【作者】 郭盛；

【导师】 郭耀杰；

【作者基本信息】 武汉大学 ， 结构工程， 2004， 硕士

【摘要】 冷弯薄壁型钢近几十年来在工程中得到广泛应用。冷弯薄壁型钢成型后截面上存在冷弯残余应力，它对冷弯薄壁型钢轴心受压构件的整体稳定性影响很大。由于冷弯薄壁型钢的加工过程复杂，对其进行理论分析难度很大，使得目前有关冷弯残余应力的研究成果极少且存在许多不足之处，以至于设计规范中至今还缺少计及它的影响的整体稳定性设计公式。 本文首先在理论上寻求突破，将冷弯加工过程分解成弯曲(加载)和回弹(卸载)两个过程分别加以分析：利用弹塑性理论求得弯曲过程中应力场的理论解；运用有限元分析软件ANSYS对回弹过程进行模拟计算，得出回弹应力场；最后将两个过程产生的应力场相叠加，得到更合理、更全面的冷弯残余应力分布，即除纵向残余应力外，还包括切向和径向残余应力；除弯曲段外，还有直边段的残余应力分布规律。 然后，根据得到的冷弯残余应力分布规律，编写能够描述这种残余应力的初应力文件，充分考虑冷弯残余应力和初弯曲、初偏心等初始缺陷的影响，运用有限元分析软件ANSYS对槽钢和卷边角钢截面形式的冷弯薄壁型钢轴心受压构件进行稳定分析，得到四种截面形式的λ-φ关系，确定了更能反映实际情况的λ-φ柱子曲线，并与现行规范进行了比较分析，发现不同截面形式和尺寸的λ-φ曲线相当接近；对长细比较大的构件，本文计算得到的稳定系数φ值与规范相当；随着长细比的减小，φ值略低于规范值。 最后，根据所得λ-φ关系拟合出实用的φ值计算公式。更多还原

【Abstract】 Coldformed thinwa1 steel membersaredely aPPlieed in the engineering in thelast several decades.The eold-forllledsidual stresses are remained in the Coldfonnedthin-wall steel members when they are formed，d it eauses a great Influenee to theoverail stability as the members are subjeeted to the axle eenter Pressure force.Themanufacture Proeess of eoldformed thinwa1 steel members 15 very comPlex，d it，5 toodiffieult to Proeeed to analyze in theoretieally.50 there are few researeh achievemenisabout the coldformed residual stresses Whieh have many faults.And thatleads to the lackof the design fonnula of the overail stability involving the influence of the eold一fonnedresidual stresses. In this Paper， theoretieal brealhrough 15 exPlored firstly，the eoldfonned Proeess ofthe members 15 divided inio0 stages:the being formed(or member’5 loading) stage andthe elastie restoration(or member，5 unloading)stage.The Stresses in the member for eachstage are derived resPeetively:based on the theory of elastiePlastie the stresses for thebeing formed stage are obtained，then using the ANSYSfinite element analysis softwareimitates the elastie restoration stage as to obtain the ealeulating values of the stresses forthe elastie restoration stage.The sus，aehieved by adding the05ges stresses，arejustthe eoldbended residual stresses Whieh are more reasonable and more comPletc:besidesthe longitudinal residual stresses，the tangential residual Stresses and the radial residualssses are gained too;ineluding the residual stresses of bent segment，the residualstresses of straight segment are obtained too. Then，the initial stresses files whieh ean deseribe residual stfCsses areitten basedon the distribution of residual stresses obtained above.Exhaustively eonsidering all initialimPerfeetion sueh as eoldbended residual stresses，initial一bending and initial-eecentrieity，and using the finite element analysis software ANSYS to analyze the stability of axleeenter Pressure members of eold一formed thin·wall ehannel steel and henuning angle steel，therelationshiPs for these four kinds of sections are obtained.ComParing the eurvewith the Code，it ean be found thateurves of differeni kinds of seetions and sizesare very close;the stability coefficientsin thisper are equal to these in Code whenmembers’ratios to slcndemess are large:but when the ratios of slendeme:5 are small，eoeffieienisin this PaPer are a little lower than those in Code. Ai last，ealeulation formula of p 15 gained by fittingrelationshiPs obtainedab0Ve.更多还原