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Shot peening technology is used to improve the fatigue strength of materials and parts, and is one of the most effective surface engineering techniques to prolong fatigue life. In this paper, according to the finite element simulation analysis of shot peening, a randomly distributed multiple-shot finite element model was established. The superimposed effects of multiple projectile impact craters in shot peening are fully considered. The effects of shot velocity, shot peening angle and shot coverage on the residual stress field and surface roughness were studied. The alloy steel 20MnTiB, widely used in the automotive industry, was used as the raw material to process the specimens. The shot peening tests of different process parameters were carried out. The test results verified the correctness and accuracy of the random distribution model of multiple-shot. The shot-peening simulation model proposed in this paper allows a more accurate analysis of the effect of shot-peening parameters on the surface residual stress field and helps to quickly set the correct shot-peening process parameters. This paper further investigates the effect of shot peening parameters on fatigue life, providing a basis for the rational development of shot peening solutions.

The compressor blade-disk system of an aero-engine is a complicated system with numerous components, and the failures of components are related. To evaluate its reliability accurately and efficiently, a fatigue reliability assessment method to handle the issues with failure dependency between components was proposed. Firstly, the finite element analysis was carried out considering the dispersion of load and material; secondly, the probabilistic distributions of stress, strain, and fatigue life of components were fitted by the response surface method; finally, the multi-component failure-dependent reliability model (MCFDM) of the compressor blade-disk system was established based on the dependent failure system reliability theory. Based on this model, the fatigue life of the blade-disk system at varying reliability levels and the reliability and failure probability at varying specified life levels were calculated. The results of MCFDM are compared with those of the independent failure reliability assessment model(IFM) and the traditional Monte Carlo method(MCM). It is demonstrated that the system reliability calculated by IFM is too optimistic, while MCM requires a large number of samples based on the finite element model directly. In comparison, MCFDM can offer results with sufficient accuracy and higher efficiency.

High-speed trains are now the most important medium- and long-distance mode of transport in many countries, and green economy is one of the important directions of high-speed train design. Aluminum alloy material is widely used in various structural parts of high-speed trains due to its advantages of high strength and low density, etc. As the speed of high-speed trains is getting faster and faster, the load on the car body structure is getting bigger and bigger, the safety, reliability and longevity of aluminum alloy structure has received wide attention. In this paper, the stress distribution, maximum stress value and maximum stress point position of aluminum alloy structural members of high-speed trains are analyzed in detail based on the real load situation, and the influence of stress level on train operation is analysed. The above work has certain reference significance for the design of high-speed train.