Numerical and Experimental Vibration Analysis of an Additive Manufactured Sensor Mounting Unit for a Wireless Valve Position Indication Sensor System

Nuclear power plants have a very large catalog of regularly manipulated manual valves. To achieve the desired performance and operating margins, skilled technical staff use these valves to control, start, stop, regulate, and throttle the flow of various fluids through plant systems. Wireless valve position indication (VPI) sensor system technology would enable online monitoring of manual valve positions. Using additive manufacturing techniques, the wireless VPI sensor system is retrofitted onto existing manual valves using a sensor mounting unit (SMU). The structural stability of the retrofitted SMU is important for reliably measuring valve position with the wireless VPI sensor system. This paper presents the design, numerical modeling, and experimental validation of SMUs for rising stem gate and rising handle globe valves. Three types of materials, i.e., ULTEM 9085, chopped carbon fiber reinforced nylon, and continuous carbon fiber reinforced nylon, were used to three-dimensionally print the SMUs. The free vibration responses of these SMUs are presented in this paper. The results show how the choice of design, material, and other printer parameters impact SMU vibration responses, especially for the first and second eigenfrequencies. Next, performance of the SMUs is evaluated through both numerical and experimental vibration analysis, and then, the consistency of outcomes using each analysis type is presented. In terms of the stiffness-to-weight ratio and eigenfrequencies, the research shows the SMU printed with 5% continuous carbon fiber reinforced nylon fared significantly better than those printed from the other two materials.