Multifunctional composites structure design with an integrated system for battery management and bubble generation control
Topic(s) : Multifunctional and smart composites
Co-authors :
Hyun-Ji RHO (KOREA, REPUBLIC OF), Hui-Jin UM (KOREA, REPUBLIC OF), Na-Hyun JEON , Ji-Hwan SHIN , Hak-Sung KIMAbstract :
Various studies have been conducted to reduce drag of underwater vehicles (UWV) [1]. An air layer (plastron) on the surface of underwater vehicle is one of the great way to reduce drag, and it could be achieved through generation of microbubbles. However, to accomplish this goal, additional energy is required for bubble generation. To solve this problem, multifunctional structures are an efficient solution because they have not only load-bearing function but also energy storage capability [2]. In our previous study, we implemented a multifunctional composites structure using 3D printed core for enhanced energy density and superior mechanical properties. The 3D-printed core sandwich structure exhibited great specific stiffness and specific strength along with improved battery protection characteristics, compared to a conventional foam core sandwich structure [3]. In this study, an integration system was designed including battery management system (BMS) and bubble generation control system based on the 3D-printed core sandwich structure, to increase energy efficiency used for drag reduction.
The multifunctional sandwich structure was fabricated using Carbon fiber-reinforced plastic (CFRP) composites for both skin and core. Then, LiPo (Lithium polymer) batteries were embedded in the empty space of core structure, which were power sources to generate microbubbles on the surface of the hull. The anode and cathode were attached on the insulating layer of multifunctional structure, and the micro bubbles were generated through electrolysis using these electrodes. The fabricated multifunctional composites specimens were immersed in a 0.5 M NaCl solution, and power was supplied using embedded LiPo battery to the electrodes to generate microbubbles. To optimize the energy efficiency for microbubble generation, a control system based on Pulse Width Modulation (PWM) was developed. Bubble size and amount were analyzed with respect to the control parameter, and the energy consumption was also evaluated. Additionally, the drop test was performed to analyze the mechanical reliability of the multifunctional composite structure integrated system. For reliability comparison, two types of multifunctional composite sandwich structures were fabricated with foam core and 3D printed core. Consequently, energy efficiency was significantly improved compared to the case without PWM control. The improvement of energy efficiency through bubble generation control was also verified in the actual underwater environment of pressure and flow rate. It was confirmed that the 3D printed corrugated structure core exhibited higher resistance to short circuit of the system.
The multifunctional sandwich structure was fabricated using Carbon fiber-reinforced plastic (CFRP) composites for both skin and core. Then, LiPo (Lithium polymer) batteries were embedded in the empty space of core structure, which were power sources to generate microbubbles on the surface of the hull. The anode and cathode were attached on the insulating layer of multifunctional structure, and the micro bubbles were generated through electrolysis using these electrodes. The fabricated multifunctional composites specimens were immersed in a 0.5 M NaCl solution, and power was supplied using embedded LiPo battery to the electrodes to generate microbubbles. To optimize the energy efficiency for microbubble generation, a control system based on Pulse Width Modulation (PWM) was developed. Bubble size and amount were analyzed with respect to the control parameter, and the energy consumption was also evaluated. Additionally, the drop test was performed to analyze the mechanical reliability of the multifunctional composite structure integrated system. For reliability comparison, two types of multifunctional composite sandwich structures were fabricated with foam core and 3D printed core. Consequently, energy efficiency was significantly improved compared to the case without PWM control. The improvement of energy efficiency through bubble generation control was also verified in the actual underwater environment of pressure and flow rate. It was confirmed that the 3D printed corrugated structure core exhibited higher resistance to short circuit of the system.