Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 99.95K | Year: 2012
A composite software design tool kit is proposed to predict composite properties using micro-mechanics augmented lamination theory. The capability will overcome shortcomings of progressive failure models and will take into account translaminar and interlaminar failure mechanisms. Starting from lamina properties, strength will be predicted for laminates subjected to tension and compression loading. Generation of allowables using scatter in fiber and matrix material properties and fabrication defects will be carried out by use of probabilistic methods to avoid the testing of large amounts of specimens before there is adequate confidence in the material properties. Integration with finite element approach will be accomplished by synthesis of telescoping composite mechanics from fiber and matrix constituents to laminate level. A significant innovation will be the accounting for damage/micro-crack induced anisotropy of the composite matrix properties. Methods to characterize the material properties under strain rate effects will be included. A commercial composite material characterization software MCQ will be enhanced and integrated into commercial (explicit/implicit) FEM codes for structural scale-up. The capability will consider effect of defects (void shape, size, distribution, and fiber waviness) and will rely on a physics-based micro-mechanics approach to reverse-engineer effective fiber/matrix constituent properties using five ASTM ply in-plane tests as input.
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase I | Award Amount: 99.80K | Year: 2010
A significant barrier to the insertion of ceramic matrix composite (CMC) materials into advanced aircraft engines is their inherent lack of toughness under foreign object Damage (FOD) as well as post FOD. Our team will develop and demonstrate a physics-based model for FOD/post FOD in CMC’s. The model will incorporate physical mechanisms associated with impact for two different CMC systems: a) matrix-dominated system and b) fiber-dominated system. Our methodology will address impact and post-impact of both “as-built” and “as-is” CMC’s. It will account for architecture (2D/3D-nano) and CMC manufacturing (layered thickness, void shape/size, interfacial strength, micro-crack formation) taking advantage of the strength and toughness enhancing effect of different length scales of CMC structure. The model will be incorporated into our commercial progressive failure analysis software GENOA, that integrates commercial FEA and enhances their accuracy limitation. It will be validated using available CMC impact test data from NAVAIR SiC/SiC and Oxide/Oxide for a range of FOD tests. We will determine the feasibility for performing impact tests with Acoustic Emission/Electrical Resistance monitoring as damage assessment and health monitoring techniques that relates to damage model and life prediction. In Phase II high temperature impact testing will be conducted to further validate our model.
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 99.99K | Year: 2010
Continuous fiber-reinforced SiC/SiC ceramics matrix composite (CMC) material is being considered in an advanced gas turbine engine intended for an aircraft or an industrial power generation system, for high temperature capability, possibly with added protection from environmental or thermal barrier coating. CMC engine parts in military/commercial vehicles allow engines to operate at higher temperatures than what a typical superalloy with or without a barrier coating can withstand, and it also significantly reduce engine weight. A successful insertion of CMC’s, particularly in Air Force’s aircraft engines, will also need to sustain aggressive corrosive environment due to “salt” attack on top of considerable damage caused by oxygen and moisture in the combustor fuel. Multidisciplinary physics-based analytical modeling proposed here deals with microstructural damages occurring due to environmental effects, such as, oxidation, recession etc., and it could be an important tool for designing and continually monitoring the health of these critical components in service. Demonstration of such a life prediction tool, which will correlate actual thermochemical and micromechanical damage processes with mechanical response, will shorten the mechanical design and analysis process of CMC components, thereby lowering cost and leading to higher reliability. These benefits will also be relevant for other NASA, DOE and DOD supported CMC application programs for power generation industries where higher temperature and lesser quality fuel will cause these damages to become more severe. BENEFIT: The application of CMC engine parts in military war fighters allows engines to operate in higher temperatures and will reduce the engine weight significantly. Analytical modeling strategy in CMC gas turbine engine design and application is an important complement to test investigation, which reduces test costs and shortens the design-to-production cycle of CMC engines. The proposed development of the micromechanical modeling technique and structural analytical tool will enable its transition to JSF and other military aircraft propulsion systems. Future use may involve hypersonic aircraft and the J-UCAS propulsion systems for weight reduction and enhanced life expectancy. Ceramic matrix composites also leverage large economic and social benefits in commercial application. Catalytic converters alone in the power generation industry enable a $38 billion pollution control business each year and have reduced air pollution by 1.5 billion tons since 1975. Demonstration of commercially available GENOA software, that can successfully predict the composite thermo-chemically-oxidization behavior, will provide the military, the aerospace industry and power generation plants with a verified analytic/design tool. Successful demonstration/verification of a life prediction analytical methodology for engine composites under service environment would reduce future certification costs of an advanced engine structure fabricated with CMC material database for future engine components.
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2006
Manufacturing defects in ceramic composite matrix require 3D fiber architectures to reinforce and toughen both in-plane and out-of-plane directions of CMCs. Modeling 3D material properties and evaluating durability of structures made of 3D composites are of great importance in their application in advanced turbine engines. Alpha Star proposes to develop a micro/macro-scale finite element failure method that accounts for both 3-D composite material and structural behaviors subject to the engine service condition. The contribution of 3-D fiber architectures to structural stiffness and strengths in both in-plane and out-of-plane directions will be accounted for in unit cells using micromechanics formulation. Assuming fiber distribution in 3D composites to be statistically uniform, the input information for a unit cell will be the fiber orientation and content in each material direction as well as the manufacturing defect content, which covers the entire family of 3D CMCs and maintains computational efficiency in the micro/macro scale FEM failure analysis. Embedding the unit cell model in the macroscopic structural analysis allows detailed micro damage to be addressed in durability evaluation of turbine engine components made of 3D CMCs. The proposed method will provide a highly efficient analytical tool for 3D CMC turbine engine design and application.
Agency: Department of Defense | Branch: Special Operations Command | Program: SBIR | Phase: Phase I | Award Amount: 99.97K | Year: 2007
The HMMWV vehicle has seen increasing weight due to the added anti-ballistic and anti-IED protection, whereas mainframe is not designed to function optimally. Ground mobility forces are conducting increased mounted operations from armored HMMWV/modified HMMWV’s. As additional armor and equipment continues to be added to the system, the performance of the existing power train/suspension/steering/chassis components are not sufficient. This causes multiple vehicle issues ranging from high stress and wear to instability and undesirable center of masses. One solution is to decrease the mass in the chassis. AlphaSTAR proposes is to employ advanced and proven finite element/program management techniques to identify chassis weight decrease opportunities and optimize the design using light weight, high-strength composite materials. AlphaSTAR will use a parametric approach to identify and define the ranking of component severity. A Value Analysis/Value Engineering (VAVE) workshop will be utilized to incorporate non-engineering design constraints as well as supplier parameters. Structural design/analysis of the composite chassis components will use AlphaSTAR’s GENOA progressive-failure-analysis and life-prediction software to develop the lightest designs. This approach will consider overall weight reduction, component and material cost, component complexity, strength, component life, and the overall practicality of decreasing HMMWV chassis weight with little or no loss in performance/durability/reliability.