CAE-Companion-2018-2019
Engineering WISSEN CAE
Functional Development: Pedestrian Protection - Head Impact
Requirements/Critical Target Values: UN R127: Impactors:
3.5 kg & 4.5 kg (Phase 2) Headform Impactor
Test Conditions & Criteria:
Phase 2
Child/Small Adult
3.5 kg / 35 km/h (9.7 m/s) / 50° BLE/WAD 1000 - WAD 1700 / Bonnet rear edge 4.5 kg / 35 km/h / 65° WAD 1700 - Bonnet rear edge/WAD 2100 < 1000 (1/2 of the Child head impact area AND 2/3 of the total impact area) <1700 (remaining area)
Adult HIC 15
Euro NCAP: Impactors:
3.5 kg & 4.5 kg Headform Impactor
Test Conditions:
Child/Small Adult 3.5 kg / 40 km/h (11.1 m/s) / 50° BLE/WAD 1000 - WAD 1500 Adult 4.5 kg / 40 km/h (11.1 m/s) / 65° WAD1500 -WAD2100 (if points betweenWAD1500 and1700 areonbonnet, use childhead)
Criteria:
maximum Score
0 Points
HIC 15
< 650
≥ 1700
Procedures: Use of full vehicle models (impact area: detailed models of all components; engine package can be rigid) High detailing for bonnet attachments, hinges, locks, sealing structures, bonnet shock damper, head light attachments, windshield wiper assemblies Connection modeling is highly significant (spot welds, adhesives etc.) Use of validated material model for windshield failure
Use of validated impactor model Typical simulation duration: 20 ms Critical Modelling Parameters: Strain rate dependency of materials in the impact area Details of spatial discretization Evaluation Criteria: Head Injury Criterion (HIC 15 ) For the optimization: use of acceleration - displacement diagrams to identify jamming Main Influencing Factors:
Geometry of vehicle front (impact points, impact behavior) Material stiffness at impact point (potential for optimization) Stiffness of geometrical package (sheet metal thickness, structural reinforcements in direction of impact, inlays, application of adhesives) Clearance between bonnet outer shell and package (min. 60 - 80 mm free displacement required, otherwise an active bonnet should be considered) No jamming elements (e.g. bonnet shock dampers, wiper axles) should be packaged directly in the impact area Homogenous support of the impactor along the full bonnet/vehicle width is required (e.g. muffin-like structure for the bonnet inner shell). Sharp stiffness gradient should be avoided.
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