188宝金博页面版

第 l 6 卷 第 4 期 2003 年 l2 月 宁 波 大 学 学 报 ( 理 工 版 ) JOURNAL OF NINGBO UNIV ER SITY ( NSE E ) V o1． 16 No ． 4 Dec ．2o o3 文 章 编 号 ： 1001． 5132( 2003)04． 0403． 07 D amage E v olution in P article R einforced P olymers under D ynamic L oad in g H UA N G Z hu— ping ， CH E N J ian— kang ， BA I Shu— lin ， J IA NG Min— qiang ( 1． Department of Mechanics and Engineer i ng Science，Peking University ，Beijing 100871，China； 2 ． College of Hydraulic and C ivil Engineer i ng．Yangzhou Un i versity ．Y angzhou 225009 ．China) A b str act ： Th e mic rodamage evolution in a partic le- f i lled polym er under dynami c loading is stu died in this paper ． F irstly ，th e constitutiv e relation of th is part ic le f i lled polym er rec en tly propos ed by th e present author s is in tr o - duc ed ．T hen ，the pr o pagation of one- dimens ional s train wav e caused by the plate im pac t is in ves tigated ，and the attenuation of stress wave is evaluated ．T hird ly ，the evolut ion of the m ic r o dam a g e is theoretica l ly stud ied by using a mic r o mecha n ical m ethod ．W hen the tensile wave app ear s in th e mater i a l，the m ic ro d amage n uc leation m ay tak e place due to th e deb o nd in g of th e inter f ac e b etween the second phas e par t ic les a n d th e m atr i x ．T he growth a n d coa l esc enc e of th ese m ic r o v oids lead to the dynamic f ailure of th e m ater i a 1 ．It is shown t h at th e m icrodamage evo- lution is in f luenc ed by several factor s ，s uch a s the pan ic le size-disper s ity ，the av erage radius of par t icles ， and the adhes iv e energy of the in ter f ace ．H owev er，dif f erent from static conditions ，the eff ec t of these fac tor s on the m ic r o v oids evolution und er d y n am ic conditions is not remark able ．T he theoretic a l analy sis ind ic ates that the spa l — lation of the mater i a l is str o ngly inf l uenced by t h e impact velocity of the projectile．F ina l ly ，according to the charac ter i stic s of the dam age ev olution ，a spallation cr i ter i on for a pan icle-f i lled polym er i c mater i a l is prop o sed ． K ey w o rds ： pan ic le— f i lled polym er ； m ic rod ama g e evolution ； stress wave p r o p agation ； spa l lation c r i ter i on C L C ilium t)er ：0 34 7 D oc um ent c ode ：A T he study oi the dy n am ic failure of m ater i als ha s been fast developed in pa s t four dec ades ．In or d er to re— v ea l th e nature of t h e dy nam ic f ailure proc ess in m ateri- a l s ，many attemp ts whic h al e ba s ed on more realistic p ic — tur e s of t h e dam age evolution have been m ad e in recent v e a r s[ ]． T hes e p ic tures show that t h e eventua l f ailure o f a dama g ed mater i al m ay be c aused by the n ucleation ， grow th and coalesc ence of enormous amount of m icr o scop — ic v oids or c rac k s ． In fac t ， t h e under s tanding of the mec ha n isms of dynamic failure ，suc h as spallation under plate imp ac t ， is of sc ientif i c a n d technologic a l interests ． V ar i ous c r i teria f o r spa l ling h ad been pr o posed in some early work s on th e dyn am ic failure pr o blem ，f o r example ， the spa l l strength or the cr i tic al tensile stress ， th e s tress gradient cr i ter i on ， a n d th e ac cumulative-d ama g e c riteri· on ，and so on ．A s a ty pical c a s e of dyn amic f ailure ， the studies of spallation men tioned above in dic ated that the dynam ic failure of m ater i a l s is a proc ess of dam age ev olu — tion a n d the effec ts of d ama g e evolution should b e includ - ed in the a n a l ysis ． T he mentioned studies were mostly foc used on the metallic mat er i als or the m eta l matr i x c ompos ite ．In rec ent )'ear s ， pan icle-f i lled p o ly mer s and p oly mer blends h ave been widely used a s engineer i ng plastics ． C lose attention has b een paid to t h e toughen ing mec ha n ism of the mater i - a Is 6]， the nucleation and grow th of m ic rovoids in the mao R ee ei ved d a t e ： 20 0 3 —0 9 — 30 ． Foundati on item ： Supported by the National Natural Science Foundation of Ch ina ( 100 320 10 ．10 172074 ．10272005 ) 维普资讯 http://www.cqvip.com