Designing a shape morphing, reusable, blood-collecting hollow tampon with shape memory wire

Abstract

This graduation report describes the design of a new suitable menstruation product for Beppy that collects blood, is reusable, has a similar (deployable) size and function as a tampon, and which is perceived as less intimidating to insert and extract than a menstrual cup. The new design, the Beppy Clover, is made from silicone and has Nitinol, which is a shape memory alloy (SMA), wire embedded. Before insertion, the Clover has a diameter similar to a single use tampon by folding it in three sections. There is no constant external force needed to keep the Clover folded. Once the product is inserted and gets into contact with the body heat and blood in the vagina, the SMA wire (Af = 35°C) reacts and will return to its programmed shape. This results in the three sections with the SMA loops embedded deploying and adapting to the vagina canal. The product will stay in place, collect blood and after 8 hours or less, depending on the flow, can it be retracted by the loop or the attachable silicone extraction cord. The cleaning process works the same as a menstrual cup, rinsing between uses and sterilising at the beginning or end of the period.
To come to this final concept, an analysis, development and evaluation were performed. In the analysis, relevant information about the menstrual cycle, the dimensions of the vagina and current insertable (period) products is gathered. Furthermore, interviews with ten people were conducted to get insights into the user experience regarding their period and period products. At last, the materials and production methods of the Beppy cup are inspected, and new possible materials are looked at to integrate into the product, like shape memory alloy. This information is brought together in a list of requirements.
In the development, three main challenges are tackled: how to integrate deployment (1), insertion (2), and extraction (3) in the design, which would satisfy the requirements and, in particular, make it look less intimidating than a cup. Prototypes were made with silicones out of 3D printed moulds to test shapes, and the proof of concept of the composite of SMA wire with silicones was tested. A concept is made from the combinations of ideas and evaluated by three people focussing on perception and first impression of the Beppy Clover. With the feedback a final design is created.
The end result of the project is a promising final concept that could be the first step in the right direction regarding development of reusable blood collecting tampons. Utilising emerging materials was interesting to research its possibilities in period products. More tests and research on the combination of silicones and SMA wire reacting to body temperature will be necessary to optimise the force of the deployment of the product. Nevertheless, the Beppy Clover achieved its goal of being a blood collecting, reusable product that is perceived as less intimidating than the cup and has a similar (deployable) size and function as a tampon.