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基于改进的正放四角锥网架结构在非均匀温度场中的数值分析模型,建立了147例数值分析模型。借助ANSYS软件的热力耦合数值分析功能,得到了网架结构高温力学特征量数据库,从杆件纵向变形与杆件应力历程的角度,研究了局部火灾下杆件间的约束效应分布规律,同时研究了温度场非均匀性、荷载比、网格尺寸对杆件约束效应的影响规律,研究表明,在局部火灾下,网架结构斜对称轴上中间位置处腹杆受到的轴向约束最强,表现为压应力增加;垂直于斜对称轴方向的杆件表现为拉应力增加;杆件轴向约束程度随温度场非均匀性的增强及网格尺寸的减小而增大;在结构高荷载比情况下,温度场非均匀性和网格尺寸对杆件轴向约束的影响尤为显著。
Based on the improved numerical analysis model of pyramidal truss structure in non-uniform temperature field, 147 numerical models were established. With the function of thermal coupling numerical analysis of ANSYS software, a database of high temperature mechanical characteristics of grid structure was obtained. From the perspective of longitudinal deformation of bar and stress history of bar, the distribution of restraining effect of bars under localized fire was studied. The influence of temperature field inhomogeneity, load ratio and mesh size on restraining effect of bars is studied. The results show that in the case of local fires, the web restraint has the strongest axial restraint in the middle position on the slant axis, Which shows that the compressive stress increases; the bar perpendicular to the axis of oblique symmetry shows an increase of tensile stress; the degree of axial restraint of bar increases with the increase of temperature field inhomogeneity and the decrease of the mesh size; In particular, the effect of temperature field inhomogeneity and grid size on the axial restraint of the bar is more pronounced.