NSML

Bulk Data Entry Defines lumped non-structural mass for a list of elements or properties.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
NSML	`SID`	`TYPE`	`ID`	`VALUE`	`ID`	`VALUE`	`ID`	`VALUE`
+	`ID`	`VALUE`	etc	etc	etc	etc	etc	etc
+	`DISTR`	`DTYPE`

Example 1

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
NSML	6	PSHELL	16	0.29

Example 2

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)
NSML	8	`ELEMENT`	11	0.01	15	0.16	24	0.09
+	25	0.01	32	0.01
+	`DISTR`	VOLUME

Definitions

Field	Contents	SI Unit Example
`SID`	Non-structural mass set identification number. No default (Integer > 0)
`TYPE`	This can be one of the properties PSOLID, PSHELL, PCOMP, PBAR, PBARL, PBEAM, PBEAML, PROD, CONROD, PSHEAR, PTUBE, or MIXED in which case the list of IDs will refer to properties of the stated type, in the case of MIXED, it can refer to a list of properties of a mixture of different types of properties. Or, it can be ELEMENT, in which case the list is of individual element IDs of elements that can have NSM. Note: A mixture of elements of different types can be included in the list of element IDs. Or, it can also be of type `ELSET`, in which case, it is an element SET ID. Note: A mixture of elements of different types can be included in the element sets. 4 No default
`ID`	Property ID, Element ID, or Element Set ID depending on the `TYPE` definition. No default (Integer > 0)
`VALUE`	A lumped mass value to be distributed over all the listed elements and elements referencing listed properties. No default (Real)
`DISTR`	Flag indicating that the information regarding the type of distribution of mass is to follow.
`DTYPE`	Identifies the type of distribution of non-structural mass. MASS Non-structural lumped mass is distributed based on mass. VOLUME Non-structural lumped mass is distributed based on volume. Blank (Default) This is the traditional method of distribution of non-structural lumped mass based on length (1D elements), Area (2D elements), or Volume (3D elements).

Comments

Refer to Non-structural Mass in the User Guide for more information on the use of this card.
Non-structural mass in this format must be selected by the NSM Subcase Information selector.
Selection of a mixture of element or property types via the TYPE field is only supported for DTYPE=MASS or VOLUME on the DISTR continuation line. For the default case when DTYPE is blank, referencing a mixture of element or property types does not apply.
The NSML Bulk Data Entry and its alternate form NSML1 allow you to allocate and smear a lumped non-structural mass value to be evenly distributed over a list of elements.
- Default Distribution (DTYPE=blank on NSML/NSML1)
  The non-structural mass value per unit area, per unit length, or per unit volume to be applied to the elements is: (1)
  $N S M_{per unit area} = \frac{V A L U E}{\sum_{i = 1}^{n} A_{i}}$
  (2)
  $N S M_{per unit length} = \frac{V A L U E}{\sum_{i = 1}^{n} L_{i}}$
  (3)
  $N S M_{per unit volume} = \frac{V A L U E}{\sum_{i = 1}^{n} V_{i}}$
  
  For the default case when DTYPE is blank, referencing a mixture of different element or property types is not supported.
- Distribution based on Mass/Volume (DTYPE=MASS/VOLUME on NSML/NSML1)
  The non-structural mass value per unit mass or volume to be applied to the elements is: (4)
  $N S M_{per unit mass} = \frac{V A L U E}{\sum_{i = 1}^{n} M_{i}}$
  (5)
  $N S M_{per unit volume} = \frac{V A L U E}{\sum_{i = 1}^{n} V_{i}}$
Where,

$n$

Number of elements in the set

$V A L U E$

Value of the lumped mass

$L_{i}$

Length of element $i$

$A_{i}$

Area of element $i$

$V_{i}$

Volume of element $i$

$M_{i}$

Mass of element $i$

An important difference between the default distribution (DTYPE=blank) and DTYPE=MASS/VOLUME, is that a mixture of multiple element types (1D, 2D, and 3D elements) can be defined on a single NSML/NSML1 entry when TYPE field is set to ELEMENT/ELSET (mixture of elements) or MIXED (mixture of properties).
The value of the non-structural mass does not change during Topology Optimization.