Publication Date


Document Type


Committee Members

Nathan Klingbeil (Committee Member), Ravi Penmetsa (Advisor), Eric Tuegel (Committee Member)

Degree Name

Master of Science in Engineering (MSEgr)


Knowledge of critical structural items for an aircraft structural system is crucial for any risk integrated design and maintenance procedure. These critical items are those whose failure can cause catastrophic damage to the entire structure or result in loss of availability. For example, failure of the fuselage longeron of an F-15 aircraft resulted in the separation of the aircraft cockpit from the rest of the structure, resulting in a complete loss of the aircraft. This is clearly a critical structural item that was identified during the design process but did not have appropriate design, manufacturing, or maintenance controls that could have prevented the accident through early detection of manufacturing flaws. While this failure is catastrophic, there can be other damage scenarios that are not catastrophic but they could lower aircraft availability due to maintenance and repair requirements.

Moreover, these critical structural items can be in areas of the aircraft that require extensive teardown in order to assess their condition. Therefore, along with the criticality of the structural failure, the location of the component also becomes important. In this research, Failure Modes Effects and Criticality Analysis (FMECA) will be used to integrate, event criticality, event frequency, and damage detection capability into one metric. This process enables integration of structural sizing and maintenance planning to minimize the operational cost while maximizing the aircraft availability. This process can also be used to quantify the impact of structural health monitoring system on the overall risk of failure of the structure.

In this research, a Boeing 707 lower wing skin with stiffeners is used to demonstrate the process of developing an FMECA procedure for structural systems. In order to make this process applicable for large scale systems efficient structural re-analysis methods that minimize the analysis cost are also implemented. This FMECA process can be used to develop design, manufacturing, and maintenance controls that ensure quality and health of the critical structural items.

Page Count


Department or Program

Department of Mechanical and Materials Engineering

Year Degree Awarded