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To metallize non-metallic surfaces by cold spray, bond layers (BLs) are often used to achieve a degree of compatibility between the substrate and the deposit and generally to mitigate the disparate properties of substrate and deposit. The objective of the present work is to design hybrid (Al-epoxy) BLs for metallization of epoxy-based carbon fiber-reinforced polymers (CFRPs) and to determine parametric effects on adhesion and deposition yield. The few studies that have focused on metal deposition onto thermoset composites have highlighted risks of erosion of the thermoset matrix and of fiber fracture. To address these problems, a BL is introduced to reduce erosion of CFRP and to provide surfaces for impinging powder to cold-weld onto and interlock. Effort is devoted to engineer a BL compatible with cold spray and to develop understanding of the quantitative effects of BL microstructure on adhesion. The BL microstructure strongly affected the adhesion of the deposit, which relied on BL-CFRP, powder-BL, and powder-powder bonding. Analysis of initial stages of deposition revealed matrix erosion and subsequent compaction, both contributing to mechanical interlocking. The findings indicate a pathway for CS deposition onto CFRP through judicious design of BLs. [ABSTRACT FROM AUTHOR]

The complex permittivity spectra and conductivity of graphite nanoplatelet (GNP)/epoxy composites were measured to assess the application potential of these materials as conductive coatings and/or microwave absorbers with high structural integrity. The frequency used ranged from 0.05 to 18.0 GHz. The measured static conductivity was in fairly good agreement with the prediction from the Neelakanta equations. For the complex permittivity, however, the measured values were much higher than those predicted. A better prediction required the use of the order function as a semiempirical parameter to account for the particle loading effect. The surface treatment using nitric acid was found to increase both the conductivity and permittivity of the GNP/epoxy composites although the effect was small, which led to the decrease in the matching thickness of microwave absorbers. [ABSTRACT FROM AUTHOR]

Byun, S.-W. and Lee, S.-E., 2023. Numerical assessment of the hydrodynamic loads for a manta type unmanned underwater vehicle: Oblique towing tank test. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 598-602. Charlotte (North Carolina), ISSN 0749-0208. Hydrodynamic loads must be accurately predicted to design robust control systems for Unmanned Underwater Vehicles (UUVs). Conventionally, these loads are estimated through either towing tank experiments (involving oblique frameworks, planar motion mechanisms, or rotating arm tests) or semi-empirical methods. With enhancements in high-performance computing capacities, the reliability of numerical analysis techniques based on computational fluid dynamics has reached the level of experiments. Therefore, this study was aimed at developing a numerical computational model for the oblique towing test of a UUV and estimating the hydrodynamic loads. Specifically, a 1:6 scale model of a manta-type UUV with a length of 12 m was developed. Simulations were performed using the commercial RANS-based viscous solver STARCCM+ (v. 17.06). The model was validated by comparing the numerical results with those of a towing tank experiment. [ABSTRACT FROM AUTHOR]

Lee, S.-E. and Lee, B.-H., 2023. Assessing the effect of wind on the motion peaks of small marine vessels. In: Lee, J.L.; Lee, H.; Min, B.I.; Chang, J.-I.; Cho, G.T.; Yoon, J.-S., and Lee, J. (eds.), Multidisciplinary Approaches to Coastal and Marine Management. Journal of Coastal Research, Special Issue No. 116, pp. 593-597. Charlotte (North Carolina), ISSN 0749-0208. The loss of stability have been regarded as a major cause of marine accidents in small ships which have continued to increase over the last decade. In most them, it is known that a strong hull load generated by a sudden wind attack often causes small vessels to capsize. In this regard, it is necessary to analyse the effect of wind load on ship motion in order to operate them safely. Therefore, the present paper aims to develop a procedure to assess the effect of wind loads on the motion of small ships. Further, the present study includes the numerical results under three conditions: wave only, uniform wind speed, and the NPD wind model. Details of the proposed procedure are presented in a flow chart. The applicability is demonstrated using an example of a 9.77-ton fishing boat under sea state five. Wind loads acting on the fishing boat were estimated in the authors' previous paper. The numerical analysis was performed using AQWA. [ABSTRACT FROM AUTHOR]