Methodology

Angeles Crest Engineering Inc (ACEI) uses advanced probabilistic engineering analyses and physics of failure to evaluate service life and failure risk of mechanical components and systems.

The technical staff of ACEI developed the Probabilistic Failure Assessment (PFA) Methodology for NASA for application in the design and reliability evaluation of spaceflight systems. PFA is a tool for managing failure risk more cost-effectively in the design, development, qualification, and production of hardware systems that incorporate advanced technology. PFA is particularly useful in advanced system development projects when information on which to base the design and verification of advanced hardware is expensive or difficult to acquire. PFA is a formal physics of failure methodology for defining design parameters and evaluating failure risk by combining information from testing and service with information from probabilistic simulation based on the physics or mechanics of failure mechanisms. Sensitivity analysis conducted as a part of PFA can be used to define test programs that are targeted to resolve high-risk issues early in a hardware development project in which new designs and technology are being used.

PFA has been applied extensively over the past ten years in the design and failure risk evaluation of components and elements of spaceflight and military systems. PFA has been applied to structural failure modes of large rocket engines, high-performance turbopumps, planetary spacecraft, high-density electronics, and large liquid propellant cannons. PFA has also been applied to erosion of electric propulsion engine components, radiation damage of charge-coupled devices, and chemical stability of a new liquid propellant.

The PFA methodology was developed, by a multi-disciplinary team of technologists that included experts in engineering design analysis and advanced statistical methods. The principal members of this team are now among the staff of ACEI. PFA was recommended by a committee of the National Research Council for widespread application in NASA and a committee of the Aerospace Division, Society of Automotive Engineers recommended implementation of PFA. PFA has also been recommended by the U.S. Army Material System Analysis Activity (AMSAA), Aberdeen, MD for application in Army systems development programs.

“Having lived long, I have experienced many
instances of being obliged by better information
and fuller consideration to change opinions even
on important subjects which I once thought right
but found to be otherwise” - Ben Franklin