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41.
Reissner板切口尖端应力应变场 总被引:2,自引:0,他引:2
本文利用双重幂级数展开法推导出Reissner板切口特征方程,进而应用Muller迭代法求得不同切口张角下特征值序列解答,最后获得Reissner板切口尖端应力应变场. 相似文献
42.
缺口件表象疲劳极限的定量化分析 总被引:1,自引:0,他引:1
测定了淬火、高温回火35CrMo钢光滑试样和三种缺口试样的三点弯曲疲劳极限,并利用ANSYS有限元软件计算了缺口试样加载时缺口截面上的应力分布.用“疲劳源形成的微细观过程理论”对试验结果进行了分析,认为,疲劳源的形成虽然发生在个别薄弱晶粒内部,是其中位错往返运动及交互作用的结果,但还必须满足一定的形变协调条件和概率条件,因而必须形成由相当多晶粒组成的“细观屈服区”.对试验结果的分析表明,如取“细观屈服区”临界尺寸(xW)等于11个奥氏体晶粒平均直径,则计算得到的缺口试样的表象疲劳极限,与实测值相比,其综合误差最小.据此计算的三种缺口试样的表象疲劳极限,其误差都小于5%.该xW可认为是材料的特征参量. 相似文献
43.
含表面缺口玻纤/环氧正交层压板的疲劳特性 总被引:1,自引:0,他引:1
本文探讨含表面缺口玻纤/环氧树脂正交层压板的疲劳力学特性,测量和分析了疲劳寿命特征及脱层扩散规律,监测了缺口张开位移,试样刚度降低随循环历史的变化特怔,结果表明,疲劳脱层扩展速率与应变能率的关系服从Paris方程,监视缺口张开位移或刚度降低的变化可能是监视和预测含表面缺口复合材料构件疲劳破坏的有效手段之一。 相似文献
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本文对反应烧结氦化硅 Si_3N_4陶瓷的断裂韧性进行实验研究,用三种不同试件进行了测试,这三种试件是:山形切口双悬臂粱试件,山形切口三点弯曲梁试件和直穿透切口三点弯曲梁试件.用有限元方法分析了直穿透切口三点弯曲梁切口宽度对应力强度因子的影响,结合断裂载荷测定值估算了材料的断裂韧性值,指出直切口无预制裂纹试件的测定值必须用有限元法进行修正才能得到正确结果. 相似文献
47.
《Macromolecular rapid communications》2017,38(22)
Spherical polymer brushes, poly(acrylic acid) (PAA)‐grafted polystyrene nanoparticle (PAA@PS), are employed as the macro‐crosslinker to prepare PAA hydrogels. Benefitting from the innumerable hydrogen bonds between highly entangled PAA chains both in bulk and on the polymer brush, the PAA/PAA@PS hydrogels combine desirable stretchability, toughness, and notch‐insensitivity. The uniaxial tensile tests show a very high fracture elongation up to 9.1 × 103% while the fracture toughness reaches 3.0 MJ m−3 and the maximum swelling ratio of the hydrogel can be 2.0 × 103 as well. After being loaded with silver nanoparticles, the PAA/PAA@PS hydrogels are employed as a recyclable catalyst successfully. 相似文献
48.
We investigated the performance limitation of a frequency-tunable photonic microwave notch filter incorporating a chirped fiber Bragg grating (FBG) as a group delay line. In particular, we carried out theoretical and experimental studies to analyze the impact of the reflectivity ripple (RR) and group delay ripple (GDR) in the chirped FBG on the output notch performance. The results of experimental and theoretical analyses performed on a photonic microwave notch filter in which an S-bending-based linearly chirped FBG was incorporated, revealed that the notch depth and notch frequency were significantly affected by imperfections in the chirped FBG. The notch depth was found to be decreased by the RRs, whereas significant fluctuations in the notch frequency were caused by the GDRs. On the basis of the obtained results, we conclude that the RR and the GDR are the fundamental factors that degrade the performance of chirped FBG-based photonic microwave filters. 相似文献
49.
三维切口尖端应力应变场 总被引:4,自引:0,他引:4
本文利用双重幂级数展开法分析三维切口尖端应力应变奇异性,通过切口边界条件导出切口特征方程,进而求得不同切口内角下特征值序列解答,最后推得切口尖端应力应变场。 相似文献
50.
To examine a simulation method for vertical sound localization, and to clarify which peaks and notches in head-related transfer functions (HRTFs) play a role as spectral cues, localization tests in the median plane were carried out using a parametric HRTF model, which is recomposed only of extracted spectral peaks and notches. The results show that the parametric HRTF recomposed using the first and second notches (N1 and N2) and the first peak (P1) provides almost the same localization accuracy as the measured HRTFs. Observations of the spectral peaks and notches indicate that N1 and N2 change remarkably as the source elevation changes, whereas P1 does not depend on the source elevation. In conclusion, N1 and N2 can be regarded as spectral cues, and the hearing system could utilize P1 as the reference information to analyze N1 and N2. 相似文献