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Anisotropy of multi-layered structure with sliding and bonded interlayer conditions

Lingyun YOU, Kezhen YAN, Jianhong MAN, Nengyuan LIU

《结构与土木工程前沿（英文）》 2020年第14卷第3期页码 632-645 doi: 10.1007/s11709-020-0617-4

摘要： A better understanding of the mechanical behavior of the multi-layered structure under external loading is the most important item for the structural design and the risk assessment. The objective of this study are to propose and develop an analytical solution for the mechanical behaviors of multi-layered structure generated by axisymmetric loading, and to investigate the impact of anisotropic layers and interlayer conditions on the multi-layered structure. To reach these objectives, first, according to the governing equations, the analytical solution for a single layer was formulated by adopting the spatial Hankel transform. Then the global matrix technique is applied to achieve the analytical solution of multi-layered structure in Hankel domain. The sliding and bonded interlayer conditions were considered in this process. Finally, the numerical inversion of integral transform was used to solve the components of displacement and stress in real domain. Gauss-Legendre quadrature is a key scheme in the numerical inversion process. Moreover, following by the verification of the proposed analytical solution, one typical three-layered flexible pavement was applied as the computing carrier of numerical analysis for the multi-layered structure. The results have shown that the anisotropic layers and the interlayer conditions significantly affect the mechanical behaviors of the proposed structure.

关键词： multi-layered structure Hankel transformation anisotropic transversely isotropic interlayer condition Gauss-Legendre quadrature

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Topology optimization of transient problem with maximum dynamic response constraint using SOAR scheme

《机械工程前沿（英文）》 2021年第16卷第3期页码 593-606 doi: 10.1007/s11465-021-0636-4

摘要： This paper proposes a novel method for the continuum topology optimization of transient vibration problem with maximum dynamic response constraint. An aggregated index in the form of an integral function is presented to cope with the maximum response constraint in the time domain. The density filter solid isotropic material with penalization method combined with threshold projection is developed. The sensitivities of the proposed index with respect to design variables are conducted. To reduce computational cost, the second-order Arnoldi reduction (SOAR) scheme is employed in transient analysis. Influences of aggregate parameter, duration of loading period, interval time, and number of basis vectors in the SOAR scheme on the final designs are discussed through typical examples while unambiguous configuration can be achieved. Through comparison with the corresponding static response from the final designs, the optimized results clearly demonstrate that the transient effects cannot be ignored in structural topology optimization.

关键词： topology optimization solid isotropic material with penalization transient response aggregation function second-order Arnoldi reduction

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横观各向同性土体三维比奥固结有限层解法

梅国雄,宰金珉,赵维炳,殷建华

《中国工程科学》 2004年第6卷第7期页码 43-47

摘要：

建立了三维横观各向同性土体固结的有限层求解方法，并编制了相应的计算程序；通过2个算例的分析对比，验证了计算方法和程序的正确性；探讨了横观各向同性地基参数对三维地基固结的影响，给出了对工程有价值的相关计算图表和结论。

关键词：有限层比奥固结三维横观各向同性

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Elasto-plastic fatigue crack growth analysis of plane problems in the presence of flaws using XFEM

Sachin KUMAR,A. S. SHEDBALE,I. V. SINGH,B. K. MISHRA

《结构与土木工程前沿（英文）》 2015年第9卷第4期页码 420-440 doi: 10.1007/s11709-015-0305-y

摘要： In this paper, elasto-plastic XFEM simulations have been performed to evaluate the fatigue life of plane crack problems in the presence of various defects. The stress-strain response of the material is modeled by Ramberg-Osgood equation. The von-Mises failure criterion has been used with isotropic hardening. The -integral for two fracture modes (mode-I and mode-II) is obtained by decomposing the displacement and stress fields into their symmetric and antisymmetric parts, then individual stress intensity factors are extracted from -integral. The fatigue life obtained by EPFM is found quite close to that obtained by LEFM.

关键词： XFEM von-Mises yield criterion isotropic hardening fatigue crack growth J-integral

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快速球磨法高效实现各向同性气雾化MnAl 粉的纳米化制备 Article

J. Rial, E.M. Palmero, A. Bollero

《工程（英文）》 2020年第6卷第2期页码 172-176 doi: 10.1016/j.eng.2019.03.013

摘要：

为了提高永磁体性能尤其是矫顽力，对气雾化MnAl粉末首次进行了30 s短时间球磨。结果表明，如此短的处理时间加上随后的退火可以高效地得到纳米结构和可控的相变。球磨过程中产生的微应变引起的缺陷与退火过程中形成的β相共同起到钉扎中心的作用，从而提高了矫顽力。研究表明，为了在磁化强度和矫顽力之间达到折中，在铁磁性τ-MnAl相和β相的形成之间找到一个平衡是很重要的。球磨（30 s）和退火后获得的矫顽力高达4.2 kOe (1 Oe = 79.6 A·m^–1)，与早期文献报道的球磨时间超过20 h时的矫顽力相当。球磨后粉末的退火温度降低了75 ℃，矫顽力提高了2.5倍，而退火后的气雾化材料的剩磁基本保持不变，为合成各向同性的MnAl基粉末开辟了一条新的途径。

关键词：永磁体纳米结构相变 MnAl 气雾化球磨法