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 EID G CID M X1 X2 X3
I11 I21 I22 I31 I32 I33
RAYL ALPHA

Example

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

Definitions

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)

Comments

  1. If the continuation is omitted, all rotary inertia is assigned zero values.
  2. The form of the inertia matrix about its center of gravity is:
    M = [ M 0.0 ( X 3 ⋅ M ) − ( X 2 ⋅ M ) M − ( X 3 ⋅ M ) 0.0 ( X 1 ⋅ M ) M ( X 2 ⋅ M ) − ( X 1 ⋅ M ) 0.0 I 11 + ( X 2 2 + X 3 2 ) M − I 12 − X 1 ⋅ X 2 ⋅ M − I 13 − X 1 ⋅ X 3 ⋅ M Symmetric I 22 + ( X 1 2 + X 3 2 ) M − I 32 − X 2 ⋅ X 3 ⋅ M I 33 + ( X 1 2 + X 2 2 ) M ]
    Where,
    M
    Input mass value
    Iij
    Input inertia values
    X1, X2, and X3
    Offsets
  3. 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.
  4. 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.
  5. For material-dependent Rayleigh damping, the equivalent viscous damping, C MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaC4qaaaa@36C0@ , is defined as:
    C = ALPHA * M MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaC4qaiabg2 da9iaabgeacaqGmbGaaeiuaiaabIeacaqGbbGaaiOkaiaah2eaaaa@3D3F@
    Where,
    ALPHA MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaeyqaiaabY eacaqGqbGaaeisaiaabgeaaaa@39E9@
    Defined on the RAYL continuation line on the material entry
    M MathType@MTEF@5@5@+= feaahqart1ev3aqatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9 vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=x fr=xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaGaaCytaaaa@36CA@
    Mass matrix
    Supported solutions for material-dependent Rayleigh damping on CONM2:
    • Nonlinear Transient Analysis
  6. This card is represented as a mass element in HyperMesh.