岩土工程高性能数值仿真及其应用T,44

岩土工程高性能数值仿真及其应用王睿2016年12月提纲高性能数值计算基本概念简介粒状非连续介质细观并行数值仿真及其应用高性能有限元数值仿真平台开发与初步应用高性能数值计算基本概念简介岩土工程对于高性能数值仿真的需求岩土工程：规模大、结构复杂、多尺度岩土材料：力学行为的细观分析高性能数值计算基本概念简介串行并行高性能数值计算基本概念简介共享内存分布式内存高性能数值计算基本概念简介共享内存分布式内存优劣势可移植性高任务分配成本低并行度低内存管理困难优劣势并行度高各CPU独立控制内存成本低可移植性较差高性能数值计算基本概念简介共享内存分布式内存混合式高性能数值计算基本概念简介目前我国超级计算机常年居于榜首但是高性能数值计算的应用还任重道远提纲高性能数值计算基本概念简介粒状非连续介质细观并行数值仿真及其应用高性能有限元数值仿真平台开发与初步应用粒状非连续介质细观并行数值仿真及其应用离散元（DEM,Cundall,1971）:计算颗粒运动与相互作用的数值方法理论基础:牛顿运动定律，动量守恒Cundall,PeterA.,andOttoDLStrack."Adiscretenumericalmodelforgranularassemblies."

Geotechnique

29.1(1979):47-65.FnFnV1V2F=Ma粒状状非连连续续介介质质细细观观并并行行数数值值仿仿真真及及其其应用用离散散元元（DEM,Cundall,1971）:计算算颗颗粒粒运运动动与与相相互互作作用用的的数数值值方方法法理论论基基础础:牛顿顿运运动动定定律律，，动动量量守守恒恒难点点：：接接触触计计算算刚度度、、阻阻尼尼线性性、、非非线线性性粘性性………法向向切向向离散散元元典典型型计计算算流流程程粒状非连续介质细细观并行数值值仿真及其应用输入接触判断接触力计算牛顿第二定律速度与位移输出下一时步计算时域tstart-tend离散元采用显显示积分算法法，可并行性性非常高粒状非连续介质细细观并行数值值仿真及其应用CPU1CPU214PPDEM(PolyarcParallel-processingDiscreteElementModeling,粒状状非非连连续续介介质质细细观观并并行行数数值值仿仿真真及及其其应应用用15PPDEM(PolyarcP粒状状非非连连续续介介质质细细观观并并行行数数值值仿仿真真及及其其应应用用OpenMP共享享内界面友好VB-GUI易于开发Fortran任意二维凸形下面以砂土液化大变形细观机理研究为例介绍其应用16Undrainedcyclicphysicaltestsonsand:Post-liquefactionshearstrain（Kutteretal.,1994）（Zhangetal.,1997）粒状状非非连连续续介介质质细细观观并并行行数数值值仿仿真真及及其其应用用17Post-liquefactionshearstrainGeneratedatliquefactionstate,definedasγ0γ0（Zhangetal.,1997）粒状非连续介介质细观并行行数值仿真及及其应用18Post-liquefactionshearstrainγ0increaseswiththenumberofloadingcycles,whilethestresspathandstress-strainrelationshipduringnon-liquefactionstateremainsunchanged（Zhangetal.,1997）粒状非连续介介质细观并行行数值仿真及及其应用19Post-liquefactionshearstrainAccumulationofγ0slowsdownandeventuallysaturates（Zhangetal.,1997）粒状非连续介介质细观并行行数值仿真及及其应用20PhysicaltestDEM粒状非连续介介质细观并行行数值仿真及及其应用21TypicalDEMResultCapturesthecyclicbehaviorobservedinlabtestsReproducesandconfirmsthegenerationandeventualsaturationofpost-liquefactionshearstrain粒状非连续续介质细观观并行数值值仿真及其其应用22InfluenceofqmaxandpinCannotaccountforthegenerationofshearstrainγ0Noinfluenceonsaturateqmax=35kPapin=100kPaqmax=25kPapin=80kPa粒状非连续续介质细观观并行数值值仿真及其其应用23InfluenceofVoidRatioeealonedoesnotdeterminesaturatedshearstrainγ0sLoadinghistoryalsoplaysaroleThereisn’tauniquerelationshipbetweeneandγ0s粒状非连续续介质细观观并行数值值仿真及其其应用24ObservationsonCoordinationNumber(averagenumberofcontactsperparticle)Initial:about3Entersliquefactionstate:2.2LiquefactionstateThecontacts(orlackof)andinternalarrangementoftheparticlesplaysanimportantroleinliquefaction粒状非连续续介质细观观并行数值值仿真及其其应用25ObservationsonCoordinationNumberThecoordinationnumberitselfcannotproperlyreflecttheincreaseinγ0Minimumcoordinationnumberineachpost-liquefactioncycle粒状非连续续介质细观观并行数值值仿真及其其应用26MicromechanicalstructureIn2D,3contactsareneededforaparticletobearloadstablyCdropsbelowacertainvalue(2.2),thesamplelosesitsabilitytobearloadandliquefiesCannotcarryloadCancarryload粒状非连续续介质细观观并行数值值仿真及其其应用27Newconcept:NeighboringParticleDistance(NPD)Definition:TheNPDofanindividualparticleisthemeansurface-to-surfacedistancebetweenthisparticleanditsnclosestneighborparticles,withnbeingthenumberofcontactsneededtosupportastableload-bearingstructure.粒状非连续续介质细观观并行数值值仿真及其其应用N:3in2DD3D2D1=028Newfabricmeasure:MeanNeighboringParticleDistance(MNPD)ThemeanvalueofNPDoverallparticlesisafabriccharacteristicorinternalvariableoftheassemblythatcanbecalledMNPDanddefinedanalyticallyby粒状非连连续介质质细观并并行数值值仿真及及其应用N:3in2DD3D2D1=029Newfabricmeasure:MeanNeighboringParticleDistance(MNPD)Notion:toreflecttheamountofrearrangementneededtoreachaload-bearingstateThesmallerMNPDis,themorestablethegranularassemblyis粒状非非连续续介质质细观观并行行数值值仿真真及其其应用N:3in2DD3D2D1=030MeanNeighboringParticleDistance(MNPD)PeaksduringliquefactionLiquefactionstateNon-LiquefactionstateMNPD粒状非连续续介质细观观并行数值值仿真及其其应用31MeanNeighboringParticleDistance(MNPD)TheMNPDmaxineachpost-liquefactioncyclefollowsasimilartrendofincreaseandsaturationasγ0StrongcorrelationbetweenMNPDmaxandγ0MaximumMNPDineachpost-liquefactioncycleMNPDmaxMNPDmax粒状非连连续介质质细观并并行数值值仿真及及其应用MeanNeighboringParticleDistance(MNPD)UniquecorrelationbetweenMNPDmaxandγ0ineachpost-liquefactioncyclefortestsonthesamematerialregardlessofspecimeninitialstates,loadingconditions,andloadinghistories.Datafrom17differenttests粒状非连连续介质质细观并并行数值值仿真及及其应用33MeanNeighboringParticleDistance(MNPD)UniquecorrelationbetweensaturatedneighboringparticledistanceMNPDmaxsandshearstrainγ0sDefinitiveconnectionbetweenγ0andMNPD!粒状非连连续介质质细观并并行数值值仿真及及其应用34粒状非连续介介质细观观并行数数值仿真真及其应用小结利用并行行离散元元数值仿仿真，建建立了砂砂土液化化大变形形宏观现现象与新新提出的的理论可可测的组组构度量量MNPD之间的确确定性关关系非连续介介质数值值仿真能能够有效效地用于于观测目目前实验验技术尚尚无法观观测的细细观量，，为进一一步揭示示岩土材材料的力力学行为为提供可可能目前我们们的研究究还以二二维单相相为主，，下一步步需要重重点进行行三维化化，并且且引入液液相开展展耦合计计算，发发展“岩岩土材料料数值试试验机””提纲高性能数数值计算算基本概概念简介介粒状非连连续介质质细观并行数数值仿真真及其应应用高性能有有限元数数值仿真真平台开开发与初初步应用用高性能有限元数数值仿真真平台开开发与初初步应用GEOS高性能有有限元数数值仿真真平台LLNL开发（Settgast等）超高并行行度分布布式内存存并行算算法多物理场场耦合计计算具有较强强的扩展展性高性能有限元数数值仿真真平台开开发与初初步应用GEOS高性能有有限元数数值仿真真平台三维弹性性波传播播算例Linearelasticity8-nodehexelement,reducedintegrationExplicittimeintegration~0.35MelementsperpartitionUpto3.375billionelements>10billionDOF1.5kmx1.5kmx1.5kmwith1mresolutionFuandSettgast高性能有限元数数值仿真真平台开开发与初初步应用GEOS高性能能有限限元数数值仿仿真平平台100亿自由由度！！高性能能有限元元数值值仿真真平台台开发发与初初步应用GEOS高性能能有限限元数数值仿仿真平平台10%overheadPartitioningthreshold:max.26neighborpartitionsFuandSettgast高性能能有限限元数数值仿仿真平平台开开发与与初步步应用用针对岩岩土工工程开开发功功能任务量量自动动分配配直接读读取A