简介：Athree-dimensionalrigidbodyontheshapeofaparallelepipedismodelledinordertorockonasideoravertexofthebase,inordertoevaluatetheseismicresponseofrigidblockslyingonahorizontalsupport.Thecenterofmassofthebodyisconsideredaseccentricwithrespecttoitsgeometriccenter.Asseismicinput,threeItalianrecordedaccelerograms,withdifferentspectralcontent,areused.Thestudyismainlyconductedtohighlightthedifferencesbetweentheseismicresponseof2Dand3Dmodelsofrigidblocks,withtheaimtounderstandif,insomecases,theuseofthe3Dmodelofrigidblockisrequiredtoobtainsaferresults.Infact,theoutcomesshowthatinsomerangesofthegeometricalandmechanicalparametersthatcharacterizetheexcitationandthebody,atwo-dimensionalmodel,whichisnotabletoconsiderthe3Drockingonavertex,canprovideunsaferesults.Inparticular,itisfoundthattheoverturningprocessofthethree-dimensionalblockcanoccurunderexcitationswhicharelowerthanthosewhichoverturnacorrespondingtwo-dimensionalblock.

简介：一个方法被建议在设计实践为使用估计地震soil-structure-interaction(SSI)效果。它对受到的2D结构适用垂直地事件砍波浪由同质的一半空间支持了。自从它保留简洁，方法是吸引人的光谱途径，克服一些困难和存在古典技术的不确，然而，它考虑身体上一致的刺激。简洁的这水平通过回答被完成能被用于免费地的5%阻尼反应系列产出设计的系列修正因素光谱考虑散布运动的纵标由相互作用效果介绍了。修正因素在结构的相对排水量和免费地的运动之间的转移功能(TF)是代表性的，它以它的最大的振幅被描述并且联系了频率。由练习工程师计算修正因素的表情被建议用实际结构的576盒子代表在参量的研究之上基于。方法在跨越大量普通基本颤动时期的10种情况中被测试。

简介：Inthispaper,weproposeanearlyanalyticexponentialtimedifference(NETD)methodforsolvingthe2Dacousticandelasticwaveequations.Inthismethod,weusethenearlyanalyticdiscreteoperatortoapproximatethehigh-orderspatialdifferentialoperatorsandtransformtheseismicwaveequationsintosemi-discreteordinarydifferentialequations(ODEs).Then,theconvertedODEsystemissolvedbytheexponentialtimedifference(ETD)method.WeinvestigatethepropertiesofNETDindetail,includingthestabilityconditionfor1-Dand2-Dcases,thetheoreticalandrelativeerrors,thenumericaldispersionrelationforthe2-Dacousticcase,andthecomputationalefficiency.Inordertofurthervalidatethemethod,weapplyittosimulatingacoustic/elasticwavepropagationinmultilayermodelswhichhavestrongcontrastsandcomplexheterogeneousmedia,e.g.,theSEGmodelandtheMarmousimodel.Fromourtheoreticalanalysesandnumericalresults,theNETDcansuppressnumericaldispersioneffectivelybyusingthedisplacementandgradienttoapproximatethehigh-orderspatialderivatives.Inaddition,becauseNETDisbasedonthestructureoftheLiegroupmethodwhichpreservesthequantitativepropertiesofdifferentialequations,itcanachievemoreaccurateresultsthantheclassicalmethods.