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Calibration and Modelling of Adipose Tissue Under Impact Loading

Hosein Naseri (Institutionen för tillämpad mekanik, Dynamik)
Gothenburg : Chalmers University of Technology, 2017.

Vehicular injury is one of the main reasons for traumatic injuries. Finite Element Human
Body Models (FEHBM) have become very popular to assess car crashes and the subsequent
injuries. It provides the possibility to predict stress and strain values in tissue level by
representing anatomical structures in details. An essential requirement for the FEHBM
is to exhibit human-life response, i.e. being biofidelic. Obese occupants are one of the
vulnerable populations at higher risk of death and severe injuries in car crashes. However,
the developed FEHBMs do not, neither in body shape nor the material properties,
represent obese population. In particular, there is no appropriate constitutive model for
adipose tissue (fat tissue) in FEHBMs. In the interaction between obese occupants and
restraint systems both the body shape and the material property of adipose tissue plays
an important role.
Therefore the first goal of this research (and the main goal of this thesis) is finding
and calibrating a biofidelic constitutive model for adipose tissue. To this end a nonlinear
viscoelastic constitutive model was formulated. To have a reliable model calibration
at large deformation and a wide range of strain rates (similar to car crash situations),
test data of two experiments were used; the frequency-sweep test and the ramp loading-unloading
shear test. Prescribing the power-law relation for shear stiffness, which is
suggested in the frequency-sweep test, as a constraint in the ramp loading-unloading
shear test considerably improved the model prediction for large deformations and high
strain rates. To investigate the effect of uncertainties in model parameters and identify
important parameters in different experiments, commonly used mechanical testing setups
were analyzed. Global sensitivity analysis was used for this purpose. It was found that
the amount of compressibility highly affects the behavior of adipose samples in high rates.
It is important specially when studying how adipose tissue behavior affects the dynamics
of obese occupant responses during crash situations.

Nyckelord: Finite element human body models, Obesity, Adipose tissue, Global sensitivity analysis, Constitutive modelling

Denna post skapades 2017-10-31. Senast ändrad 2017-10-31.
CPL Pubid: 252887


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Institutioner (Chalmers)

Institutionen för tillämpad mekanik, Dynamik (1900-2017)


Teknisk mekanik
Annan medicinteknik

Chalmers infrastruktur


Datum: 2017-11-23
Tid: 13:15
Lokal: MC room, Hörsalsvägen5
Opponent: Jonas Stålhand, Linköping university