Simulation of Uterus Active Contraction and Fetus Delivery in ls-dyna

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Reproductive Biology

Background:

• Vaginal childbirth is a complex biomechanical process involving uterine contractions to expel the fetus.
• Understanding the mechanics of uterine active contraction is crucial for simulating fetal delivery.

Purpose of the Study:

• To develop and investigate a finite element method (FEM) model simulating uterine active contraction and fetal delivery.
• To analyze the biomechanical behavior of uterine muscle tissue during labor.

Main Methods:

• Modeled active contraction using contractile fibers (1D truss elements) with the Hill material model.
• Represented uterine microstructure and anisotropy with fibers in longitudinal, circumferential, and normal directions across seven regions.
• Utilized a Neo Hookean hyperelastic model for passive uterine tissue.
• Simulated three cycles of active contraction and subsequent fetal delivery using LS-DYNA.

Main Results:

• Successfully modeled three-dimensional active uterine contractions, including anisotropy and wave propagation.
• Demonstrated the model's ability to perform large deformations and simulate the pushing effect on the fetus.
• Analyzed cyclic active contraction behaviors and their role in fetal expulsion.

Conclusions:

• The developed FEM model accurately represents uterine active contraction and its biomechanical role in fetal delivery.
• This model provides a foundation for simulating the complete second stage of labor when integrated with pelvic structure models.
• Further integration will enable comprehensive biomechanical simulations of the entire vaginal childbirth process.