Fiber-reinforced polymer matrix composite materials display quite complex deformation and failure behavior under ballistic/blast impact loading conditions. This complexity is generally attributed to a number of factors such as (a) hierarchical/multi-length scale architecture of the material microstructure; (b) nonlinear, rate-dependent and often pressure-sensitive mechanical response; and (c) the interplay of various intrinsic phenomena and processes such as fiber twisting, interfiber friction/sliding, etc. Material models currently employed in the computational engineering analyses of ballistic/blast impact protective structures made of this type of material do not generally include many of the aforementioned aspects of the material dynamic behavior. Consequently, discrepancies are often observed between computational predictions and their experimental counterparts. To address this problem, the results of an extensive set of molecular-level computational analyses regarding the role of various microstructural/morphological defects on the Kevlar fiber mechanical properties are used to upgrade one of the existing continuum-level material models for fiber-reinforced composites. The results obtained show that the response of the material is significantly affected as a result of the incorporation of microstructural effects both under quasi-static simple mechanical testing condition and under dynamic ballistic-impact conditions.

关键词：纤维增强复合材料;基体材料;力学性能;聚合物;轴向载荷

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Military piers in marine environments are typically supported atop steel-reinforced concrete piles that are subject to corrosion and concrete deterioration. The failure of even one pile presents a risk of catastrophic structural failure and interruption of operations. Patching deteriorated concrete does not stop corrosion of the reinforcement and may even accelerate it. An impact and corrosion protection wrap (ICPW) system, incorporating a composite structural wrap and cathodic protection system, was designed to rehabilitate deteriorated steel-reinforced concrete marine piles in service at Kawaihae Harbor, HI. The purpose of the technology is to reduce pier life-cycle costs and downtime by inhibiting corrosion-related damage to steel-reinforced concrete piles. The ICPW system consists of a composite reinforced polymeric wrap with an integrated galvanic anode to provide protection in the tidal splash zone. Corrosion activity in 20 rehabilitated piles on two piers was monitored using reference electrodes and data loggers. Results of the demonstration indicate that the system can protect and extend the life of in- service reinforced concrete structural piles in a corrosive marine environment. An economic analysis determined that full implementation of the system on all piles of the two demonstration piers would provide 3.16 return on investment.

关键词：阴极保护；腐蚀；聚合物；钢筋混凝土；高分子材料

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We have designed and synthesized highly porous COFs and MOFs as functional architectures that are capable of capturing volatile TICs. In parallel, we have explored novel crystalline porous materials that have reactive sites and functionalities, which can be controlled by an external stimulus. We demonstrated that reticular chemistry facilitates the design and synthesis of new robust COFs, as well as isoreticular covalent functionalization and metallation. In addition, a MOF with self-contained photo- active switches was prepared. As stimuli-responsive functional molecules that can release multiple copies of nucleophilic agents to combat electrophilic CWAs, we have developed linear/branched oligoether/esters. Upon cleavage of a Si-O bond, fast and repetitive QM rearrangement occur along the molecular backbone to release phenoxide derivatives that detoxify OP agent simluant. The progress of such reaction could be visually monitored by a large enhancement in the fluorescence intensity, which allows for detection and detoxification achieved by a single integrated molecular system. These functional modules could be grafted onto chemically modified inorganic surfaces. Shape-persistent conducting polymers were also prepared from borasiloxane cage molecules. The light-absorbing properties and electrical conductivities of these materials change in a reversible fashion upon exposure to volatile TICs.

关键词：学战剂；中和；多孔材料；高分子材料；化学剂仿制品

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Reconfigurable multifunctional structures, which allow combined changes of shape, functionality and mechanical properties on demand, require new adaptive materials and novel chemistry that permit reversible modulation of mechanical properties in effective manner. They also demand the development of robust modeling and design tools based on a fundamental understanding of the complex and time-variant properties of the material and mechanization structure in diverse environments. In this research, we: (1) developed two new classes of two-way shape memory polymers (SMPs); (2) fostered these two SMPs to free- standing SMP composites with enhanced reversible modulation through novel composite design; (3) pursued a fundamental understanding of underlying physics of the proposed two-way SMPs and composites; (4) established modeling and simulation-design tools for applications of these novel materials for reconfigurable aerospace structures; and (5) explored design, fabrication and testing of novel SMP devices enabling for Air Force applications.

关键词：复合材料；聚合物；执行器；自适应系统；机械性能

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The major accomplishments during the tenure of this proposal include: Designed target test patterns of optical grating devices and fabricated e-beam lithography-based master molds. Printed micro and nanostructures using a newly developed spin-on nanoprinting (SNAP) technique. SNAP is a simple and easy technique to print any optical structures. The contractor demonstrated that this technique can be used to print grating structures on a silicon substrate.

关键词：光电子技术；光栅（光谱）；聚合物；铵化合物；脱氧核糖核酸

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X-ray diffraction (XRD) is a powerful analysis method that allows researchers to noninvasively probe the crystalline structure of a material. This includes the ability to determine the crystalline phases present, quantify surface residual stresses, and measure the distribution of crystallographic orientations. The Structures and Materials Division at the NASA Glenn Research Center (GRC) heavily uses the on-site XRD lab to characterize advanced metal alloys, ceramics, and polymers. One of the x-ray diffractometers in the XRD lab (Bruker D8 Discover) uses three different x-ray tubes (Cu, Cr, and Mn) for optimal performance over numerous material types and various experimental techniques. This requires that the tubes be switched out and aligned between experiments. This alignment maximizes the x-ray tube s output through an iterative process involving four set screws. However, the output of the x-ray tube cannot be monitored during the adjustment process due to standard radiation safety engineering controls that prevent exposure to the x-ray beam when the diffractometer doors are open. Therefore, the adjustment process is a very tedious series of blind adjustments, each followed by measurement of the output beam using a PIN diode after the enclosure doors are shut. This process can take up to 4 hr to perform. This technical memorandum documents an in-house project to motorize this alignment process. Unlike a human, motors are not harmed by x-ray radiation of the energy range used in this instrument. Therefore, using motors to adjust the set screws will allow the researcher to monitor the x-ray tube s output while making interactive adjustments from outside the diffractometer. The motorized alignment system consists of four motors, a motor controller, and a hand-held user interface module. Our goal was to reduce the alignment time to less than 30 min. The time available was the 10-week span of the Lewis' Educational and Research Collaborative Internship Project (LERCIP) summer internship program and the budget goal was $1200. In this report, we will describe our motorization design and discuss the results of its implementation.

关键词：衍射仪；全自动控制；对齐；控制器；X射线衍射仪

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Laminated Carbon Fiber Reinforced Polymer (CFRP) composites are very effective in weight saving in aeronautical structural components. It is, however, difficult to detect damage such as delamination, matrix cracks, and local fiber breakages caused by low velocity impact loading. In the previous study in 2009, Time Domain Reflectometry (TDR) method was applied to a unidirectional laminated CFRP structure for the first time. In 2010, the research applied the TDR method for the CFRP laminates. In the present study, therefore, actual impact damage is employed instead for the TDR. Electrical contact between fiber fragments exists in these micro-buckling regions although the electrical resistance becomes very high at the micro-buckling point. We have to investigate the applicability of the TDR method for the impact damage. A low speed impact test is performed to a cross-ply CFRP plate, and impact damage is made at the surface of the CFRP plate. TDR is applied to the cross- ply CFRP plate. The result shows that the reflected signal can be observed after the impact test. This result indicates that the TDR method is useful for detection of the low speed impact damages.

关键词：复合材料；纤维增强塑料；屈曲；碳纤维

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The dynamic viscoelastic properties of solution polymerized styrene-butadiene (SSBR) filled with different proportion of carbon black and silica were studied by using the rubber processing analyzer (RPA2000) and DMA under different scanning conditions.The results indicated that in the first strain sweeping process,the storage modulus (G') reduced gradually with the increase of ratio of carbon black,and the function of coupling agent (Si69) decreased.During the secondary strain sweeping process,it was found that with the increase of sweeping time interval,the stress softening phenomenon abates.On the other hand,through three strain sweeping,it was considered that the effect of Payne was not caused only by the factor of filler-net.

关键词：炭黑；二氧化硅；SSBR；动态特性

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Numerical simulation of impact events on fabric-based protective systems requires accurate mechanical characterization of the constituent material at similar strain rates as the impact event. Because Kevlar (Kevlar is a registered trademark of DuPont Company) yarn is woven into fabric to make protective equipment, the strength of the individual filaments may become compromised as a result of the crimping, weaving process, or finishing process. To elucidate and quantify any damage to the fibers as a result of the weaving or post treatment finishing process, single fibers were extracted from the warp and weft directions of plain woven, hydrophobically treated Kevlar cloth and the strength was measured over a wide range of strain rates and compared to the response of fibers extracted from an unwoven yarn. The tensile strength of fibers from the warp, weft, and unwoven Kevlar were evaluated at 0.001 s 1, 1 s 1, and approximately 1000 s 1 using a Bose Electroforce test setup and a Hopkinson tension bar modified for fiber experiments. A wide range of gage lengths from 2 to 150 mm was investigated to find the effect of defect distribution on the tensile strength of the single fibers. The results show that fibers taken from the weft direction of the woven fabric decreased in strength 38compared to the unwoven fiber. The warp fibers were a minimum of 20weaker than unwoven and weft fibers at all loading rates. Measured Young s Modulus as a function of strain rate and tensile strength as a function of gage length are also presented in this technical report.

关键词：纤维；负载力；；聚合物；高分子材料

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This is a highly productive research project (13 papers in three years, on journals of Nature Photonics, Advanced Materials, Advanced Functional Materials, Angewandte Chemie International Edition, etc) aiming to (a) understand the potential of conjugated polymer based solar cell under simulated space radiation conditions, (2) develop and improving tandem polymer solar cell structures - constantly pushing the envelope of organic solar cell performance; (3) develop novel polymers for high efficiency OPV. In addition, we also conducted research in utilizing metal grating electrode to improve OPV light harvesting.

关键词：宇宙射线；聚合物；太阳能电池；降解

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