System Level Design and Analysis of the ACES Modular Ejection Seat

McDonnell Douglas originally developed the Advanced Concept Ejection Seat (ACES II) in the 1970’s. The USAF has contracted Goodrich Universal Propulsion Company (UPCO) and Concurrent Technologies Corporation (CTC) to develop a modular version of ACES for the F-15. The modular design will allow seat removal without having to first remove the canopy from the aircraft. ANSYSTM Workbench 9.0 shaped the modular design, enabling CTC to meet the demanding structural requirements for the new seat. Due to the complex loads this seat is subjected to, a system level analysis was developed. This linear analysis consists of approximately sixty structural components, uses a mixture of shell and solid elements and consists of approximately 320,000 nodes and 200,000 elements. Bonded contact was used to join the components together. This model allowed CTC to quickly and efficiently examine the effects of many load cases on the entire seat system when problem areas were identified and the geometry could be updated without eras ing existing contact pairs, loads and boundary conditions. The ability to easily update and quickly solve the numerical model allowed for multiple iterations, resulting in an optimized design. The system analysis also allowed CTC to examine complex load cases, which were not possible during the original design in the 1970’s. Modifying and verifying multiple designs were easily accomplished using ANSYS Workbench. This approach ensures that the new modular design will meet all requirements during structural testing and qualification.

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