The common development phase of a twist beam axle (TBA) usually starts with several concepts, based either on benchmarking or empirical values. Based on these concepts, the first computer-aided design (CAD) models are designed and then converted into finite element (FE) and multibody simulation (MBS) models so that the stiffness and kinematic characteristics can be evaluated. From these first results, which concept is suitable to fulfill all the requirements can be determined. The selected concept will be further optimized via numerous CAD and computer-aided engineering (CAE) iterations until it meets all concept targets. Due to this process, the quality and development time of the final phase strongly depend on the chosen concept.
The presented algorithm, fast conception of twist beam axles (FastCon-TBA), is a user-friendly software development tool that simplifies the process described above and makes it more efficient. Based on the concept variables, FastCon analytically evaluates all relevant kinematic and elastokinematic characteristics. To calculate these properties, each part of the TBA is idealized as a beam. Each beam element can have a specific orientation and cross section, which allows it to approximate the deformation behavior of the TBA. By considering the boundary conditions and external loads, each beam deformation is calculated. The complete deformation behavior can be described by superpositioning all the deformations.
FastCon combines this calculation with an optimization algorithm. By using a marking system, FastCon reduces the multi-dimensional nonlinear optimization problem to a scalar optimization. Hence, an optimal concept according to the given boundary conditions (e.g., package space) and requirements can be developed in a few minutes.
Based on an example calculation, this paper describes the development process with FastCon and its results compared to an FE model. Another example shows how FastCon is used to develop a concept with the given package space of a production vehicle and then compared to the serial TBA.