Back to Statics Of Rigid Bodies repository
Virtual work2D

Small-displacement compatibility

Apply constraint-compatible virtual displacements to levers, pulleys, mechanisms, and force-direction optimization.

Open the complete lesson

Advanced engineering statics simulation

Virtual Work Equilibrium Suite

Five distinct, constraint-compatible virtual-work models; efficiency is separated from geometry.

Inspect dx/dθ and dy/dθ before applying force equilibrium.

Link length
1.8 m
m
0.33.5

Drag for exploration or enter an exact value. Press Enter to apply and Escape to restore.

Generalized link angle
40 deg
deg
590

Drag for exploration or enter an exact value. Press Enter to apply and Escape to restore.

compatible virtual motion
δxδyOne coordinate θ = 40° determines both motions
Required input
kinematic only
Virtual-work residual
0.00e+0 N
Should be near zero
dx/dθ
-2.314 m/rad
dy/dθ
2.758 m/rad
|dy/dx|=2757759995.228
δW=Fiδri+Miδθi=0\delta W=\sum \mathbf{F}_i\cdot\delta\mathbf{r}_i+\sum M_i\delta\theta_i=0

Compatibility is derived first; arbitrary independent dx and dy values would violate the mechanism constraint.

Concept question: Predict dy/dθ for the selected link length and angle.

Model scope and verification

Scope: Educational rigid-body statics model using the selected geometry, stated idealizations, and displayed SI units.

Acceptance check: Check the governing equilibrium, compatibility, geometry, or limiting-condition statement before accepting the numerical result.