Multibody System Modeling of Flexible Twist Beam Axles in Car Suspension Systems

Abstract

Dynamic simulation techniques that are based on Multibody system approaches have become an important topic in studying the performance of various mechanical components that comprise an automotive system. One of the challenging issues in such studies is the ability to properly account for the flexibility of certain parts in the system. One example where this is important is the design of twist beam axles in car suspension systems where twisting deformations are present. These deformations are geometrically nonlinear and require a special handling. In this paper two multibody system approaches that are commonly used in overcoming such problem are examined. The first method is a sub-structuring technique that is based on the popular method of component mode synthesis. This method is based on dividing the flexible component into sub-structures, in which, the linear elastic structural theory is sufficient to describe the deformation of each sub-structure. Using this method the deformation of the beam is described using the mode shapes of vibration of each sub-structure. The equations of motion, in this case, are written in terms of the system’s generalized coordinates and modal participation factors. In the second method a Multibody System (MBS) solver and an external nonlinear Finite Element Analysis (FEA) solver are coupled together in a co-simulation manner. The nonlinear FEA solver, in this case, is used in modeling the deformation of the twist beam. The forces due to the nonlinear deformations of the flexible beam are communicated to the MBS solver at certain attachment points where the flexible body is attached to the rest of the multibody system. The displacements and velocities of these attachment points are calculated by the MBS solver and are communicated back to the nonlinear FEA solver to advance the simulation. The two methods described above will be reviewed in this paper and an example of a twist beam axle in a car suspension system model will be examined twice, once using the sub-structuring method, and once using the co-simulation method. The numerical results obtained using both methods will be analyzed and compared.

Collaborative Optimization for Torsion Beam Opening Direction and Rubber Bushing Installation Angle of Torsion Beam Suspension to Improve Frequency Response Characteristics of the Vehicle

“…ey are the subconstruction method and the cosimulation method. Finally, the two methods are compared and analyzed, the results show that the simulation time required by the subconstruction method is shorter than that of the cosimulation method, and the communication interval of the cosimulation method has a great influence on the simulation accuracy and simulation time [9]. Choi et al proposed a multidisciplinary method of automatic optimization of torsion beams and generated optimal design parameters such as thickness and shape.…”

Numerical Simulation of the Kinematic Behavior of a Twist Beam Suspension Using Finite Element Method

“…But the software is somehow limited because it does not enable using variable pro files along the beam and also there are three possible locations predetermined of coil spring . Sinokrot el at [13] presented two different mu ltibody system modeling techniques for the simulation of flexib le twist beam axles. One uses the method of co mponent mode synthesis together with a sub-structuring technique for modeling the flexible beam that is done by dividing the beam into a set of sub-structures each of which is flexible.…”

Super-element global modal parameterization for efficient inclusion of highly nonlinear components in multibody simulation

“…3. In all cases, δ acts as the modal amplitudes of the linearized deviations of the system, as shown inFig.…”