🎲 Results

The result components read the model that comes back out of Run Analysis or Natural Vibration. There is no separate result object — the analysis attaches its output to the AlpacaModel itself.

Underneath, results are recorded by the MPCO recorder written by M. Petracca and G. Camata at ASDEA Software Technology, and read back from the MPCO file that the analysis leaves in the AlpacaResults folder beside the Grasshopper document. An MPCO Recorder chooses what goes into it.

Components in this tab

Component	Nickname	Reads
Nodal Displacements	Nodal Displacements	Displacement, rotation, velocity, acceleration at every node.
Reaction Forces	Reaction Forces	Force and moment at every support, in the support's own axes.
Node Forces	Node Forces	The forces every beam and truss brings into a node, for designing the joint.
Beam Forces	Beam Forces	N, Vy, Vz, Mx, My, Mz along every beam.
Beam Stresses	Beam Stresses	Axial, bending, shear, torsion and Von Mises stresses along every beam.
Utilisation	Utilisation	How much of its resistance every steel beam uses, to EN 1993-1-1.
Shell Forces	Shell Forces	Membrane, bending and shear resultants on every shell.
Brick Stresses	Brick Stresses	The six stress components and Von Mises on every solid.

Nodal Displacements

Reads displacement, rotation, velocity and acceleration at every node of an analysed model.

One value per node, in global axes, in the order the nodes were assembled. Velocity and acceleration are recorded by a transient analysis only. After a Natural Vibration analysis, Step picks the mode and Displacement and Rotation are that mode's shape.

Reaction Forces

Reads the force and the moment carried by every support of an analysed model.

One value per support, given in the support's own axes, so a Support placed on a Plane reports along that plane rather than along the global axes. SupportPosition gives both where each support sits and the frame its reactions are in.

Node Forces

Reads the forces that every beam and truss brings into a node, for designing the joint there.

Pick the nodes by Point or by NodeTag, or leave both empty for every node a beam meets. One branch per node, with an item per member: its section forces at that end, signed as Beam Forces signs them, and the force and moment it puts on the node in global axes.

Beam Forces

Reads the internal forces along every beam element of an analysed model — axial force, two shears, torsion and two bending moments.

Each output is a tree with one branch per element, holding the values at the element's integration sections from the I end to the J end, in local axes. N is positive in tension.

Beam Stresses

Recovers the stresses along every beam from its forces with elastic beam theory: σN, the bending stress from each moment, the extreme direct stress σmax and σmin, the peak shear from the shear forces and from torsion, and Von Mises.

They depend on the section's shape, not its material. Same tree layout as Beam Forces, in MPa.

Utilisation

Checks every beam against the design code of its material — steel to EN 1993-1-1: cross-section class, axial force, shear, torsion, bending, bending with axial force and shear, flexural and lateral-torsional buckling, and bending with compression as a member (6.3.3, Annex B). One value per check per beam, 1 at the limit, with a Report of every number worked out on the way.

The steel grade comes from the beam's material. Torsional and torsional-flexural buckling are not checked yet.

Shell Forces

Reads the stress resultants of every shell element of an analysed model — membrane forces pxx, pyy and pxy, bending moments mxx, myy and mxy, and transverse shears vxz and vyz.

All of them per unit width and in the shell's local axes. Each output is a tree with one branch per element, holding the values at the element's integration points.

Brick Stresses

Reads the stress state of every solid element of an analysed model — the six components of the stress tensor plus the Von Mises equivalent stress.

One value per element, in global axes or in the element's own. An SSP Brick has a single integration point; a Ten Node Tetrahedron has four, and gives their mean, the stress at its centre. The four node tetrahedra of a definition made before Ten Node Tetrahedron replaced them are read too, at their one point.

The modal report — masses, centre of mass, participation factors and ratios — is no longer a component of its own: it is in the Modal Report menu of Natural Vibration.

Common inputs

Every component except Utilisation shares the same three inputs (Utilisation checks one Step at a time and has no History):

Name	Nick	Type	Default	Description
AlpacaModel	AlpacaModel	Model	—	The analysed model.
History	History	Boolean	false	Read every recorded step instead of one. Step is then ignored.
Step	Step	Integer	0	Which analysis step to read. For a modal model, which mode.

History is how you get a time history out in one go. With it set, each output gains a step index in front of whatever index it already had:

Component	With History = false	With History = true
Nodal Displacements	a list, one item per node	a tree {step}, that step's value per node
Reaction Forces	a list, one item per support	a tree {step} for the force and the moment; SupportPosition stays a flat list, since supports do not move
Node Forces	a tree {tag}, one branch per node	a tree {step; tag}, every output alike
Beam Forces	a tree {element}	a tree {step; element}
Beam Stresses	a tree {element}	a tree {step; element}
Shell Forces	a tree {element}	a tree {step; element}
Brick Stresses	a list, one item per element	a tree {step}, that step's value per element

How many steps there are to read is set by NumIncr on Analysis Step.

Reading the numbers

• Forces are in kN, moments in kN·m, lengths in m, rotations in rad.
• Beam and shell results come back as a data tree, one branch per element; brick stresses are a flat list, one value per element.
• Beam and shell results are in local axes; nodal results are in global axes; reactions are in the support's own axes.
• Shell and brick stresses are in kN/m²; Beam Stresses are in MPa (N/mm²), the unit design strengths are given in. One MPa is 1000 kN/m².
• Utilisations have no unit: 1 is exactly at the limit.

To see any of this in the viewport rather than as numbers, use the matching component in Visualisation.