Question

Ansys 中beam4实常数中Ixx—扭转惯性矩是什么，是极惯性矩吗？

Answer 1

the torsional moment of inertia (IXX), and the material properties. For stiffness purposes, the torsional moment of inertia, if IXX is equal to 0.0 or not specified, is assumed to be equal to the polar moment of inertia (IYY + IZZ). For inertial purposes, the torsional (rotational) moment of inertia used is the polar moment of inertia, and is therefore not affected by the value entered for IXX. The IXX value should be positive and is usually less than the polar moment of inertia.
以刚度为目的，IXX是扭转惯性矩，如果IXX＝0或不指定，系统会假设IXX=IYY+IZZ（极惯性矩）；以惯性为目的，扭转惯性矩使用的就是极惯性矩，并且不会受输入的IXX值的影响（即不管输入的IXX为多少，在这种情况下，IXX都等于极惯性矩。IXX值应该为正且总是小于极惯性矩。
只是做了大致的翻译，如果懂英语请看英文原版。