This article presents the methodical development of a subframe for a novel
on-the-road-modular vehicle concept, which was developed for the U-Shift
project. The subframe serves as the basis for a modular chassis. This chassis
offers the possibility to exchange chassis components by the operator, which
means after completion by the manufacturer, and thus to adapt the vehicle to
different purposes. According to the applied methodology, the relevant wheel
loads are determined and a geometric reference model is created. By defining the
relevant load cases, the forces acting on the subframe, and thus the physical
boundary conditions, can be determined from the wheel loads. In addition to the
wheel loads and the geometric boundary conditions, no other vehicle parameters
are required for the development of the subframe. The results of the topology
optimization are used to identify areas of the geometric reference model that
are not exposed to high loads. Based on the results of the topology
optimization, a suitable combination of manufacturing processes and suitable
materials can also be determined. After the basic topology has been determined,
a welded construction is derived from square tubes and plates. Subsequently,
excess stresses at critical points are identified in simulation and analysis
processes, and constructive changes are made to reduce them. Through validation
by simulation of the relevant load cases, a proof of compliance with the
physical boundary conditions can be provided. The actually manufactured subframe
is presented, and the potential of the modular construction for the development
of a chassis modular kit is explained.
