RHEOLOGY BULLETIN Publication Oi the Society Oi Rheology
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RHEOLOGY BULLETIN Publication oi the Society oi Rheology Volume 35 No. 3 September, 1966 ANNUAL WINTER MEETING TRAVEL TO ATLANTIC CITY THE SOCIETY OF RHEOLOGY The best air service to Atlantic City is via Philadelphia, serviced by 11 leading airlines: Allegheny, American, Delta, MIRAMAR HOTEL - MOTEL Eastern, Lufthansa, National, Northeast, Northwest, Pan SANTA BARBARA, CALIFORNIA American, TWA and United. Limousine service delivers FEBRUARY 6-8, 1967 conventioners directly to Atlantic City hotels and motels in 65-75 minutes. The service operates several times daily A ccomm odations and is increased as demand requires to meet the needs of For reservations and preregistration send request before convention attenders. Make reservations through airline January 1, 1967 to M. C. Shen, North American Aviation ticket agents or travel agencies, with the Salem Transpor- Science Center, 1049 Camino Dos Rios, Thousand Oaks, tation Company or the Yellow Limousine Company at the California with name, address, affiliation, dates of arrival and International Airport - Philadelphia. Limited direct air departure, and accommodations desired. Single rooms are service to Atlantic City is offered by Allegheny Airlines available at $10, $12 or $16 a day. There are also twin- from Boston, New York City, Pittsburgh and Washington, bedded rooms costing $8 a person. Give the name of person D. C. Personalized air service is offered by Southern Jersey to share twin room if possible. Airways operating from Bader Field, just five minutes from Call for Papers most hotels. Deadline for abstracts of papers for the Winter Meeting Train service to the convention site is by connection with is December 1, 1966. Please confine abstracts to 400 words the Pennsylvania-Reading Seashore Lines at 30th Street or and send to Chairman of Program Committee: North Broad Street Stations of the Pennsylvania Railroad J. L. White, (Chairman), U. S. Rubber Company, Research in Philadelphia. Laboratory, Wayne, New Jersey. Bus schedules prevail for those coming from short dis- A. Eisenberg, Department of Chemistry, University of tances. Forty daily buses operate from the Port Authority California, Los Angeles, California. Bus Terminal in New York City. Two companies - Public D. J. Plazek, Mellon Institute, 4400 Fifth Avenue, Pitts- Service and Lincoln - offer non-stop service from New York burgh, Pennsylvania 15213. to Atlantic City in hours, via the Garden State Parkway. N. W. Tschoegl, Division of Engineering and Applied From Philadelphia, Public Service operates non-stop service Mechanics, California Institute of Technology, Pasadena, to Atlantic City in 75 minutes. California. Motorists traveling from the west may utilize continuous turnpike and expressway systems. THE BINGHAM MEDAL, 1966 Dr. Prince E. Rouse of the Los Alamos Scientific Laboratory ANNOUNCEMENTS has been selected as the 1966 recipient of the Bingham Medal, 1. The Ultrasonics Symposium sponsored by the Group on in recognition of work carried out while he was associated Sonics and Ultrasonics of the IEEE will be held on with The Franklin Institute. His theoretical formulation October 12-15, 1966 at the Statler Hilton Hotel, Cleveland, of the problem of the dynamics of polymer chains, published Ohio. Among the principal topics to be featured are: in 1953, provided a physically realistic mode! whose rheo- Industrial Ultrasonics, Phonon Interactions, Medical logical behavior could be expressed in a simple and useful Ultrasonics, Microwave Devices and Techniques, Ma- fashion. His concurrent experimental studies, in collabor- terials and Continuum Mechanics and Military Sonics ation with K. Sittel and E. D. Bailey, provided the first and Ultrasonics. of many confirmations of the essential validity of this model. 2. A joint symposium on the Rheology and Texture of Most of our present descriptions of the rheological properties Foodstuffs will be held at the School of Pharmacy, of amorphous polymers and polymer solutions have been University of London, Brunswick Square, London W.C.I derived directly from this pioneering work of Rouse. on the 5th and 6th January, 1967. The Award will be presented at the banquet during our 3. Deformation and Flow in High Polymer Systems was annual meeting to be held at the Traymore Hotel in Atlantic the theme of the British Society of Rheology Conference City, October 31 to November 2. John D. Ferry of the at Loughborough University of Technology on September University of Wisconsin will introduce Dr. Rouse. 14, 15, and 16, 1966. 1 Finally, certain comparisons are made between other exist- ing theories of nonlinear constitutive equations and the RHEOLOGY BULLETIN writer's theory. Raymond R. Myers, Editor 'R. A. Schapery, "Application of Thermodynamics to Thermomechanical, Fracture, and Birefringent Phenomena Department of Chemistry in Viscoelastic Media," J. Appl. Phys., 3-5, 1964, 0pp. Kent State University 1451-1465. 2R. A. Schapery, "A Theory of Nonlinear Thermovisco- Kent, Ohio, 44240 elasticity Based on Irreversible Thermodynamics," Proe. 5th U. S. Nat. Cong. Appl. Mech, June 1966, pp. 511-530. 3R. A. Schapery, "An Engineering Theory of Nonlinear PROGRAM Viscoelasticity with Applications," Int. J. Solids and Structures, 2, July, 1966. 37th ANNUAL MEETING 10:15 a.m. Break SOCIETY OF RHEOLOGY A-3 Traymore Hotel, Atlantic City, N.J. 10:30 a.m. "Nonlinear Viscoelastic Response from the Vieiv- October .'51 - November '2, 1966 point of Kinetic Theory," J. C. HALPIN, Air Force Materials Laboratory, Wright-Patterson AFB, Ohio. MONDAY, OCTOBER 31, 1966 Modern continuum mechanics has successfully contrib- uted to the theory of nonlinear viscoelastic phenomena SESSION A - Monday Morning through the studies of the restrictions imposed on the permissible forms of constitutive equations by general Chairman: N. W. TSCHOEGL, California Institute of Tech- invariance principles, and by the more special invariance nology, Pasadena, California requirements which pertain to the structural symmetries of the material. Although invariance considerations im- A-l pose serious restrictions on the form an adequate theory 8:45 a.m. INVITED LECTURE: "The Rheology of Metals", must take; the theory still remains undefined and quite E. W. HART, General Electric Company, Schenectady, arbitrary in nature. In effect the invariance principle New York. defines the criterion by which one may judge whether a proposed constitutive relationship is permissible or not Theories of Bulk Viscoelastic Behavior. but it does not define the specific structure of the con- stitutive relationships. The solution of the problem is A-2 then undefined unless additional information is obtained 9:45 a.m. "Physical Aspects of Simplified Constitutive Equa- from the molecular theories and nonequilibrium thermo- tions Derived from Irreversible Thermodynamics," R. A. dynamics and statistical mechanics. SCHAPERY, Purdue University, Lafayette, Indiana. Relatively simple constitutive equations for nonlinear Recently this author has presented an approximate viscoelastic media, with and without transient temper- treatment of the problem utilizing the Kinetic Theories ature, have been developed by the writer in a series of of the elastic and viscoelastic response of rubber like three papers.1-2'»' Specifically, single-integral expressions solids. The result of this effort was the formulation of a for multiaxial behavior were derived by combining irre- single integral constitutive relationship in which the non- versible thermodynamic principles with assumptions based linearity is introduced through the measure of strain; a on actual nonlinear response of unfilled and filled polymers. nonlinear function of the strain or strain tensor. Extensive These equations readily yield, as a special case, nonlinear experimental data obtained independently by this author relaxation moduli wherein strain and time-dependence and T. L. Smith for simple uniaxial tension have been appear as separate factors; this form has been observed presented which substantiates the essential characteristics by many investigators for wide ranges of strain, time of the deformation function. An additional test of the and temperature, and is the basis for Halpin's molecular theory is the execution of multiple step creep and recovery theory of nonlinear viscoelasticity. experiments. Experimentation indicates that the single integral approach can predict the response to a variable This paper deals with physical aspects of these equations excitation history. In fact it is possible to predict the in greater detail. Predicted and experimental mechanical increasing and decreasing sides of a stress-strain cycle and behavior is compared using several common uniaxial and as a consequence one obtains a prediction of the energy biaxial loading histories; good agreement is shown for a stored and energy dissipated for the cycle. The theory wide variety of polymeric materials. Physical significance predicts a proportional relationship of the energy stored of the nonlinear material property functions is brought or dissipated upon the square of the nonlinear deformation out in this comparison, and it is shown how these functions function at the point of maximum extension for the cycle. can be evaluated graphically by using uniaxial and biaxial Experimentation also supports this point. Consequences test data. A sufficient number of tests required to com- of this form of linearization, which reduces a nonlinear pletely characterize an incompressible material is discussed. problem to linear mechanics,