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Santhosh U.,Structural Analytics, Inc. | Ahmad J.,Structural Analytics, Inc.
Journal of Composite Materials | Year: 2014

In the present work, a mechanistic modeling approach is pursued for material characterization and for modeling inelastic deformation of polymer matrix composite components. The model attempts to capture the dominant micromechanical deformation mechanisms in laminated composites caused by matrix inelasticity at elevated temperatures. Given material characteristics of the constituent materials, the model can be used in predicting stress, time and temperature-dependent response of a composite under a broad range of thermal and mechanical load conditions. This article describes the modeling approach and examples of its use in a finite element analysis framework. Examples include analyses of simple test specimen coupons, stress concentration at holes and a structural element configuration of a polymer matrix composite. In each case, the model predictions are compared with the experimental measurements. © The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions. nav.


Gowayed Y.,Auburn University | Ojard G.,Aerojet Rocketdyne | Prevost E.,Aerojet Rocketdyne | Santhosh U.,Structural Analytics, Inc. | Jefferson G.,Air Force Research Lab
Composites Part B: Engineering | Year: 2013

Defects created during the manufacture of an oxide/oxide and two non-oxide (SiC/SiNC and MI SiC/SiC) ceramic matrix composites (CMCs) were categorized as follows: (1) Intra-yarn defects such as dry fibers, (2) Inter-yarn defects such as those at crossover points, matrix voids, shrinkage cracks and interlaminar separation, and (3) Architectural defects such as layer misalignment. Their impact on elastic properties was analytically investigated using a stiffness averaging approach considering the defects to have volumetric and directional influences. In-plane tensile and shear moduli as well as the through-thickness compressive modulus were experimentally evaluated. Results of analytical model were around 7% on average from the mean value of the experimental data. It was observed that interlaminar separation drastically reduced the through-thickness modulus by about 63% for the SiC/SiNC, 40% for the MI SiC/SiC and around 32% for the oxide/oxide composites. Shrinkage cracks in oxide/oxide composite reduced the in-plane tensile and shear moduli by 14% and 8.8%, respectively. © 2013 Elsevier Ltd. All rights reserved.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 149.84K | Year: 2015

ABSTRACT:Innovative research and development leading to a dual-use advanced technology product is proposed. The product is a methodology and associated software for CMC component analysis under aircraft engine hot-section service loading and environmental conditions using coupon test data as input to models. SAI proposes to further develop and validate a mechanistic damage-based non-linear deformation model that SAI has been developing under prior Air Force programs to make it suitable for CMC component analyses under service loading and environment conditions and non-uniform fiber structures. Once developed and validated, the methodology would be used in cost effective development of CMC components by the Air Force and its major suppliers. The proposed methodology would be applicable to a broad class of CMCs and components for military and commercial applications. The approach includes direct consideration of relevant defect and damage mechanisms. Phase I will include characterization and modeling of existing CMC data obtained from Roll-Royce Corporation and the Boeing Company (our industry endorsers). The models will be validated against experimental data from sub-element and feature specimens relevant to CMC components. Predictions will be compared with experimental measurements to assess the modeling approach and feasibility for a comprehensive methodology development in Phase II. BENEFIT:Due to the proliferation in potential applications of ceramic matrix composites in military and commercial aerospace engines, and in industrial gas turbine and nuclear industries, the proposed dual-use high technology product has an immediate and expanding market. Potential customers would include Rolls-Royce, Pratt and Whitney, General electric Aerospace, the Boeing Company, Solar Turbines, Inc. and General Atomics. SAI will market the methodology, the software and technical expertise (services) to these and other industries.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 149.95K | Year: 2015

ABSTRACT: Innovative research and development leading to a dual-use advanced technology product is proposed. The product is a methodology and associated software for modeling nonlinear response of carbon-fiber reinforced composite materials such as carbon/carbon (C/C) and carbon/silicon-carbide (C/SiC), and design of their components. Once developed and validated, the methodology would be used in cost effective development of C/C and C/SiC components, such as Thermal Protection Systems (TPS) and missile cones by the Air-Force and its major hypersonic weapons suppliers. The proposed methodology would be applicable to a broad class of C/C and C/SiC components for military and commercial applications. An innovative Physics-Based mechanistic modeling approach is proposed. The approach, based on an existing validated modeling approach for SiC/SiC Ceramic-Matrix Composites, includes direct consideration of relevant defect and damage mechanisms and environmental degradation. Utilization of existing models developed for similar materials and building on them will result in shorter model development times and more efficient use of Air-Force resources. Phase I will include characterization of deformation and damage in mechanistic model for C/C and C/SiC materials mostly from literature in order to understand any deformation mechanisms unique to these material systems. The models will be validated against benchmark and sub-element test data. Predictions will be compared with experimental measurements to assess the modeling approach and feasibility for a comprehensive methodology development in Phase II. BENEFIT: Due to the proliferation in potential applications of C/C and C/SiC composites in military applications such as TPS and shields for hypersonic bodies, and in commercial applications, such as aircraft brakes, the proposed dual-use high technology product has an immediate and expanding market. The biggest benefit of the proposed product is in its ability to improve the design of carbon-reinforced composite components taking advantage of its inherent nonlinear behavior. SAI will market the methodology, the software and technical expertise (services) to these and other industries.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 749.30K | Year: 2014

ABSTRACT: The goal of the proposal is to develop a physics-based methodology and associated software to simulate the Polymer Impregnation and Pyrolysis (PIP) manufacturing process for Ceramic Matrix Composites (CMCs). The proposed methodology is based on a mechanistic (physics-based) model that includes direct consideration of experimental observations of the manufacturing steps in pursuit of optimum manufacturing conditions. This is of prime importance to both of our industrial sponsors COI Ceramics, Inc. (COIC) and United Technologies. Once developed and thoroughly validated, the methodology would be used in cost effective development of CMC components by the Air Force and its major aerospace engine suppliers. In Phase I the feasibility of using this methodology has been demonstrated by qualitative comparison with experimental observations of open porosity. Basic elements of mass and heat transfer models were also developed. The proposed Phase II effort aims to further develop, validate and integrate the models using test data from a detailed experimental program. Close coordination with COIC, who will fabricate S400 material used in the program and lead the experimental effort, will ensure that test data will be generated to support the modeling effort and that the model will realistically simulate the manufacturing process. BENEFIT: Due to the proliferation in potential applications of ceramic matrix composites in military and commercial aerospace engines and in industrial gas turbine industries, the proposed dual-use high technology product has an immediate and expanding market. The biggest benefit of the proposed product is in its ability to improve the PIP manufacturing process for CMCs by optimizing the process input variables and making the process more efficient. Thus the product will help to reduce manufacturing cost. The product can also be useful in modifying manufacturing process in order to achieve targeted structural properties. SAI will market the methodology, the software and technical expertise (services) to CMC manufacturers and other the end-users of CMC materials.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 749.80K | Year: 2012

ABSTRACT: Innovative research and development leading to a dual-use advanced technology product is proposed. The product is a methodology and associated software for a damage-based non-linear deformation model to study the effect of manufacturing defects and service-induced damage in Ceramic Matrix Composites (CMCs). Once developed, the model would be used in conjunction with non-destructive evaluation (NDE) methods to predict the effect of defects and damage on structural properties, component life and residual strength. The primary focus is on 2D SiC/SiC and S200 CMCs for the gas turbine components. However the methodology would be applicable to a much broader class of CMCs and components for military and commercial applications. An innovative mechanistic (physics-based) modeling approach is proposed. The approach includes direct consideration of relevant defect and damage mechanisms. During Phase I models to describe the effect of defects such as matrix porosity and fiber fracture were developed and it was also demonstrated how the quantitative model inputs can be obtained using NDE techniques such as X-ray CT-scan. In Phase II we propose to continue the development and validation of the methodology in order to extend the applicability of the model to a variety of conditions relevant to aircraft operating conditions. NDE and laboratory test data needed to validate the model will be obtained under subcontract with Triton Systems, Inc. Pratt & Whitney. BENEFIT: Due to the proliferation in potential applications of ceramic matrix composites in military and commercial aerospace engines and in industrial gas turbine industries, the proposed dual-use high technology product has an immediate and expanding market. In conjunction with NDE techniques the proposed product will benefit these programs by improving the process of evaluation of as-manufactured CMC parts to sufficiently meet desired structural properties and design goals. The proposed product will also be useful in in-service component inspection and evaluation to estimate residual properties. SAI will market the methodology, the software and technical expertise (services) to these and other industries.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase II | Award Amount: 749.88K | Year: 2012

ABSTRACT: The goal of the proposal is to develop life-prediction methodology and associated software for a damage-based non-linear deformation model to study the effect of manufacturing defects and service-induced damage in Ceramic Matrix Composites (CMCs). Once developed and thoroughly validated, the methodology would be used in cost effective development of CMC components by the Air Force and its major aerospace engine suppliers. The proposed methodology is based on a mechanistic (physics-based) model that includes direct consideration of defect and damage mechanisms, and environmental degradation relevant to CMCs. In Phase I the feasibility of using methodology to model effect of defects and to do life prediction of CMC materials has been demonstrated by comparison with limited amount of experimental data. The proposed Phase II effort aims to extend the applicability of the model to a variety of conditions relevant to aircraft operating conditions. The resulting enhancements will be experimentally validated and demonstrated. BENEFIT: Due to the proliferation in potential applications of ceramic matrix composites in military and commercial aerospace engines and in industrial gas turbine industries, the proposed dual-use high technology product has an immediate and expanding market. One benefit of the proposed product is in improving the process of evaluation of as-manufactured CMC parts to sufficiently meet desired structural life. The proposed product will also be useful in in-service component inspection and evaluation to estimate residual life. SAI will market the methodology, the software and technical expertise (services) to these and other industries.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 98.87K | Year: 2011

Innovative research and development leading to a dual-use advanced technology product is proposed. The product is a methodology and associated software for a damage-based non-linear deformation model to study the effect of manufacturing defects and service-induced damage in Ceramic Matrix Composites (CMCs). Once developed, the model would be used in conjunction with non-destructive evaluation (NDE) methods to predict the effect of defects and damage on structural properties, component life and residual strength. The primary focus is on 2D SiC/SiC HiPerComp CMC for the gas turbine components. However the methodology would be applicable to a much broader class of CMCs and components for military and commercial applications. An innovative Physics-Based mechanistic modeling approach is proposed. The approach includes direct consideration of relevant defect and damage mechanisms and environmental degradation. Phase I will involve characterization of the mechanistic model for CMC materials selected by Pratt & Whitney for exhaust nozzle application. The models will be validated against already available test data and against test data generated by our partner, Triton Systems, Inc., under Topic AF103-153. Predictions will be compared with experimental measurements to assess the modeling approach and feasibility for a comprehensive methodology development in Phase II. The proposed product is a comprehensive defect and damage assessment methodology and associate software for its implementation. BENEFIT: Due to the proliferation in potential applications of ceramic matrix composites in military and commercial aerospace engines and in industrial gas turbine industries, the proposed dual-use high technology product has an immediate and expanding market. SAI will market the methodology, the software and technical expertise (services) to these and other industries.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 99.40K | Year: 2011

Innovative research and development leading to a dual-use advanced technology product is proposed. The product is a methodology and associated software for a damage-based non-linear deformation model to study the effect of manufacturing defects and service-induced damage in Ceramic Matrix Composites (CMCs). Once developed and validated, the methodology would be used in cost effective development of CMC components by the Air Force and its major aerospace engine suppliers. The proposed methodology would be applicable to a broad class of CMCs and components for military and commercial applications. An innovative mechanistic (physics-based) modeling approach is proposed. The approach includes direct consideration of relevant defect and damage mechanisms. Phase I will include characterization and modeling of existing CMC data obtained from Pratt & Whitney and COI Ceramics, Inc. (our industry endorsers). The models will be validated against benchmark test data involving CMCs containing defects and damage. Predictions will be compared with experimental measurements to assess the modeling approach and feasibility for a comprehensive methodology development in Phase II. BENEFIT: Due to the proliferation in potential applications of ceramic matrix composites in military and commercial aerospace engines and in industrial gas turbine industries, the proposed dual-use high technology product has an immediate and expanding market. SAI will market the methodology, the software and technical expertise (services) to these and other industries.


Grant
Agency: Department of Defense | Branch: Air Force | Program: SBIR | Phase: Phase I | Award Amount: 147.00K | Year: 2013

ABSTRACT: Innovative research and development leading to a dual-use advanced technology product is proposed. The product is a physics-based methodology and associated software for a analytical model to simulate the manufacturing process for Ceramic Matrix Composites (CMCs). Once developed and validated, the methodology would be used in the cost effective development of CMC components by the Air Force and its major CMC suppliers. The proposed methodology would be applicable to a broad class of CMCs and components for military and commercial applications. The approach includes direct consideration of relevant mechanisms involved in the Polymer Impregnation and Pyrolysis (PIP) process for CMCs, whose modeling is of immediate interest to COI Ceramics, Inc. (COIC), who along with United Technologies Research Center are our industry endorsers. Phase I will include modeling of specific stages used in the PIP process using existing data obtained from COIC under subcontract, and quantification of material properties with the goal of satisfying a set of target properties for the composite. The models will be validated against benchmark test data and predictions will be compared with experimental measurements in order to assess the modeling approach and feasibility for a more comprehensive methodology development in Phase II. BENEFIT: Due to the proliferation in potential applications of Ceramic Matrix Composites in military and commercial aerospace engines and in industrial gas turbine industries, the proposed dual-use high technology product has an immediate and expanding market. SAI will market the methodology, the software and technical expertise (services) to CMC manufacturers and other the end-users of CMC materials.

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