简介：蠕变性能是评价沥青混合料的重要指标之一。利用三分点小梁弯曲试验对沥青混合料的蠕变性能进行研究,探讨加载水平对蠕变曲线的影响。通过对试验蠕变曲线的拟合,获取沥青混合料的粘弹性参数,利用有限元方法对沥青混合料小梁的弯曲蠕变试验进行数值模拟,得出不同温度及不同荷载条件下沥青混合料小梁蠕变规律,并与试验结果进行比较。研究表明,同一温度下,随着应力水平的增大,永久变形会随之增大,且稳定期应变发展速率也会增大;粘弹性数值分析结果与试验结果吻合良好,可以反映沥青混合料蠕变前2个阶段的变形特征。

简介：选用3种沥青混合料加热方法进行试验,并将其与即拌即用方法进行对比。结果表明,采用微波技术对沥青混合料进行加热,加热时间短,材料受热均匀,且加热后的混合料各项性能指标非常接近即拌即用水平,故采用微波技术替代烘箱对沥青混合料进行加热是可行的。

简介：针对目前混合式油罐测量系统（以下简称HTMS）标准密度误差普遍不够理想的现状，对HTMS标准密度初始精度及使用和维护HTMS过程中造成HTMS标准密度精度损失的原因进行了分析。认为做好仪表选型、提高安装施工质量、正确调试HTMS、正确使用和维护HTMS系统，是降低HTMS标准密度误差和提高HTMS标准密度精度的有效办法。

简介：以中山市沙古公路隆平中桥桥头处的软基处理为例，按照补充定额中所列明的工作内容为主线，介绍气泡混合轻质土在桥台处理中的应用，并进行相应的造价分析。

简介：Inordertostudycavitationcharacteristicsofa2-Dhydrofoil,themethodthatcombinesnonlinearcavitationmodelandmixed-iterationisusedtopredictandanalyzethecavitationperformanceofhydrofoils.ThecavitationelementsarenonlinearlydisposedbasedontheGreenformulaandperturbationpotentialpanelmethod.Atthesametime,themethodthatcombinescavityshapeforfixedcavitylength(CSCL)iterationandcavityshapeforfixedcavitationnumber(CSCN)iterationisusedtoworkoutthethicknessandlengthofhydrofoilcavitations.Throughanalysisofcalculationresults,itcanbeconcludedthatthejumpofpressureandvelocitypotentiallyexistbetweencavitationendareaandnon-cavitationsareaonsuctionsurfacewhencavitationoccursonhydrofoil.Incertainanglesofattack,thecavitationnumberhasanegativeimpactonthelengthofcavitations.Andunderthesameangleofattackandcavitationnumber,thebiggerthethicknessofthehydrofoil,theshorterthecavitationslength.

简介：Inthenormaloperationcondition,aconventionalsquare-rootcubatureKalmanfilter(SRCKF)givessufficientlygoodestimationresults.However,ifthemeasurementsarenotreliable,theSRCKFmaygiveinaccurateresultsanddivergesbytime.ThisstudyintroducesanadaptiveSRCKFalgorithmwiththefiltergaincorrectionforthecaseofmeasurementmalfunctions.Byproposingaswitchingcriterion,anoptimalfilterisselectedfromtheadaptiveandconventionalSRCKFaccordingtothemeasurementquality.Asubsystemsoftfaultdetectionalgorithmisbuiltwiththefilterresidual.Utilizingaclearsubsystemfaultcoefficient,thefaultysubsystemisisolatedasaresultofthesystemreconstruction.Inordertoimprovetheperformanceofthemulti-sensorsystem,ahybridfusionalgorithmispresentedbasedontheadaptiveSRCKF.Thestateanderrorcovariancematrixarealsopredictedbythepriorifusionestimates,andareupdatedbythepredictedandestimatedinformationofsubsystems.Theproposedalgorithmswereappliedtothevesseldynamicpositioningsystemsimulation.TheywerecomparedwithnormalSRCKFandlocalestimationweightedfusionalgorithm.ThesimulationresultsshowthatthepresentedadaptiveSRCKFimprovestherobustnessofsubsystemfiltering,andthehybridfusionalgorithmhasthebetterperformance.Thesimulationverifiestheeffectivenessoftheproposedalgorithms.