项目13货物加固技术任务2加固强度计算66课件

项目13货物加固技术

Project13GoodsFasteningTechniques

任务2加固强度计算FasteningStrengthCalculation王晓明WangXiaoming对称拉牵加固时，拉牵位置如下图所示O——拉牵绳在货物上的拴结点B——O点在车地板上的投影BC——O点所在纵向垂直平面至车辆边线的距离A——拉牵绳在车辆上的拴结点知识点一常用加固方法的强度计算KnowledgePointIStrengthCalculationforCommonFasteningMethodsThepullingpositionoffasteningthroughsymmetricaltractionisshownasbelow.O--knotofthepullingropeonthecargo（1）采用拉牵加固时，每根拉牵绳应承受的力ForcebearedbyeachpullingropewhenthecargoisfastenedbytractionB--projectionofpointOonthewagonfloorBC--distancefromthelongitudinalverticalplanewherepointOislocatedtotheedgeofthewagonA--knotofthepullingropeonthewagon防止纵向移动时：防止横向移动时：知识点一常用加固方法的强度计算preventinglateralmovement:当同一方向有n根拉牵绳时，每根应承受的拉力可按下式计算：preventinglongitudinalmovement:Whenthenumberofpullingropesinthesamedirectionisn,thepullingforcebornbyeachropecanbecalculatedaccordingtothefollowingformula:==防止纵向倾覆时：防止横向倾覆时：preventinglateraloverturningpreventinglongitudinaloverturning==（KN）（KN）（KN）（KN）KnowledgePointIStrengthCalculationforCommonFasteningMethods(longitudinalmovement)(lateralmovement)(longitudinaloverturning)(lateraloverturning)(lateral)(longitudinal)知识点一常用加固方法的强度计算上式中l纵——货物纵向倾覆点至拉牵绳在货物上拴结点所在横向垂直平面间的距离，mm

l横——货物横向倾覆点至拉牵绳在货物上拴结点所在纵向平面间的距离，mmIntheaboveequation,l(longitudinal)isthedistancebetweenthelongitudinaloverturningpointofthecargoandthetransverseverticalplanewheretheropeknotislocatedonthegoods,mml(lateral)isthedistancebetweenthelateraloverturningpointofthecargoandthelongitudinalplanewhereofropeknotislocatedonthegoods,mmKnowledgePointIStrengthCalculationforCommonFasteningMethods知识点一常用加固方法的强度计算每根拉牵绳应承受的力：S≥max{S纵移，S横移，S纵倾，S横倾}选用钢丝绳拉牵时，钢丝绳的破断拉力不得小于2S。选用镀锌铁线或盘条拉牵时，每根拉牵绳需要股数为：（股）式中P许——一股镀锌铁线或盘条的许用拉力，kNThepullingforcebornbyeachpullingrope:Thebreakingforceshallnotbelessthan2Swhenthewireisusedfortraction.Whenusinggalvanizedironwireorcoiledwirefortraction,thenumberofstrandsrequiredforeachpullingropeshallbeP(allowablepullingforce)isthepermissiblepullingforceofastrandofgalvanizedironwireorcoiledwire,kNKnowledgePointIStrengthCalculationforCommonFasteningMethods(longitudinalmovement)(lateralmovement)(longitudinaloverturning)(lateraloverturning)(allowablepullingforce)(strand)知识点一常用加固方法的强度计算注意事项Cautions使用镀锌铁线、钢丝绳捆绑加固货物，应依据所加固货物的拴结点情况，尽量考虑对称拉牵Whenusinggalvanizedironwireorsteelwireropetofastengoods,consideringtheknottingstatusofthegoodsfastened,symmetricaltractionshouldbechosenasfaraspossible.弹性变形较大，抗拉能力较小的镀锌铁线，不宜作为重量较大货物捆绑加固用，一般当计算所需的单道拉牵镀锌铁线在14股以上时，应改用钢丝绳加固Galvanizedironwirewithlargeelasticdeformationandsmalltensilecapacityshouldnotbeusedforthefasteningofrelativelyheavygoods.Generally,whenthenumberofsinglepullinggalvanizedironwirerequiredismorethan14,thegoodsshouldbefastenedbythewireropeinreplacement.KnowledgePointIStrengthCalculationforCommonFasteningMethods知识点一常用加固方法的强度计算注意事项Cautions多股镀锌铁线拉牵加固时，需用绞棍绞紧，绞棍应置于拉牵铁线的中部，绞紧适度，不得过紧过松。绞棍留用时须固定；不留用时须采取措施防止铁线回松Whenthemulti-strandedgalvanizedironwireisusedforfastening,itshouldbetightenedwithastrandedstick.Thestrandedstickshouldbeplacedinthemiddleofthepullingironwiretotightenthestrandappropriately,avoidingmakingittootightortooloose.Thestickshouldbefixedifitwillbeusedagain;whenitwillnotbeusedagain,measuresmustbetakentopreventthewirefrombecomingloose.拉牵绳与车底板的夹角一般应接近45°。若捆绑加固主要用于防止货物水平移动时，拉牵绳与车底板的夹角可小于45°；若主要用于防止货物倾覆，拉牵绳与车底板的夹角应适当大于45°Theanglebetweenthepullingropeandthewagonfloorshouldgenerallybecloseto45°.Ifthefasteningismainlyadoptedtopreventhorizontalmovement,theanglebetweenthepullingropeandthewagonfloorcanbelessthan45°;topreventgoodsoverturning,appropriatelygreaterthan45°,PointIStrengthcalculationforcommonfasteningmethods知识点一常用加固方法的强度计算注意事项Cautions多股小直径钢丝绳捆绑加固货物时，两端绳头用钢丝绳夹头正反扣紧固定后，应用铁质绞棍绞紧，在此种情况下，绞棍必须留用并予以固定Whenmultiple-strandedwireropeswithsmalldiameterareusedforfastening,afterthetwoendsoftheropearelockedandfixedwiththewireropechuck,theyshallbetightenedwithanironstrandedstick,inwhichcasethestickmustberetainedand