6110柴油机曲轴两种平衡方案的试验研究

对6110柴油机曲轴带有四块或八块平衡块的两种平衡方案的平衡特性和曲轴中间主轴承负荷进行了理论分析，同时通过主轴承螺栓的应力实测对理论分析结果进行了验证。     

轴瓦合金材料疲劳强度试验方法(ISO/DP7905/4)及试验应力计算

按ＩＳＯ／ＤＰ７９０５／４标准的要求，研制了小型轴瓦疲劳试验机。它可应用实物轴瓦作合金材料疲劳强度试验，为确定试验载负、瓦口径向变形与试验应力三者间的关系，按薄壁组合曲梁理论建立了有关公式，并用有限元法及电测法对这些公式进行了校核，证明完全满足精度要求。     

B系列柴油机连杆烧瓦故障分析及对策

本文从B系列柴油机在使用中产生连杆烧瓦故障的统计及曲轴、连杆关键质量特性的检验数据入手，通过对连杆大端轴承润滑及油膜分布、承载能力研究，论证了造成连杆烧瓦故障的主要原因，并提出了解决方法。     

A comparison of Mode III threshold under simple shear and RCF conditions

A novel experimental method, previously developed by the authors, has been applied in order to promote Mode III co-planar crack propagation in a bearing steel. The method consists in out-of-phase multiaxial fatigue tests, adopting a stress history typical of sub-surface RCF, onto specimens containing micro-notches that were previously subjected to Mode I pre-cracking at R = −2. Three defect sizes, expressed in terms of Murakami’s √area parameter, equal to 630 μm, 315 μm and 220 μm were considered. The experimental data clearly show that the threshold conditions for out-of-phase tests is lower than in simple torsional tests, thus promoting the shear growth. This enhanced damage mechanism, which cannot be described neither in terms of fatigue criteria nor in terms of crack driving force at the crack tip, is characterised by intense plastic deformation and rubbing of the crack lips with an opening of the crack faces. In order to compare the multiaxial and torsional fatigue test results the effect of this type of opening on the friction of the crack faces will be investigated.     

Journal bearings design for a novel revolving vane compressor

This paper presents the theoretical details of the journal bearing design for Revolving Vane (RV) rotary type compressor. The mathematical models, force analysis, and the theoretical design analysis for the dynamically loaded journal bearing of the compressor are presented. The variations of the minimum oil film thickness and the maximum film pressure developed are shown and the influences of design parameters, compressor configurations, and operating conditions on the journal bearing performance are described. For an air-conditioning compressor of 1.5 kW cooling capacity, the lowest minimum oil film thickness for lower and upper journal bearings is 6.6 μm and 4.3 μm respectively, when the cylinder is simply supported and the rotor is cantilever-supported. The lowest minimum oil film thickness for the journal bearing, which supports the cylinder, reduces to 4.0 μm if the cantilever-type support is used. Besides that, a short-fat configuration of RV compressor is favorable in the interest of lowering bearing forces.     

干涉对复合材料层合板连接系统的极限挤压强度影响

本文对复合材料层合板单面螺纹抽钉紧固件干涉配合连接结构和高锁螺栓间隙配合连接结构的静挤压强度进行了试验研究.分别考虑了不同干涉量配合和间隙配合对紧固件连接结构极限挤压强度的影响.在静拉伸试验中,采用了卡口引伸计来实时监测孔的变形量.根据ASTM D 5961挤压试验方法标准,得到极限挤压强度及偏移量为2%的2%偏移挤压...     

多缸柴油机曲轴平衡重的合理配置

在外部平衡性能良好的曲轴上加装平衡重，通常是为了减小曲轴所受弯矩，但平衡重的安装将影响主轴承载荷的大小和分布。经过大量计算求得了一个工作循环中轴承载的最大值，平均值及其比值随平衡重增大而变化的规律。由此得出，合理的重配置应使轴承载荷的最大值达到最小。基地此结论导出了几组平衡重计算公式。文末还给出了算便。     

基于随机共振的轴承早期微弱故障诊断

针对早期轴承微弱信号难以发现、检测精度低等问题,提出一种基于随机共振的轴承早期微弱故障诊断方法。首先利用排列熵对周期信号的敏感特性,提出一种新的信号筛选方法来对信号进行初步滤波筛选;其次采用随机共振算法对故障信号进行噪声辅助增强,以信噪比为目标函数,采用麻雀搜索算法对随机共振系统参数k、a、b、h进行寻优,最后将寻优后的参数送入随机共振系统进行检测。仿真结果表明：该方法可以有效检测出强噪声中的未知微弱故障信号。     

Rolling element bearing fault diagnosis using wavelet packets

A method is proposed for the analysis of vibration signals resulting from bearings with localized defects using the wavelet packet transform (WPT) as a systematic tool. A time–frequency decomposition of vibration signals is provided and the components carrying the important diagnostic information are selected for further processing. The proposed method is designed in such a way that it can exploit the underlying physical concepts of the modulation mechanism, present in the vibration response of faulty bearings. The flexibility of the WPT and the systematic parameter selection criteria, help in the minimization of interventions by the end user. The method is evaluated using simulated and experimental signals.     

Scuffing Behavior of Piston-Pin/Bore Bearing in Mixed Lubrication—Part II: Scuffing Mechanism and Failure Criterion

Surfaces and subsurfaces of test specimens that failed in scuffing were examined. A scuffing criterion is developed stating that scuffing failure would occur when the maximum surface tangential traction is larger than the modified shear strength. A scuffing uncertainty factor is introduced to reflect the influence of factors that affect wear and scuffing and the inaccuracy in modeling.