CONM2

Bulk Data Entry Defines a concentrated mass at a grid point of the structural model.

Attention: Valid for Implicit and Explicit Analysis

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
CONM2	2	15		49.7
	16.2		16.2			7.8

Field	Contents	SI Unit Example
`EID`	Unique element identification number. No default (Integer > 0)
`G`	Grid point identification number. No default (Integer > 0)
`CID`	Coordinate system identification number. Default = 0 (Integer ≥ -1)
`M`	Mass value. No default (Real)
`X1`, `X2`, `X3`	Offset distance from the grid point to the center of gravity of the mass in the coordinate system defined by `CID`, unless `CID` = -1, in which case `X1`, `X2`, and `X3` are the coordinates (not offsets) of the center of gravity of the mass in the basic coordinate system. Default = 0.0 (Real)
`Iij`	Mass moments of inertia measured at the mass center of gravity. If `CID` is zero, then `Iij` is defined in the basic coordinate system. If `CID` > 1, then `Iij` refers to the local coordinate system. If `CID` is -1, then `Iij` refers to the basic coordinate system. Default = 0.0 (Real)
`RAYL`	Continuation line flag for material-dependent Rayleigh damping 5
`ALPHA`	Rayleigh damping coefficient for the mass matrix 5 Default = 0.0 (Real ≥ 0.0)

If the continuation is omitted, all rotary inertia is assigned zero values.
The form of the inertia matrix about its center of gravity is:(1)
$M = [\begin{matrix} M & 0.0 & (X 3 \cdot M) & - (X 2 \cdot M) \\ M & - (X 3 \cdot M) & 0.0 & (X 1 \cdot M) \\ M & (X 2 \cdot M) & - (X 1 \cdot M) & 0.0 \\ I 11 + (X 2^{2} + X 3^{2}) M & - I 12 - X 1 \cdot X 2 \cdot M & - I 13 - X 1 \cdot X 3 \cdot M \\ Symmetric & I 22 + (X 1^{2} + X 3^{2}) M & - I 32 - X 2 \cdot X 3 \cdot M \\ I 33 + (X 1^{2} + X 2^{2}) M \end{matrix}]$

Where,

M

Input mass value

Iij

Input inertia values

X1, X2, and X3

Offsets
If CID = -1, the offsets are computed internally as the difference between the grid point location and X1, X2, and X3. The grid points may be defined in a local coordinate system, in which case the values of $I_{ij}$ must be in a coordinate system that parallels the basic coordinate system.
If CID > 0, then X1, X2, and X3 are defined by a local Cartesian system, even if CID references a spherical or cylindrical coordinate system.
For material-dependent Rayleigh damping, the equivalent viscous damping, $C$ , is defined as:(2)
$C = ALPHA * M$
Where,

$ALPHA$

Defined on the RAYL continuation line on the material entry

$M$

Mass matrix

Supported solutions for material-dependent Rayleigh damping on CONM2:
- Nonlinear Transient Analysis
This card is represented as a mass element in HyperMesh.