筒形桅杆有限元计算模型及无刚度奇点的消除方法研究

本文提出了一个用于消除空间杆梁结构有限元模型中的无刚度“奇点”的元素及相应的刚度矩阵计算公式。在无刚度“奇点”出现处以此元素替代拉压杆元,可使空间杆梁结构模型中的无刚度“奇点”消失,能够在不增加整个计算模型自由度的情况下提高计算结果的精度。在微型计算机上运用全部三维12自由度梁单元计算模型、拉压杆元——加弹性支座计算模型和本文提出的计算模型对某型军舰的桅杆结构进行了实例计算比较。计算结果表明:用本文方法得到的应力值、位移值与全部三维12自由度梁单元模型的计算结果符合良好。

Finite Element Model of Barrel Mast and Singularity Elimination Method

In this paper, a new type of elements and the stiffness matrix have been developed, which can be used to eliminate the singularity in the finite element model such as space truss and frame. The sigularities in the finite element model can be eliminated by using this type of elements to replace the bar elements where the singularities appear. Theresults can be obtained more accurately, and the number of degree of freedom is unchanged. The authors calculate the mast of a ship on a personal computer employing following three models: model 1:the space frame elements; model 2:the space truss elements and the elastic supports; model 3:the space truss elements and the elements developed in this paper. The calculation shows that the stresses and displacements calculated with model 3 are in good agreement with those calculated with model 1.