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弹性阶段以提高低匹配接头弯曲承载能力为目标,基于有限单元法针对X形坡口低匹配对接接头三点弯曲形状设计,从材料力学方法角度出发,考察了双侧余高对称时低匹配对接接头的焊缝余高、盖面焊道宽度、焊趾过渡圆弧半径等形状参数对三个危险区弯曲应力集中系数的影响.结果表明,对母材与焊缝交界处突变区与焊缝底部中心区的影响规律为焊缝余高影响最大,盖面焊道宽度影响次之,焊趾圆弧半径影响最小;对焊趾部位影响规律为盖面焊道宽度的影响较大,焊趾圆弧半径和焊缝余高影响均较小.选择合适的形状参数可以提高低匹配接头弯曲承载能力. 相似文献
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弹性状态以低匹配接头能够达到与母材“弯曲等承载能力”(EBLCC)为目标,对低匹配对接接头焊缝几何形状临界条件进行了理论分析,推导了低匹配接头满足弯曲等承载条件的最低余高以及最小熔宽,并给出了弹性状态低匹配弯曲等承载接头设计准则.分析了圆弧替代抛物线曲线的可行性,给出了适用于工程应用方便的三圆相切低匹配弯曲等承载接头设计方法,并进行了弯曲试验验证.结果表明,设计的三圆相切低匹配弯曲等承载接头能够达到与母材弯曲承载能力,满足弯曲等承载要求.文中给出的设计准则与设计方法可使低匹配接头按照母材的弯曲承载能力进行设计,为弹性状态低匹配接头弯曲承载能力设计提供重要的理论依据. 相似文献
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根据对接接头的应力分布特点,提出了低匹配接头焊缝与母材具有相等静载承载能力的条件,即焊根处应力集中因子与接头匹配比(焊缝金属与母材的屈服强度的比值)相等。通过有限元计算及其结果的回归分析,建立了对接接头几何参数与焊根处应力集中因子经验方程。针对高强钢焊接结构的应用,以焊缝与母材静载等强承载为原则,进行了低匹配对接接头的几何形状设计。结果表明,该几何形状设计不仅可在较大范围内选择匹配比而不必降低应用载荷,而且接头断裂模式由局部屈服断裂向整个接头的全面屈服断裂转变,该接头设计对于高强钢低匹配接头的应用具有重要意义。 相似文献
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基于有限单元法针对含中心裂纹的低匹配对接接头形状设计,以最大限度提高接头的抗断能力为目标,从断裂力学角度出发,考察了含中心裂纹的低匹配对接接头的焊缝余高高度、盖面焊道宽度、焊趾过渡圆弧半径等形状参数对其形状因子的影响.结果表明,焊缝余高高度对含中心裂纹的低匹配对接接头形状因子影响最为显著,盖面焊道宽度的影响次之,焊趾过渡圆弧半径的影响最小.选择合适的形状参数可以提高含中心裂纹低匹配对接接头的抗断能力. 相似文献
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EffectsofstrengthmatchingandcrackdepthonthefractureparametersforweldedjointsTangWeiandShiYaowu(Xi'anJiaotongUniversity)Abstra... 相似文献
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目的分析转向架用SMA490BW钢对接接头的应力集中系数,提高转向架焊接接头的超高周疲劳性能,保障高速列车的安全可靠运行。方法对转向架用SMA490BW钢对接接头的超高周疲劳试样进行有限元建模,应用有限元软件ABAQUS计算不同焊趾过渡圆弧半径、焊趾倾角下接头的应力集中系数,并通过Origin软件分析建立应力集中系数(Kt)与焊趾过渡圆弧半径(r)、焊趾倾角(θ)的关系。结果当r=0.2 mm,θ分别为10°,20°,30°,40°,50°,60°时,Kt分别为1.391,1.747,1.976,2.263,2.425,2.525;当θ=30°,r分别为0.2,0.5,1,1.5,2,2.5,3,4 mm时,Kt分别为1.976,1.763,1.535,1.419,1.345,1.306,1.257,1.201。结论应力集中在对接接头焊趾处较大,r和θ对Kt有显著影响。r相同时,Kt随θ的增大而增大;θ相同时,Kt随r的增大而减小。应力集中系数关系方程对于焊趾处应力集中的改善以及转向架对接接头的超声疲劳试样设计具有指导意义。 相似文献
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激光焊接I-core三明治板常用的刚度设计公式,没有考虑接头几何参数的影响,在实际应用中其准确性受到影响. 通过外伸三点弯曲试验,对六种接头几何参数的I-core全钢三明治板的弯曲刚度和剪切刚度进行测量,并结合有限元计算,分析了接头几何参数对弯曲刚度和剪切刚度的影响. 结果表明,增加焊缝宽度可显著提高弯曲刚度和剪切刚度,而焊缝宽度大于60%芯板厚度后,焊缝宽度对刚度的影响减小. 间隙对刚度的影响可忽略.基于此结果,对三明治板设计时常用的刚度公式进行了修正. 相似文献
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F.Q.Tian D.Y.He X.Y.Li Y.W.Shi D.Zhang 《金属学报(英文版)》2004,17(6):934-939
Welded joint is a mechanical heterogeneous body, and mechanical heterogeneity has great effect on dynamic fracture behaviour of welded joints. In the present investigation, dynamic response curve and dynamic J-integral of practical undermatched welded joint and whole base and whole weld three-point-bend (TPB) models containing longitudinal crack are computed. Dynamic J-integral is evaluated using virtual crack extension (VCE) method and the computation is performed using MARC finite element code. Because of the effect of inertia,dynamic load response curve of computed model waves periodically. Dynamic J-integral evaluated by VCE method is path independent. The effect of inertia has little influence on dynamic J-integral curve. The value of dynamic J-integral of undermatched welded joint is lower than that of whole base metal and higher than that of whole weld metal. The results establish the foundation of safety evaluation for dynamic loaded welded structures. 相似文献
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采用填充ER316焊丝的光纤激光-MIG电弧复合焊方法,焊接间隙为0.5 mm、厚度为1 mm的SUS444铁素体不锈钢薄板对接接头和搭接接头,研究了获得成形良好的对接接头和搭接接头的工艺参数窗口和极限焊接速度,并对焊缝进行了着色渗透检验和拉伸试验. 结果表明,合理匹配焊接速度和焊接电流,是获得成形良好的大间隙接头的关键;当焊接速度过小或焊接电流过大时,较大的热输入导致焊缝过度熔透,焊缝成形不良;当焊接速度过大或焊接电流过小时,较小的热输入导致焊缝未熔透. 对接接头焊缝成形质量良好且熔透的极限焊接速度可达12 m/min,而搭接接头的极限焊接速度为5 m/min. 成形良好的焊缝均未发现表面裂纹. 拉伸试验表明,对接接头断裂在母材上;搭接接头绝大部分断裂在熔合线附近,极限焊接速度下获得的搭接接头的抗拉强度是母材的84.2%. 相似文献
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Research on the creep damage and interfacial failure of dissimilarmetal welded joint between 10Cr9Mo1 VNbN and 12Cr1MoV steel 总被引:2,自引:0,他引:2
0 IntroductionAnewmodified 9Cr Mosteel (SA2 13T91orT91)pos sessesimprovedhightemperaturestrength ,excellentductili ty ,weldability ,heatfatigueproperties .Therefore ,T91hasbeenwidelyusedinelectricpower,petrochemicalplant,nu clearpowerstation ,andsoon[1~3] .Itisappliedtothefinalstagesofsuperheatersandreheatersinfossil firedpowerplants .However,lowalloypearlitesteel(12Cr1MoV)isstillusedintheearlierstages .Thus,therearealotofdissimilarmetalweldedjoints (DMWJs)betweenSA2 13T91and12Cr1Mo… 相似文献
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以6156铝合金为主要研究对象,对比了其激光填丝焊与自熔焊各自特点,探讨了焊缝表面成形、焊缝熔宽的影响因素及接头的抗拉强度与疲劳强度变化规律.结果表明,功率在1 800 W左右,焊接速度在2~3.5 mm/min,送丝速度在2~3.5 mm/min范围能获得较好的焊缝表面成形;接头焊后不经热处理抗拉强度可达314.3 MPa,为母材强度的81.3%,且有良好的抗疲劳性能;铝合金激光焊具有焊接速度高、焊缝成形美观、焊接参数范围广的特点,是一种良好的焊接方式. 相似文献
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The complexity of joining Ti6Al4V alloy enhances with reduction in sheet thickness. The present work puts emphasis on microplasma arc welding (MPAW) of 500-μm-thick Ti6Al4V alloy in butt joint configuration. Using controlled and regulated arc current, the MPAW process is specifically designed to use in joining of thin sheet components over a wide range of process parameters. The weld quality is assessed by carefully controlling the process parameters and by reducing the formation of oxides. The combined effect of welding speed and current on the weld joint properties is evaluated for joining of Ti6Al4V alloy. The macro- and microstructural characterizations of the weldment by optical microscopy as well as the analysis of mechanical properties by microtensile and microhardness test have been performed. The weld joint quality is affected by specifically designed fixture that controls the oxidation of the joint and introduces high cooling rate. Hence, the solidified microstructure of welded specimen influences the mechanical properties of the joint. The butt joint of titanium alloy by MPAW at optimal process parameters is of very high quality, without any internal defects and with minimum residual distortion. 相似文献
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The effects of joint design on the mechanical properties of AL7075-T6 aluminum sheet were studied on the latest automated
gas-tungsten arc-welding system. Using ER5356 filler metal, full-penetration welds were made on workpieces with various included
joint angles. Testing of the mechanical properties of the joints was done in the as-welded, naturally aged, and postweld heat-treated
conditions. The results show that by using crack-resistant filler, and by selecting the proper joint design and postweld heat
treatment, strong, dependable welds can be produced on thin AL7075 sheet material. An elasticity model of the weld joint was
established to help understand the mechanical behavior of the joints. An undermatched joint design is shown to be capable
of achieving a joint strength that matches the strength of the base alloy. 相似文献