Composites

ABAQUS/Boeing Commercialize New Composites Cracking Software

One of the big issues in assessing damage to composite aircraft components relates to flaws that are barely visible on the surface but may be considerable within a composite component's structure. An add-on to general purpose finite-element analysis (FEA) software from ABAQUS, tested and refined at Boeing, could help an aircraft designer understand the stiffness and strength, both original and residual, of a composite component, as well as its lifetime and damage tolerance. Called Virtual Crack Closure Technique (VCCT), this software addition could even play a role in simulating how ultimate properties are affected after a repair, along with guidelines for the repair.

VCCT offers an understanding of composite structural performance under load and the way it fails, noted Dale Berry, manager of engineering applications for ABAQUS, better than traditional stress analysis software. "Does it fail immediately when cracked or fractured, or does it exhibit residual strength and over what time period? This is what VCCT can help analyze, by extending the virtual testing of composite structures."

ABAQUS has now licensed this Boeing intellectual property geared to predict reliability of major composite structural components through fracture and failure mechanics and will market it to Boeing, Boeing's suppliers, and other third parties. The add-on will be available by year's end; within three to five years, a software package with VCCT incorporated into ABAQUS should be ready.

"VCCT layered on top of our FEA functionality," said Berry, "can give a user a straightforward way to examine a composite structure from the component to the system level, from the stringer to the wing box to the entire wing and fuselage. VCCT can help an engineer model and understand load transfer in cracks or flaws that occur in interfacial layers, bonded joints, and at bimaterial interface [composites to metal]." — By Vicki P. McConnell