This section contains shape functions for 3-D shell elements.
These elements are available in a number of configurations, including
certain combinations of the following features:

triangular or quadrilateral.

- if quadrilateral,
with or without extra shape functions (ESF).

with or without rotational degrees of freedom (RDOF).

- if with RDOF, with or without shear deflections (SD).

with or without midside nodes.

### 11.6.1. 3-D 3-Node Triangular Shells without RDOF (CST)

These shape functions are for 3-D 3-node triangular shell elements without RDOF, such as
SHELL131 or SHELL132:

### 11.6.2. 3-D 6-Node Triangular Shells without RDOF (LST)

These shape functions are for 3-D 6-node triangular shell elements
without RDOF, such as SHELL281 when used
as a triangle:

### 11.6.3. 3-D 3-Node Triangular Shells with RDOF but without SD

These shape functions are for the 3-D 3-node triangular shell elements with RDOF, but without
shear deflection.:

### 11.6.4. 3-D 4-Node Quadrilateral Shells without RDOF and without ESF
(Q4)

These shape functions are for 3-D 4-node triangular shell elements without RDOF and without
extra displacement shapes:

### 11.6.5. 3-D 4-Node Quadrilateral Shells without RDOF but with ESF (QM6)

These shape functions are for 3-D 4-node quadrilateral shell elements without RDOF but with
extra shape functions:

### 11.6.6. 3-D 8-Node Quadrilateral Shells without RDOF

These shape functions are for 3-D 8-node quadrilateral shell
elements without RDOF, such as SHELL281:

### 11.6.7. 3-D 4-Node Quadrilateral Shells with RDOF but without SD and
without ESF

These shape functions are for 3-D 4-node quadrilateral shell
elements with RDOF but without shear deflection and without extra
shape functions:

### 11.6.8. 3-D 4-Node Quadrilateral Shells with RDOF but without SD and
with ESF

These shape functions are for 3-D 4-node quadrilateral shell
elements with RDOF but without shear deflection and with extra shape
functions: