A modal derivatives enhanced Rubin substructuring method for geometrically nonlinear multibody systems.

Area of Science:

• Mechanical Engineering
• Computational Mechanics
• Multibody Dynamics

Background:

• Flexible multibody systems (FMS) are crucial in engineering.
• Accurate modeling of nonlinear elastic behavior in FMS is challenging.
• Existing model order reduction (MOR) techniques have limitations in capturing complex dynamics.

Purpose of the Study:

• To develop a novel MOR technique for 3D FMS with nonlinear elasticity.
• To enhance the accuracy and computational efficiency of FMS simulations.
• To address limitations of current MOR methods like Craig-Bampton.

Main Methods:

• Adoption of the mean-axis floating frame approach.
• Integration with an enhanced Rubin substructuring technique.
• Augmentation of the Rubin basis with modal derivatives of free-interface and attachment modes to capture bending-stretching coupling and nonlinearities.

Main Results:

• The proposed method demonstrates higher accuracy compared to the Craig-Bampton method.
• Significant computational speed-ups are achieved in simulations.
• The mean-axis frame leads to smaller relative displacements and rotations, improving accuracy.
• The enhanced Rubin method better accounts for geometric nonlinearities.

Conclusions:

• The novel MOR technique provides a more accurate and efficient solution for 3D FMS with nonlinear elastic behavior.
• The method effectively handles bending-stretching coupling and geometric nonlinearities.
• While offline computation cost increases due to reduced sparsity, the overall performance gains are substantial.