Report 106310 Concept Design of a Crash Management System for ...
Report 106310 Concept Design of a Crash Management System for ...
Report 106310 Concept Design of a Crash Management System for ...
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3 <strong>Crash</strong> <strong>Management</strong> <strong>System</strong> 15<br />
To assign the optimal structural shape <strong>for</strong> the crash management system, a topology<br />
optimisation <strong>of</strong> the free space is executed. The principle <strong>of</strong> the topology optimisation is<br />
shown in Fig. 3-14.<br />
Fig. 3-14: Topology optimisation <strong>of</strong> free design space<br />
The results <strong>of</strong> the topology optimisation are interpreted as illustrated in Fig. 3-15. The upper<br />
crash bumper improves the self protection per<strong>for</strong>mance. The lower bumper serves as an<br />
underrun protection device. Regarding the crash boxes aluminium extrusion pr<strong>of</strong>iles with<br />
different cross sections are considered. While rectangular pr<strong>of</strong>iles show a good buckling<br />
behaviour and <strong>of</strong>fer many opportunities to connect these pr<strong>of</strong>iles to other parts <strong>of</strong> the body<br />
construction, their capability to absorb energy is just average. In contrast to rectangular<br />
pr<strong>of</strong>iles, cylindrical pr<strong>of</strong>iles provide the best possibilities to absorb energy, but they show<br />
disadvantages in buckling behaviour. Furthermore they may cause problems due to their<br />
diminished fixing capability. A good solution <strong>for</strong> this conflict is the use <strong>of</strong> octagonal pr<strong>of</strong>iles.<br />
They provide a high de<strong>for</strong>mation <strong>for</strong>ce, show a good buckling behaviour and <strong>of</strong>fer enough<br />
assembling possibilities [ADA95]. The lateral support beams (red coloured) are necessary to<br />
fulfil the ECE-R 93 requirements. To avoid redundancy <strong>of</strong> bumper systems, the original steel<br />
bumper is omitted.<br />
Self<br />
protection<br />
Model <strong>of</strong> free<br />
design space<br />
Front underrun<br />
protection<br />
Applied<br />
load<br />
Rein<strong>for</strong>cement <strong>for</strong><br />
ECE-approval<br />
Fig. 3-15: Aluminium crash management system<br />
Optimised topology<br />
<strong>for</strong> crash structure<br />
Aluminium<br />
crash boxes
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