Abstract
An equivalent mechanism (EM) is a computationally inexpensive concept model capable of simulating crash modes with a straightforward link to FE models. A library approach is presented to enable the use of EM in the vehicle conceptual design process for crashworthiness, based on a prototype implementation into LMS Imagine.Lab AMESim, an integrated platform for multi-domain system simulation from the concept phase onwards. The library allows easy assembly of structures and setup of test cases, performing fast simulations with geometric visualization of crash modes. The elements developed for the library are divided in beam, joint and boundary condition components. Beam and joint components are characterized through FE simulations of collapsing thin-walled structures. Boundary condition components allow clamping beams and simulate contact condition with rigid walls. Once characterized, the components are re-usable in different assemblies. The simulation of a C-shaped structure impacting against a rigid wall is presented as application case for validation of the model through comparison with the correspondent detailed FE simulation. The conceptual model replicates accurately the deformation mode of the full FE model, and the simulation runs 480 times faster. The deceleration hihistory and final displacement of the wall are estimated by running both the detailed and the concept simulation and compared to each other. A maximum difference of 15% for the displacement and of 0.4% for the deceleration peak, which are acceptable values for the conceptual phase of automotive body design.
KEYWORDS – Conceptual design, Crashworthiness, Simulation, Equivalent mechanism, AMESim.