@@ -164,13 +164,13 @@ After solving this problem, the motor was integrated into the machine to do furt
The next change that was made was to screw legs onto the construction so that when it was flipped upside down a simplified tensile test could be performed (Pic. 6). The test was modelled after a simplified tensile test described by Michigan Tech [^18]. To make the machine flippable, the LEGO motor was integrated in a way, that made it possible to easily take it off the machine.
*Picture 6: Property testing machine mark 2 (“DAS MASCHIN”) in tear test configuration (left) and tensile strength configuration (right).*
The machine was then used to get [tear strength data](/duesseldorf/experiments) on our 100% cotton cloth which we wanted to use as our standard of comparison (Fig. 7). This worked relatively well in weft direction, but failed in warp direction, as the clamps and Newton meter were not strong enough to hold the textile / measure the force at a point, where the textile would tear. Even though the standard deviation for the data in weft direction was relatively low, conclusions on how well the machine works compared to professional Universal Testing machines [^15], as a comparative test with such a machine and with the same cotton cloth was not possible, due to organizational constraints.
Later on, the machine was also used for doing the same in the context of a [tensile test](/duesseldorf/experiments). Throughout these experiments, we realized that many improvements could be made for more reliable tests. These include stronger Newton meters or, as we discussed with a member of iGEM Münster, knowledgeable in the field, we could switch to an Arduino or Raspberry Pi based system, implementing a stepper motor, giving us a digital readout in terms of the voltage change of the motor over time. With this data, we could then properly calculate the applied force at a given time.
*Figure 7: Tear strength of a 100% cotton cloth in different directions (weft & warp) measured with the property testing machine “DAS MASCHIN”.*
A further modification that was made on the first property testing machine was to repurpose it, creating an interactive game teaching others about the basic principles of our tests. This was already used at the [sustainability day](/duesseldorf/human-practices) at our University, as well as at the [JuniorJam in Münster](/duesseldorf/collaborations).
