In the development phase of complex mechanical and mechatronic systems reliable dynamic simulation results are of highest importance. A meaningful fatigue assessment of built-up structures like car bodies, truck frames or bolted housings of electronic devices often requires consideration of the occurring contact stresses.
However, the underlying nonlinear contact conditions have the potential to increase the computational effort tremendously. Thus, accurate but still fast numerical models become necessary.
Structural Dynamics of Built-Up Structures
MAMBA is a tailored software solution for this type of analysis. To achieve feasible simulation throughput the contact analysis is performed in two steps. First is the identification of the contact interfaces as well as the creation of a reduced order model out of a FEM model for the respective built-up structure. Second is the contact simulation based on this streamlined model. The following picture illustrates the underlying simulation process when applied for the fatigue assessment of a commercial vehicle frame.
The MAMBA model order reduction is a modal approach utilizing an extended reduction basis capable of capturing the occurring contact stresses. This functionality is accessible within a preprocessing module that interacts with commercial FEM solvers and offers the following benefits.
- Automated detection of contact interfaces
- Contact ready model reduction
- Pretension of bolted connections
The MAMBA contact simulation relies on the streamlined model for the built-up structure. This model then is analyzed either as part of a multibody dynamics model or as free body subject to imposed interface loads. The first analysis setting is denoted as “multibody solution” while the second is denoted as “standalone solution”.
The next picture illustrates both analysis settings based on an exemplary dynamic contact simulation of a car body structure.
The MAMBA multibody solution is accessible via a subroutine, which interacts with commercial multibody dynamics solvers. It is the preferred choice in case the contact stresses within the built-up structure influence the global behavior of the multibody system and offers the following benefits.
- Seamless integration into flexible multibody dynamic models
- Capture contact within flexible bodies
The MAMBA standalone solution is accessible via a solver module. It is the suggested choice in case the interface loads are available in advance and offers the following benefits.
- Wizard for fast setup of the simulation model
- Tailored solver for short contact analysis time
- Parallel simulation of maneuvers
Based on MAMBA the CAE engineer is ready for the dynamic analysis of built-up structures, either for evaluation of the vibrational behavior or for improved fatigue assessment. The next picture illustrates the fatigue assessment results for the battery bracket of a passenger car as an exemplary use case.