Linear Complementarity Framework for 3D Steady-State Rolling Contact Problems Including Creepages with Isotropic and Anisotropic Friction for Circular Hertzian Contact

In this article, the problem of 3D steady-state rolling contacts with dry friction for circular Hertzian contacts is formulated mathematically as a linear complementarity problem (LCP). The complementarity variables are the traction and the relative slip of contact regions, in which a polyhedral friction law is employed. The present work uses the general expressions describing the surface deformations due to uniform traction over a rectangular area on an elastic half-space to derive the influence coefficient matrix for rolling contact problems. Three possible creepage types—that is, longitudinal, lateral, and spin creepage—are considered in this work. Firstly, the numerical results are verified against the existing numerical solutions and good agreement has been found. Secondly, the anisotropic friction is studied by the verified approach. Some numerical examples are provided to illustrate the current LCP method for both isotropic and anisotropic friction in which the combined effects of the three kinds of creepage on the traction distribution are shown.     

视觉检测与激光精密测量在轴承加工检测中的应用

机器视觉测量技术是利用机器模拟人类视觉对待测工件的各种参数进行测量的一种新兴技术,测量速度快。利用面阵CCD传感器拍摄图像并结合相应的平面标定算法,即可测得工件的平面尺寸。此方法测量速度快,但精度相对较低。高精度激光位移传感器的测量精度较高,但测量速度相对较慢。结合以上两种视觉传感器的优点,提出一种同时具有高速、高精度特点的精密测量方法,并将其应用在精密轴承的制造、加工、检测中。     

Development of efficient production routes based on strip casting for advanced high strength steels for crash-relevant parts

Twin roll strip casting can be an effective alternative to produce high manganese TWIP steel, which provides extraordinary mechanical properties. In the work presented, 1.5–3 mm thin hot strips with up to 30 wt% manganese were produced directly from the melt and further processed to cold strip. An adapted thermo-mechanical treatment, consisting of cold rolling with or without subsequent annealing, enables to adjust different material states, such as recrystallised or strengthened state, and thus to tailor the mechanical properties. As an example for the superior crash behaviour of high manganese TWIP steels, dynamic crash tests were carried out using cold rolled Fe–29Mn–0.3C steel in different material states.     

Hydrogen sorption properties of Ti–Cr alloys synthesized by ball milling and cold rolling

Three Ti–Cr alloys with nominal compositions of TiCr_x (x = 2, 1.8 and 1.5) were synthesized by cold rolling and ball milling of as-cast ingots, and their microstructures and hydrogenation properties were studied. X-ray diffraction showed that TiCr_x transformed from a mixture of C14 and C15 Laves phases to a metastable BCC phase after 5 h of ball milling under argon. Cold rolling did not lead to the formation of a metastable BCC phase but only to the reduction of TiCr_x size particles under 20 nm. Surprisingly, the hydrogen absorption/desorption curves of cold rolled and ball milled samples at 323 K were quite similar. This result proves that hydrogen storage properties do not depend only on microstructure and that cold rolling could be an interesting method to synthesize hydrogen storage materials.     

浅议无缝钢管连轧机组的轧制中心线

无缝钢管连轧机组的轧制中心线是否居中,直接决定着产品质量的优劣。介绍了无缝钢管连轧机组轧制中心线的确定及校核,并指出轧制中心线对产品质量的影响,同时对轧机设备的设计提出了建议。     

异常情况下转子系统的不平衡响应特性

用Riccati传递矩阵法计算分析了支撑系统异常情况下转子的不平衡响应特性。分析结果表明，支撑刚度不对称情况下，在转子上加对称不平衡量，不仅激发一阶分量，同时还激发出明显的二阶分量，同样，加反对称不平衡量，不仅激发二阶分量，同时还能激发出明显的一阶分量，转子不平衡响应特性发生了很大变化。该结论对于指导机组动平衡具有非常重要的工程应用价值。     

应用频谱分析法检测诊断风机故障实例

在风机设备运行期间进行状态检测，并对其振动进行频谱分析和轴承特征故障频率分析，排除了故障同时也验证分析了结论，利用该方法对设备振动进行分析，以达到预测性维修的目的。     

圆锥轴承套圈车削自动线的研制

ZZX-01圆锥轴承套圈自动车削生产线具有高精度、高效率、高可靠性及大批量生产等优点,文章介绍了其现代设计方法、研制规划及工作原理.     

希尔伯特变换原理在轴承故障诊断中的应用

阐述希尔伯特变换及解调的基本原理，并据此对振动信号进行幅值及相位解调与分析，为旋转机械故障诊断提供早期和准确的故障信息。     

轴向进给式螺纹滚压的模具设计及数值模拟

介绍了轴向进给式螺纹滚压的原理及过程,根据被加工零件尺寸的要求设计了轴向进给式的滚压模具。应用有限元分析软件DEFORM-3D模拟了轴向进给式螺纹滚压过程,通过分析滚压过程的等效应力,得到了滚压过程的变形规律,这对实验具有一定的指导作用。