A large defense company used our analysis and test services to address particularly challenging aspects of a two-axis stabilized satellite transceiver system required to operate on-the-move in extreme environments. They also used AES as an objective third party to evaluate and validate the performance of subsystems. The following case studies illustrate several of these analyses and tests.
Structural analysis and shock isolation design for severe environment
The product is required to survive a very severe ballistic shock. AES created a finite element model of the structure and bearings, extracted modes, and evaluated survivability in a hard-mounted configuration. After verifying that shock isolation was required, AES designed the required shock isolation system. AES re-analyzed the design with isolation and implemented minor structural modifications required to survive the ballistic shock.
Finite element model of satellite transceiver
Plot of fundamental mode shape for hard-mounted system
Stress contour for hard-mounted design
Stress contour for isolated design showing acceptable stress levels
Structural dynamics and structure/servo coupling evaluation
In order to achieve a stabilization performance capable of rejecting base motion disturbances, the torsional structural modes that couple into the control loop must be evaluated. AES conducted structural analysis and provided mechanical open loop transfer functions to the customer. AES verified that there was adequate margin in the structural design to guarantee stabilization performance.
Torsional mode shape
Open loop mechanical transfer function
Transfer function equation
Experimental modal analysis
An existing product was evaluated using experimental modal analysis techniques to predict response to new environments and validate analyses. AES instrumented the hardware with multiple accelerometers, measured acceleration responses, and generated animations to visualize the mode shapes.
Existing production design on
slip plate of electrodynamic shaker
Animated shape of fundamental mode
Thermal analysis and thermal testing
AES designed a cooling solution for electronics with a tight packaging constraint operating under the severe thermal and solar loading experienced in Iraq. AES developed a forced convection solution, and analyzed it via computational fluid dynamics (CFD) modeling to ensure performance.
Flow Field Predicted by CFD Analysis
Temperature Contours from CFD Analysis
Due to the critical nature of this system, AES also created a prototype of the cooling solution, instrumented it with heaters to simulate the thermal loads from the electronics, thermocouples to measure the critical interface temperatures, and anemometers to measure the flow field. The testing verified that the design and analysis.
Inside of plenum showing patch heaters and thermocouples
Thermal test setup
Heat Exchanger Evaluation and Verification Testing
AES completed an independent evaluation of an air-to-air heat exchanger design provided by a 3rd party. AES instrumented the system with heaters, thermocouples and anemometers. Data was gathered and reduced to calculate the critical heat exchanger metrics used to evaluate performance. AES confirmed that the heat exchanger effectiveness was as high as could be expected given the geometric constraints of design.
Heat Exchanger with radome attached
Heat Exchanger with arrows showing air flow
Radome Hail Impact Testing
AES developed and executed a test to verify an unusual performance requirement – structural integrity of a radome under a hail strike from a two inch diameter hail stone traveling at 130 mph. AES identified and contracted with an independent laboratory, developed test plans, and executed the tests. AES verified the structural integrity of the radome subjected to the severe hail strikes.
