Altair RISE

A program to recognize and reward our most engaged community members

Nominate Yourself Now!

What's the meaning of mass error in out file?

Hello everyone,

What's the real meaning of mass error in the engine out file? No mass scaling was defined in the input file, however, the mass error in the engine out file was not zero and it stayed the same all the process.

Does Mass element have effect on this?

Best Wishes

Roy

Find more posts tagged with

English

Radioss

Accepted answers

All comments

Altair Forum User

Hi Roy,

Do you have any Type 2 interface in the model?. And if Spotflag =1 is used in the Interface Type 2, then there are added mass on master nodes. Indeed the slave node inertia with respect to the center of the closest master segment – let IS + mSd2 where, IS is the slave node inertia; mS is its mass and d is its distance to the center of the segment - is equilibrated by added mass on master nodes.

Altair Forum User

Hi Roy,

Do you have any Type 2 interface in the model?. And if Spotflag =1 is used in the Interface Type 2, then there are added mass on master nodes. Indeed the slave node inertia with respect to the center of the closest master segment – let IS + mSd2 where, IS is the slave node inertia; mS is its mass and d is its distance to the center of the segment - is equilibrated by added mass on master nodes.

Hi George P,

Type 2 was used in my model. You mean the mass error was introduced by the Type 2 contact? Does this have any bad effect on the simulation result? Or this formulation was used in which condition?

Best Wishes

Roy

Altair Forum User

Hi Roy,

Due to the Spotflag formulation in Type 2 interface mass is added in the model. If the value of mass error is very less you can ignore it.

The slave nodes height with respect to the master segments should be as small as possible. Indeed, the geometrical concordance is necessary for Interface Type 2 to work normally, and will help getting a lower added mass. Please go through the FAQ in Help Menu on Kinematic Conditions where this is well explained.

This formulation is used for spotwelds or rivets.