中文摘要：

在车身结构概念设计阶段，需要对梁单元赋截面并调整截面的方向。研究了UG中调整截面方向的规律，设计了一种调整梁截面方向的工具。主要介绍了调整截面方向的方法：首先在UG的草图中建立简化的截面，利用坐标转换公式及形心公式计算主惯性轴，然后建立一个向量V控制草图中的截面方向，最后通过坐标变换得到空间调整截面方向的向量。利用此工具对某款轿车进行了分析，结果表明，采用此方法不仅大大提高了车身结构概念设计的效率，而且提高了设计的精度。

英文摘要：

The beams element,endued with sections,should adjust the orientation of sections at the phase of car body structure concept design.The rule how to adjust orientation of beam sections in UG is studied,the tools for adjusting section orientation of beams are designed,and the method that can adjust section orientation is introduced.At first,a simply section is created in the sketch of UG,then the principal moment of inertia is calculated by coordinate transition formula and a vector V which controls the orientation of section is created.A vector that adjusted the orientation of section is received by coordinate transition.The car is analyzed by tool.The result shows this method not only improves the efficiency of car body structure concept design but also improves the design precision.