一种基于精细有限元模型的螺纹连接结构数值方法研究

A METHOD OF METICULOUS FEM MODELING FOR THREADED BOLT

针对螺纹连接结构力学响应和螺纹上应力分布问题,提出了一种基于Patran软件的螺纹连接结构的精细有限元建模方法。利用Patran软件的前处理功能,将结构的含螺纹区域离散为螺纹层、过渡层和常规层。常规层采用常规方法单独建模,螺纹层、过渡层则采用双导线法建模。首先建立两条螺旋线,以及螺纹层和过渡层截面的平面单元,通过一定的方法将平面单元绕两条螺旋线旋转生成三维实体单元,最后合并过渡层与常规层的对应节点形成含螺纹区域的整体有限元模型。采用该方法对口型含螺纹连接结构在不同预紧力状态的响应进行了建模分析,获得了螺纹上的应力分布、结构的最大应力,以及螺杆中部的应力响应。结果表明,螺纹的应力分布特征和结构最大应力位置与已有的研究结果比较吻合。在预紧力10 N·M到70 N·M的七种工况下,计算所获得的螺杆上应力与实验结果相比,最小相对误差为0.5%,最大相对误差为4.8%,两者吻合较好。

A method of meticulous modeling for threaded bolt in finite element software patran was presented in this article. In this method, the analyzed structure was divided into three regions, thread region, conventional region and transition region. The conventional region was modeled with the conventional method, however, the thread region and the transition region were modeled using the Glide-Guide method. Firstly, two helical lines and the plane elements were created. Secondly, the plane elements were rotated along the lines, then the three dimensional elements for the helical model were obtained. Finally, the nodes of the transition region elements and the conventional region elements were edited so that the whole model was attained. Comparing to the existing method, this method is simpler, and the elements are all standard elements. A structure with threaded bolt under pre-tension force was analyzed. The distribution of stress in the thread, the stress in the thread bar and the maximum equivalent stress were calculated. The stress in the thread bar is identical to the experiment resuhs perfectly, and the maximal relative error is less than five percent.