Title: Overview and Status of “Composite Joints with Inherent Disbond Arrest Capability (COJAC)” Program

Authors: Jonathan Bartley-Cho, and William C. Nickerson

DOI: 10.33599/nasampe/s.19.1457

Abstract: In the design and development of future naval air systems, several challenges exist in meeting acquisition and operational cost and performance goals. Many of these challenges can be addressed using bonded composite structures technology, provided structural integrity/reliability concerns are addressed. Bonding enables low cost but high composite content airframes that reduce 1) aircraft structural weight fraction and 2) maintenance cost associated with fatigue, corrosion, and survivability. However, widespread use of primary bonded composite airframe structures is currently constrained by structural integrity and reliability concerns. These concerns are reflected in the JSSG-2006 guidelines which states that primary bonded structures must sustain a residual strength capability at limit load or better “without a safety of flight failure with a complete bond line failure or disbond”. One way to address this criterion is to use Z-pinning as a disbond arrestment feature in the bondline. Under the “Composite Joints with Inherent Disbond Arrest Capability (CoJAC)” program, Z-pin technology in the form of “stubble” concept will be applied to co-bonded joints based on 3D woven Pi preforms. Funded by the Office of Naval Research (ONR) and led by Northrop Grumman Aerospace Systems (NGAS), the goal of the CoJAC program is to assess the feasibility of the Z-pin stubble-based co-bonded Pi joints to meet the JSSG requirement by combination of automated Z-pin insertion technique and autoclave-based co-bonding. This paper will provide an overview and current status of the program.

References: 1. Mouritz, A.P., “Design Dilemma for Z-Pinned Composite Structures”, 27th International Congress of the Aeronautical Sciences, 2010 2. Stephen B. Clay and Amanda K. Pommer, “Z-Pin Stubble Technology Advanced Research (ZSTAR)”, April 2008, Final Report, AFRL-RB-WP-TR-2008-3017

Conference: SAMPE 2019 - Charlotte, NC

Publication Date: 2019/05/20

SKU: TP19--1457

Pages: 8

Price: FREE