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1、接触笔记1、efinng contactpar i ABQUS/Stanarder he selectioof cona airurfces, hree ke fctr must etemined hen creatn cnat formulto: e oat dctizatin; thtrackig apoh; and the ssignment o“mastr” ad “save” oles th rpev srfaces。1.1 conta disctiztionBAQU/Stanaoffer two cona dscreiation ion:traditona “nod-tourace
2、 diretzto nd tre“urfac-tosface” dictzton。1.。1 Node-osurfae ontact dicretiationTraitoal nodeosuface scretiztn h the owing hracterstc: Te sae odere onstraed not to penetrat intoaster sfc; hwever, the ds f the maste surface cn, pniple,pnetrat th sav surace Th cotct irecti is bsed onthe orlof temastesur
3、face.T only nformaton eedd or the lvesace isheloatioand suracee assiad witha nde; T directiofthe slave surface normal and slae ufae curvture re not rlevant.Thus,the slav suface c bedfedas agoupof noes-a obased urace。deto-surfc iscreiati s avilaleeven f andsed surace not usd i hecotact pai defntonig1
4、 Ne-tosurfa cntdicetizaio1.。2 urface-to-uface cont disrtiainToptimze res acracy, surfaetorce disctizai conside tesha ofbt theslavean mster surfces in theeginof onactcosrants.Surtosurface disrtizat ha the follig ey chaacteristics: Contactcndiins are nforced in an ae sse over he slav surfa, ater n at
5、dicrete poits(such asat slv nodes,as i the se ofno-to-urfadiseizaon)Theefe,some penraton ay e obsrve idivdua nodes; howevr, lage, unetetedentratio at nodes int th slve surfae do o occur withisdicetiai. Surace-tosufa dicretizatio not aplicale if a noe-ased surae is ue inthe cact ir diiion。在某一个迭代步中,面对
6、面的接触计算成本一般较点对面的接触的计算成本高,但多数情况下这个成本不会高很多,只有在下列情况下才会让计算成本急剧增大: 模型的绝大部分区域被包含于接触中; 当主动面比从属面网格划分还要精细时; Multielayers ofshelsae involved in cont, suc that te asr surfaofne conat pair atsas the slave urfae faother cont pair.尽管如此,但点对面的接触需要花费更多的迭代步才能达到数值稳定,从某种意义上来说,在一个分析步中,无法判定到底是用点对面接触还是面对面接触计算成本低.1.2 Contac
7、t rakig aproaeI AAQU/Standdthrere twotrckg approachestoaccoun fo th elativemotion o theto uaefrnga cotact pair in mcanical contact simltons: The finiteslding tacing apa he smaldng racn approach1.3 Fndetal choics affectg he contac formulatonYr hice f cot direizaon a taing aproach have nsidrble mpact
8、on ansis I adtion o the qualitie alrady dicused, cerai cminatins of discretiaions and trackingapproaches ae therwn chratertics and mtations aite wth them。 These charcteritiare summarizdn Tab 1. You should ls cnsd t soutio csts assciadwiththevarou contactfomulatosTal1 Cmparisoof ontact orulatiocaract
9、eritics。4选择主动面和从属面的几个原则 alytial rgid urfces and rigid-eentbased surfaemst alas be the aesurfac。 based srface n actlya a slave srfacnd alwaysuses ndeo-surfce cnac ae sufacesmusawa be attace defmae bodies r dforablbedeinedagi。oth rfacs n acontactpair cann be rid rface with te ecepton f defrle srfaes e
10、ined asrigd一般来说,当定义两个基于单元的面作为解除对作用面时,当存在一个较小的面和一个较大的面时,一般将较小的面定义为从属面。当两个面大小接近时,选取较“硬”的面或单元划分笔记粗糙的面作为主动面。值得注意的是,“硬的面不一定是材料弹性模量大的材料,比如当一个薄金属片和一个橡胶材料接触时,此时就应该将薄金属片所属的面定义为从属面。当两个面区域接近,“硬度”也接近时,此时往往需要反复尝试才能得到较好的结果。与点对面接触相比,面对面接触中主动面和从属面的选取,对计算结果的影响并不是很大.但是,当错误的将网格粗糙的面定义为从属面时,此时也许会引起计算成本的急剧增加。定义接触对为了定义一个接
11、触对,必须指定一对接触面或者一个自接触的面,一个tact ormulation。每一个接触对可以定义不同的作用面性质。1。51Deiigonact etween o sepaate sufacWhen acotact pair cotaisosurface,te msr ad avesrfcs e notalowed t icldeany f te sae nodes and you st chose which surface wll be te slave and whh will be e masr.AS/aard定义接触默认采用的是有限滑移、点对面接触。如果定义的是小滑移,默认的也吃采
12、用点对面接触。1。2 用对称的主从接触对提高接触模拟精度对于点对面接触,主动面上的节点很容易enetate到从属面上去,此时,提高从属面上单元的网格划分精度,有助于减少这样的刺入,提高运行速度.才外,让两个面都是基于单元定义时,可以用symetrc mster-savemeod.T useh hod, defie two contatpar using h sae to sufaes, ut switch tholes of mt ad sae surfc rthe t contc pars。 Timethod cuses AAUS/tandardto treat ac surface asa matesurace and,tu, involves addial computaion expes beueotat seareusbondue wc for tesae contact pi. The ncred ccurayprovided by this mehodmust e cpared to the additioal coputationl ctAll of