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direction, S-N as Y-direction with N as positive direction. According to Right-hand Law, H-L will be Z-direction with H as positive direction. The current entering into governing volume P from... entering into governing volume P from governing volumes E, S, N, H and L can also be expressed by Ohm Law as follows: Ii+1, j, k=(Vi+1, j, k-Vi, j, k)/Ri+1, j, k(7) Ii, j-1, k=(Vi, j-1, k-Vi, j, k)/Ri......
locations and heterogeneity of the weld metal properties. The traditional approach is to apply the S-N curve as described in BS 5400 or in IIW documents [6]. However, the fatigue life estimation..., S) (2) The second order polynomial (regression) equation used to represent the response surface ‘Y’ is given by  ......
; (1) 式中:t为系数,t=2;S为标准差;N为测量次数.表1中还列出了不同高温热暴露时间的α2+γ层片晶团的尺...不广泛. 2.3 热暴露时间对疲劳性能的影响 合金4-4-1在经过一系列的热暴露后的四点弯曲室温疲劳(S-N)曲线如图7所示.由图7可以看出,在未进行热暴露的情况下,它的最大应力-疲劳周次关系处于较低的应力水平,热暴露后,该关系对应的应力值呈现增加的趋势,而这个趋势在10 000 h的热暴露后变得更为明显.这样看来,合金4-4-1的疲劳抗力对长期高温热暴露所出现的显微组织的变化并不特别......
,支点锚固区也未见有滑移. 图10 关键测点主拉应力-循环次数变化曲线 Fig.10 Principal tensile stress-cycle number relationship of key points 根据结构疲劳裂纹出现前,疲劳试验实测应力幅及加载循环次数,可以对结构疲劳寿命进行估计. 根据描述结构疲劳性能的S-N曲线,任意应力幅σi与对应的循环次数Ni满... fatigue loading, out-plane deformation occurs in the crossbeam and results in the out-plane fatigue crack. According to Miner’s fatigue accumulation damage rule and referring to EC3 code, the fatigue......
) [2] MAO Y, CAI, Q W, WEI, S B. Influence of deformation parameters on texture of AZ31Magnesium alloy [J]. Journal of Plasticity Engineering, 2008, 15(6): 4-7. [3] MORITA S, OHNO N, TAMAI F, KAWAKAMI..., 158: 363-376. [10] CHEN N Z, WANG G, SOARES C G. Palmgren-Miner’s rule and fracture mechanics-based in section planning [J]. Engineering Fracture Mechanics, 2011, 78: 3166-3182. [11] JARDIN A, LEBLOND......
for aluminum in 4 N HCl [J]. Colloids and Surfaces A, 2008, 322: 97-102. [13] YURT A, ULUTAS S, DAL H. Electrochemical and theoretical investigation on the corrosion of aluminium in acidic solution containing some Schiff bases[J]. Applied Surface Science, 2006, 253: 919-925. [14] BEHPOUR M, GHOREISHI S M, NIASARI M S, EBRAHIMI B. Evaluating two new synthesized S-N Schiff bases on the corrosion......
, YOOINL J, SANGSHIK K. S-N Fatigue behavior of anodized 7050-T7451produced in different electrolytes[J]. Metallurgical and Materials Transactions A, 2012, 43(6): 2002-2011. [9] SHA G, CEREZO A. Early...] ADACHI H, OSAMURA K, OCHIAI S. Mechanical property of nanoscale precipitate hardening aluminum alloys[J]. Scripta Materialia, 2001, 44(8): 1489-1492. [4] LI Zhi-hui, XIONG Bai-qing, ZHANG Yong......
; (22) 3.2 钢筋的疲劳失效准则 钢筋是以脆性断裂为疲劳破坏的标志,一般是以钢筋应力幅值是否超过疲劳破坏的允许应力幅值作为钢筋疲劳破坏依据.如对于HRB400钢筋,可参考文献[11]中的S-N方程确定. 4 疲劳荷载作用下的结构分析过程 基于前述计算模型和有限元分析方法,N次疲劳后的结构受力性能分析流程如图2所示.若需要对...规律进行分析总结的基础上,基于"变形唯一性"假定和混凝土材料在静态荷载与疲劳荷载作用下破坏的相似性,以残余应变作为等效参量,建立疲劳荷载与静载分析的等效关系,由1次静力加卸载构造出与疲劳N次损伤等效的状态梁,进而引入材料的疲劳损伤本构模型,建立构件受疲劳荷载作用的等效静力分析方法,基于ABAQUS有限元软件平台高效地实现高周疲劳荷载作用下钢筋混凝土梁的疲劳累计损伤过程分析和剩余承载力预测. 1......
[6] found a smooth transition in S-N curves of hot-rolled Mg alloys AZ31 and AZ61. FONTE and FREITAS [7] found the intersection of steady torsion on fatigue crack growth of semi-elliptical cracks... M M, GE Q, JACKSON J A, KUCHEYEV S O, FANG N X, SPADACCINI C M. Ultralight, ultrastiff mechanical metamaterials [J]. Science, 2014, 344(6190): 1373-1377. [3] LUO A A. Magnesium: Current and potential......
特征见表1,其中湖南省样本中未统计小轿车. 从表1可见:各省份地区汽车荷载均存在超载现象,其中贵州,湖南和湖北的超载程度较大. 2 结构的相对疲劳损伤 由疲劳累积损伤模型,结构的疲劳性能可用S-N曲线描述,其曲线方程为 (1) 式中:N为应力幅值作用总次数;S为应力幅值;C为材料疲劳细节参数;m为疲劳强度曲线参数,对钢结构,一般取3.0[12].Miner线性累积损伤理论为 (2) 式中:D为疲劳......