Overview of Composite Airframe Life Extension Program Project 2: Tools for Assessing the Durability and Damage Tolerance of Fastened Composite Joints

Abstract

In anticipation of performing service life extension programs (SLEP) for modern tactical airframes in the United States Air Force (USAF) with composite materials, AFRL has funded and continuing to fund several projects on developing various tools for durability and damage tolerance (DADT) assessment of composite structures under a multi-year contract called Composite Airframe Life Extension (CALE) program. Under the “Tools for Assessing the Durability and Damage Tolerance of Fastened Composite Joints†or simply Project 2, Northrop Grumman Corporation (NGC) developed two sets of tools for bolted composite assemblies: 1) parametric modeling methods for rapid durability assessment; and 2) progressive damage analysis (PDA) methods for detailed damage tolerance assessment.. The development, maturation, and assessment of these two types of tools were supported by testing at NGC and AFRL. This paper will briefly describe the project, key test and modeling results, along with recommendations for future activities in further development of methods for DADT assessment of composite structures.