简介:Wefurtherconsidertheeffectofrodstrengthbyemployingthecompressiblepenetrationmodeltostudytheeffectofcompressibilityonhypervelocitypenetration.Meanwhile,wedefinedifferentinstancesofpenetrationefficiencyinvariousmodifiedmodelsandcomparethesepenetrationefficienciestoidentifytheeffectsofdifferentfactorsinthecompressiblemodel.Tosystematicallydiscusstheeffectofcompressibilityindifferentmetallicrod-targetcombinations,weconstructthreecases,i.e.,thepenetrationsbythemorecompressiblerodintothelesscompressibletarget,rodintotheanalogouslycompressibletarget,andthelesscompressiblerodintothemorecompressibletarget.Theeffectsofvolumetricstrain,internalenergy,andstrengthonthepenetrationefficiencyareanalyzedsimultaneously.Itindicatesthatthecompressibilityoftherodandtargetincreasesthepressureattherod/targetinterface.Themorecompressiblerod/targethaslargervolumetricstrainandhigherinternalenergy.Boththelargervolumetricstrainandhigherstrengthenhancethepenetrationoranti-penetrationability.Ontheotherhand,thehigherinternalenergyweakensthepenetrationoranti-penetrationability.Thetwotrendsconflict,butthevolumetricstraindominatesinthevariationofthepenetrationefficiency,whichwouldnotapproachthehydrodynamiclimitiftherodandtargetarenotanalogouslycompressible.However,ifthecompressibilityoftherodandtargetisanalogous,ithaslittleeffectonthepenetrationefficiency.
简介:Thegoverningequationsofsurface-deformationinfully-penetratedGTAWweldpoolarederived.ThesolutionschemeoftheLagrangemultiplier,whichmakesthetopsurface-deformationequationbecoupledwiththatforthebottom-surfaceofasingleweldpool,isgivenout.Throughnumericalanalysisofweldpoolsurface-deformationinGTAW,itisfoundthatthereisclearcorrelationbetweenthepenetrationextentandtheLagrangemultiplier,inadditiontotherelationshipbetweenthepenetrationextentandthemaximumdepressionandhumpaswellasthedepressedvolumeofthetopsurfaceofweldpool.Itlaysgoodfoundationfortop-sidesensingbasedweldpenetrationcontrol.
简介:Thispaperexaminestheimpactofforeignpenetrationonthepublicfirminamixedoligopolisticmarket.Throughtheestablishmentofamixeddoubleoligopolymarket,thispaperanalyzeshowtheshareofforeigninvestmentaffectstheenvironmentalpolicy,thepollutantemission,andthesocialwelfareundertheconditionofthestatetax.Theresultsshowthat:first,theintroductionofforeigninvestmenthassomecrowding-outeffectsonthesociallevelofoutput.Second,theentryofforeigninvestmentincreasestheprofitofthepublicfirmbyalargemargin,andthemaximumprofitoftheprivatefirmhasbeenreduced.Third,theincreaseofforeigninvestmentinpublicfirmdoesnotnecessarilyimprovetheenvironment.
简介:Inlightofdiwatheory,thccarth’scrustcvolvcdinproccssofgcosynclinc-platform-diwaandspi-ra11ydcvc1opcd’Thcmincralsformcdindiwastagearcundoubtlymorccomp1icatcdtbanthoscformcdintbctwocarlicrstagcsandinan1orcadvanccdtypc.Bccauscofthcnonhomogcncityal1dthelimitationinthedisttibutionofmcta1logcnicsubstanccsi
简介:增加焊接穿入的A-TIG的机制被使用我们为不锈钢开发了的激活的流动学习。流动和焊接水池的温度领域上的流动的效果被PHOENICS软件模仿。它证明没有流动,液体流动将沿着焊接水池然后在下面的表面是外面的,导致flatter焊接水池形状。与流动,氧,从否定价值把表面紧张毕业生的温度依赖改变到积极价值,能在焊接穿入上引起重要变化。液体流动将沿着向中心然后在下面的焊接水池的表面是里面的。这个液体流动模式高效地把热转移到焊接根并且生产相对深、狭窄的焊接。这个变化是穿入增加的主要原因。而且,弧建设能引起焊接宽度变得更狭窄并且变得更深的穿入,但是这不是穿入增加的主要原因。焊接水池表面和弧侧面的液体流动上的流动的效果在焊接的常规TIG并且在由使用高速度的摄像机焊接的A-TIG被观察。液体流动行为被微集中的X光检查传播录像观察系统在实时规模设想。结果显示与更狭窄的宽度和更深的穿入导致焊接祷告的更强壮的里面的液体流动模式能显然在焊接的A-TIG的情况中被识别。流动能在焊接水池改变液体流动的方向。它与模拟结果有一个好协议。
简介:Thespudcanfoundationhasbeenwidelyusedinoffshoreengineeringforjack-uprigs.However,'punchthrough'failureoftenoccurswhereastrongersoillayeroverlaysasoftersoillayer.Inthisstudy,spudcanpenetrationintodoublelayeredsoilsisinvestigatednumerically.Thesoilprofileissetupasastrongersoillayeroverlayingasoftersoillayer,withthesoilstrengthratio(bottomsoilstrength/topsoilstrength)variedfrom0.1to1.0(1meansuniformsoil).Thebearingbehaviourisdiscussedandthebearingcapacityfactorsaregivenforvariouscasesinvolvingdifferentlayerthicknessesanddifferentstrengthratiosofthetwoclaylayers.Thedevelopmentoftheplasticzonesandtheeffectofsoilselfweightonthebearingcapacityarealsodiscussed.Fromthisstudy,itisfoundthat,whenaspudcanisdistantfromthesoillayerboundary,thespudcancanbeanalysedwithsinglesoillayerdata.However,whenaspudcanbecomesclosertothesoilboundarylayer,theinfluenceofthelowersoftsoillayerissignificant,andthebearingcapacityofthespudcandecreases.Thecriticaldistanceisanindicationoftheoccurrenceof'punchthrough'failure.Thecriticaldistancebetweenthespudcanandthelayerboundaryislargerforaroughspudcanthantheoneforasmoothone,andthecriticaldistancedecreaseswithincreasingsoilstrengthratio.Thedepthofcavityformedduringinitialspudcanpenetrationdependsonthetoplayersoilstrength,soilstrengthratioandunitsoilself-weight,andthecavityaffectsthespudcanbearingbehaviouraswell.
简介:为了开发一个双人脚踏车弹头,那能有效地破坏具体目标,这篇论文借助于实验与不同的锥角度和班机材料探索塑造的费用的穿入表演进具体目标。穿入过程和由塑造的费用和动能射弹的具体目标的破坏机制被分析并且比较。试验性的结果建议运动精力充沛的射弹和塑造的充电能够破坏损坏的具体目标,而是大小是不同的。与动能射弹相比,塑造的费用有穿入的更多的重要效果进目标,并且引起很大的spalling区域。因此,塑造的费用对双人脚踏车弹头的第一阶段的充电相当合适。当洞直径变得更大时,随塑造的费用班机锥角度的增加,穿入的深度逐渐地减少,这也被发现。有铜班机的穿入深度比铝班机大,但是洞直径相对更小,并且有钢班机的塑造的起诉在上述二诉讼之间。有100°的一个锥角度的塑造的费用能形成喷气射弹费用(JPC)。与JPC,有具体目标上的最佳深度和直径的一个洞能被形成,它保证秒阶段弹头顺利渗透进洞并且在最佳深度爆炸在具体目标完成破坏的需要的水平。
简介:杰克起来,单位广泛地在在全世界钻工程正在起一个成功的作用,并且他们的安全和效率在研究和工程实践拿越来越多的吸引力。spudcan穿入深度的精确预言在决定杰克起来联合起来是否是可行的在这个地点操作是相当有帮助的。太大的穿入深度的预言可以在随后的抽取过程由于潜在的困难导致犹豫或甚至一个地点的拒绝;一样在操作期间由于可能的不稳定性的问题太小的深度预言是真的。然而,在预兆的结果之间的偏差和最后的地数据通常存在,特别当strong-over-soft土壤在阶层被包括时。最终的决定在很大程度上有时取决于实际经验,不是指南给的预兆的结果。它是有点危险的,但是没有选择。因此,特别在有strong-over-soft土壤侧面的阶层,为spudcan穿入深度的一个可行预兆的方法着急地被需要由杰克起来工业。鉴于这,预言spudcan穿入的方法上的全面调查被执行。为不同土壤侧面的类型,为spudcan穿入深度的预兆的方法被建议,并且相应实验也被进行验证这些方法。另外,验证建议方法的可行性推进,在华南海遇到的一个实际工程盒子是也介绍了,并且相应数字、试验性的结果也被介绍并且讨论。
简介:ThenormalhypervelocityimpactofanAl-thinplatebyanAl-spherewasnumericallysimulatedbyusingtheadaptivesmoothedparticlehydrodynamics(ASPH)method.Inthismethod,theisotropicsmoothingalgorithmofstandardSPHisreplacedwithanisotropicsmoothinginvolvingellipsoidalkernelswhoseaxesevolveautomaticallytofollowthemeanparticlespacingasitvariesintime,space,anddirectionaroundeachparticle.UsingtheASPH,theanisotropicvolumechangesunderstrongshockconditionarecapturedmoreaccuratelyandclearly.ThesophisticatedfeaturesofmeshlessandLagrangiannatureinherentintheSPHmethodarekeptfortreatinglargedeformations,largeinhomogeneitiesandtracingfreesurfacesintheextremelytransientimpactprocess.Atwo-dimensionalASPHprogramiscodedwithC++.Thedevelopedhydrocodeisexaminedforexampleproblemsofhypervelocityimpactsofsolidmaterials.Theresultsobtainedfromthenumericalsimulationarecomparedwithavailableexperimentalones.Goodagreementisobserved.
简介:DearSir,IamDrKatrinaA.Mears,fromtheDepartmentofOphthalmologyandVisualSciences,UniversityofIowaCarverCollegeofMedicine,200HawkinsDrive,IowaCity,Iowa,USA.Iwishtopresentacaseofendophthalmitissecondarytoglobepenetrationfromahydrogelscleralbucklewhich,tothebestofourknowledge,isthefirstreportedcase
简介:Keyholeplasmaarcweldingexperimentsareconductedtomeasuretheweldgeometryandpenetrationatdifferentmomentsduringtheinitialphasefromignitingarctoquasi-steadystate.Indirectinformationonkeyholeformationandevolutioninplasmaarcweldingcanbeextractedbasedontheweldmacrophotographatcrosssection.Ithaslaidfoundationtoverifythemathematicalmodelsofkeyholeplasmaarcwelding.
简介:Athermalconductionmodelisappliedtospeedupthenumericalanalysisofthetemperaturedistributionandtheweldpoolgeometryoffullpenetrationingastungstenarc(GTA)welding.Withconsideringbothtopandbottomfreesurfacedeformationoffull-penetratedweldpool,three-dimensionalweldpoolwithmeltingfrontandsolidificationfrontispredicted.Weldingexperimentsareconductedtomeasurethemeltingfrontcurvesatthetopsurfaceandthelongitudinalsectionoftheweld.Itshowsthatthepredictedandmeasuredresultsareingoodagreement.
简介:Theobliquepenetrationperformanceoflightweighthybrid-coredsandwichplatesareinvestigatednumerically.Tocomposethehybrid-core,ceramicprismsareinsertedintopyramidalmetallatticetrussesandfixedusingepoxyresin.Three-dimensionalfiniteelementsimulationsarecarriedoutforthehybridcoredsandwichimpactedat15°,30°,45°,and60°obliquitybyahemisphericalprojectile.Theballisticlimit,theenergyabsorbedbytheconstitutingelements,andthecriticalobliqueanglearequantified.Thephysicalmechanismsunderlyingthefailureandtheinfluenceoffundamentalsystemparametersareexplored.Theangleofobliquityisfoundtohavesignificantinfluenceontheballistictrajectoryanderosionoftheprojectile,thusitisimportantfortheimpactresponseandpenetrationresistanceofthesandwich.Forobliqueanglesequaltoorlargerthan45°,theprojectilemovesmainlyhorizontallyandcannoteffectivelypenetrateacrossthesandwich.