Ship Structures Laboratory
The Ship Structures Laboratory focuses on marine structures subjected to hydrostatic and hydrodynamic loads. Midshipmen majoring in Naval Architecture & Marine Engineering (ENM) or Ocean Engineering (EOE) receive hands-on experience in testing and analyzing marine structures using physical and numerical tools.
Capabilities and Resources
Several machines are utilized at USNAfor testing marine structures.
Ship Structures Panel Test Machine
The Ship Structures Panel Test Machine is located at the USNA Structures Laboratory. This is a very rare machine with unique capabilities. The machine is capable of applying in-plane compressing and lateral loads simultaneously on structural panels up to 9 ft x 6 ft in size. A compression load (up to 500,000 lbf) can be applied statically or dynamically as a sinusoidal shape load curve; simultaneously a water-pressurized bladder can apply up to 20 psi of lateral pressure to the panel plating. This machine is used regularly by midshipmen taking EN358 (Ship Structures) Course as well as midshipmen conducting research projects related to marine structures. This is a very rare machine with unique capabilities.
Figure 1. Ship Structures Panel Test Machine
Figure 2. Test panel set-up in the Ship Structures Panel Test Machine.
The Ship Structure laboratory utilizes segmented models with a backspline beam to examine global loads on ship structures. Backspline beams can be instrumented with traditional strain gauges or fiber optic sensors to measure strain and calculate wave bending moments and shear forces on the hull.
Figure 3. Segmented model with Backspline Beam
Figure 4. Strain Gauges Used to measure Global Hull Girder Loads
Fiber Optic Sensors
In addition to traditional sensors, the Ship Structures Laboratory utilizes state of the art Fiber Optic sensors to measure strain and pressure in ship model testing. The fiber optic technology provides greater capabilities by covering much larger surface area of the model.
Figure 5. Fiber Optic Sensors Placed on a model
Figure 6. A Model with a Combination of Fiber Optic Pressure Sensor, Piezoelectric Pressure Sensors, and Load Cell.