6533b7d7fe1ef96bd1267666

RESEARCH PRODUCT

Contribution to the investigation of dynamic responses of human tissues under high velocity impacts using finite element modeling

Jianbo Shen

subject

Méthode des éléments finisConstitutive modelingHuman tissuesFinite element analysisModélisation constitutive[PHYS.MECA.BIOM] Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph]High velocity impactImpact à haute vitesseTissus humainsFracture des côtesRib fractures

description

Thoracic injuries happen frequently in various frameworks of high velocity impact biomechanics. Rib fractures and lung injuries are the most common hard and soft tissue injuries in human thorax. This thesis aims to contribute to the investigation of dynamic responses of human tissues especially ribs and soft tissues under high velocity impacts using finite element modeling. Firstly, a novel strain-rate-dependent elasto-hydrodynamic constitutive law of the synthetic polymer Styrene-Ethylene-Butylene-Styrene (SEBS) gel was proposed and implemented as a user material subroutine in Radioss (Altair Hyperworks) to interpret dynamic behaviors of SEBS gel under various loading configurations. Numerical analysis validates the accuracy of the model and reveals that the strain-rate-dependence effect is significant in SEBS gel especially for high strain rates, which indicates the necessity of taking the strain rate dependence into consideration when modeling the SEBS gel as a human soft tissue substitute. Then, this study numerically investigated the effect of geometrical and mechanical parameters on dynamic behaviors of isolated porcine ribs submitted to high velocity impacts using three point bending (3PB) Split Hopkinson Pressure Bar (SHPB) apparatus. Sensitivity studies highlight the significant effect of geometrical parameters on dynamic behaviors of ribs, and the consideration of the effect of mechanical parameters like loading mode and strain rate sensitivity in FE rib models is also needed. Finally, this thesis also developed human rib FE models with various material properties including human rib cortical bone material properties from different loading modes (tension and compression), strain rates and ages as well as porcine rib material properties, in order to better understand rib structural responses and fracture locations under dynamic anterior-posterior bending. Numerical force-displacement relationship, cortical strain, rotation and fracture locations correspond well with published experimental data. Moreover, numerical rib structural responses are found to be sensitive to human cortical bone material properties from different loading modes, strain rates and ages. Therefore, it is necessary to consider these factors when establishing rib FE models. Overall, this thesis helps better understand dynamic responses of human tissues in high velocity impact (HVI) contexts, and the proposed constitutive law of the SEBS gel and the established rib FE models can be employed in a global thorax model for human trauma investigations.

https://theses.hal.science/tel-03703916