Automation of ATD positioning for crash analysis simulation
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Mobility engineering (MPMOB), MSc
Publicerad
2023
Författare
Asadi, Khashayar
Karlsson, Kristoffer
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
In alignment with the United Nations target 11.2, regulators enforce minimum safety
requirements in different new car markets, at the same time consumer information
organizations and car manufacturers strive to make cars safer. Standardized test
procedures using anthropomorphic test devices (ATD) are commonly used to evaluate
car crashworthiness and occupant protection. Using computer aided engineering
(CAE) utilizing finite element (FE) analysis, standardized test procedures can be
reconstructed in simulations. Although, safety development using CAE can be
complex given the variations found in standardized test procedures in different new
car markets.
This study developed an automated positioning method using intersection checks and
node-to-node distance minimization for ATDs in CAE. The method was developed
for the Hybrid III adult ATDs for frontal crash evaluation and was implemented for
use at the car manufacturer using the simulation pre-processor ANSA’s application
programming interface. Three ATDs were considered and were positioned
automatically in car environment models. To evaluate the methods positioning
performance, an automatically positioned 50th percentile Hybrid III male model was
compared with physical positioning. The driver’s position in US NCAP full frontal
rigid barrier 35 mph was used. The automatically positioned Anthropomorphic Test
Device was positioned within two standard deviations of physical positioning for both
X- and Z- coordinates in five out of six measurement locations.
Furthermore, two application studies were performed using sled simulations and a
mid-size SUV developed at the car manufacturer. The studies were again assessed
using the Hybrid III 50th percentile male and the US NCAP Full Frontal Rigid Barrier.
The first study assessed global injury criteria reproducibility as results can vary due to
model decomposition, i.e., numerical noise. In the environment and load case studied,
global injury criteria showed a Coefficient of Variation regarding reproducibility of
0,65% to 4,22%. The second study assessed global injury criteria sensitivity to
variations in hip-positioning. The hip-positions were retrieved from physical
positioning. In this study, chest deflections showed variations up to 3.5 mm and femur
force variations up to one kN for hip-positions within two standard deviations of data
in physical Anthropomorphic Test Device positioning. Generally, injury criteria were
more sensitive to H-point variations then model decomposition. These results stress
the importance of achieving the correct H-point position, in CAE and in physical
crash tests.
Beskrivning
Ämne/nyckelord
Hybrid III , ATD , dummy , H-point , positioning , CAE