Not listed MESOSCOPIC DISTINCT ELEMENT METHOD-ENABLED MULTISCALE COMPUTATIONAL DESIGN OF CARBON NANOTUBE-BASED COMPOSITE MATERIALS THERE IS A SUSTAINED EFFORT TO DEVELOP SUPER-LIGHTWEIGHT COMPOSITES BY USING POLYMER IMPREGNATION OF CARBON NANOTUBE (CNT) SHEETS. THIS PROMISING AREA IS STILL IN ITS EARLY STAGES AND SIGNIFICANT PROGRESS IS REQUIRED BEFORE CNT-BASED COMPOSITES CAN BE USED IN LOAD BEARING AEROSPACE STRUCTURES. OUR OBJECTIVE IS TO DEVELOP A BROAD SCOPE MULTISCALE MODELING METHODOLOGY ABLE TO SIMULATE THE MECHANICS OF THESE MATERIALS. THIS NEW DEVELOPMENT WILL ALLOW FOR THE COMPUTATIONAL DESIGN OF NETWORK-BASED MATERIALS AND IS BEYOND SOA AS CURRENT STRUCTURAL DESIGN OF SUCH MATERIALS DOES NOT INTEGRATE ALL RELEVANT SCALES AND DOES NOT ACCOUNT FOR THE MICROSTRUCTURE EVOLUTION. THE TEAM INCLUDES RESEARCHERS WITH COMPLEMENTARY EXPERTISE IN ATOMISTIC MESOSCALE AND CONTINUUM MODELING MULTISCALE LINKING POLYMER-BASED NANOCOMPOSITES AND SCIENTIFIC COMPUTING IN ORDER TO CREATE VERIFY AND VALIDATE A UNIQUE MULTISCALE METHODOLOGY FOR FIBROUS NANOMATERIALS. THE DEVELOPED METHODOLOGY WILL ACCOUNT FOR THE CNT INTERTUBE AND TUBE-MATRIX LOAD TRANSFERS WILL REPRESENT THE STRUCTURE OF THE NETWORK ON MULTIPLE SCALES AND WILL INTEGRATE DISCRETE AND CONTINUUM STOCHASTIC REPRESENTATIONS. THE INNOVATION RESIDES IN THE TWO MAIN METHODS THAT WILL BE DEVELOPED AND INTEGRATED IN ORDER TO ACCOMPLISH OUR RESEARCH OBJECTIVE: (I) THE MESOSCOPIC DISTINCT ELEMENT METHOD (MDEM) TO CAPTURE IN A BOTTOM-UP MANNER THE INTERACTIONS AT THE MESOSCALE AND (II) A METHOD TO COUPLE MESOSCOPIC AND STOCHASTIC CONTINUUM REPRESENTATIONS OF THE CNT NETWORKS AND CNT NANOCOMPOSITES. THE PROPOSED WORK MEETS THE OBJECTIVES OF NASA S RESEARCH SOLICITATION FOR COMPUTATIONALLY GUIDED STRUCTURAL NANOMATERIALS DESIGN (TOPIC 5): - THE PROPOSED CONCEPTS OF MESOSCOPIC DISTINCT ELEMENTS INTERACTING VIA MESOSCOPIC CONTACTS AND THEIR INTEGRATION WITH A CONTINUUM STOCHASTIC FORMULATION ENABLE A POTENTIALLY TRANSFORMATIVE TECHNOLOGY FOR BRIDGING ATOMISTIC AND MACRO-SCALE COMPUTATIONS. THE TECHNICAL COMPATIBILITY WITH THE CLASSICAL DISTINCT ELEMENT METHOD (DEM) A SOLID MECHANICS METHOD ALLOWS FOR THE EMBEDDING OF THESE CONCEPTS INTO AN EXISTING CODE LAMMPS AND THUS FOR THE CREATION OF EASY-TO-USE ADVANCED SIMULATION ENVIRONMENTS. - MDEM WILL ALLOW THE SIMULATION OF MASSIVE FIBROUS ENSEMBLES NOT ONLY THROUGH PARALLEL COMPUTING BUT ALSO THROUGH EFFICIENT COARSEGRAINING. A CNT-POLYMER SYSTEM WILL BE REPRESENTED WITH LARGE DISTINCT ELEMENTS WHICH CAPTURE FOR EXAMPLE SEVERAL THOUSAND ATOMS INTO ONE ELEMENT. - THE PROPOSED INTERACTIONS BETWEEN ELEMENTS CAN RESOLVE VERY WELL THE INDIVIDUAL CNT MECHANICS INCLUDING THEIR NON-LINEAR ELASTIC AND FAILURE BEHAVIORS AND ARE FREE OF INTERTUBE CORRUGATION ARTIFACTS REGARDLESS OF THE SIZE OF THE ELEMENTS OR THE UNDERLYING CYLINDRICAL AND FLATTENED SHAPE OF THE CNT. BY COMBINING ADVANCED ATOMISTIC SIMULATION METHODS WITH MODERN SCIENTIFIC COMPUTING TECHNIQUES WE WILL CREATE A DIVERSE COLLECTION OF CONTACT MODELS TO ENABLE A CLOSE REPRESENTATION OF EXPERIMENTALLY OBSERVED MORPHOLOGIES. - THE MDEM MODELS WILL BE LINKED WITH A STOCHASTIC CONTINUUM REPRESENTATION OF THESE SYSTEMS THAT CAN BE USED TO SOLVE BOUNDARY VALUE PROBLEMS DEFINED ON THE MACROSCOPIC SCALE. THE METHOD DEVELOPMENTS WILL EMPOWER STRAIN TO FAILURE SIMULATIONS AND VISUALIZATIONS OF MASSIVE ENSEMBLES OF BOTH CYLINDRICAL AND FLATTENED CNTS WITH AND WITHOUT THE THERMOPLASTIC AND THERMOSET POLYMERS. THE PLANNED VERIFICATION AND EXPERIMENTAL VALIDATION OF THE CREATED MULTISCALE MODELING AND SIMULATION FRAMEWORK WILL BESTOW A SEMI-QUANTITATIVE PREDICTIVE NATURE TO THE SIMULATED CNTS COMPOSITE MECHANICAL PROPERTIES. THE PROPOSED EFFORT WILL ACCELERATE PROGRESS BY PROVIDING THE ABILITY TO GUIDE EXPERIMENTAL DESIGN THROUGH SIMULATIONS. THIS IS OF INTEREST FOR NASA AS THE SIGNIFICANT MASS REDUCTION OF THE AEROSPACE STRUCTURES AFFORDED BY CNT-BASED MATERIALS WILL HAVE A TRANSFORMATIV $0 12/20/19 6 MESOSCOPIC DISTINCT ELEMENT METHOD-ENABLED MULTISCALE COMPUTATIONAL DESIGN OF CARBON NANOTUBE-BASED COMPOSITE MATERIALS THERE IS A SUSTAINED EFFORT TO DEVELOP SUPER-LIGHTWEIGHT COMPOSITES BY USING POLYMER IMPREGNATION OF CARBON NANOTUBE (CNT) SHEETS. THIS PROMISING AREA IS STILL IN ITS EARLY STAGES AND SIGNIFICANT PROGRESS IS REQUIRED BEFORE CNT-BASED COMPOSITES CAN BE USED IN LOAD BEARING AEROSPACE STRUCTURES. OUR OBJECTIVE IS TO DEVELOP A BROAD SCOPE MULTISCALE MODELING METHODOLOGY ABLE TO SIMULATE THE MECHANICS OF THESE MATERIALS. THIS NEW DEVELOPMENT WILL ALLOW FOR THE COMPUTATIONAL DESIGN OF NETWORK-BASED MATERIALS AND IS BEYOND SOA, AS CURRENT STRUCTURAL DESIGN OF SUCH MATERIALS DOES NOT INTEGRATE ALL RELEVANT SCALES AND DOES NOT ACCOUNT FOR THE MICROSTRUCTURE EVOLUTION. THE TEAM INCLUDES RESEARCHERS WITH COMPLEMENTARY EXPERTISE IN ATOMISTIC, MESOSCALE AND CONTINUUM MODELING, MULTISCALE LINKING, POLYMER-BASED NANOCOMPOSITES, AND SCIENTIFIC COMPUTING IN ORDER TO CREATE, VERIFY, AND VALIDATE A UNIQUE MULTISCALE METHODOLOGY FOR FIBROUS NANOMATERIALS. THE DEVELOPED METHODOLOGY WILL ACCOUNT FOR THE CNT INTERTUBE AND TUBE-MATRIX LOAD TRANSFERS, WILL REPRESENT THE STRUCTURE OF THE NETWORK ON MULTIPLE SCALES, AND WILL INTEGRATE DISCRETE AND CONTINUUM STOCHASTIC REPRESENTATIONS. THE INNOVATION RESIDES IN THE TWO MAIN METHODS THAT WILL BE DEVELOPED AND INTEGRATED IN ORDER TO ACCOMPLISH OUR RESEARCH OBJECTIVE: (I) THE MESOSCOPIC DISTINCT ELEMENT METHOD (MDEM) TO CAPTURE IN A BOTTOM-UP MANNER THE INTERACTIONS AT THE MESOSCALE, AND (II) A METHOD TO COUPLE MESOSCOPIC AND STOCHASTIC CONTINUUM REPRESENTATIONS OF THE CNT NETWORKS AND CNT NANOCOMPOSITES. THE PROPOSED WORK MEETS THE OBJECTIVES OF NASA S RESEARCH SOLICITATION FOR COMPUTATIONALLY GUIDED STRUCTURAL NANOMATERIALS DESIGN (TOPIC 5): - THE PROPOSED CONCEPTS OF MESOSCOPIC DISTINCT ELEMENTS INTERACTING VIA MESOSCOPIC CONTACTS AND THEIR INTEGRATION WITH A CONTINUUM STOCHASTIC FORMULATION ENABLE A POTENTIALLY TRANSFORMATIVE TECHNOLOGY FOR BRIDGING ATOMISTIC AND MACRO-SCALE COMPUTATIONS. THE TECHNICAL COMPATIBILITY WITH THE CLASSICAL DISTINCT ELEMENT METHOD (DEM), A SOLID MECHANICS METHOD, ALLOWS FOR THE EMBEDDING OF THESE CONCEPTS INTO AN EXISTING CODE, LAMMPS, AND THUS FOR THE CREATION OF EASY-TO-USE ADVANCED SIMULATION ENVIRONMENTS. - MDEM WILL ALLOW THE SIMULATION OF MASSIVE FIBROUS ENSEMBLES NOT ONLY THROUGH PARALLEL COMPUTING BUT ALSO THROUGH EFFICIENT COARSEGRAINING. A CNT-POLYMER SYSTEM WILL BE REPRESENTED WITH LARGE DISTINCT ELEMENTS, WHICH CAPTURE, FOR EXAMPLE, SEVERAL THOUSAND ATOMS INTO ONE ELEMENT. - THE PROPOSED INTERACTIONS BETWEEN ELEMENTS CAN RESOLVE VERY WELL THE INDIVIDUAL CNT MECHANICS, INCLUDING THEIR NON-LINEAR ELASTIC AND FAILURE BEHAVIORS, AND ARE FREE OF INTERTUBE CORRUGATION ARTIFACTS, REGARDLESS OF THE SIZE OF THE ELEMENTS OR THE UNDERLYING CYLINDRICAL AND FLATTENED SHAPE OF THE CNT. BY COMBINING ADVANCED ATOMISTIC SIMULATION METHODS WITH MODERN SCIENTIFIC COMPUTING TECHNIQUES, WE WILL CREATE A DIVERSE COLLECTION OF CONTACT MODELS TO ENABLE A CLOSE REPRESENTATION OF EXPERIMENTALLY OBSERVED MORPHOLOGIES. - THE MDEM MODELS WILL BE LINKED WITH A STOCHASTIC CONTINUUM REPRESENTATION OF THESE SYSTEMS THAT CAN BE USED TO SOLVE BOUNDARY VALUE PROBLEMS DEFINED ON THE MACROSCOPIC SCALE. THE METHOD DEVELOPMENTS WILL EMPOWER STRAIN TO FAILURE SIMULATIONS AND VISUALIZATIONS OF MASSIVE ENSEMBLES OF BOTH CYLINDRICAL AND FLATTENED CNTS, WITH AND WITHOUT THE THERMOPLASTIC AND THERMOSET POLYMERS. THE PLANNED VERIFICATION AND EXPERIMENTAL VALIDATION OF THE CREATED MULTISCALE MODELING AND SIMULATION FRAMEWORK WILL BESTOW A SEMI-QUANTITATIVE PREDICTIVE NATURE TO THE SIMULATED CNTS COMPOSITE MECHANICAL PROPERTIES. THE PROPOSED EFFORT WILL ACCELERATE PROGRESS BY PROVIDING THE ABILITY TO GUIDE EXPERIMENTAL DESIGN THROUGH SIMULATIONS. THIS IS OF INTEREST FOR NASA, AS THE SIGNIFICANT MASS REDUCTION OF THE AEROSPACE STRUCTURES AFFORDED BY CNT-BASED MATERIALS WILL HAVE A TRANSFORMATIV Other Administrative Action $0 12/20/19 Not listed MESOSCOPIC DISTINCT ELEMENT METHOD-ENABLED MULTISCALE COMPUTATIONAL DESIGN OF CARBON NANOTUBE-BASED COMPOSITE MATERIALS THERE IS A SUSTAINED EFFORT TO DEVELOP SUPER-LIGHTWEIGHT COMPOSITES BY USING POLYMER IMPREGNATION OF CARBON NANOTUBE (CNT) SHEETS. THIS PROMISING AREA IS STILL IN ITS EARLY STAGES AND SIGNIFICANT PROGRESS IS REQUIRED BEFORE CNT-BASED COMPOSITES CAN BE USED IN LOAD BEARING AEROSPACE STRUCTURES. OUR OBJECTIVE IS TO DEVELOP A BROAD SCOPE MULTISCALE MODELING METHODOLOGY ABLE TO SIMULATE THE MECHANICS OF THESE MATERIALS. THIS NEW DEVELOPMENT WILL ALLOW FOR THE COMPUTATIONAL DESIGN OF NETWORK-BASED MATERIALS AND IS BEYOND SOA AS CURRENT STRUCTURAL DESIGN OF SUCH MATERIALS DOES NOT INTEGRATE ALL RELEVANT SCALES AND DOES NOT ACCOUNT FOR THE MICROSTRUCTURE EVOLUTION. THE TEAM INCLUDES RESEARCHERS WITH COMPLEMENTARY EXPERTISE IN ATOMISTIC MESOSCALE AND CONTINUUM MODELING MULTISCALE LINKING POLYMER-BASED NANOCOMPOSITES AND SCIENTIFIC COMPUTING IN ORDER TO CREATE VERIFY AND VALIDATE A UNIQUE MULTISCALE METHODOLOGY FOR FIBROUS NANOMATERIALS. THE DEVELOPED METHODOLOGY WILL ACCOUNT FOR THE CNT INTERTUBE AND TUBE-MATRIX LOAD TRANSFERS WILL REPRESENT THE STRUCTURE OF THE NETWORK ON MULTIPLE SCALES AND WILL INTEGRATE DISCRETE AND CONTINUUM STOCHASTIC REPRESENTATIONS. THE INNOVATION RESIDES IN THE TWO MAIN METHODS THAT WILL BE DEVELOPED AND INTEGRATED IN ORDER TO ACCOMPLISH OUR RESEARCH OBJECTIVE: (I) THE MESOSCOPIC DISTINCT ELEMENT METHOD (MDEM) TO CAPTURE IN A BOTTOM-UP MANNER THE INTERACTIONS AT THE MESOSCALE AND (II) A METHOD TO COUPLE MESOSCOPIC AND STOCHASTIC CONTINUUM REPRESENTATIONS OF THE CNT NETWORKS AND CNT NANOCOMPOSITES. THE PROPOSED WORK MEETS THE OBJECTIVES OF NASA S RESEARCH SOLICITATION FOR COMPUTATIONALLY GUIDED STRUCTURAL NANOMATERIALS DESIGN (TOPIC 5): - THE PROPOSED CONCEPTS OF MESOSCOPIC DISTINCT ELEMENTS INTERACTING VIA MESOSCOPIC CONTACTS AND THEIR INTEGRATION WITH A CONTINUUM STOCHASTIC FORMULATION ENABLE A POTENTIALLY TRANSFORMATIVE TECHNOLOGY FOR BRIDGING ATOMISTIC AND MACRO-SCALE COMPUTATIONS. THE TECHNICAL COMPATIBILITY WITH THE CLASSICAL DISTINCT ELEMENT METHOD (DEM) A SOLID MECHANICS METHOD ALLOWS FOR THE EMBEDDING OF THESE CONCEPTS INTO AN EXISTING CODE LAMMPS AND THUS FOR THE CREATION OF EASY-TO-USE ADVANCED SIMULATION ENVIRONMENTS. - MDEM WILL ALLOW THE SIMULATION OF MASSIVE FIBROUS ENSEMBLES NOT ONLY THROUGH PARALLEL COMPUTING BUT ALSO THROUGH EFFICIENT COARSEGRAINING. A CNT-POLYMER SYSTEM WILL BE REPRESENTED WITH LARGE DISTINCT ELEMENTS WHICH CAPTURE FOR EXAMPLE SEVERAL THOUSAND ATOMS INTO ONE ELEMENT. - THE PROPOSED INTERACTIONS BETWEEN ELEMENTS CAN RESOLVE VERY WELL THE INDIVIDUAL CNT MECHANICS INCLUDING THEIR NON-LINEAR ELASTIC AND FAILURE BEHAVIORS AND ARE FREE OF INTERTUBE CORRUGATION ARTIFACTS REGARDLESS OF THE SIZE OF THE ELEMENTS OR THE UNDERLYING CYLINDRICAL AND FLATTENED SHAPE OF THE CNT. BY COMBINING ADVANCED ATOMISTIC SIMULATION METHODS WITH MODERN SCIENTIFIC COMPUTING TECHNIQUES WE WILL CREATE A DIVERSE COLLECTION OF CONTACT MODELS TO ENABLE A CLOSE REPRESENTATION OF EXPERIMENTALLY OBSERVED MORPHOLOGIES. - THE MDEM MODELS WILL BE LINKED WITH A STOCHASTIC CONTINUUM REPRESENTATION OF THESE SYSTEMS THAT CAN BE USED TO SOLVE BOUNDARY VALUE PROBLEMS DEFINED ON THE MACROSCOPIC SCALE. THE METHOD DEVELOPMENTS WILL EMPOWER STRAIN TO FAILURE SIMULATIONS AND VISUALIZATIONS OF MASSIVE ENSEMBLES OF BOTH CYLINDRICAL AND FLATTENED CNTS WITH AND WITHOUT THE THERMOPLASTIC AND THERMOSET POLYMERS. THE PLANNED VERIFICATION AND EXPERIMENTAL VALIDATION OF THE CREATED MULTISCALE MODELING AND SIMULATION FRAMEWORK WILL BESTOW A SEMI-QUANTITATIVE PREDICTIVE NATURE TO THE SIMULATED CNTS COMPOSITE MECHANICAL PROPERTIES. THE PROPOSED EFFORT WILL ACCELERATE PROGRESS BY PROVIDING THE ABILITY TO GUIDE EXPERIMENTAL DESIGN THROUGH SIMULATIONS. THIS IS OF INTEREST FOR NASA AS THE SIGNIFICANT MASS REDUCTION OF THE AEROSPACE STRUCTURES AFFORDED BY CNT-BASED MATERIALS WILL HAVE A TRANSFORMATIV $0 12/19/18 5 MESOSCOPIC DISTINCT ELEMENT METHOD-ENABLED MULTISCALE COMPUTATIONAL DESIGN OF CARBON NANOTUBE-BASED COMPOSITE MATERIALS THERE IS A SUSTAINED EFFORT TO DEVELOP SUPER-LIGHTWEIGHT COMPOSITES BY USING POLYMER IMPREGNATION OF CARBON NANOTUBE (CNT) SHEETS. THIS PROMISING AREA IS STILL IN ITS EARLY STAGES AND SIGNIFICANT PROGRESS IS REQUIRED BEFORE CNT-BASED COMPOSITES CAN BE USED IN LOAD BEARING AEROSPACE STRUCTURES. OUR OBJECTIVE IS TO DEVELOP A BROAD SCOPE MULTISCALE MODELING METHODOLOGY ABLE TO SIMULATE THE MECHANICS OF THESE MATERIALS. THIS NEW DEVELOPMENT WILL ALLOW FOR THE COMPUTATIONAL DESIGN OF NETWORK-BASED MATERIALS AND IS BEYOND SOA, AS CURRENT STRUCTURAL DESIGN OF SUCH MATERIALS DOES NOT INTEGRATE ALL RELEVANT SCALES AND DOES NOT ACCOUNT FOR THE MICROSTRUCTURE EVOLUTION. THE TEAM INCLUDES RESEARCHERS WITH COMPLEMENTARY EXPERTISE IN ATOMISTIC, MESOSCALE AND CONTINUUM MODELING, MULTISCALE LINKING, POLYMER-BASED NANOCOMPOSITES, AND SCIENTIFIC COMPUTING IN ORDER TO CREATE, VERIFY, AND VALIDATE A UNIQUE MULTISCALE METHODOLOGY FOR FIBROUS NANOMATERIALS. THE DEVELOPED METHODOLOGY WILL ACCOUNT FOR THE CNT INTERTUBE AND TUBE-MATRIX LOAD TRANSFERS, WILL REPRESENT THE STRUCTURE OF THE NETWORK ON MULTIPLE SCALES, AND WILL INTEGRATE DISCRETE AND CONTINUUM STOCHASTIC REPRESENTATIONS. THE INNOVATION RESIDES IN THE TWO MAIN METHODS THAT WILL BE DEVELOPED AND INTEGRATED IN ORDER TO ACCOMPLISH OUR RESEARCH OBJECTIVE: (I) THE MESOSCOPIC DISTINCT ELEMENT METHOD (MDEM) TO CAPTURE IN A BOTTOM-UP MANNER THE INTERACTIONS AT THE MESOSCALE, AND (II) A METHOD TO COUPLE MESOSCOPIC AND STOCHASTIC CONTINUUM REPRESENTATIONS OF THE CNT NETWORKS AND CNT NANOCOMPOSITES. THE PROPOSED WORK MEETS THE OBJECTIVES OF NASA S RESEARCH SOLICITATION FOR COMPUTATIONALLY GUIDED STRUCTURAL NANOMATERIALS DESIGN (TOPIC 5): - THE PROPOSED CONCEPTS OF MESOSCOPIC DISTINCT ELEMENTS INTERACTING VIA MESOSCOPIC CONTACTS AND THEIR INTEGRATION WITH A CONTINUUM STOCHASTIC FORMULATION ENABLE A POTENTIALLY TRANSFORMATIVE TECHNOLOGY FOR BRIDGING ATOMISTIC AND MACRO-SCALE COMPUTATIONS. THE TECHNICAL COMPATIBILITY WITH THE CLASSICAL DISTINCT ELEMENT METHOD (DEM), A SOLID MECHANICS METHOD, ALLOWS FOR THE EMBEDDING OF THESE CONCEPTS INTO AN EXISTING CODE, LAMMPS, AND THUS FOR THE CREATION OF EASY-TO-USE ADVANCED SIMULATION ENVIRONMENTS. - MDEM WILL ALLOW THE SIMULATION OF MASSIVE FIBROUS ENSEMBLES NOT ONLY THROUGH PARALLEL COMPUTING BUT ALSO THROUGH EFFICIENT COARSEGRAINING. A CNT-POLYMER SYSTEM WILL BE REPRESENTED WITH LARGE DISTINCT ELEMENTS, WHICH CAPTURE, FOR EXAMPLE, SEVERAL THOUSAND ATOMS INTO ONE ELEMENT. - THE PROPOSED INTERACTIONS BETWEEN ELEMENTS CAN RESOLVE VERY WELL THE INDIVIDUAL CNT MECHANICS, INCLUDING THEIR NON-LINEAR ELASTIC AND FAILURE BEHAVIORS, AND ARE FREE OF INTERTUBE CORRUGATION ARTIFACTS, REGARDLESS OF THE SIZE OF THE ELEMENTS OR THE UNDERLYING CYLINDRICAL AND FLATTENED SHAPE OF THE CNT. BY COMBINING ADVANCED ATOMISTIC SIMULATION METHODS WITH MODERN SCIENTIFIC COMPUTING TECHNIQUES, WE WILL CREATE A DIVERSE COLLECTION OF CONTACT MODELS TO ENABLE A CLOSE REPRESENTATION OF EXPERIMENTALLY OBSERVED MORPHOLOGIES. - THE MDEM MODELS WILL BE LINKED WITH A STOCHASTIC CONTINUUM REPRESENTATION OF THESE SYSTEMS THAT CAN BE USED TO SOLVE BOUNDARY VALUE PROBLEMS DEFINED ON THE MACROSCOPIC SCALE. THE METHOD DEVELOPMENTS WILL EMPOWER STRAIN TO FAILURE SIMULATIONS AND VISUALIZATIONS OF MASSIVE ENSEMBLES OF BOTH CYLINDRICAL AND FLATTENED CNTS, WITH AND WITHOUT THE THERMOPLASTIC AND THERMOSET POLYMERS. THE PLANNED VERIFICATION AND EXPERIMENTAL VALIDATION OF THE CREATED MULTISCALE MODELING AND SIMULATION FRAMEWORK WILL BESTOW A SEMI-QUANTITATIVE PREDICTIVE NATURE TO THE SIMULATED CNTS COMPOSITE MECHANICAL PROPERTIES. THE PROPOSED EFFORT WILL ACCELERATE PROGRESS BY PROVIDING THE ABILITY TO GUIDE EXPERIMENTAL DESIGN THROUGH SIMULATIONS. THIS IS OF INTEREST FOR NASA, AS THE SIGNIFICANT MASS REDUCTION OF THE AEROSPACE STRUCTURES AFFORDED BY CNT-BASED MATERIALS WILL HAVE A TRANSFORMATIV Other Administrative Action $0 12/19/18 4 MESOSCOPIC DISTINCT ELEMENT METHOD-ENABLED MULTISCALE COMPUTATIONAL DESIGN OF CARBON NANOTUBE-BASED COMPOSITE MATERIALS THERE IS A SUSTAINED EFFORT TO DEVELOP SUPER-LIGHTWEIGHT COMPOSITES BY USING POLYMER IMPREGNATION OF CARBON NANOTUBE (CNT) SHEETS. THIS PROMISING AREA IS STILL IN ITS EARLY STAGES AND SIGNIFICANT PROGRESS IS REQUIRED BEFORE CNT-BASED COMPOSITES CAN BE USED IN LOAD BEARING AEROSPACE STRUCTURES. OUR OBJECTIVE IS TO DEVELOP A BROAD SCOPE MULTISCALE MODELING METHODOLOGY ABLE TO SIMULATE THE MECHANICS OF THESE MATERIALS. THIS NEW DEVELOPMENT WILL ALLOW FOR THE COMPUTATIONAL DESIGN OF NETWORK-BASED MATERIALS AND IS BEYOND SOA, AS CURRENT STRUCTURAL DESIGN OF SUCH MATERIALS DOES NOT INTEGRATE ALL RELEVANT SCALES AND DOES NOT ACCOUNT FOR THE MICROSTRUCTURE EVOLUTION. THE TEAM INCLUDES RESEARCHERS WITH COMPLEMENTARY EXPERTISE IN ATOMISTIC, MESOSCALE AND CONTINUUM MODELING, MULTISCALE LINKING, POLYMER-BASED NANOCOMPOSITES, AND SCIENTIFIC COMPUTING IN ORDER TO CREATE, VERIFY, AND VALIDATE A UNIQUE MULTISCALE METHODOLOGY FOR FIBROUS NANOMATERIALS. THE DEVELOPED METHODOLOGY WILL ACCOUNT FOR THE CNT INTERTUBE AND TUBE-MATRIX LOAD TRANSFERS, WILL REPRESENT THE STRUCTURE OF THE NETWORK ON MULTIPLE SCALES, AND WILL INTEGRATE DISCRETE AND CONTINUUM STOCHASTIC REPRESENTATIONS. THE INNOVATION RESIDES IN THE TWO MAIN METHODS THAT WILL BE DEVELOPED AND INTEGRATED IN ORDER TO ACCOMPLISH OUR RESEARCH OBJECTIVE: (I) THE MESOSCOPIC DISTINCT ELEMENT METHOD (MDEM) TO CAPTURE IN A BOTTOM-UP MANNER THE INTERACTIONS AT THE MESOSCALE, AND (II) A METHOD TO COUPLE MESOSCOPIC AND STOCHASTIC CONTINUUM REPRESENTATIONS OF THE CNT NETWORKS AND CNT NANOCOMPOSITES. THE PROPOSED WORK MEETS THE OBJECTIVES OF NASA S RESEARCH SOLICITATION FOR COMPUTATIONALLY GUIDED STRUCTURAL NANOMATERIALS DESIGN (TOPIC 5): - THE PROPOSED CONCEPTS OF MESOSCOPIC DISTINCT ELEMENTS INTERACTING VIA MESOSCOPIC CONTACTS AND THEIR INTEGRATION WITH A CONTINUUM STOCHASTIC FORMULATION ENABLE A POTENTIALLY TRANSFORMATIVE TECHNOLOGY FOR BRIDGING ATOMISTIC AND MACRO-SCALE COMPUTATIONS. THE TECHNICAL COMPATIBILITY WITH THE CLASSICAL DISTINCT ELEMENT METHOD (DEM), A SOLID MECHANICS METHOD, ALLOWS FOR THE EMBEDDING OF THESE CONCEPTS INTO AN EXISTING CODE, LAMMPS, AND THUS FOR THE CREATION OF EASY-TO-USE ADVANCED SIMULATION ENVIRONMENTS. - MDEM WILL ALLOW THE SIMULATION OF MASSIVE FIBROUS ENSEMBLES NOT ONLY THROUGH PARALLEL COMPUTING BUT ALSO THROUGH EFFICIENT COARSEGRAINING. A CNT-POLYMER SYSTEM WILL BE REPRESENTED WITH LARGE DISTINCT ELEMENTS, WHICH CAPTURE, FOR EXAMPLE, SEVERAL THOUSAND ATOMS INTO ONE ELEMENT. - THE PROPOSED INTERACTIONS BETWEEN ELEMENTS CAN RESOLVE VERY WELL THE INDIVIDUAL CNT MECHANICS, INCLUDING THEIR NON-LINEAR ELASTIC AND FAILURE BEHAVIORS, AND ARE FREE OF INTERTUBE CORRUGATION ARTIFACTS, REGARDLESS OF THE SIZE OF THE ELEMENTS OR THE UNDERLYING CYLINDRICAL AND FLATTENED SHAPE OF THE CNT. BY COMBINING ADVANCED ATOMISTIC SIMULATION METHODS WITH MODERN SCIENTIFIC COMPUTING TECHNIQUES, WE WILL CREATE A DIVERSE COLLECTION OF CONTACT MODELS TO ENABLE A CLOSE REPRESENTATION OF EXPERIMENTALLY OBSERVED MORPHOLOGIES. - THE MDEM MODELS WILL BE LINKED WITH A STOCHASTIC CONTINUUM REPRESENTATION OF THESE SYSTEMS THAT CAN BE USED TO SOLVE BOUNDARY VALUE PROBLEMS DEFINED ON THE MACROSCOPIC SCALE. THE METHOD DEVELOPMENTS WILL EMPOWER STRAIN TO FAILURE SIMULATIONS AND VISUALIZATIONS OF MASSIVE ENSEMBLES OF BOTH CYLINDRICAL AND FLATTENED CNTS, WITH AND WITHOUT THE THERMOPLASTIC AND THERMOSET POLYMERS. THE PLANNED VERIFICATION AND EXPERIMENTAL VALIDATION OF THE CREATED MULTISCALE MODELING AND SIMULATION FRAMEWORK WILL BESTOW A SEMI-QUANTITATIVE PREDICTIVE NATURE TO THE SIMULATED CNTS COMPOSITE MECHANICAL PROPERTIES. THE PROPOSED EFFORT WILL ACCELERATE PROGRESS BY PROVIDING THE ABILITY TO GUIDE EXPERIMENTAL DESIGN THROUGH SIMULATIONS. THIS IS OF INTEREST FOR NASA, AS THE SIGNIFICANT MASS REDUCTION OF THE AEROSPACE STRUCTURES AFFORDED BY CNT-BASED MATERIALS WILL HAVE A TRANSFORMATIV Funding Only Action $135.8k 1/5/18