两平行圆盘间或两圆球间存在二阶流体时的挤压流动

为了进行湿颗粒群的离散元模拟,研究两圆球颗粒间二阶流体在挤压流动时的法向粘性力．首先用小参数法对两平行圆盘间二阶流体挤压流动的速度场和正应力分布进行了近似分析,然后用类似的方法,分析任意两圆球间二阶流体的挤压流动,得到了压力分布和法向粘性力的解析解．     

Singular integral equations and boundary element method of cracks in thermally stressed planar solids

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热载荷作用下平面裂纹问题的奇异积分方程与边界元法

从边界积分方程出发,导出了二维裂纹体热传导问题及热弹性问题的积分方程组,继而使用奇积分方程与边界元相结合的方法,为其建立了相应的数值求解方法。此外,利用奇异积分方程的主部分析法,严格地证明了裂纹尖端温度梯度的１／√ｒ奇异性,并且给出了奇性温度梯度场的精确解。最后,对一些典型例子,做了数值计算。     

两平行刚性圆盘挤压理想刚塑性介质时压力规律研究

两平行刚性圆盘挤压理想刚塑性介质时,通常考虑圆盘与介质的界面之间存在部分滑移,对库仑摩擦条件下的压力规律做了进一步的研究,同时,引入更合理的速度场,假设圆盘边缘处滑移速度一定,介质的滑移速度随着半径线性变化,得到了压力分布规律,对不同的摩擦条件及用不同方法计算得到的结果进行了对比。     

部分信息下一类一主多从激励策略

本文研究在部分信息下,一主多从且从者之间非合作的激励问题,给出了寻找主者的激励策略的一般方法;并对线性二次情形提出了仿射型激励策略所应满足的充分条件.     

Analysis of multiple interfacial cracks in three-dimensional bimaterials using hypersingular integro-differential equation method

By using the concept of finite-part integral, a set of hypersingular integro-differential equations for multiple interracial cracks in a three-dimensional infinite bimaterial subjected to arbitrary loads is derived. In the numerical analysis, unknown displacement discontinuities are approximated with the products of the fundamental density functions and power series. The fundamental functions are chosen to express a two-dimensional interface crack rigorously. As illustrative examples, the stress intensity factors for two rectangular interface cracks are calculated for various spacing, crack shape and elastic constants. It is shown that the stress intensity factors decrease with the crack spacing.     

Squeeze flow of a second-order fluid between two parallel disks or two spheres

The normal viscous force of squeeze flow between two arbitrary rigid spheres with an interstitial second-order fluid was studied for modeling wet granular materials using the discrete element method. Based on the Reynolds‘ lubrication theory, the small parameter method was introduced to approximately analyze velocity field and stress distribution between the two disks. Then a similar procedure was carried out for analyzing the normal interaction between two nearly touching, arbitrary rigid spheres to obtain the pressure distribution and the resulting squeeze force. It has been proved that the solutions can be reduced to the case of a Newtonian fluid when the non-Newtonian terms are neelected.     

热载荷作用下平面裂纹问题的奇异积分方程与边界无法

从边界积分方程出发,导出了二维裂纹体热传导问题及热弹性问题的积分方程组,继而使用奇异积分方程与边界元相结合的方法,为其建立了相应的数值求解方法。此外,利用奇异积分方程的主部分析法,严格地证明了裂纹尖端温度梯度场的1/√r 奇异性,并且给出了奇性温度梯度场的精确解。最后。对一些典型例子,做了数值计算。     

用于准脆性材料破坏过程数值模拟的虚拟连接单元法

将有限变形单元与虚拟连接单元相结合,用于模拟准脆性材料破坏过程.首先基于精确的有限变形理论,采用第二类Piola-Kirchhoff应力与Green-Lagrange应变作为能量共轭的应力、应变对,推导出虚拟连接单元的单元刚度矩阵;通过数值算例,验证该单元的正确性与合理性,给出虚拟连接单元高度的取值范围,并与无此单元时...