Applied Mechanics Division Newsletter 2018
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Theodore Von KÃ
http://oac.cdlib.org/findaid/ark:/13030/kt2f59p3mt No online items Guide to the Papers of Theodore von Kármán, 1871-1963 Archives California Institute of Technology 1200 East California Blvd. Mail Code 015A-74 Pasadena, CA 91125 Phone: (626) 395-2704 Fax: (626) 793-8756 Email: [email protected] URL: http://archives.caltech.edu © 2003 California Institute of Technology. All rights reserved. Guide to the Papers of Theodore Consult repository 1 von Kármán, 1871-1963 Guide to the Papers of Theodore von Kármán, 1871-1963 Collection number: Consult repository Archives California Institute of Technology Pasadena, California Contact Information: Archives California Institute of Technology 1200 East California Blvd. Mail Code 015A-74 Pasadena, CA 91125 Phone: (626) 395-2704 Fax: (626) 793-8756 Email: [email protected] URL: http://archives.caltech.edu Encoded by: Francisco J. Medina. Derived from XML/EAD encoded file by the Center for History of Physics, American Institute of Physics as part of a collaborative project (1999) supported by a grant from the National Endowment for the Humanities. Processed by: Caltech Archives staff Date Completed: 1978; supplement completed July 1999 © 2003 California Institute of Technology. All rights reserved. Descriptive Summary Title: Theodore von Kármán papers, Date (inclusive): 1871-1963 Collection number: Consult repository Creator: Von Kármán, Theodore, 1881-1963 Extent: 93 linear feet Repository: California Institute of Technology. Archives. Pasadena, California 91125 Abstract: This record group documents the career of Theodore von Kármán, Hungarian-born aerodynamicist, science advisor, and first director of the Daniel Guggenheim Aeronautical Laboratory at the California Institute of Technology. It consists primarily of correspondence, speeches, lectures and lecture notes, scientific manuscripts, calculations, reports, photos and technical slides, autobiographical sketches, and school notebooks. -
Chapter 10: Composite Micromechanics
Application of the Finite Element Method Using MARC and Mentat 10-1 Chapter 10: Composite Micromechanics 10.1 Problem Statement and Objectives Given the micromechanical geometry and the material properties of each constituent, it is possible to estimate the effective composite material properties and the micromechanical stress/strain state of a composite material. The objectives of this project are (1) to determine the effective stiffness c c ν c ν c properties E1 , E2 , 12 , 23 of a unidirectional composite material and (2) to determine the strain concentration factor in the matrix region when the composite material is subjected to a uniform transverse normal strain in the X 2 direction. NOTE TO ME 424 CLASS: Only do Part (2). 10.2 Background A composite material is often defined as a combination of two or more materials fabricated in such a way that the individual constituents (materials) can still be readily identified in the final form. If designed properly, this combination of materials yields a composite material that exhibits the best properties of each constituent as well as some advantageous properties not exhibited by the individual constituents. One example of such a material is a unidirectional fiber reinforced composite, which is often used in aerospace structures. An idealized micromechanical view of a unidirectional fiber reinforced composite material is shown in Figure 10.1. In these materials, the fibers have a very small diameter and a very high length-to-diameter ratio. This geometry yields excellent stiffness and strength characteristics in the fiber, since the crystals tend to align along the fiber axis and there are fewer internal and surface defects than in the bulk material. -
Micromechanics As a Basis of Stochastic Finite Elements And
Micromechanics as a basis of stochastic finite elements and differences: An overview M Ostoja-Starzewski Department of Materials Science and Mechanics Michigan State University, East Lansing, MI 48824-1226 A generalization of conventional deterministic finite element and difference methods to deal with spatial material fluctuations hinges on the problem of determination of stochastic constitutive laws. This problem is analyzed here through a paradigm of micromechanics of elastic polycrystals and matrix-inclusion composites. Passage to a sought-for random meso-continuum is based on a scale dependent window playing the role of a Representative Volume Element (RVE). It turns out that the microstructure cannot be uniquely approximated by a random field of stiffness with continuous realizations, but, rather, two random continuum fields may be introduced to bound the material response from above and from below. Since the RVE corresponds to a single finite element, or finite difference cell, not infinitely larger than the crystal size, these two random fields are to be used to bound the solution of a given boundary value problem at a given scale of resolution. The window- based random continuum formulation is also employed in analysis of rigid perfectly-plastic mate rials, whereby the classical method of slip-lines is generalized to a stochastic finite difference scheme. The present paper is complemented by a comparison of this methodology to other existing stochastic solution methods. 1. INTRODUCTION a locally isotropic form The necessity to account for random effects in determining a.. = X(x, co) 5..e +2u(x, co)e.. n ^ the response of a mechanical system is due, in general, to »J iJ kk 'J {Li> three different sources: random external forcing, random is adopted by simply postulating one or both elastic constants, boundary conditions, and random material parameters. -
MICROMECHANICS of STRESS-INDUCED MARTENSITIC TRANSFORMATION in MONO- and POLYCRYSTALLINE SHAPE MEMORY ALLOYS; Ni-Ti
Advanced Materials for the 21st Century: The 1999 Julia R. Weertman Symposium, 1999 TMS Fall Meeting in Cincinnati, OH, USA., Oct. 31-Nov.4, pp.385-396 MICROMECHANICS OF STRESS-INDUCED MARTENSITIC TRANSFORMATION IN MONO- AND POLYCRYSTALLINE SHAPE MEMORY ALLOYS; Ni-Ti Y. Liang, M. Taya and T. Mori* Department of Mechanical Engineering University of Washington Seattle, WA 98195-2600 Abstract Stress-induced martensitic transformation in single crystals and polycrystals are examined on the basis of micromechanics. A simple method to find a stress- and elastic energy-free martensite plate (combined variant), which consists of two variants, is presented. External and internal stresses preferentially produce a combined variant, to which the stresses supply the largest work upon its formation. Using the chemical energy change with temperature, the phase boundary between the parent and martensitic phases is determined in stress-temperature diagrams. The method is extended to a polycrystal, modeled as an aggregate of spherical grains. The grains constitute axisymmetric multiple fiber textures and a uniaxial load is applied to the fiber axis. The occurrence and progress of transformation are followed by examining a stress state in the grains. The stress is the sum of the external stress and internal stress. The difference in the fraction of transformation and, thus, in transformation strains between the grains causes the internal stress, which is calculated with the average field method. After a short transition stage, all the grains start to transform, and the external uniaxial stress to continue the transformation increases linearly thereafter. The external stress at the end of the transition is defined as the macroscopic yield stress due to the transformation in polycrystals. -
Mechanics of Materials Across Nano to Geological Time and Length Scales in Honor of the Pioneering Contributions of Professor Ares J
Mechanics of Materials across Nano to Geological Time and Length Scales In honor of the pioneering contributions of Professor Ares J. Rosakis on the occasion of his 60th birthday September 16-17, 2016; Martinos Auditorium (Granoff Center for the Creative Arts) 154 Angell St, Brown University, Providence, RI Program September 16, 2016 07:30 – 08:20 am Breakfast – Studio 1 (Granoff 4th floor) 08:20 – 08:30 am Welcome Remarks by Larry Larson, Dean of Engineering, Brown University Session 1: Session Chair: D.Henann, Brown University Seismo-mechanics 08:30 – 09:00 am Ares and the sorting out of bi-material rupture dynamics James R. Rice, Harvard University 09:00 – 09:30 am Earthquake fracture speeds: past, present and future Shamita Das, Oxford University 09:30 – 10:00 am The Diversity of Earthquakes and Energy Partitioning Hiroo Kanamori, California Institute of Technology 10:00 – 10:30 am Dynamic imaging of spontaneously evolving friction in laboratory earthquakes Nadia Lapusta, California Institute of Technology 10:30 – 11:00 am Break (lower lobby) Session 2: Session Chairs: R.P.Singh, Oklahoma State University Dynamic Fracture Mechanics V.Eliasson, University of California, San Diego 11:00 – 11:30 am Two Advances in Quasibrittle Fracture Mechanics: Fracking Simulations and Testing of Postpeak in Composites Zdenek Bazant, Northwestern University 11:30 – noon Visualization and quantification of dynamic crack penetration vs. branching at a weak interface in a brittle bilayer Hareesh Tippur, Auburn University noon – 12:30 pm Shock Initiated -
Viscoelastic Behavior of Polymer-Modified Cement
applied sciences Article Viscoelastic Behavior of Polymer-Modified Cement Pastes: Insight from Downscaling Short-Term Macroscopic Creep Tests by Means of Multiscale Modeling Luise Göbel 1,2,*,†, Markus Königsberger 2,3 ID , Andrea Osburg 1 ID and Bernhard Pichler 2 1 F.A. Finger-Institute for Building Material Engineering, Bauhaus-Universität Weimar, 99423 Weimar, Germany; [email protected] 2 Institute for Mechanics of Materials and Structures, TU Wien—Vienna University of Technology, 1040 Vienna, Austria; [email protected] (M.K.); [email protected] (B.P.) 3 BATir Department, Université libre de Bruxelles (ULB), 1050 Bruxelles, Belgium * Correspondence: [email protected]; Tel.: +49-3643-584743 † Current address: Coudraystraße 11 A, 99423 Weimar, Germany. Received: 28 February 2018; Accepted: 21 March 2018; Published: 23 March 2018 Abstract: Adding polymers to cementitious materials improves their workability and impermeability, but also increases their creep activity. In the present paper, the creep behavior of polymer-modified cement pastes is analyzed based on macroscopic creep tests and a multiscale model. The continuum micromechanics model allows for “downscaling” the results of macroscopic hourly-repeated ultra-short creep experiments to the viscoelastic behavior of micron-sized hydration products and polymer particles. This way, the increased creep activity of polymer-modified cement pastes is traced back to an isochoric power-law-type creep behavior of the polymers. The shear creep modulus of the polymers is found (i) to be two orders of magnitude smaller than that of the hydrates and (ii) to increase considerably with increasing material age. The latter result suggests that the creep activity of the polymers decreases with the self-desiccation-related decrease of the relative humidity inside the air-filled pores of cement paste. -
Prof. James Norman Goodier
Professor James Norman Goodier (1905 – 1969) See: https://en.wikipedia.org/wiki/James_N._Goodier Applied Mechanics Stanford University Biography from Wikipedia: James Norman Goodier (October 17, 1905 – November 5, 1969) was professor of applied mechanics at Stanford University known for his work in elasticity and plastic deformation. He was born in Preston, Lancashire, England and studied engineering at Cambridge University. He was awarded a Commonwealth Fund Fellowship which enabled him to continue his studies at the University of Michigan where he earned his doctorate in 1931 under the direction of Stephen Timoshenko with a dissertation titled Compression of Rectangular Blocks, and the Bending of Beams by Nonlinear Distributions of Bending Forces. Timoshenko moved to Stanford University in 1936 and Goodier eventually succeeded him there. He was co-author of two classic books in this field: "Theory of Elasticity," with Timoshenko, 1951; and "Elasticity and Plasticity," with P. G. Hodge, Jr., 1958 and was awarded the Timoshenko Medal by the American Society of Mechanical Engineers in 1961. He was chairman of the Applied Mechanics Division of the American Society of Mechanical Engineers 1945-46, and was elected Fellow of that Society in 1964. He had more than fifty doctoral students, one of whom was George F. Carrier. Memorial Resolution, Stanford University by Erastus H. Lee, Miklos Hetenyi and Harold C. Schmidt: Norman Goodier died on Wednesday, November 5, 1969 after a brief illness. He was born on October 17, 1905, in Preston, Lancashire, England where he attended municipal schools and won scholarships to study at Cambridge University. In 1927 he was awarded the B.A. -
Chiral Metamaterial Predicted by Granular Micromechanics: Verified With
1 Chiral Metamaterial Predicted by Granular Micromechanics: Verified with 2 1D Example Synthesized using Additive Manufacturing 3 4 5 Anil Misra1*, Nima Nejadsadeghi 2, Michele De Angelo 1,3, Luca Placidi 4 6 7 8 1Civil, Environmental and Architectural Engineering Department, 9 University of Kansas, 1530 W. 15th Street, Learned Hall, Lawrence, KS 66045-7609. 10 2Mechanical Engineering Department, 11 University of Kansas, 1530 W. 15th Street, Learned Hall, Lawrence, KS 66045-7609. 12 3Dipartimento di Ingegneria Civile, Edile-Architettura e Ambientale, Università degli Studi 13 dellAquila, Via Giovanni Gronchi 18 - Zona industriale di Pile, 67100 LAquila, Italy 14 3International Telematic University Uninettuno, 15 C. so Vittorio Emanuele II 39, 00186 Rome, Italy 16 *corresponding author: Ph: (785) 864-1750, Fax: (785) 864-5631, Email: [email protected] 17 18 19 20 21 22 23 Continuum Mechanics and Thermodynamics 24 25 26 27 28 Abstract 29 Granular micromechanics approach (GMA) provides a predictive theory for granular material 30 behavior by connecting the grain-scale interactions to continuum models. Here we have used 31 GMA to predict the closed-form expressions for elastic constants of macro-scale chiral granular 32 metamaterial. It is shown that for macro-scale chirality, the grain-pair interactions must include 33 coupling between normal and tangential deformations. We have designed such a grain-pair 34 connection for physical realization and quantified with FE model. The verification of the 35 prediction is then performed using a physical model of 1D bead string obtained by 3D printing. 36 The behavior is also verified using a discrete model of 1D bead string. -
Spring Issue • March 2008
ALUMNI REGISTRATION Volume 7 • Spring Issue • March 2008 The Department of Civil and Environmental Engineering is always interested in how our alumni are doing. We hope you will take time to complete the Alumni Update information below. Please include information on your recent professional and personal developments, along with a high-quality photo if available. Please email your information to [email protected] or mail submissions to Civil and Environmental Engineering, Louisiana State University, 3418 Patrick Taylor Hall, Baton Rouge, LA 70803-6405. Name: _______________________________________ Year of Graduation: _______________ Home Address: _________________________________________________________________ Home Telephone: _____________________________ Email: ___________________________ Company: ___________________________________ Title: ____________________________ Volume 7 • Spring Issue March 2008 Business Address: ______________________________________________________________ A Foundation Of Excellence Program Business Telephone: _________________________ Message from the Chair News: _____________________________________________________________________________ Welcome to another exciting issue of our as a volunteer, a sponsor, a participant or a newsletter. This is our first newsletter for spectator, the success of this conference 2008 and we anticipate it to be a very suc- will depend on the combined effort of the ___________________________________________________________________________________ cessful year for the department. -
New Horizons in Materials Mechanics
New Horizons in Materials Mechanics Symposium June 5th - 7th, 2013 in celebration of the 70th birthday of Prof., Dr.Tech. Viggo Tvergaard The Viggo Tvergaard Symposium: New Horizons in Materials Mechanics Th e Viggo Tvergaard Symposium: New Horizons in Materials Mechanics is a tribute to a world leading scientist on the occasion of his 70th birthday. Th roughout his career Viggo has made important scientifi c contributions to the fi eld of solid mechanics. His central interests have been plasticity, materials me- chanics, fracture mechanics, and structural stability and his research has revolved around these subjects and their intersections. In the 44 years of Viggo’s academic career until now, he has been a highly active scientist and he has developed international relations and collaborations with the strongest researchers around the world, many of whom are gathered at this symposium. Viggo has been a central teacher and advisor at the Technical University of Denmark. He has undertaken teaching on all levels from basic Strength of Materials courses to advanced courses on Plasticity, Fracture Mechanics and General Continuum Mechanics. Viggo has been advisor for numerous PhD student’s, of which many hold infl uential positions in Danish industries. Th e scientifi c accomplishments of Viggo have been recognized by the community on many occasions, and we shall not try to list them, but only mention that Viggo’s recent election for president of IUTAM serves as recognition that Viggo is not only a gift ed scientist and educator, but also a person who will have the great impact on our research fi eld for years to come. -
Stephen P. Timoshenko
NATIONAL ACADEMY OF SCIENCES STEPHEN P. TIMOSHENKO 1878—1972 A Biographical Memoir by C. RICHARD SODERBERG Any opinions expressed in this memoir are those of the author(s) and do not necessarily reflect the views of the National Academy of Sciences. Biographical Memoir COPYRIGHT 1982 NATIONAL ACADEMY OF SCIENCES WASHINGTON D.C. STEPHEN P. TIMOSHENKO December 23, 1878-May 29, 1972 BY C. RICHARD SODERBERG HE MAJOR FACTS of the life of Stephen P. Timoshenko Tare by now well known. He was born as Stepen Prokof- yevich Timoshenko* in the village of Shpotovka in the Ukraine on December 23,1878. Stephen's father, born a serf, had been brought up in the home of a landowner, who later married Stephen's aunt. His father subsequently received an education as a land surveyor and practiced this profession until he himself became a landowner of some means. Timoshenko's early life seems to have been a happy one, in pleasant rural surroundings. 'The concluding decades of the nineteenth century were a period of relative tranquility in Russia, and the educational ideals of the middle class were not much different from, and certainly not inferior to, those of their counterparts in Western Europe. He concluded his secondary education with a gold medal at the technical realschulet in Romny, near Kiev. His father had rented an NO~E: The Academy would like to express its gratitude to Dr. J. P. Den Hartog for his help in the preparation of this memoir after the death of C. Richard Soderberg in 1979. *The spelling of Russian names and terms follows that of E. -
A Tribute to Dr. Daniel C. Drucker 1918 - 2001
SEM History Experimental Techniques November/December 2001, Vol. 25, No. 6 and January/February 2002, Vol. 26, No. 1 A TRIBUTE TO DR. DANIEL C. DRUCKER 1918 - 2001 SESA President 1960-61 Dan was a highly esteemed member of SESA/SEM and the recipient of more honors and awards than any other member in the history of SEM. His activity with the Society began with the Eastern Photoelastic Conferences which later became the SESA. For reasons which he couldn't remember he did not attend the first meeting of the new society, but soon joined it and was very active for many years. Dan was a member of the Executive Committee when the momentous decision was made for the Society to hire a headquarters staff and to initiate the monthly magazine Experimental Mechanics. Later he was the President when the new mode was made operational, and there were many difficult growing pains during the transition. I was on the Executive Committee at that time and got my first glimpse of his extraordinary ability to settle the sensitive problems without hurting anyone's feelings. Dan was the recipient of the Society's two highest honors, the Murray Lectureship and Honorary Member. He also received the M. M. Frocht Award. Dan continued his association with SEM, and in recent years was a speaker at the SEM 50th Anniversary Celebration, and served as a member of the SEM Educational Foundation and of the International Advisory Board for Experimental Mechanics. Dan Drucker was born in New York City and started his engineering career as a student at Columbia University.