A complete strategy for efficient and accurate multibody dynamics of flexible structures with large lap joints considering contact and friction

Abstract

This paper deals with the dynamics of jointed flexible structures in multibody simulations. Joints are areas where the surfaces of substructures come into contact, for example, screwed or bolted joints. Depending on the spatial distribution of the joint, the overall dynamic behavior can be influenced significantly. Therefore, it is essential to consider the nonlinear contact and friction phenomena over the entire joint. In multibody dynamics, flexible bodies are often treated by the use of reduction methods, such as component mode synthesis (CMS). For jointed flexible structures, it is important to accurately compute the local deformations inside the joint in order to get a realistic representation of the nonlinear contact and friction forces. CMS alone is not suitable for the capture of these local nonlinearities and therefore is extended in this paper with problem-oriented trial vectors. The computation of these trial vectors is based on trial vector derivatives of the CMS reduction base. This paper describes the application of this extended reduction method to general multibody systems, under consideration of the contact and friction forces in the vector of generalized forces and the Jacobian. To ensure accuracy and numerical efficiency, different contact and friction models are investigated and evaluated. The complete strategy is applied to a multibody system containing a multilayered flexible structure. The numerical results confirm that the method leads to accurate results with low computational effort.

On the relevance of inertia related terms in the equations of motion of a flexible body in the floating frame of reference formulation

“…When terms including W 1 , W 2 and W 3 can be neglected, the simulation time decreases significantly in cases where models with a high number of flexible bodies and/or when flexible bodies with many modes are considered. Note that the latter becomes more and more relevant because there is a tendency to consider more and more local effects in flexible multibody dynamics (see, for example, [18][19][20][21] and [26]). In order to illustrate the potential, two examples are given.…”

Dynamic Modeling and Projection-Based Reduction Methods for Bladed Disks With Nonlinear Frictional and Intermittent Contact Interfaces

“…31are not identity matrices. Such reduction bases may be obtained by augmenting linear reduction bases with modal derivatives to capture the effect of nonlinearity on the linear modes [173][174][175]. However, this strategy can be computationally expensive and the number of reduction modes yielded might be quite large, and consequently not offer sufficient reduction in DoFs.…”

A Reduced Order Model for Joint Assemblies by Hyper-Reduction and Model-Driven Sampling

“…In their work, they formulate Trial Vector Derivatives (TVDs) for time domain analysis and use them for test cases where the normal contact, in particular, is accorded predominant importance. A comparison of the efficiency of different contact and friction models has also been presented in [15]. Hughes et al [16] proposed an interface reduction method where they use System-level Characteristic Constraint (SCC) modes and Properly Orthogonal Interface Modal Derivatives (POIMDs).…”