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Analysis of SNL/MSU/DOE Fatigue Database Trends for Wind Turbine Blade Materials 2010-2015

Mandell, John F.; Samborsky, Daniel D.; Miller, David A.; Agastra, Pancasatya; Sears, Aaron T.

Wind turbine blades are designed to several major structural conditions, including tip deflection, strength and b uckling during severe loading, as well as very high numbers of fatigue cycles and various service environments. The MSU Database Program has, since 1989, addressed the broad range of properties needed for current and potential blade materials through stati c and fatigue testing and test development in cooperation with Sandia National Laboratories and wind industry and supplier partners. This report is the latest in a series, giving test results and analysis for the period 2010 - 2015. Program data are compiled in a public database [1] and other reports and publications given in the cited references. The report begins with an executive summary and introductory material including background discussion of previous related studies. Section 3 describes experimental methods including processing, test methods, instrumentation and test development. Section 4 provides static tension, compression and shear stress - strain properties in three directions using coupons sectioned from a thick infused unidirectional glass/epoxy laminate. The nonlinear, shear dominated static properties were characterized with loading - u nloading - reloading (LUR) tests in tension and compression to increasing load levels, for +-45O laminates. Section 5 explores the origins of tensile fatigue sensitivity in glass fiber dominated laminates with variations in fabric architecture including speci ally prepared fabrics and aligned strand laminates. Several types of resins are considered, with variations in resin toughness and bonding to fibers, as well as cure cycle variations for an epoxy. Conclusions are drawn as to the limits of tensile fatigue r esistance and the effects of resin type and fabric architecture, including the behavior of a commercial aligned glass strand product. Interactions between cyclic fatigue response and creep are addressed for off - axis (+-45O) glass/epoxy laminates in Sectio n 6. The nonlinear fatigue and creep stress - strain and cumulative strain response are characterized in tension and compression as a function of stress level, cycles and cumulative time, using square and sinewave loading over a broad range of frequency. The results are analyzed in terms of the cycles and cumulative time under load. A cumulative strain failure criterion is established, and used to construct shear and tension constant life diagrams (CLD's) with data for nine R - values. The effects of a more duc tile urethne resin are also explored. A previous study of thick adhesives testing is extended to mixed mode fracture mechanics testing in Section 7. Mechanisms of static and fatigue crack extension near the laminate adherend interface are reported in deta il. Data are presented for mixed mode adhesive fracture, compared to mixed mode fracture in ply delamination. Fatigue crack growth exponents are also developed for a mixed mode cracked lap shear coupon. The data for fatigue trends and relative failure stra ins and exponents are compared for various blade component materials in Section 8. The effects of temperature and seawater saturation are considered for selected materials of interest for wind and hydrokinetic turbine blades in Section 9. Section 10 gives detailed conclusions for each section. A cknowledgements The research presented in this report was carried out under Sandia National Laboratories purchase orders 1325028 an d 1543945 between 2010 and 2015, with support from the DOE Wind and Water Technologies Office . In addition to the authors listed, significant contributions were made by Patrick Flaherty, Pancastya Agastra, Michael Schuster, and Michael Voth. Industry m aterials suppliers include Vectorply, Saertex, OCV, AGY, Bayer, Ashland, 3M and Nextel. Industry suppliers with significant contributions to the study were Hexion, PPG, Reichhold, Gurit and NEPTCO. Intentionally Left Blank

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TYPE SAND Report YEAR 2016
DOIOSTI

Microsystem Enabled Photovoltaics

Nielson, Gregory; Cruz Campa, Jose L.; Okandan, Murat; Lentine, Anthony L.; Sweatt, W.C.; Gupta, Vipin P.; Tauke-Pedretti, Anna; Jared, Bradley H.; Resnick, Paul; Cederberg, Jeffrey; Paap, Scott M.; Sanchez, Carlos A.; Biefeld, Robert M.; Langlois, Eric; Yang, Benjamin; Koleske, Daniel; Wierer, Jonathan; Miller, William K.; Elisberg, Brenton; Foulk, James W.; Luna, Ian; Saavedra, Michael P.; Alford, Charles; Ballance, Mark; Wiwi, Michael; Samora, Sally; Chavez, Julie; Pipkin, Jennifer R.; Nguyen, Janet; Anderson, Ben; Gu, Tian; Agrawal, Gautum; Nelson, Jeffrey

Abstract not provided.

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TYPE Presentation YEAR 2016
OSTI

Accelerating cost-effective deployment of solar generation on the distribution grid

Broderick, Robert J.

The Task 1 objective is to “expedite the PV interconnection process by revising the screening process in California”. The goal of this task is to develop a data-driven, validated approach to determining feeder limits that can simplify interconnection processes and lead to greater PV adoption across the California distribution system.

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TYPE Other Report YEAR 2016
DOIOSTI

Enhanced grid operation and optimized PV penetration utilizing highly distributed sensor data

Broderick, Robert J.

This task describes R&D activities to establish methods to cost-effectively achieve very high PV penetration scenarios (well beyond 100% of peak load at the feeder level) by leveraging distributed inverters to increase situational awareness and provide local voltage support. The grid performance and reliability objectives (SI vision) of this proposal were selected to enhance feeder planning models that can better characterize and quantify the electric power system including the secondary system servicing customers. The Communication objective was selected to demonstrate how visibility and control of behind-the-meter systems and distributed storage at large scale can be optimized to address system reliability and variability impacts, and to maximize the value of solar in high PV penetration scenarios. The goal of this project was to achieve enhanced grid operation and optimized PV penetration utilizing highly distributed sensor data via three subtasks 1.1-1.3.

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TYPE Other Report YEAR 2016
DOIOSTI

Basic Research of Intrinsic Tamper Indication Markings and Patterns Defined by Pulsed Laser Irradiation (Final Report)

Adams, David P.; Murphy, Ryan D.; Saiz, David J.; Yalisove, Steven M.; Bahr, David F.; Lawrence, Samantha K.; Moody, Neville R.; Neiser, Geneva; Sobczak, Catherine

Pulsed laser irradiation has been used to create complex, intrinsic markings that can be used as unique identifiers for authentication and asset protection. Markings have been made on the surface of various materials by rapidly scanning a focused laser beam across a designated area as large as several square inches. Markings include macro-scale patterns, such as barcodes, that contain encrypted information. More complex markings are comprised of macro-scale patterns and embedded, unique micro-scale features. Micro-scale features form spontaneously during scanned laser irradiation and have different shapes, spacings, color and other characteristics that are virtually impossible to recreate. The macro-scale patterns can be interrogated rapidly in the field using a digital camera, while the embedded micro-scale features are best evaluated in the laboratory using microscopy or related optical techniques. Interrogated markings are compared with archived maps of the original patterns (obtained at the time of their manufacture) to determine component authenticity. The majority of experiments have involved marking planar solids. A new instrument that marks non-planar substrates is described for future work.

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TYPE Other Report YEAR 2016
DOIOSTI

Evaluation and correction of timing inconsistencies from the Thor 1 and Thor 2 experiments at the Nevada National Security Site

Phillips-Alonge, Kristin E.; Abbott, Robert; Rourke, William T.'.

Active source seismic data was collected at the Nevada National Security Site using the Seismic Hammer(TM) (SH), under contract from HK Exploration. The SH generates a seismic pulse by dropping a 13 metric ton mass from a height of 1.5 m. Post-survey evaluation of collected data revealed inconsistencies in shot trigger time that required additional analysis and correction using cross-correlation and/or time shifts derived from manual picks of trigger times. While the primary analysis for which this data set was collected is independent of the knowledge of shot trigger time, other processing methods require highly precise knowledge of the trigger time. In order to make the Thor data set more usable to the larger community, additional work was undertaken. Results using the preferred method of cross-correlation were found to be satisfactory. An improved timing fiducial approach is required to reduce timing errors.

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TYPE SAND Report YEAR 2016
DOIOSTI

CUBIT: Geometry and Mesh Generation Toolkit (15.1 User Documentation)

Blacker, Teddy D.; Owen, Steven J.; Staten, Matthew L.; Quadros, William; Hanks, Byron; Clark, Brett W.; Meyers, Ray J.; Ernst, Corey; Merkley, Karl; Morris, Randy; Mcbride, Corey; Stimpson, Clinton J.; Plooster, Michael; Showman, Sam

CUBIT is a full-featured software toolkit for robust generation of two- and three-dimensional finite element meshes (grids) and geometry preparation. Its main goal is to reduce the time to generate meshes, particularly large hex meshes of complicated, interlocking assemblies. It is a solid-modeler based preprocessor that meshes volumes and surfaces for finite element analysis. Mesh generation algorithms include quadrilateral and triangular paving, 2D and 3D mapping, hex sweeping and multi-sweeping, tetrahedral meshing, and various special purpose primitives. CUBIT contains many algorithms for controlling and automating much of the meshing process, such as automatic scheme selection, interval matching, sweep grouping, and also includes state-of-the-art smoothing algorithms.

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TYPE Other Report YEAR 2016
DOIOSTI
Results 43901–44000 of 99,299
Results 43901–44000 of 99,299