Certification Modeling for Composites with Voids and Wrinkles for Engines and Structures

ABSTRACT: This SBIR will model the effects of voids/wrinkles on interlaminar strength and fatigue, detecting defect locations, testing curved specimens; and develop void/wrinkle generation models for contoured composite structures to improve their integrity and reduce rejection rates.Accordingly, the target contribution of this effort has been summarized as understanding the effects of void and wrinkling defects on structural integrity such that useful accept/reject criteria can be developed leading to reduced conservatism; and understanding generation of the critical defects including their location, size and shape; and possibly developing practical engineering criteria quantifying the critical defects.Phase I effort will determine the technical feasibility of the proposed concept to meet the Project objectives.During Phase II, a modeling and testing program will assess flaws versus change of strength/fatigue performance of thick, curved composite structures.Testing will be of a scope to provide validation within the program budget, and may be limited to void or wrinkle flaws. The model will compare location of the critical flaws, quantify uncertainties in properties, and predict performance of the curved test specimens.; BENEFIT: The design and analysis tools capturing the effects of the manufacturing irregularities on structural integrity of contoured composite parts, implemented into commercial-off-the-shelf finite element analysis software, will create a huge impact on certification modeling of composites for engines and structures.Furthermore, quantifying the critical defects composite parts from cure-process simulation could be essential for closing the loop on effective control of the manufacturing process to prevent formation of the critical defects.The tools developed in this effort will enable effective integration of design, manufacturing, and certification of composite parts.The ability to design and build critical composite parts right the first time has been desperately needed by industry.For example, rotorcraft OEMs currently about 40% of the budget to design a new part is already spent before starting fatigue qualification.As a result, the part cannot be redesigned after problems are found; and the design can only be patched.The analysis tools enabling accurate structural strength and fatigue predictions for composite parts must capture their manufacturing complexity and variability to avoid costly trial-and-error iterations.Based on the feedback provided to Team Members, the Rotorcraft Industry and research labs are anxious to acquire the tools developed in the proposed effort for immediate applications in the new designs including CH-53K, CSAR, JMR and FVL aircraft as well the current and future design upgrades.Similar feedback has been received from the fixed-wing aircraft OEMs and the engine manufacturers.Also, naval and offshore applications including oil and gas industry markets, increasingly utilizing thick and curved thermosetting polymeric composite structures, are extremely interested in the enabling technology.We expect to capture these markets by 2020 if the proposed effort is funded.