ACCEL2

Bulk Data Entry Defines static acceleration loads at a specific SET of GRID points in the model. Additionally, scale factors for varying direction acceleration loads can be defined using tabular data.

Attention: Valid for Implicit and Explicit Analysis

Format


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
ACCEL2	`SID`	`SSID`	`CID`	`A`	`N`	`N`	`N`
	`DIR`	`TID`

Example


(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
ACCEL2	100	4	0	2.0	1.0	3.0	5.0
	X	11

Definition


Field	Contents	SI Unit Example
`SID`	Acceleration load set identification number. (Integer > 0)
`SSID`	Identification for a SET of Grid points at which the acceleration load is applied. Integer Specifies an identification number for the set. <String> Specifies a user-defined string label for the set. 5 (Integer > 0 or <String>)
`CID`	Coordinate system identification number. = 0 (Default) References the basic coordinate system (Integer ≥ 0, or blank)
`A`	Scale factor for the acceleration load vector. Default = blank (Real, if non-zero loading is required, then `A` should be non-zero)
`N`,`N`,`N`	Acceleration load vector components in the coordinate system `CID`. Default = blank (Real, if non-zero loading is required, then a minimum of one `Ni` should be non-zero)
`DIR`	Component direction of the acceleration load variation. Default = blank (Character; one of X, Y, or Z)
`TID`	Identification number of a TABLED1 entry that specifies the Location (`LOCi`) versus Scale Factor (`VALi`) values (similar to the ACCEL entry). Default = blank (Integer > 0)

Comments

The acceleration load applied to all grid points in the referenced SSID SET in the model is given by:
$a = V A L_{C} * V A L_{V} * N$ $a = V A L_{C} * V A L_{V} * N$
Where,

$a$ $a$

Acceleration load.

$N$ $N$

Vector with components N, N, and N.

$V A L$ $V A L$

Directional varying scale factor which is defined based on DIR and TID fields. This is not mandatory and if DIR and TID are both blank.

$V A L_{C}$ $V A L_{C}$

Is applied and a constant acceleration load is applied for the whole model.

The scale factor VAL for each grid in the specified SET SSID in the model is automatically determined by linear interpolation between VALi for the DIR component of the corresponding LOCi between which the required grid point lies. If the GRID point's DIR coordinate in the coordinate system CID is outside the range specified by LOCi, the corresponding VAL is determined either from VAL1 or VALn (Figure 1). A minimum of two pairs of (LOCi and VALi) should be specified.

Figure 1. Acceleration Load Factor (VAL) versus Location along DIR (LOC)
The acceleration loads specified in the ACCEL2 entry can be combined with other loads, such as FORCE, MOMENT, GRAV, ACCEL, and ACCEL1, through the LOAD Subcase Information Entry. The SID on the ACCEL entry should be unique with regard to any other load entry.
The acceleration load does not include effects, due to mass on SPOINTs.
The ACCEL2 entry is similar to the ACCEL entry. The ACCEL load is applied to the entire model while the ACCEL2 load is calculated similar to ACCEL but applied only to the specified SET of grid points (SSID). Additionally, an extra scale factor A is applied to the acceleration load vector.
String based labels allow for easier visual identification of sets, including when being referenced by other cards. For more details, refer to String Label Based Input File in the Bulk Data Input File.
This card is represented as a force load in HyperMesh.