涂层材料的断裂分析(英文)

和基体厚度相比,涂层很薄,因此细观力学模型可把基体作为半无限弹性体。由于涂层和基体材料的膨胀系数及弹性系数不匹配,涂层材料中残余热应力的解析解为 E_c/(1-γ_c)·(α_s-α_c)△T。用有限元法校核,该应力和解析解吻合得好。通过对涂层产生裂纹驱动力和断裂韧性的讨论,提出了抗裂涂层厚度公式。     

弹性半无限空间中矩形孔收缩的复变函数解答

随着城市建设的发展,矩形隧道的应用越来越多,但针对矩形隧道的理论研究却鲜有见闻。针对矩形隧道,建立了半无限空间矩形隧道的弹性理论计算模型,采用最小二乘迭代方法确定共形映射函数的各项系数,并将计算区域映射为复平面上的一个同心圆环;运用Muskhelishvili复变函数方法,将计算区域内的应力函数展开成为Laurant级数的形式,给定了地表零应力边界和矩形孔口径向位移边界,求得了半无限空间矩形隧道在给定位移条件下的应力场和位移场。分析了不同高宽比、不同泊松比、不同埋深对位移场和应力场的影响,总结了矩形隧道位移场和应力场的一般规律。结果表明：高宽比偏小、泊松比偏大、埋深偏小都会使得沉降槽不再是类高斯曲线的形状,这些参数的变化也会在不同程度上影响应力场和位移场的大小和分布。     

Alekseevskii-Tate revisited:An extension to the modified hydrodynamic theory of long rod penetration

The modified hydrodynamic theory of long rod penetration into semi-infinite targets was established independently by Alek-seevskii and Tate over forty years ago and since then many investigators contributed much to the development of the high speed penetration mechanics.However,in all the models proposed so far,the target resistance Rt is not well defined and usually determined by adjusting it until the predicted depth of penetration comes to an agreement with experimental data.In this paper,assumptions are...     

一类非光滑非凸分式半无限规划的最优性

在一致Fb-凸函数，一致Fb-伪凸和一致Fb-拟凸等广义凸性函数的基础上，研究了一类分式半无限规划问题，得到了涉及这些广义凸性函数的一类非光滑分式半无限规划的一些最优条件。     

大型水池接触有限元分析

对于大型水池的计算,由于存在底板和地基的相互作用,因而很复杂,实际上底板和地基的相互作用是两种不同介质的接触问题.本文把地基看作是连续的半空间体,采用接触理论,对弹性地基上水池底板及大型水池,进行了有限元分析,并与按传统弹性理论法计算结果进行了对比,验证了本模型及求解方法的有效性.     

微粒群优化算法在相关新产品组合投入的应用

引入新产品最佳投入期和相关收益的概念，在产品生命周期量化描述前提下，提出一个非线性半无限规划的相关新产品组合投入模型，并用微粒群优化算法(PS0)求解，仿真实例表明，微粒群优化算法在求解组合优化问题时简便且易于实现，具有很强的实用性。     

Elastic and elastic-perfectly plastic analysis of an axisymmetric sinusoidal surface asperity contact

ABSTRACT

Closed-form finite-element empirical models are available for elastic and elastic–plastic spherical and sinusoidal contact. However, some of these models do not consider the effect of interaction with adjacent asperities or require extensive numerical resources because they employ a full 3-D model. Therefore this work has analysed and quantified the behaviour of an elastic and elastic- perfectly plastic axisymmetric sinusoidal surface in contact with a rigid flat for a wide range of material properties and different values of the amplitude to wavelength ratio from initial to complete contact (high load). The numerical results agreed well with the Hertz model and the Jackson–Green elastic–plastic spherical contact model at low loads. Empirical equations for elastic and also elastic-perfectly plastic cases are formulated for the contact pressure, contact area and surface separation. From the current analysis, it is found that it is not any single parameter, but different combinations of material properties and surface roughness that govern the whole contact behaviour. The critical value of the amplitude of the sinusoidal asperity below which it will deform completely elastically from initial to complete contact is established. At low values of amplitude normalized by the critical amplitude, it was found that the contact behaved similar to a spherical contact, with the average pressure (hardness) always remaining lower than three times the yield strength. However, at higher values the average pressure increased toward a value as high as six times the yield strength at complete contact. All of these equations should be useful in rough surface contact modelling, lubrication analysis, electrical contact modelling and in many other applications.     

当均布垂直荷载作用时半无限弹性体内侧向变位的计算

文献［１］提出了计算地基表面侧向变位的方法，本文则就均布垂直荷载作用的情况下，提出了计算半无限弹性体内侧向变位的方法，可作为文献［１］的补充。     

近距离煤层联合开采条件下工作面合理错距确定

为避免近距离煤层联合开采条件下上煤层工作面回采过程中顶板周期来压波及下煤层工作面或上下煤层同步来压而相互影响,通过现有矿压及弹性半无限体理论的运用并结合现场实测数据分析给出石圪节煤矿联采条件下工作面合理错距的选取方法.研究表明:1)据煤矿地质及煤岩物理力学特性运用矿压理论初定工作面错距；2)结合理论或现场实测分析层间应力分布影响区域,修正工作面错距；3)现场实践最终确定合理错距.选取初定的工作面错距及层间应力主要影响区横向范围值之和作为近距离煤层合理错距,可避免下煤层煤体承受上煤层的连续高应力状态.     

伸出式侵彻体垂直侵彻半无限靶数值模拟

对伸出式侵彻体垂直侵彻半无限靶板的物理过程进行了描述,分析了侵彻过程中一些重要参量的变化规律,并对此过程进行了三维数值模拟,模拟结果与试验结果有较好的一致性;与具有相同质量相同外径的基准杆进行了比较,结果表明,在火炮速度范围内,伸出式侵彻体相对基准杆有较大的穿深增益,而且这种穿深增益随着撞击速度的增加而逐渐增加.