简介:Itisveryimportanttomeasurelocaldeformationsforanin-depthunderstandingofmechanicalpropertiesandfracturemechanismofstructuralandfunctionalmaterials.Inthispaper,differenttypesofmodelgridfabricationmethodsandmanytypesofelectronMoiremethodsusinganelectronbeamdrawingsystem,ascanningelectronmicroscopeorafocusionbeamarereported,togetherwiththeirapplicationsinthemeasurementofdeformationsoccurringinvariousengineeringsandmaterialsscienceresearch.
简介:装载的风是为控制大跨度的房顶结构的设计的最重要的负担之一。相等的静态的风负担,能通常瞄准决定特定的回答,被结构的设计者广泛地使用。为对多反应适用的相等的静态的风负担的一个方法在这份报纸被建议。相应于特别山峰回答的一个修改loadresponse-关联(纵向冗余码校验)方法被介绍,并且类似算法实现了因为组反应被描述。算法的主要想法是二回答能被放进一个组如果一回答的价值接近另外的反应的,当结构受到瞄准另外的反应的相等的静态的风负担时。基于修改纵向冗余码校验,组织反应方法被提出到装载的构造等价物静电干扰风。这种技术能同时为一些组织回答复制山峰回答。验证它的计算精确性,方法被用于实际大跨度的房顶结构。计算结果看那在一样的组的回答的类似什么时候高,有高精确性的相等的静态的风负担和相等的静电干扰的合理大小弯屈分发能被完成。
简介:射击peening是由在金属性的材料的表面附近产生压缩剩余应力增加疲劳生活和抵抗到腐蚀疲劳的一个广泛地使用的表面处理方法,裂开,等等。压缩剩余应力和凹部侧面是重要因素评估射击peening过程的有效性。在这份报纸,最大的压缩剩余应力和凹部的最大的深度上的无尺寸的参数的影响被调查。第一,处理影响最大的压缩剩余压力和凹部的最大的深度的参数的无尺寸的关系被维的分析方法推出。第二,无尺寸的变量上的每个无尺寸的参数的影响被有限元素方法调查。而且,相关实验公式基于模拟结果为每个无尺寸的参数被给。最后,比较被做,好同意在模拟结果和实验公式之间被发现,它证明一条有用途径为分析每个单个参数的影响在这份报纸被提供。
简介:Asimplifiedmultisupportresponsespectrummethodispresented.Thestructuralresponseisasumoftwocomponentsofastructurewithafirstnaturalperiodlessthan2s.Thefirstcomponentisthepseudostaticresponsecausedbytheinconsistentmotionsofthestructuralsupports,andthesecondisthestructuraldynamicresponsetogroundmotionaccelerations.Thismethodisformallyconsistentwiththeclassicalresponsespectrummethod,andtheeffectsofmultisupportexcitationareconsideredforanymodalresponsespectrumormodalsuperposition.Iftheseismicinputsateachsupportarethesame,thesupportdisplacementscausedbythepseudostaticresponsebecomerigidbodydisplacements.Theresponsespectruminthecaseofmultisupportexcitationsthenreducestothatforuniformexcitations.Inotherwords,thismultisupportresponsespectrummethodisamodificationandextensionoftheexistingresponsespectrummethodunderuniformexcitation.Moreover,mostofthecoherencycoefficientsinthisformulationaresimplifiedbyapproximatingthegroundmotionexcitationaswhitenoise.Theresultsindicatethatthissimplificationcanreducethecalculationtimewhilemaintainingaccuracy.Furthermore,theinternalforcesobtainedbythemultisupportresponsespectrummethodarecomparedwiththoseproducedbythetraditionalresponsespectrummethodintwocasestudiesofexistinglong-spanstructures.Becausetheeffectsofinconsistentsupportdisplacementsarenotconsideredinthetraditionalresponsespectrummethod,thevaluesofinternalforcesnearthesupportsareunderestimated.Theseregionsareimportantpotentialfailurepointsanddeservespecialattentionintheseismicdesignofreticulatedstructures.
简介:Thetriple-to-doublecoincidenceratio(TDCR)methodofliquidscintillationcount-ingisanabsolutemeasurementmethodofradioactivity.TheformulationoftheTDCRmethodandtheestablishedTDCRliquidscintillationcounterarepresentedinthispaper.TheNISTstandardreferencematerial(SRM)oftritiumwaterwasmeasuredtoverifytheperformanceoftheTDCRliquidscintillationcounter.
简介:Inthiswork,anovelmethodforsculpturedsurfacesubdivisiontoimprovethemachinery'sabilityandefficiencyin5-axisCNCmachiningcomplexsurfaceisintroduced.Themethodsubdividesautomaticallyamonolithicconvexorconcaveorsimultaneouslycomplexsculpturedsurfaceintoanumberofsurfacepatchesandachievesthegoalofsimilarnormaldirectionsandsmalldifferencebetweenthecurvaturesineverypatchbyusingweightfuzzyclusteralgorithmwhichtakesthecurvaturesandnormalvectorsofthesculpturedsurfaceintoaccountsimultaneously.TheinclinationanglevariationbetweeneverytwoCutterContactPoints(CCPoints)isdecreasedineverypatchtoavoidlarge-anglerotationoftooltosavemachiningtimewhenaflat-endmillisused.Thisworkcontributestoautomating5-axisCNCtoolpathgenerationforsculpturedpartmachiningandformingafoundationforfurtherresearch.
简介:目的:探讨64层螺旋CTA技术在肝癌介入治疗中的应用价值。方法:对55例肝癌患者在肝动脉化疗栓塞(TACE)术前行肝脏动脉期和静脉期的增强扫描,采用三维VR、MIP、MPR技术重建血管三维图像,并与介入治疗术中DSA图像做对比研究。结果:本组55例患者,对肝动脉2级血管的显示率差异无统计学意义;对肝动脉3级血管的显示率差异有统计学意义;CTA能够显示腹腔动脉及其主要分支的三维结构,观察与腹主动脉夹角较DSA更方便;CTA发现肝动脉变异13例(23.6%),与DSA完全符合。结论:64层螺旋CT三维血管成像技术可以很好显示肝癌供血血管的走行、分布、变异情况,提高TACE的准确性和成功率,对肝癌介入治疗有着重要价值。