Brick

The brick is a 3D solid hexahedral element based on the OpenSees SSPbrick formulation — Stabilized Single Point. One integration point plus a stabilization term, which keeps it free of the shear locking that a fully integrated 8-node brick suffers from in bending, and cheap with it.

Use it for volumetric behaviour: foundations, cores, massive walls, blocks, soil volumes.

🔧 Grasshopper component

SSP BrickAlpaca4d ▸ 02_Element

Inputs

MeshMeshHexahedral mesh with 8 vertices, in m.

Passed through CleanHexahedron to put the corners in the order OpenSees expects.

MaterialMaterialAn nD material.

Uniaxial materials are not accepted.

ColourColourAlpaca4d brick colourDisplay colour in the Rhino viewport.

ElementIdText(empty)Optional name for the element, used to pull its results out later.

Free text, and yours to repeat: one name over twenty meshes labels all twenty, and asking for it returns all twenty. Give a list to name them apart.

Outputs

ElementElementBrick element, to be connected to Assemble.

Note

One component makes one element. To build a solid region, graft a list of hexahedral meshes into the component — Mesh Series to Brick and Mesh Loft exist to produce them.

Constructs one brick element from one hexahedral mesh.

📈 When to use it

Use it when

• You need a full 3D stress state — confinement, triaxial behaviour, contact with soil or massive concrete.
• The region cannot be represented accurately by beams or shells.
• You are studying stress concentrations inside a body.

Do not use it when

• The body is thin compared to its in-plane dimensions → use Shell.
• The behaviour is bending-dominated and member-like → use ForceBeamColumn.
• Your geometry only meshes into tetrahedra → use Ten Node Tetrahedron.

🔗 Relation to OpenSees

element SSPbrick $eleTag $n1 $n2 $n3 $n4 $n5 $n6 $n7 $n8 $matTag $bx $by $bz

• The 8 mesh vertices map to $n1 … $n8.
• $matTag is the Material input.
• The body forces $bx $by $bz are not exposed by the component and are left at the OpenSees default. Self-weight is applied instead as equivalent nodal loads by Gravity Load.

Note that a brick node has 3 DOF, not 6. A brick sharing a node with a beam or shell therefore transfers force but no moment.