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Numerical Model

Numerical technique:

Geometrical model assembly:

SolidWorks 3D CAD.

Numerical Simulation package:

ANSYS 14.5, implements the FEM.

Elements Type: Tetrahedral with 4 nodes

Mesh: 11,600 elements for model A,

15,700 elements for model B.

Model Geometry - compatible with the 37

th

week of gestation: uterus is 290mm long,

210mm wide and 10mm thick.

Case A: Maximal cervical dimensions.

Case B: Minimum cervical dimensions.

Boundary Conditions:

The uterus is fixed at its upper part.

The cervix is fixed at the bottom, around

its exterior diameter.

To simulate the support of pelvic

ligaments, a thin disk was added

surrounding the top of the cervix, and was

fixed around its outer scope.

The entire uterine cavity is filled with

amniotic fluid ( ), which

puts hydrostatic pressure on the model.

The models were applied with the normal

elasticity modulus of uterine and cervical

tissue ( ).

Student name:

Meital Bistri

Department: Medical Engineering

Advisor name: Dr.

Zoya Gordon

Analysis of the stresses evolving in

cervix during pregnancy

2015

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1

The human uterine cervix maintains the

uterus closed during gestation to ensure

a normal development of the fetus.

As pregnancy progresses, uterine volume

and pressure increase and the cervix has

to withstand larger forces, including

dynamic fluctuations.

The competent cervix stays firm and its

canal is closed.

Cervical incompetence is the inability of

the cervix to conserve the developing

pregnancy, which usually leads to

preterm delivery.

Early detection of an incompetent cervix

is important in helping to prevent preterm

labor. However, the diagnosis of cervical

incompetence is very difficult to make.

The project studies the behavior of the

cervix under the influence of the stresses

exerted on it during pregnancy.

Analyzing the distribution of the

stresses and strain evolving in cervix

during pregnancy.

To investigate the correlation between

the geometry of the cervix, and the

stresses, leading to its deformation, while

taking into consideration the mechanical

properties of the cervical tissue.

A

B

2. Objectives

1. Background

3. Methods