1. 研究目的与意义（文献综述）

in the automobile production process, a large amount of metal materials need to be processed. among these, there are a large number of metal materials that need to withstand a variety of loads, and their working environments are also different. as the most serious and dangerous form of failure of metal parts, fractures are detested by the automotive industry^【1】. this will not only bring serious economic losses, but also have a great danger to human life. therefore, effectively improving the ability of materials to resist fatigue and fracture is an eternal theme faced by engineers in research and production^【2】.

the shot peening process is a surface treatment process in which the high-speed projectile impacts the surface of the component so that the surface layer of the component obtains residual compressive stress, thereby changing the surface mechanical properties of the component material. as a typical mechanical processing, component surface cold treatment process, shot peening has a unique, other surface strengthening process does not have the advantage: not limited by the type of material, static strength and shape, and its strengthening effect is outstanding. therefore, the shot peening process has been widely used in many fields of aerospace, aerospace, military, automotive and other machinery manufacturing^{【3 -5】}.

spring steel is generally divided into carbon spring steel and alloy spring steel according to chemical composition. depending on the carbon content and the different elements added, it can be used to produce coil springs or leaf springs for automobiles^【6】. vehicle spring steel needs to meet certain technical requirements, reduce non-metallic impurities, control chemical composition, and improve surface strength and dimensional accuracy^【7-8】. in this paper, through the process analysis of 60si2mn vehicle spring steel shot peening, comprehensive analysis of the principle and method of shot peening, and the establishment of multiple projectile impact strength model and component mechanical model, according to the finite element simulation results put forward shot peening parameters optimization program. using abaqus software simulation to numerically simulate shot peening can overcome the disadvantages of cumbersome and time-consuming experiment process, and can easily change the shot peening parameters to study the effect of different shot peening parameters on shot peening.

2. 研究的基本内容与方案

(1) extensively collect data to understand the principle and method of mechanical surface strengthening, to understand the research status of shot peening and numerical analysis at home and abroad, analyze the process characteristics of shot peening, and compare the advantages and disadvantages of different mechanical reinforcement methods.

(2) analyze the process of shot peening for vehicle spring steel, establish the impact hardening model of multiple projectiles, and establish the component mechanical model.

(3) based on the obtained data, the influence of shot peening parameters on the residual stress field was studied.

3. 研究计划与安排

1-2 (7 semester, 19 to 20 weeks) determine the topic of design plan, descriptions of the graduation design selection (parameters), the campus information collection.

3 (8 semester 1 week) design, document retrieval, complete the opening report.

(2-3 weeks) practice outside, the data collection outside, finish internship report.

4. 参考文献（12篇以上）

[1] liu ruwei, zhang laibin, wang ruiguo, song qingan, wu chengmin. the origin and development history of shot blasting technology (1870-1954)[j]. china foundry equipment and technology, 2012(03):1-3.

[2] xue wenjuan, liu linsen, wang kaiyang, wang lian, yang yaping. application and development of shot peening technology[j]. material protection, 2014, 47(05): 46-49 8.

[3]lu gang. vehicle spring and its development perspective[j]. urban vehicles, 2008(07):49-53.