A finite-element-method-based formulation for flexible multibody dynamics, particularly targeting flexible link mechanisms, is proposed. The formulation is composed of two techniques : kinematics of largely displaced Euler beam element and direct coordinate partitioning. The kinematics is basically a corotational method. Direct coordinate partitioning, which is effective only in finite-element-based multibody dynamics, partitions the independent and dependent degrees of freedom hinge by hinge. A computational example on a slider crank with an assembly error shows the validity of the formulation and the developed program, SPADE.