Design and development of a three-component force/moment sensor for underwater hydrodynamic tests

• A three-component force/moment sensor with novel configuration was proposed for under water hydrodynamic tests.
• High sensitivity of 1 mV/V was considered for each component using intentional stress concentration technique.
• A high value of moment to force ratio as well as coupling error less than 2.25% was found.
• The sensor was designed so as to easily mount the strain gauges and to reduce fluid/structure interactions.
• The converged results of finite element simulation were in a very good agreement with the experimental outcomes.

In this paper, a three-component force/moment sensor is designed and constructed for underwater hydrodynamic force/moment measurements in water channel laboratory. First, an appropriate sensing structure to measure lift and drag forces as well as pitching moment is designed using finite element method (FEM). The sensing structure configuration and the corresponding dimensions are thus chosen so as to acquire acceptable sensitivity and negligible interference error amongst the components considering desired loading capacities. The appropriate locations of strain gauges on the hosted structure are found via the finite element analysis. The sensitivities of lift, drag and moment components are respectively estimated as 1.01 mV/V, 1.08 mV/V and 0.96 mV/V using FEM simulation. Finally, the experimental strain gauge-based three-component sensor is developed and calibrated. The experimental sensitivities of the sensor components are respectively measured as 1.04 mV/V, 1.15 mV/V and 1.00 mV/V for lift, drag and moment components through calibration tests. Besides, an interference error less than 2.25% is found amongst the sensor components. The experimental outcomes clearly reveal a very good agreement with the FEM simulation results through which the validity of the design procedure is affirmed.