Gravity Loading Results in a Zero displacement

[Eigen]

Dear All,

I have 1 storey structure to analyze under the gravity loading, I defined the ElasticBeamColumn Element where it has an option for the line mass( mass per length) to be applied to the ElasticBeamColumn element but it seems that it doesn't take any effect, OpenSees produces the zero displacements. Can you enlighten this topic for me ?

If that line mass is not intended for the linear elasticity, but to the eigenvalue solutions, then which mass matrix formation(I think its a diagonal )is used ?

And also can you enlighten me why some of the commercial applications such as SAP2000 produces the positive, semi-definite mass matrices. On which basis they are assuming the singular mass matrix, nowhere in FEM literature I've seen anyone suggesting the singular mass matrix?


Regards,

[fmk]

sorry for the confusion. the use of the mass option varies between elements, depending on who wrote them.

that mass option is used to define the element's mass and is not used in load calculation. you need to create a load pattern and place a uniform load on the beam in that pattern.