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Computational Mechanics: International Conference on Computational Methods in Nonlinear Mechanics, Austin, Texas, 1974 PDF

329 Pages·1975·4.214 MB·English
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Preview Computational Mechanics: International Conference on Computational Methods in Nonlinear Mechanics, Austin, Texas, 1974

Lecture Notes ni Mathematics Edited by .A Dold and .B Eckmann Series: Texas Institute for Computational Mechanics (TICOM) Adviser: .J .T Oden 164 lanoitatupmoC Mechanics International Conference on Computational Methods in Nonlinear Mechanics, Austin, Texas, 1974 Edited by .J .T Oden Springer-Verlag Berlin.Heidelberg (cid:12)9 New York 1975 Editor Prof. .J Tinsley Oden Department of Aerospace and Engineering Mechanics University of Texas at Austin Austin, Texas 78712 USA Library of Congress Cataloging in Publication Data Computational mechanics. (Texas tracts in computational mechanics) (Lec- ture notes in mathematics ; 461) "With the exception of chapter 27 all of these lectures were also delivered at the International Conference on Computational Methods in Nonlinear Mechanics held in Austin, Texas, in September, 1974." Bibliography: p. Includes index. .i Mechanics, Analytic--Congresses. 2. Nonlin- ear theories--Congresses. I. Oden, John Tinsley, 1936- II. International Conference on Com- putational Methods in Nonlinear Mechanics, Austin, Tex.~ 1974. III. Series. IV. Series: Lecture notes in mathematics (Berlin) ; 461. QA3.L28 no. 461 QASOI 510'.8s 551'.O1'515 75-14390 AMS Subject Classifications (1970): 62-02, 70-02, 73-02, 76-02 ISBN 3-540-07169-5 Springer-Verlag Berlin (cid:12)9 Heidelberg (cid:12)9 New York ISBN 0-387-07169-5 Springer-Verlag New York (cid:12)9 Heidelberg (cid:12)9 Berlin This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photo- copying machine or similar means, and storage ni data banks. Under w 54 of the German Copyright Law where copies are made for other than private use, a fee is payable to the publisher, the amount of the fee to be determined by agreement with the publisher. (cid:14)9 by Springer-Verlag Berlin (cid:12)9 Heidelberg 1975. Printed in Germany. Offsetdruck: Julius Beltz, Hemsbach/Bergstr. ECAFERP This volume contains a collection of special invited lectures no computational methods in nonlinear mechanics prepared by specialists from a wide collection of disciplines. With the exception of Chapter 2, all of these lectures were also delivered at the International Conference no Computational Methods in Nonlinear Mechanics held in Austin, Texas, in September 1974, which saw held under the sponsorship of the .U .S National Science Foundation. ehT original intention of the meeting, dna for collecting this set of lectures, saw to bring together in one place the latest results no computational methods for nonlinear problems from a rebmun of diverse areas in the hope that techniques that dah been found successful in eno area yam have some impact no problems in other areas. In addition, it saw hoped that the state-of-the-art in certain areas of computational mechanics could eb summarized. I believe that a reader ohw examines the contents will agree that both of these objectives have been accomplished. J. T. nedO Austin, 1975 ELBAT FO STNETNOC ECAFERP ................................................................ iii LIST FO SROTUBIRTNOC ................................................... vii SERUTCEL Bilateral Algorithms and Their Applications .W F. Ames and .M Ginsberg .................................... A Plate Analogy for Plane Incompressible Viscous Flow J. H. Argyris, P. C. Dunne, and B. Bichat ..................... 33 Finite Elements and Fluid Dynamics .G J. Fix ...................................................... 47 Experience with Forward Marching Nonlinear Solutions of the Navier Stokes Equations J. E. Fromm .................................................... 17 Perturbation Procedures in Nonlinear Finite Element Structural Analysis .R H. Gallagher ................................................ 75 Computational Methods for Stress Wave Propagation in Nonlinear Solid Mechanics .W Herrmann, L. D. Bertholf, and S. L. Thompson ................ 19 nO Free Surface Problems: Methods of Variational and Quasi Variational Inequalities J. L. Lions .................................................... 129 Continuous and Discontinuous Finite Element Approximations of Shock Waves in Nonlinear Elastic Solids J. T. Oden and L. .C Wellford, Jr .............................. 149 nO the Solution of Large, Sparse Sets of Nonlinear Equations .W .C Rheinboldt ............................................... 169 Vl Recent Developments dna Problem Areas in Computational Fluid Dynamics .P J. Roache ...................................................... 591 Regularization in Celestial Mechanics .V Szebehely ...................................................... 752 Iterative Solution of Linear dna Nonlinear Systems Derived from Elliptic Partial Differential Equations .D .M Young ....................................................... 562 Visco-Plasticity, Plasticity, Creep dna Visco-Plastic Flow (Problems of small, large dna continuing deformation) .O .C Zienkiewicz ................................................. 792 LIST FSOROTUBIRTNOC .W .F senaP J. L. Lions tnemtrapeD of Mechanics dna Hydraulics IRIA - Laboria ehT University of lowa eniamoD ed uaeculoV lowa City, lowa 04225 truocneuqcoR .B .P 5 05187 eL Chesnay, France J. .H Argyris Institute fur Statik dnu kimanyD red Luft J. .T nedO dnu nenoitkurtsnoktrhafmuaR tnemtrapeD of ecapsoreA gnireenignE Universitat Stuttgart dna Engineering scinahceM Stuttgart, tseW ynamreG ehT University of saxeT at Austin Austin, saxeT 21787 .L .D Bertholf Sandia Laboratories .W .C Rheinboldt Albuquerque, weN Mexico 51178 retupmoC Science Center University of Maryland .B Bichat College Park, Maryland 24702 Institut fur Statik dnu kimanyD red Luft dnu nenoitkurtsnoktrhafmuaR .P J. ehcaoR Universitat Stuttgart Science Applications, Inc. Stuttgart, tseW ynamreG 221 aL Veta .N .E Albuquerque, weN Mexico 80178 .P .C ennuD Institut fur Statik dnu kimanyD der Luft .V Szebehely dnu Raumfahrtkonstruktionen Department of Aerospace Engineering Universitat Stuttgart dna Engineering scinahceM Stuttgart, tseW ynamreG ehT University of Texas at Austin Austin, Texas 21787 .G J. Fix tnemtrapeD of Mathematics .S .L nospmohT ehT University of Michigan Sandia Laboratories nnA Arbor, Michigan 40184 Albuquerque, weN Mexico 51178 J. .E mmorF .L .C Wellford, Jr. I. .B .M Department of Civil Engineering Monterey dna Cottle sdaoR University of Southern California naS Jose, California 41159 soL Angeles, California .R .H Gallagher .D .M gnuoY tnemtrapeD of Structural Engineering Department of Mathematics Cornell University ehT University of Texas at Austin Ithaca, weN York 05841 Austin, Texas 21787 .M grebsniG .O .C Zienkiewicz retupmoC noitarepO~secneicS hcraeseR tnemtrapeD of Civil Engineering nrehtuoS Methodist University University of Wales, aesnawS Dallas, saxeT aesnawS 2AS 8PP, United modgniK .W nnamrreH aidnaS Laboratories ,euqreuqublA weN ocixeM 87115 LARETALIB SMHTIROGLA DNA THEIR SNOITACILPPA .W F. Ames and .M Ginsberg I.I Introduction. In this paper, algorithms providing iterative improvable upper and lower bounds are constructed for certain classes of nonlinear ordinary and partial differential equations arising in transport phenomena. Developments are based upon the construction of antitone functional operators which are oscillatory contrac- tion mappings. Following the mathematical details, which include sketches of con- vergence and uniqueness proofs, several examples will be presented. Application of the general results will be made to nonlinear diffusion, non-Newtonian (power law) boundary layer flow and to diffusion with a generalized radiation condition. 1.2 Preliminary Definition. Let R and *R be partially ordered metric spaces and T be an operator whose domain D c R and range W c R*. Then T is said to be syn- tone if v ~ w implies Tv ~ wT for every v, w c D and strictly syntone if v < w implies Tv < .wT T is said to be antitone if v ~ w implies Tv ~Tw for every v, w E .D T is monotone if it is either syntone or antitone. A bilateral or error bounding algorithm for the solution of an operator equation produces a sequence of approximate solutions such that the true solution is bounded between every pair of successive approximations. 1.2.1 Introductory Example. sA a motivation for what follows consider the elementary nonlinear equation +C~T~ = -y(y - 2) , y(O) = 1 (1.1) u~ the exact solution of which is (1.2) y(t) = 2/I + exp (-2t) Problem (I.I) is convertible to the operator form y = TY, from which successive ap- proximations nY = TYn-I can be developed, in a variety of ways. If the classical Picard procedure is employed (I.I) becomes Yd n = -Yn-l(Yn-I - 2), Yn(O) = 1 (l.3a) and the integral form is t nY = 1 - f Yn-l(Yn-I - 2)dt (l.3b) W~ 0 sA a first alternative a Newton-Picard approximation to (I.I) gives nYd 2 dt + 2Yn-I - lYn = Yn-I ' nY (0) = 1 (I .4a) with the associated integral form 1i f O - nY = exp -2 (Yn 1 l)ds 2 2 (Yn 1 - l)dr ds + 1 - - Yn-I _ - i i f exp- f i i - 0 0 (l.4b) Lastly an approximation which leads to a Bilateral algorithm, as will eb subsequently demonstrated, carries (I.I) into Yd n dt = -Yn(Yn-I - 2) , Yn(O) = 1 (l.5a) with the integral form ;i ex i (l.5b) = (Yn-I - 2)ds Clearly, (l.3b), (l.4b) and (l.5b) all have the form nY = TYn-I but the properties and complexities of the operators are vastly different. Since direct comparison is not the present purpose only the properties of (l.5b) will eb briefly examined. If it is assumed that Yn-I < nY then it follows from (l.5b) that exp S'1 s 2, SOPxe s 2' I t t = Yn+l 0 0 that is nY > Yn+l and (l.5b) is antitone. yB na analogous argument if it is assumed that Yn-I > nY then nY < Yn+l" From (l.5b) it follows that each iterate is positive. Thus, beginning with Yl = 0 it follows that Yl < Y2" yB application of (l.5b) the following inequalities result: Yl < 2Y ' 3Y < 2Y ' 3Y < 4Y ' 5Y < 4Y .... (1.6) Since Yl 3Y the following inequalities result: (I .7) Yl < 3Y ' 4Y < 2Y ' 3Y < 5Y ' 6Y < 4Y .... sA a consequence of the foregoing analysis the even subsequence {Y2n } is seen to form a monotonic decreasing sequence of upper bounds to the exact solution. Since it is bounded below the subsequence sah a limit "EY ehT ddo subsequence {Y2n+l } forms a monotonic increasing sequence of lower bounds to the exact solution. It is bounded above since every ddo term is less than all the even terms. Hence the ddo subse- quence sah a limit "OY Upon proof (deleted here) of uniqueness dna convergence to the solution of the original problem a bilateral algorithm sah been estaCDlished. Moreover na estimate of the absolute error, at any step of the exact iteration, nac eb made from ly n - Yn_ll. Further discussion of error analysis will eb given sub- sequently. ehT bilateral algorithm (l.5b), for problem (I.I), sah been carried out nu- merically by Ginsberg I. Implementation for the computer saw accomplished by using truncated Chebyshev polynomial approximations for the integral of (l.5b). Such ap- proximations are found in practice to eb "close" to minimax approximations. Some of the results dna comparisons with the exact solution (1.2) are shown in Table I.I. ehT convergence is very rapid, requiring two iterates (after OY = )O at x = 0.25 dna four at x = 1.00. 1.3 Literature dna Applications. In this section, some literature dna ap- plications are reviewed. 1.3.1 Some Applications. Even though bilateral algorithms have not been readily available a number of applications appear in the literature. nA early application is eud to Weyl 2 (see also semA 3) ohw studied the Blasuius problem f'" * ff" = 0 , f(O) = f'(O) = 0 , f'(~) = 2 (1.8) yb means of what is won called a bilateral algorithm. Barnov 4 reports that non- linear differential equations representing flexural dna torsional vibration of smaeb or buckling of rods often cannot eb easily solved either analytically or yb existing numerical methods in such a yaw that the positional relationship between the approxi- mate dna exact solutions is accurately revealed. A bilateral approach is helpful here; Baranov sah developed such a method for his specific equations. In naval war- fare problems involving the esu of the Lanchester equations, Fabry 5 sah defined a two-sided bounding scheme which offers a means of studying variations of certain parameters before the equations are solved by some conventional (nonbounding) method. TABLE I.I BILATERAL SOLUTION ROF y' = - y(y - 2) , y(O) = 1 analytic solution lower bound upper bound x = 0.25 505097149588391.1 025585902017846.1 y = 907304266819442.1 383958467203442.1 145489890390942.1 x = 0.50 764804281726941.1 167828858192817.2 y = 010062751711264.1 986659188979254.1 263466362558625.1 x = 0.75 105198159195687.0 4.481684580133818 y = 1.635148952387287 661194665515655.1 1.964470533182715 426776114294236.1 1.650773795468340 x = l.O0 0520600043748203.0 546039890650983.7 y = 567559551495167.1 063806498261724.1 510758329162138.2 649251773419737.1 661302671242268.1 525515168507067.1 840910946574667.1 :ETON esehT results are obtained from the program of Ginsberg I. ehT halting criteria consisted of a check every two iterations which used (n + l) (cid:141) 0.5 (cid:141) Ol -15 sa a bound no roundoff error dna xam (fan_if, lanl, lan+ll) sa a bound no the truncation error. For each iteration 9 terms (n = 8) are used in each vehsybehC expansion.

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