Long Term Durability of Structural Materials. Durability 2000 Proceedings of the Durability Workshop, Berkeley, California, 26–27 October, 2000 PDF
Preview Long Term Durability of Structural Materials. Durability 2000 Proceedings of the Durability Workshop, Berkeley, California, 26–27 October, 2000
FOREWORD This volume addresses the basic mechanisms of long term deterioration of engineering materials and the development of short term laboratory or in-situ tests which will allow prediction of the extent of this long term deterioration. All machines, structures and facilities deteriorate over a period of years or decades and eventually wear out, break down, or become unproductive or unsafe. Replacement costs to counter the deterioration are enormous. For instance, the US Federal Highway Administration (FHWA) estimates that in the US there is an annual accruing "bridge deficiency" of $ 2.3 billion (in 1980 dollars) and that the total expenditure for bridge repair and replacement from 1981 through 2000 was $ 102.6 biUion. Similar costs can be documented in many other sectors, from transportation and manufacturing to electronics and MEMS. Understanding how to design components and structures for optimal life performance is therefore very important and becomes essential when new materials or new application areas are considered. Of high importance is also the understanding of how to determine the optimal time to replace existing components or structures and development of techniques to prolong their usefixl life. Once this understanding has been reached and it has become possible to closely determine the life cycle of the most critical components of a structure or system, then it becomes feasible to develop design methodology and/or inspection, monitoring, and replacement strategies which allow significant extension of the life of the complete system. This will result in significant savings to society. In order to reach this desirable goal it is necessary to closely understand deterioration mechanisms at different scales and to have available short term tests that can be used to reliably predict long term deterioration, durability and performance, as discussed in this volume. Objectives of the workshop This book contains the proceedings of a workshop held at Berkeley, CA in October 2000. It brought together engineers and scientists, who have received research grants from the National Science Foundation under the 1998 initiative "Long Term Durability of Materials and Structures: Modeling and Accelerated Techniques" (NSF 98-42). The purpose was to share results from the study of long- term durability of materials and structures. The major objective was to develop new methods for accelerated short-term laboratory or in-situ tests, which allov/ accurate, reliable prediction of long- term performance of materials, machines and structures. To achieve this goal it was important to understand the fundamental nature of the deterioration and damage processes in materials and to develop innovative ways to model the behavior of these processes as they affect the life and long- term performance of components, machines and structures. The researchers discussed their approach to include size effects in scaling up from laboratory specimens to actual structures. Accelerated testing and durability modeling techniques developed were validated by comparing their results with performance under actual operating conditions. The main mechanisms of the deterioration discussed included environmental effects and/or exposure to loads, speeds and other operating conditions that are not fully anticipated in the original design. A broad range of deterioration damage, such as fatigue, overload, ultraviolet damage, corrosion, and wear was presented. A broad range of materials of interest was also discussed, including the full spectrum of construction materials, metals, ceramics, polymers, composites, and coatings. Emphasis was placed on scale-dependence and history of fabrication on resulting mechanical behavior of materials from the macrosc^e to the microscale. In summary, the objective of this workshop was to establish a holistic discussion of deterioration mechanisms relevant to structural and construction materials. Topics included the physics and chemistry of the deterioration mechanism, develop new equipment to determine the degree of distress caused by the deterioration and test the new methodology in field conditions. We hope that the results of the workshop can lead to improved durability, life cycle performance, safety, reduced maintenance and lower cost which in turn should lead to superior machines and structures. Paulo J.M. Monteiro Ken P. Chong Jom Larsen-Basse Kyriakos Komvopoulos Editors WORKSHOP ATTENDEES Javier Balma KenP.Chong,PhD,PE Civil & Environmental Engineering Director, Mechanics & Materials Program University of Kansas CMS/Engineering Directorate 2008 Learned Hall National Science Foundation Lawrence KS 66045 4201 Wilson Blvd, Suite 545 785-864-3826 Arlington VA 22230 ibalmafgiukans.edu 703-292-7008 kchongfglnsf.gov Zdenek P. Bazant, PhD, SE Walter P. Murphy Professor of Civil Richard M. Christensen, PhD Engineering & Materials Science Research Professor Northwestern University Aeronautics & Astronautics EvanstonIL 60208-3109 Stanford University 847-491-4025/848-491-3351 Durand Bldg, Rm. 387A z-bazant(a)jiorthwestem.edu Stanford CA 94305-40035 christensen(g>stanford.edu Raimondo Betti, PhD Civil Engineering & Mechanics Julio F. Davalos, PhD Columbia University C.W. Benedum Distinguished Teaching 610MuddBldg Professor, Civil & Environmental New York NY 10027 Engineering 212-854-6388 College Engineering & Mineral Resources betti(g>civil.columbia.edu ESB, Rm 611, Evansdale Drive West Virginia University Zednek Bittnar Morgantown WV 26506-6103 Chair, Dept of Structural Mechanics 304-292-3031, X.2632 Czech Technical University davalos(glcemr. wvu.edu Prague 6, Czeck Republic ++420-2-2435-3869 Grace Hsuan, PhD bittnar(a)isv.cvut.cz 475 Kedron Avenue Folsom PA 19033 Scott Case, PhD 215-895-2785 Materials Response Group [email protected] Engineering Science & Mechanics 121-CPatton Hall, MC 0219 Y.C. Jerry Jean, PhD Virginia Tech University Chemistry and Physics BlackburgVA 24061 Chair, Dept of Chemistry 540-231 -3140 University of Missouri-Kansas City scase(a),vt.edu 5009 RockNill Road Kansas City MO 64110 816-235-2295 [email protected] Christopher H.M. Jenkms, PhD, PE Dr. Victor C. Li, FASCE, FASME Director, Compliant Structures Laboratory Professor & Director, ACE-MRL Mechanical Engineering Civil & Environmental Engineering 501 E. Saint Joseph Street University of Michigan Rapid City SD 57701 2326 G.G.Brown Bldg 605-394-2406 Ann Arbor Ml 48109-2125 [email protected] 734-764-3368 vcli(a),engin.um ich.edu William Jordan, PhD, PE Chair, Mechanical Engineering Program Richard A. Livingston, PhD Louisiana Tech University Senior Physical Scientist Ruston LA 71272 Office of Infi-astructure R&D, HRDI 318-257-4304 Federal Highway Administration iordanrg>coes.latech.edu 6300 Georgetown Pike McLean VA 22101 Jacob Jome, PhD 202-493-3063 Chemical Engineering dick.livingston(a)igate.fhwa.dot.gov University of Rochester Rochester NY 14627 Hongbing Lu, PhD 716-275-4584 School of Mechanical & Aerospace iome(g).che.Rochester.edu Engineering 218 Engineering North Akira Kuraishi Okalahoma State University Graduate Student Stillwater OK 74078 Aeronautics & Astronautics hongbin(a)jnaster.ceat.okstste.edu Stanford University Durand Bldg Rm. 006D Wes Limi, Chief, Office of Infrastructure Stanford CA 94305-4035 Research, MS-42 650-723-3524 California Department of Transportation akirakfg.leland.stanford.edu New Technology And Research Program 1101 R Street Kyriakos Komvopoulos, PhD Sacramento CA 95814 Mechanical Engineering 916-324-2713 5143 Etcheverry Hall [email protected] University of California, Berkeley Berkeley CA 94720-1740 Sankaran Mahadevan, PhD 510-642-2563 Director of Graduate Studies kvriakos(a),me.berkelev.edu Dept of Civil & Environmental Engineering Box 6077, Station B Jom Larsen-Basse, PhD Vanderbilt University Director, Surface Engineering & Material Nashville TN 37235 Design Program 615-322-3040 Civil & Mechanical Systems Division sankaran.mahadevan(a)vanderbilt.edu National Science Foundation 4201 Wilson Blvd,Rm 545 Arlmgton VA 22230 Gerald H. Meier, PhD 703-292-7016 Materials Science & Engineering [email protected] 848 Benedum Hall University of Pittsburgh Pittsburgh PA 15261 412-624-9720 [email protected] Yasushi Miyano, PhD Tom Sandreczki Materials System Research Laboratory Dept of Chemistry Kanazawa Institute of Technology University of Missouri-KC 3-1 Yatsukaho, Matto, 5009 Rockhill Road Ishikawa 924-0838, Japan Kansas City MO 64110 mivano(alneptiine.kanazawa-it.ac.ip [email protected] Paulo J. Monteiro, PhD Jian-Ku Shang, PhD Civil & Environmental Engineering Materials Science & Engineering 725 Davis Hall University of Illinois at Urbana-Champaign University of California, Berkeley 1304 West Green Street 510-643-8251 Urban IL 6180 [email protected] 217-333-9268 j [email protected] Doug Parks Division of Materials Engineering & C.T. Sun Testing Services School of Aeronautics & Astronautics 5900FolsomBlvd Purdue University Sacramento CA 95819-4612 West Lafayette IN 47907-1282 916-227-7007 765-494-5130 doug [email protected]. gov [email protected] Ramana M. Pidaparti Michael Tolin Mechanical Engineering (Caltrans) Division of Materials & Purdue School of Engineering & Testing Services Technology, lUPUI 5900 Folsom Blvd 723 W. Michigan Street Sacramento CA 95819 IndianapoUs IN 46202-5132 916-227-5297 317-274-6796 michael tolin(a),dot.ca.gov ramana(a),engr.iupci.edu Stephen W. Tsai, Professor/Research Arron Rambach Durand Building, Rm 381 California DOT (Caltrans) Dept of Aeronautics & Astronautics 5900 Folsom Blvd Stsmford University Sacramento CA 95819 Stanford CA 94305-4035 916-227-7236 650-725-3305 arronJam [email protected] [email protected] Robert A. Reis Clifton Vining Division of Materials Engineering & Dept of Mechanical Engineering Testing Services Louisiana Tech University 5900 Folsom Blvd Ruston LA 71272 Sacramento CA 95819 916-227-7287 Aleksandra Vinogradov, PhD [email protected] Mechanical & Industrial Engineering Montana State University Alberto A. Sagues, PhD, PE 220 Roberts Hall Distinguished University Professor BozemanMT 59717 Civil & Environmental Engineering 406-994-6284 University of South Florida ENB-118 [email protected] 4202 E. Fowler Avenue Tampa FL 33620-5350 813-974-5819 [email protected] Paul Viraiani Max Yen, PhD Federal Highway Administration Director, Materials Technology Center 6300 Georgetown Pike Southern Illinois University McLean VA 22101 Carbondale IL 62901-6603 202-493-3052 618-536-7525 paul.vinnani(glfliwa.dot.gov jsulivan(g)^iu.edu Yunping Xi, PhD Civil, Environmental & Architectural Engineering Campus Box 428 University of Colorado Boulder CO 80309 303-492-8991 xiy{albechtel.colorado.edu xi WORKSHOP ATTENDEES Long Term Durability of Structural Materials PJ.M. Monteiro, K.P. Chong, J. Larsen-Basse, K. Komvopoulos (Eds) © 2001 Elsevier Science Ltd. All rights reserved INITIATIVE ON LONG TERM DURABILITY OF MATERIALS AND STRUCTURES J. Larsen-Basse and K.P. Chong National Science Foundation Arlington, VA 22230, USA ABSTRACT Fundamental research in durability of materials and structures have shown great potential for enhancing the functionality, serviceability and increased life span of our civil and mechanical infrastructure systems and as a result, could contribute significantly to the hnprovement of every nation's productivity, environment and quality of Hfe. This initiative is aimed at developing innovative short-term laboratory or in-situ tests, which allow accurate, reliable prediction of long-term performance of materials, machines and structures. It is especially needed for new materials since such data are non-existing. The intelligent renewal of aging and deteriorating civil and mechanical infrastructure systems includes efficient and innovative use of high performance composite materials for structural and material systems. In this paper the NSF initiative on durability modeling and accelerated tests, as well as research needs are presented. KEYWORDS Durability, accelerated tests, modeling, designer materials, life-cycle performance. INTRODUCTION Demands for better-performing, longer-lasting, safer, more economical, and more environmentally fiiendly structures and machines are constantly pushing the envelope of technological capabilities and engineering practice. As a result there are relentless moves towards close tolerances and use of realistic life-cycle design, condition-based maintenance, and performance-based design. Li this environment, the engineering designer is faced with the problem of finding usefiil and relevant materials property data for use in the design of machines and structures which are expected to provide top performance for an extended period of time. He or she will typically have access to "hard" data, i.e., repeatable and reproducible results from short term laboratory tests, such as simple hardness, fatigue, imiaxial yield and firacture tests; and even results from somewhat more complex standard tests, such as fracture toughness or short-term salt spray or ultraviolet chamber exposure tests. The designer usually also has some much more "soft", qualitative information on how a material has performed in the past under a given combination of time, temperature, mechanical load, environment, etc. in the same or similar applications. The skilled designer will usually be able to draw from his or her experience of connections between these sets of "hard" and "soft" information for one particular material to make educated estimates of how a different material, which gives somewhat similar results in short term tests, will perform under not-too- different sets of long-term complex mechanical and environmental loading conditions. This approach has served reasonably well in the past but has several shortcomings relative to the new demands on tight design for performance. For example: - it depends heavily on the experience and background of the designer, - it does not deal well with synergistic interactions of several different types of loading, for example cyclic stress and long-term corrosion. For creep of metals and viscoelastic materials, use of the Larson-Miller parameter and similar approaches serve as semi-empirical ways to add the effects of temperature and time, but similar parameters are lacking for most other situations, - it does not readily allow for comparison of different classes of materials, for which the short-term test results vary substantially, for example steel and polymer-matrix composites. This inhibits or delays the adoption of new materials for many critical applications, and - it does not provide adequate information to allow direct design-for-performance in specific, long- term applications. For example, wear testing by the popular pin-on-disk apparatus may be a simple way to discriminate between different materials for, say, hip implant use, but it is only marginally relevant to a material's performance in the actual service and it does not permit any useful life-cycle design. With this general background in mind a number of NSF program directors held informal discussions over a period of time. Some of the questions considered were the following: - Have recent advances in the fields of modeling, computation, understanding of basic materials properties, sensing, control, probability analysis, etc., reached the stage where we really can do better than outlined by the problem set above, where we can begin to predict long-term performance from short-term tests by quantitative approaches? And where we can confidently operate with lower safety margins or safety factors and closer prediction of life to failure or time until maintenance is necessary? - Do we understand the different processes well enough to be able to closely predict their long-term synergistic interactions, such as the combined effects of stress, corrosion and temperature variations? - Is there some basic generic approach, which has general applicability in diverse cases, maybe, including model-based simulation and uncertainty and probability considerations? - Do we have some quantitative or semi-quantitative ways of dealing with new materials, new combinations of external loadings and environmental effects, or changes in these factors during the life of a machine or structure? - Are there any new short-term tests or NDE techniques that need to be developed to provide some of the necessary information in a useful manner? And - What new research should we try to stimulate in order to expedite development in this field? - What are the long-term field data available and how do them compare with the research results of proposed methods? Durability of new materials involves the synthesis, laboratory and field testing, accelerated tests and modeling, etc. Fig. 1 illustrates the size effects and mechanics (Boresi and Chong, 2000) involved. Materials Structures/machines Infrastructure Submicro4evel meso4evel macro4evel systems integration Molecular scale Microns Meters Up to km scale ~micro-mecliaiiics ~meso-inecliaiiics ^beams '"bridge systems ^nanotechnology ~interfacial ^columns ^airplanes designer materials smart structures high performance systems Fig. 1. Scales in Materials and Structures The discussions initially resulted in the support of a workshop focused on problems in the infrastructure materials area, funded by NSF and organized by the Board on Infrastructure and the Constructed Environment under the National Advisory Board of the National Research Council of the Academy (NRC 1999). From the report of this workshop and additional discussions an NSF research investment initiative was subsequently developed. It led to the research discussed at this meeting. THE NRC WORKSHOP The workshop was held at the National Academy of Sciences on August 24 and 25 of 1998. It defined its role as ". a reconnaissance-level assessment of models and methods that are being used, or potentially could be used, to determine the long-term performance of infrastructure materials and components." (NRC 1999) The objectives were (NRC 1999): - "define the objectives for infrastructure-based research that would use accelerated testing and computational simulations to determine life-cycle performance - assess the state of the knowledge base to identify gaps and overlaps in research activities - establish outcome-oriented metrics for setting research priorities - identify promising lines of research and collaborations" The participants agreed that a "root cause" of the deterioration and failure of any system is related to materials but that accelerated-testing methods, while they may potentially be used to rank the performance of materials in real-world systems, they are not at present sufficiently reliable to make system-life predictions. The workshop proposed that development of useful life-prediction models for infrastructure systems would require some of the following advances (NRC 1999): a better fundamental understanding of infrastructure materials and systems, including interfaces and degradation modes and spanning all size scales a better understanding of the relevant characteristics of the operating environment development of standardized test methods and databases development of sensors for monitoring systems during construction and use incorporation of economic models in life-cycle cost analyses. The workshop also suggested that major obstacles to adaptation of life-cycle prediction models and accelerated test procedures for infrastructure applications are two interrelated factors: - poor integration of the relevant engineering community into materials-based infrastructure research, and - concerns about risk and liability - It expressed the opinion that "practicing engineers have little opportunity to develop the same level of trust in simulation models and accelerated laboratory tests as they have in their many years of empirical field observations." The workshop concluded that..."life-prediction models and accelerated-testing procedures have the potential to increase the deployment of new materials in infrastructure applications and to improve traditional materials..."
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