E5042

E5042	WARNING: E5042	THERE WERE n NEGATIVE EIGENVALUES FOUND
	Cause:	One or more negative eigenvalues were detected in a normal modes or modal response analysis. For a normal structure, all eigenvalues (modal frequencies) should be greater than zero (flexible modes) or near to zero (rigid-body modes). Typically, a negative eigenvalue indicates a mechanism may be present or possibly an instability if prestress is included. A negative eigenvalue may also indicate a problem with the accuracy of the eigensolution, possibly due to a setting or a problem in the model.
	Action:	Investigate the model for the following issues: · If the model contains multipoint constraint equations, verify that the equations are valid and contain rigid body motion terms when required. · If a PRESTRESS MODAL analysis is being performed, check that the prestress loading is not beyond the buckling limit of the structure.
	Remarks:	See Autodesk Inventor Nastran Solver User's Manual, Section 11, "Linear Prestress Modal Analysis", for more information.