A stochastic visco-hyperelastic model of human placenta tissue for finite element crash simulations.
Placental abruption is the most common cause of fetal deaths in motor-vehicle crashes, but studies on the mechanical properties of human placenta are rare. This study presents a new method of developing a stochastic visco-hyperelastic material model of human placenta tissue using a combination of uniaxial tensile testing, specimen-specific finite element (FE) modeling, and stochastic optimization techniques. In our previous study, uniaxial tensile tests of 21 placenta specimens have been performed using a strain rate of 12/s. In this study, additional uniaxial tensile tests were performed using strain rates of 1/s and 0.1/s on 25 placenta specimens. Response corridors for the three loading rates were developed based on the normalized data achieved by test reconstructions of each specimen using specimen-specific FE models. Material parameters of a visco-hyperelastic model and their associated standard deviations were tuned to match both the means and standard deviations of all three response corridors using a stochastic optimization method. The results show a very good agreement between the tested and simulated response corridors, indicating that stochastic analysis can improve estimation of variability in material model parameters. The proposed method can be applied to develop stochastic material models of other biological soft tissues.
University of Michigan Transportation Research Institute, 2901 Baxter Road, Ann Arbor, MI 48109, USA. jwhu@umich.edu
Jingwen
J
Hu
Kathleen D
KD
Klinich
Carl S
CS
Miller
Jonathan D
JD
Rupp
Giseli
G
Nazmi
Mark D
MD
Pearlman
Lawrence W
LW
Schneider
D000054:Acceleration; D000063:Accidents, Traffic; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D010920:Placenta / Q000502:physiology*; D011247:Pregnancy; D013269:Stochastic Processes; D013314:Stress, Mechanical; D014783:Viscosity