有两个warning帮我看下如何解决

* * * W A R N I N G * * *
ZERO VALUES WERE DETECTED ON THE DIAGONAL DURING EQUATION
ASSEMBLY.
THESE VALUES WERE CHANGED TO 0.1E-09
TO OBTAIN FURTHER INFORMATION, USE THE STANDARD SOLVER.


* * * W A R N I N G * * *
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