Simulation and Testing of Wave-Adaptive Modular Vessels

This study provides a comprehensive performance analysis of Wave-Adaptive Modular Vessels (WAM-V) using simulations and testing data. WAM-Vs are a new class of marine technology that build upon the advantages of lightweight, low-draft, catamaran construction. Independent suspensions above the hulls isolate the passengers and equipment from the harsh sea environment. Enhanced understanding of the relationship between suspension and vehicle performance is critical for future missions of interest to the U.S. Navy.

Throughout this study, the dynamic properties of three different WAM-Vs were evaluated. A multi-body dynamics simulation was developed for the 100-ft WAM-V 'Proteus' based on an automotive 4-post shaker rig. The model was used to characterize the sensitivities of different suspension parameters and as a platform for future models. A 12-ft unmanned surface vessel (USV) was instrumented and sea trials were conducted in the San Francisco Bay. A dynamic 4-post simulation was created for the USV using displacement inputs calculated from acceleration data via a custom integration scheme. The data was used to validate the models by comparing the model outputs to sensor data from the USV.

A vertical hydrodynamics testing rig was developed to investigate the interaction between the pontoons and the water surface to improve the understanding of how hydrodynamic forces affect suspension performance. A model was created to accurately simulate the hydrodynamic forces that result from vertical pontoon motion. The model was then scaled to fit a 33-ft WAM-V prototype. The 33-ft WAM-V was instrumented and sea trials were conducted in Norfolk, VA. The WAM-V's suspension was upgraded based on the testing results. A 2-post rig was also built for evaluating the 33-ft WAM-V's dynamics. Two dynamic models were made for the 33-ft WAM-V to evaluate different suspension designs.

The results from this study have numerous impacts on the naval community and on the development of WAM-Vs. The methodology for testing and evaluation will allow for future WAM-V designs to be compared under controlled circumstances. The performance of WAM-Vs can then be compared against conventional platforms to determine their suitability for future missions. Simulation development will enable future WAM-Vs to be evaluated prior to undergoing sea trials. The hydrodynamic models become a powerful design tool that can be easily scaled and combined with the 4-post models. By providing the simulations and test data to future vessel designers, the designers will be able to intelligently evaluate numerous iterations early in the design phase, improving performance and safety.