Selective laser melting (SLM) is one of the most promising metal additive manufacturing technologies. SLMed Al-Si alloys have been widely used in the rail transport, aerospace, and automotive industries. Recently, the fatigue and fracture properties of SLMed Al-Si alloys have attracted considerable attention due to their application in critical load-bearing structures. This review aims to better understand the recent progress on the fatigue and fracture investigations of SLMed Al-Si alloys, especially AlSi10Mg, with emphasis on the effect of defects, heterogeneous microstructure, residual stress, and post-treatment methods. In addition, fatigue and fracture modeling methods are discussed. Finally, the challenges and future research opportunities are prospected.

Although the cage slip of cylindrical roller bearings has been measured and studied experimentally, it is difficult to use current experimental measurement to detect the cage slip of the bearing in actual service or engineering environment. The problem is attributed to the limit on the space for current test instruments that can be installed arbitrarily in laboratory, but not in actual environment. A novel measurement based on strain detection is presented. This measurement can be used to obtain the cage slip of the bearing in service or large bench test. The technique is demonstrated and validated in principle by an experimental system. The system is developed to obtain the strain signal of the outer ring in loaded zone as well as the speed signal of the cage and the inner ring at the same time. Under given test load–speed conditions, the cage slip based on strain detection was compared with the cage slip based on speed detection. Experimental results showed that cage slip ratio curves based on strain responses agreed very well with those based on speed signals. In this way, it is revealed that frequency characteristics of strain signals can be used to obtain internal cage slip of cylindrical roller bearings.

The load spectrum is a crucial factor for assessing the fatigue reliability of in-service rolling element bearings in transmission systems. For a bearing in a high-speed train gearbox, a measurement technique based on strain detection of bearing outer ring was used to instrument the bearing and determine the time histories of the distributed load in the bearing under different gear meshing conditions. Accordingly, the load spectrum of the total radial load carried by the bearing was compiled. The mean value and class interval of the obtained load spectrum were found to vary non-monotonously with the speed and torque of gear meshing, which was considered to be caused by the vibration of the shaft and the bearing cage. As the realistic service load input of bearing life assessment, the measured load spectrum under different gear meshing conditions can be used to predict gearbox bearing life realistically based on the damage-equivalent principle and actual operating conditions.