BGMod — Mass and load

m/b/FMass, damping and loadMechanicalLoad · Масса и нагрузка

M mechanical · state π_m = m v

Combines a mass, viscous damper and constant external force at a common velocity. Positive load force opposes extension and assists retraction; its sign does not follow velocity.

v = π_m/m · dπ_m/dt = F_M − b v − F_load
E = m v²/2 · P_loss = b v² · P_load = F_load v

Parameter	Meaning / unit	Default
m	Mass > 0 [kg]	100
b	Viscous coefficient ≥ 0 [N·s/m]	1500
v0	Initial velocity [m/s]	0
force	Constant signed load [N]	10000

Initialization: π_m,0 = m v0. Cylinder position is initialized separately.
Outputs: Momentum, velocity, specified external force, kinetic energy, damping loss and load power.
Scope: Internal I, R and Se with a 1-junction. No position-dependent load or dry friction.

Classic bond graph

Implemented internal graph: 1 + I + R + Se. All branches share v; F_M = m dv/dt + bv + F_load. The outward bond to Se represents the signed opposing load: positive F_load absorbs power during extension and supplies power during retraction. For b = 0 the damping branch contributes zero effort. Half-arrows set positive power references; dashed pink arrows carry signals only. Causal strokes are omitted because they depend on the connected model.