UCIN-DYNOCOMBS — Software for the Dynamic Analysis of Constrained Multibody Systems

DYNOCOMBS simulates the dynamics of constrained multibody systems [1]. The systems simulated may have general (three-dimensional) motion including translation between adjoining bodies and closed loops. Arbitrary force systems may be applied to the bodies and between the bodies.DYNOCOMBS uses Kane’s equations to simulate the dynamics [2]. Partial velocity and partial angular velocity vectors form fundamental arrays in the development of the governing equations. DYNOCOMBS also uses Euler parameters to avoid geometrical singularities.Constraint equations arising from the geometric and kinematic constraints (closed loops or specified motion) are appended to the dynamics equation. The resulting system of equations is reduced to a consistent set by using orthogonal complement arrays.The governing differential equations are solved using a fourth-order Runge-Kutta procedure — although other integration techniques may be employed.As input, the user supplies a body connection array, geometrical and physical properties of the bodies, constraint conditions, applied forces, and initial conditions. As output, DYNOCOMBS provides a description of the system configuration and movement at equal time intervals. Forces exerted on the bodies of the system are also provided.The language of Dynocombs is Fortran.The following paragraphs provide an outline of the theoretical basis of DYNOCOMBS. Example simulations are also discussed.