基于刚度变化率法的空间杆系结构破坏预测研究

Failure prediction of spatial truss structure based on stiffness changing rate method

为研究空间杆系结构的破坏预测方法,针对六角星型穹顶结构进行了理论和实验研究.利用MATLAB数值模拟分析了结构在荷载作用下的变形规律,获得了四种工况下结构刚度矩阵行列式及其变化率在结构破坏过程中的变化特点,建立了基于刚度变化率的空间杆系结构破坏预测方法.为验证理论分析可靠性,进行了相应结构的室内模型破坏试验,并将实测结果与应力变化率法进行对比分析.结果表明,空间杆系结构刚度矩阵行列式在结构破坏前存在明显突变,可用于预测结构破坏并比较不同初始缺陷对结构稳定承载力的影响.结构模型实验验证了刚度变化率法具有预测杆件群失稳破坏的能力,并提高了应力变化率法预测结构破坏的效率.

In order to Study the failure prediction method of spatial truss structure, a star-type dome structure was analyzed theoretically and experimentally. The structural deformation under external loading was numerically analyzed by MATLAB, through which the structural stiffness matrix determinant values under four working conditions were obtained. The characteristic of determinant value changing rate of struetural stiffness matrix during structural failure process was achieved, by which the failure prediction method of spatial truss structure on the basis of stiffness changing rate is established. In order to verify the reliability of theoretical analysis, destructive experiment on laboratory model was conducted and compared with the stress changing rate method. The result shows that, significant change of structural stiffness matrix determirLant of spatial truss structure was observed before structural failure occurred, which could be used to predict structural failure and analyze the influence of different initial damage on structural stability bearing capability. The prediction ability of bar group buckling by stiffness changing rate was verified by the model test, and the efficiency of structure damage prediction was improved compared with stress changing rate method.