isolation layer make the anti-impact protection of engineering structures become a research hotspot.At present,the research on impact protection in the construction field focuses on the impact resistance of traditional structural components,such as structural circular steel tube and CFST,while the research of energy dissipation components and new impact resistant components for the field of construction structure is deficient.In view of that,this paper propose to combine rigid polyurethane foam(RPUF)with excellent energy dissipation characteristics with the most commonly used thin-walled circular steel tube in the field of building materials to form composite components,and to study the axial crush and impact properties of short columns and the lateral impact performance of long columns in order to obtain a new type of composite with high efficiency energy absorption to protect structure stand with impact loads.The rigid polyurethane foam with density of 300kg/m~3 and the most commonly used Q235 straight seam welded tube in the building structure are selected,and the RPUF filled circular steel tube specimens are prepared by spontaneous foaming,and the experimental and numerical simulation studies are carried out,the main research contents are divided into the following parts:(1)Study on axial crushing performance of short column members of RPUF filled circular steel tubeThe axial crushing test of 6 sets of short column members of RPUF filled circular steel tube was carried out,and the energy dissipation characteristics of RPUF filled circular steel tube and empty steel tube under axial crushing load were compared and analyzed.The axial crushing finite element model of RPUF filled circular steel tube short column member is established,the parameter analysis is carried out,the influence of tube diameter,wall thickness and specimen height on axial pressure energy dissipation ability is discussed,and the average compression force formula of RPUF filled circular steel tube short column member is obtained by theoretical analysis.(2)Study on axial impact performance of short column members of RPUF filled circular steel tubeBased on the axial impact test of 8 sets of short column members of RPUF filled circular steel tube,the difference of mechanical properties between impact load and axial pressure load is analyzed,and the influence of tube diameter,wall thickness,specimen height and impact speed on the energy dissipation ability of RPUF short column members under axial impact load is analyzed by finite element simulation.(3)Study on lateral impact performance of long column members of RPUF filled circular steel tubeThe lateral impact test of 34 groups of RPUF filled circular steel tube and 18 sets of long column members of empty steel tube was carried out,the difference of lateral impact performance of RPUF filled tube and empty steel tube was compared and analyzed,and four failure modes under lateral impact of long column members of RPUF filled circular steel tube were summarized,and the form and diameter thickness ratio of hammer head were,span ratio,impact position,impact angle and impact speed have many factors on the lateral impact performance of RPUF filled circular steel tube long column members.