简介:Anintervaloptimizationmethodforthedynamicresponseofstructureswithintervalparametersispresented.Thematricesofstructureswithintervalparametersaregiven.Combiningtheintervalextensionwiththeperturbation,themethodforintervaldynamicresponseanalysisisderived.Theintervaloptimizationproblemistransformedintoacorrespondingdeterministicone.Becausethemeanvaluesandtheuncertaintiesoftheintervalparameterscanbeelecteddesignvariables,moreinformationoftheoptimizationresultscanbeobtainedbythepresentmethodthanthatobtainedbythedeterministicone.Thepresentmethodisimplementedforatrussstructure.Thenumericalresultsshowthatthemethodiseffective.
简介:Inthispaper,anewzigzagmethodforplatestructuresandageneticalgorithm(GA)ofdynamicsourceseedspacesaredevelopedandacombinationofthemisusedtodealwithlargescalebuilt-upstructuraloptimization.ThenewGAcombinedwiththezigzagmethodcanworkefficientlywhencopingwithlargescalestructuraloptimizationincludeddisplacementandstressconstraints.ExamplesshowthatthisGAisrobustandcanbeusedformanycomplexstructuraloptimizationproblems.
简介:在这篇论文,为设计优化的一个方法elasto塑料捆绑结构基于参量的变化原则(PVP)被建议。优化试图在许可的节点排水量的限制下面发现最小的重量/卷答案。Thedesign优化是有平衡限制(MPEC)的数学编程的明确的表达。在优化克服互补限制的数字困难,重复进程,包括二次的编程(QP)和更新的进程,被采用著名计算机生产厂商他优化方法。而且,elasto塑料的弄弯捆绑成员在设计优化被看作限制。combinational优化策略为排水量限制和弄弯的限制被建议,它包括上面提及的方法和一个最佳的标准。三个数字例子被举证明方法的有效性求婚了。
简介:Inthispaper,amathematicalmodelfortopologyoptimizationoftrussstructureswithconstraintsofdisplacementandsystemreliabilityundermultipleloadingcasesisconstructed.Inordertoavoidthedifficultyofcomputingthestructure’ssystemreliability,asolvingapproachispresentedinwhichthefailureprobabilityofsystemisdividedintothesumofallbars’failureprobabilitybymeansofreliabilitydistribution.Inaddition,bydrawingintothereliabilitysafetyfactorandthefundamen-talrelationshipinstructuralmechanics,allprobabilityconstraintsofdisplacementandstressareequiv-alentlydisplayedasconventionalformandlinearfunctionofthedesignvariables.Theoptimizationproblemwithmultipleconstraintsistreatedbythecompactconstrainttacticsandissolvedbytheim-provedsimplexmethod.Theexamplesshowthattheapproachproposedinthispaperisfeasibleandef-ficient.
简介:Phononicmaterialswithspecificband-gapcharacteristicsatdesiredfrequencyrangesareingreatdemandforvibrationandnoiseisolation,elasticwavefilters,andacousticdevices.Theattenuationcoefficientcurvedepictsboththefrequencyrangeofbandgapandtheattenuationofelasticwave,wherethefrequencyrangescorrespondingtothenone-zeroattenuationcoefficientsarebandgaps.Therefore,theband-gapcharacteristicscanbeachievedthroughmaximizingtheattenuationcoefficientatthecorrespondingfrequencyorwithinthecorrespondingfrequencyrange.Becausetheattenuationcoefficientcurveisnotsmoothinthefrequencydomain,thegradient-basedoptimizationmethodscannotbedirectlyusedinthedesignoptimizationofphononicband-gapmaterialstoachievethemaximumattenuationwithinthedesiredfrequencyrange.Toovercomethisdifficulty,theobjectiveofmaximizingtheattenuationcoefficientistransformedintomaximizingitsCosine,andinthisway,theobjectivefunctionissmoothedandbecomesdifferentiable.Basedonthisobjectivefunction,anovelgradient-basedoptimizationapproachisproposedtoopenthebandgapataprescribedfrequencyrangeandtofurthermaximizetheattenuationefficiencyoftheelasticwaveataspecificfrequencyorwithinaprescribedfrequencyrange.Numericalresultsdemonstratetheeffectivenessoftheproposedgradient-basedoptimizationmethodforenhancingthewaveattenuationproperties.
简介:一个代理人联合为技术和粒子群优化建模的代理人的基于的粒子群优化(SBPSO)算法被用于合成压力容器的基于可靠性的柔韧的设计(RBRD)。SBPSO的算法和效率通过数字例子被显示。为细丝创伤的一个模型有金属性的班机的合成压力容器然后被网分析学习,它的回答被使用有限元素方法分析(由软件ANSYS表现了)。为最大化性能因素的一个优化问题被在圆柱的部分,金属班机的厚度和dropoff区域尺寸选择螺旋状的厚度的弯屈的取向为设计变量提出。为合成的层和金属班机的力量限制被分别地使用Tsai-Wu失败标准和协定失败标准构造。方法建议了的数字例子表演能有效地解决RBRD问题,和建议模型的最佳的结果能满足某些可靠性要求并且有坚韧性到设计变量的变化。
简介:Thebandgap,animportantcharacteristicoftheperiodicstructure,isdispersionrelated,whichcanbedesignedbytailoringthelayoutofmaterialswithintheperiodicmicrostructures.Atypicalexampleofaperiodicstructureisphononiccrystals(PnCs),whicharetraditionallyfabricatedfromtwo-phasematerials.Herein,weinvestigatethetopologiesofperiodicthree-phasePnCs.Themicrostructuresofthethree-phasePnCsareoptimizedusingatwo-stagegeneticalgorithm,andthreecasestudiesareproposedtoobtainthefollowing:(1)themaximumrelativebandgapwidth,(2)themaximumabsolutebandgapwidth,and(3)themax-imumbandgapataspecifiedfrequency.Moreimportantly,thethree-phasematerialprovidessignificantadvantagescomparedtothetypicaltwo-phasematerials,suchasalow-frequencybandgap.Thisresearchisexpectedtocontributehighlytovibrationandnoiseisolation,elasticwavefilters,andacousticdevices.