简介：Mechanisminteractionbetweencrackswithdifferentorientationanglesisanalyzedbasedontheprincipleofsuperpositionandaflatteningmethod.Itisfoundthatthemaximuminteractioneffectdoesnotoccurwhenthemicrocrackisalongthedirectionparallelorperpendiculartotheprincipaltensilestress,whichisdifferentfromtheconclusiondrawnbyOrtiz(1987).Themechanismofmicrocrackgenerationandtheeffectofthemicrocrackzoneonthemaincracktiparestudied.Itisconcludedthatthemicrocrackzonehaseffectonthemaincracktip,whichincreaseswiththeincreaseofmicrocrackdensityandlength.

简介：Forafinitebeamwithanonzerogapdistance,anasymmetricconcentratedloadcanbeeitherinsideoroutsideofthecontactzone.Anewgoverningequationisgivenforthecaseofaconcentratedloadoutsidethecontactzone.Bynumericallysolvingtheleft-sideandright-sidecontactlengthsofthebeam,acriterionisestablishedtodeterminewhethertheconcentratedloadisinsideoroutsidethecontactzone.Amoregeneralapproachonthetensionlesscontactofabeamisthuspresented.

简介：Atheoreticalmodelthattakesintoaccountthefree-volumeaidedcooperativeshearingofsheartransformationzones(STZs)isdevelopedtoquantitativelyunderstandtheductile-to-brittletransition(DBT)ofmetallicglasses.TheSTZdilatationalstrainisdefinedastheratioofSTZ-activatedfreevolumetoSTZvolumeitself.ThemodeldemonstratesthattheSTZdilatationalstrainwillincreasedrasticallyandexceedthecharacteristicshearstrainofSTZastemperaturedecreasesbelowacriticalvalue.ThiscriticaltemperatureisingoodagreementwiththeexperimentallymeasuredDBTtemperature.OurresultssuggestthattheDBTofmetallicglassesisunderpinnedbythetransitionofatomic-clustermotionsfromSTZ-typerearrangementstodilatationalprocesses(termedtensiontransformationzones(TTZs)).

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