Modeling the mechanics of a medical compression stocking through its components behavior: Part 1-modeling at the yarn scale

The goal of this article is to propose practical and scientific explanations about the mechanics of compression by the medical compression stocking (MCS) to the phlebologist and angiologist societies. The first part presents the principle of pressure generated by the MCS. We explain how the surface of MCS fabric is structured from the yarn scale and how each component of the yarn contributes to generate the desired compression. The second part is dedicated to the mechanical behavior modeling of the covered yarn, which is the main yarn component of the elastic knitted fabric of the MCS. The structure analysis shows that the properties of the inlaid yarns reflect significantly the global behavior of the fabric. Therefore, by characterizing the elastic properties of the inlaid yarn, it is possible to predict the mechanical behavior of the entire MCS fabric. We suggest a few approaches to model the covered elastic yarns used in different types of products. The third part describes an identification procedure aiming to calculate the unknown parameters of the mathematical models with the yarn elongation curves. The principle is to divide the general model into several sub-models in order to avoid considering simultaneously a great number of parameters in the identification procedure. The last part presents a set of identification results that compare measured values with simulated data. With a reliable model of the elastic yarns, an efficient strategy can be conducted to define the proper inlaid yarn (for the MCS construction), aiming to treat efficiently vein diseases at different stages according to medical prescription and the patient's need.