# B21H

2D Displacement Based Bernoulli Beam With Lumped End Hinges

* Number of Nodes: 2
* Number of DoFs: 3 (Translation, Translation, Rotation)

## Syntax

```
element B21H (1) (2) (3) (4) [5] [6]
# (1) int, unique element tag
# (2) int, node i
# (3) int, node j
# (4) int, section tag
# [5] double, normalized length of each end hinge, default: 0.2
# [6] bool string, nonlinear geometry switch, default: false
```

## Remarks

1. The interior is assumed to be elastic so the response can be precomputed. For each end hinge, two integration points are used.
2. To use the corotational formulation for nonlinearity, please turn on the switch `[6]`.
3. This element may not be that useful since the plastic rotation of end hinges are constrained by the displacement interpolation function, which is a cubic polynomial.
4. Unlike 3D beam elements, there is no need to attach an `orientation` to 2D beam elements.
