叶切面最大厚度数值计算与应用

以叶切面最大厚度的数值计算方法为基础,探讨叶切面最大厚度计算的计算机实现,介绍叶切面厚度数值计算法的应用实例.     

Natural frequencies of vibration of a class of solids composed of layers of isotropic materials

In a recent paper, the Ritz method with simple algebraic polynomials as trial functions was used to obtain an eigenvalue equation for the free vibration of a class of homogeneous solids with cavities. The method presented is here extended to the study of a class of non-homogeneous solids, in which each solid is composed of a number of isotropic layers with different material properties. The Cartesian coordinate system is used to describe the geometry of the solid which is modelled by means of a segment bounded by the yz, zx and xy orthogonal coordinate planes and by two curved surfaces which are defined by fairly general polynomial expressions in the coordinates x, y and z. The surface representing the interface between two material layers in the solid is also described by a polynomial expression in the coordinates x, y and z. In order to demonstrate the accuracy of the approach, natural frequencies are given for both a two- and three-layered spherical shell and for a homogeneous hollow cylinder, as computed using the present approach, and are compared with those obtained using an exact solution. Results are then given for a number of two- and three-layered cylinders and, to demonstrate the versatility of the approach, natural frequencies are given for a five-layered cantilevered beam with a central circular hole as well as for a number of composite solids of more general shape.     

双丝杠驱动机构同步分析

介绍了双丝杠驱动机构工作原理,论述了双丝杠运动产生不同步的原因以及如何判定与解决同步问题。     

膨胀套导向机构的设计

通过分析膨胀套在实际使用产生滑移受阻现象、卡死现象原因的实质,并在分析产生问题原因的基础上提出了改进措施即：增加导向机构。     

Development of sclerometric method of studying activation of parameters of damage and fracture of friction deformable surfaces

The article presents a brief review of the wear models based on the kinetic thermofluctuation approach. The materials were developed using SamGTU sclerometric programming software and a set of instruments developed at Samara Engineering University for assessing the parameters of kinetic thermoactivation for surface fracture deformed by friction. The first obtained results of assessments and the estimated prediction of wear resistance exemplified by tribocouple of the aircraft chassis are presented.     

Method of implementation of the positive gradient of mechanical properties of triboengineering materials

Modern methods of implementation of the rule of positive gradient of mechanical properties are considered; this rule was formulated by I.V. Kragelskii and its application serves to minimize the friction and wear of solids. The given methods include the application of coatings with the method of finishing antifricton abrasion-free treatment; application of new metal-cladding lubricating materials; and creation of a nanostructural state of the surface iron nitride layer by nitriding steel with a positive gradient of hardness normal to the surface.     

轮胎单个横沟泵吸噪声计算方法研究

以205/50R16子午线轮胎为对象,建立具有横向花纹沟槽的有限元法分析模型,利用Abaqus/Explicit进行瞬态滚动分析,得到滚动轮胎单个横沟的体积变化。将其导入Fluent中,利用计算流体力学方法对单个横沟泵吸效益流场进行分析,并结合Lighthill声学类比理论预测横向沟槽的噪声,同时基于涡声理论验证流场与噪声之间的关系。结果表明,单个横沟泵吸噪声第一峰值集中在0.8～2.0 kHz附近,仿真数据与试验结果在趋势上具有一致性;且噪声的声压峰值出现在泵吸状态发生转变的时间段;在时域中的3个噪声峰值出现涡量变化较大的时间段,已确定噪声的变化可由涡量来反映。     

Analysis of models of friction in suspensions of vehicles

An analysis of the correctness of calculations during the modeling of oscillations of vehicles is carried out. A substantial difference between the calculation and experimental data in octave-frequency bands has been found and a low efficiency of suspensions of sprung seats has been emphasized. A comparative analysis of models of friction and dynamic characteristics used during the modeling of suspensions of vehicles is carried out. It has been shown that models of Coulomb and viscous friction do not ensure the required precision of the modeling process. A new model of friction in the form of totalities of models of elastic and viscous friction, as well as the implementation of this model using computer simulation, which ensures a calculation error of 5–15%, have been proposed.     

我校工业设计教育改革初探

针对目前市场对工业设计人才的需求,本文论述了我校在工业设计教育方面的改革措施,着重介绍了我校工业设计教育在软件和硬件方面所进行的一系列的改革。     

Analysis of similarity of physical processes during simulation of cooling of machine crystallizers

Similarity criteria describing physical the processes of boiling and condensation of a heat carrier were determined with a model and natural experiments based on the analysis of dimensions of parameters in the heat exchange problem during cooling of a crystallizer by heat pipes. Relationships of the geometrical sizes of heat pipes (diameter, length) were estimated. The novelty of the results is confirmed by patents of invention of catalyst cooling by heat pipes.