This presentation was made at the NAFEMS Americas Seminar "Model-Based Engineering: What is it & How Will It Impact Engineering Simulation" held on the 1st of October 2019 in Columbus Ohio

Resource Abstract

The original aircraft survivability analysis, hit calculations, has been around since the beginning of aircraft survivability. Described in the renowned Aircraft Survivability Bible, The Fundamentals of Aircraft Combat Survivability Analysis and Design by Robert E. Ball, essentially, slow, low flying, and easy to detect aircraft will have poor survivability. Also, Ball describes as hits on the aircraft increases, the aircraft survivability greatly decreases as seen in Figure 1. Two components are described by Ball to make up an aircraft survivability, susceptibility and vulnerability. Where, susceptibility is the aircraft’s likelihood to be hit and vulnerability is the aircraft’s likelihood to withstand a hit. With Ball’s established aircraft survivability methodologies, other efforts have arisen to expand upon and improve aircraft survivability existing methodologies in more detail.



Recently developed methods with addition to Ball’s approach form a higher fidelity assessment of aircraft survivability. The new considerations take into account various qualities including aircraft velocity, reload speed, lethal envelope, and others. The idea to supplement Ball is to more consider the entire scenario, rather than just hits on the aircraft. By taking into account other important factors, more reasonable aircraft survivability metrics can be attained. The lethal envelope and detection envelope is a powerful consideration, giving context to the aircraft and enemy entity relationship.



A lethal envelope and the detection envelope are volumes in which the aircraft is detectable and/or vulnerable to hits from an enemy entity. The envelopes are dome-like volumes with the enemy entity centered; Figure 2 describes each envelope. There are many lethal envelope factors associated to calculate the total aircraft survivability as seen in Figure 3. With the combination of envelopes and Ball’s methods, a basis for advanced aircraft survivability analysis is founded. Next step is to apply various analyses to adapt to more challenging and new aircraft survivability threats. These include digital pheromones, loyal wingman, and swarming.



Having the analyses described and understood, the base architecture of the framework was created. In Figure 4, the initial, high-level architecture of the framework is shown. The architecture organizes the framework in an object-oriented sense, enabling the various strengths of object-orientation to be translated into the framework development (i.e. scalability, readability, etc.). At the highest-level, the framework is shown, existing in its entirety. The framework acts mostly as the main method by compiling, executing, and referencing the lower level classes. Composed of analysis, scenario, and simulation at lower levels, each is designed to support important roles.



Today, most aircraft survivability tools are models coveted by various agencies for expensive licenses or US government contracts. Many analyses exist with strong capabilities to provide better aircraft survivability understanding. By generating an open-source aircraft survivability framework, the analyses have been implemented to promote a robust tool. The open-source and available framework encourages the aircraft survivability and M&S communities to fortify, enhance, and create robust aircraft survivability aware aircraft and aircraft survivability methodologies. Model-Based System Engineering (MBSE) methodologies have been implemented to better VV&A system requirements early. An object-oriented language with the AGILE method leverages System Engineering (SE) strengths including attributes, requirement and constraints, and system life cycles. With these methods combined, the aircraft design process would greatly benefit from utilizing AirSurF to effective know critical flight performance parameters, mitigating present and emerging threats to the modern aircraft. In all, AirSurF provides great opportunities for new and existing aircraft designs and survivability analyses to be implemented, further developed, and better understood.