请各位帮我看看这个模型运行出现负的周期是什么原因，如何解决，谢谢！
* * * W A R N I N G * * *
ZERO OR NEGATIVE MODAL-MASS VALUES WERE DETECTED DURING ITERATION,
THE RESULTING EIGEN-MODES MAY NOT BE VALID - CHECK THEM CAREFULLY !!
THE STRUCTURE IS UNSTABLE OR ILL-CONDITIONED !!
CHECK THE STRUCTURE CAREFULLY FOR:
- INADEQUATE SUPPORT CONDITIONS, OR
- ONE OR MORE INTERNAL MECHANISMS, OR
- ZERO OR NEGATIVE STIFFNESS PROPERTIES, OR
- EXTREMELY LARGE STIFFNESS PROPERTIES, OR
- BUCKLING DUE TO P-DELTA OR GEOMETRIC NONLINEARITY, OR
- A FREQUENCY SHIFT (IF ANY) ONTO A NATURAL FREQUENCY
NUMBER OF EIGEN MODES FOUND = 3
NUMBER OF ITERATIONS PERFORMED = 7
NUMBER OF STIFFNESS SHIFTS = 0
附件:
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GHJ2_V9_V11.rar (2013-4-21 19:50, 22.11 K) / 下载次数 76