Fracture

218

HooK RIL\.II<\V:,

treatment, of plant stress and the firxure and torsion problrms and an elementary wcount of the stability problem for struts. Chapters 8 and 8 give :tn elcrnentnry trcntrnent~ of elastic wave ntotion, including vibrations of rods and plates. and the effecrts of viscosity in solids. The latter effect is taken into account by assuming linear relations between stress and strain and their time rates of w,riat,ion. The book forms a useful introduction to thr subject, but no indication is given of the fundamental dilliculties inherent in u number of problems e.g. the theory of thermoel:lstic~ity, the description of viswclastic prolwrtics, and the approxirn:rtions used in plate and shell theory. J. )z. AIIXINS

Fracture: Edited by B. I,. Avenxnc~r. 11. K. FELBECK. c. 'I'.I~SIIX and D. .\. 'I'mm4s. l'hc Technology l’ress. blassarhusctts Institute of ‘I’whnology and John \Vilcy and Sons, Nrw York ; Chupman I% I-Tall Ltd.. London, 1030. pp. xvii -1. 64(i, 57, THIS book records the prot‘eedings of the Int~rn~~tio~lal (‘onferencc on the :2torttit: ~Ie~!In~r~isl~~s of Fracture, neld at Swampscott, ?&ssachuselts in the sprin g of lM9. The twenty-seven paprrs presented at the C’onfereme, which are print cd in full with discussions. were concerned almost exclusively with the fine scalr mcchanisnls of fracture in metals, cerarniw and polymers. A valuable feature of the publication is the prcscntation of summarizctl reports of gcncral discussions on the current status of knowledge in this iicltl. The classit work of Grillith on the frwt,urc of glass fibrcs, published :~bont forty ye:trs ago, provided the key t.o our lln(~erst~n~~ill~ of the differmees between tbc theoretic:rI and re:ll strengths of brittle solids. It remains the basis of many prcsrnt-day ideas on frwt.ure. Tct less then twenty years ago the fracture behnviour of’ rnct:ds w:w c*omrnonly diwusscd in terms of an unexplained and uncertain mxteri:ll constant. tlir critical strws for fr:ac%urr. Elucidation of the role of plastic deformation in thr fracture of qginccring materials awaited developments in dislocation theory. Thus the work dcscribrtl in this book is largclp the prodrwt of t,he last decade. It has been a Itcriod of rwrwrkablc progress.

The enq&asis girm to britt.le fracture in steel n4lwts o~ltst~~n(li~~~ lnwgress in this li&l. Thtrc is rather pcnrral ag~wment that wacks arc nwlc:itcct by the conversion of glide tlislocations into (*a&y dislow~tions. If these are to slnwrd in the form of n srowing crack. their concentnltion of elastics energy must not bc tlispcrsed by plastic flow. Thcorctical itlws on the ductile -brittk transition :~dv;mcctl by I’I:TC~II;md (‘o.wI~~.L go far towards gi\irg :L unilird picture. which takes account. of the main effwts of rrriwostructure. temperatnrc, strain rate and the dcgrtrc:of tmsialit> of t,he npf~lied stress. XIan~- ~rroblems remain unsol\-cd. but swh :whie\-enwnts arc alrcarly sul’ficicnt invot\-cd tic xt. the hwrt of the to justify 13ninwrr’s cwnnwnt that ” ‘I’hc atontic ~~~~~l~~~~is~~is true tlnitcrst:rntlitl~.” This book will be of unique value to rese:wc*hworkcw c~onc~crncdwith def’orrn:~tion ;cntl fracture. It is recolrlrrrcnded to all who srck :I wicntific* untlcrst;mtling of nn:clnmic~al propcrtirs. I). V. \VILSOS