摘要
采用考虑剪切变形的Timoshenko梁的刚度矩阵,用抗剪刚度和抗弯刚度之比来考虑剪切变形对抗弯刚度的影响,得出空腹结构连续化成一根杆件的刚度矩阵。在单元刚度计算时,弦杆(或柱肢)和腹杆均采用了有效轴压刚度,考虑了空腹结构组成杆件的初弯曲对整体结构稳定的影响。采用FORTRAN语言编制了程序。算例表明简化算法计算结果与传统杆系模型有限元方法计算结果吻合良好,用于钢管混凝土空腹结构的极限承载力分析,可大幅度减少单元数,从而简化计算,节省机时。探讨了相关屈曲和剪切变形对钢管混凝土空腹结构极限承载力的影响。研究结果表明,随着长细比的增大,剪切变形影响逐渐减小,随着弦杆与腹杆的面积比的增大,剪切变形影响增大。对于钢管混凝土格构柱,当λ1>λ(λ1为柱肢长细比;λ为柱整体长细比)时,发生柱肢局部屈曲失稳;当λ1<λ时,发生整体屈曲失稳;在λ1=λ及其附近时,柱肢与整体的相关屈曲最明显。
Based on continuous assumption, laced CFST member can be simplified as a beam element. Stiffness matrix of Timoshenko beam was adopted to calculate the equivalent solid member stiffness matrix of the laced structure, in which the ratio of shear rigidity to bending rigidity was taken into account. Efficient axial rigidity was used in the element stiffness matrix to consider initial deformation influence on uhimate stability load-carrying capacity. A program of finite element method in FORTRAN language was presented. Calculation example shows that calculation result by the presented simplified method agrees well with that of general FEM with beam and bar elements. It can be used to analyze the ultimate load-carrying capacity of CFST laced structure with less element numbers and can simplify the calculation and save computer time. The influence of correlative buckling and shearing deformation on ultimate load-carrying capacity was discussed. The result shows that （1） the influence of sheafing deformation decreases with increasing of the slendemess ratio; （2） the influence of sheafing deformation increases with increasing of the area ratio of chord member and web member; （3） local buckling of chord member occurs for CFST laced column with λ1 〉 λ （λ1 is chord member slenderness ratio; λ is column slenderness ratio） and buckling of column occurs for λ1 〈 λ Relative buckling is obvious for λ1 = λ or so.
出处
《公路交通科技》
CAS
CSCD
北大核心
2009年第8期51-56,共6页
Journal of Highway and Transportation Research and Development
基金
国家自然科学基金资助项目(50578042)
关键词
桥梁工程
相关屈曲
有限元
钢管混凝土
空腹结构
非线性
剪切变形
bridge engineering
correlative buckling
finite element
concrete-filled steel tube （CFST）
laced structure
nonlinearity
shear deformation
