Development of high natural frequency load cell for yarn tension sensors

In this MSc thesis, load cell based yarn tension sensors were designed, manufactured, and tested experimentally. The design process started by examining the load cell's physical and mathematical fundamentals, studying its working principles, and conducting a scientific literature review. In the development stage, load cells were designed by a CAD program (SOLIDWORKS), and the design properties were studied in a FEA program (ANSYS). Among the properties focused on in the analysis process were the Natural frequency and Strain. Three load cell designs with different geometry were chosen, and further analysis was done regarding the effect of the design parameters on their properties. Finally, they were manufactured in a CNC machine according to the designed drawings. Aluminum alloy was used in the manufacturing of the three load cells. The high strain areas were marked in ANSYS analysis, and the strain gauges were chosen and installed. Regarding the experimental tests, the developed sensors were tested using a bobbin creel and a winding unit. The sensors were positioned simultaneously on the creel's outlet, and the yarn tension traces were recorded at four different winding speeds and three different low pass filter frequencies. Then the tension levels were evaluated and compared with results acquired from commercially available sensor. Finally, Digital signal processing (DSP) was applied to the data through MATLAB to improve and analyze the resulting signals. Experimental data showed that the tension sensors using the developed load cells could be used for dynamic yarn tension measurement in the textile processes.