PSI - Issue 37

6

A. Prokhorov et al. / Procedia Structural Integrity 37 (2022) 540–546 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

545

a

b

Fig. 6. Temperature evolution during the fatigue tests measured for Armco-iron (a), Titanium Grade 2 (b).

4. Conclusion The conclusion of current work is opening with the idea that design of the specimen geometry and laser shock peening procedure are important part of the fatigue research. The results of the measurements are highly dependent on the conditions of the tests. During this work two types of materials were tested. Each material was investigated in initial condition and peened state. All tests show that the specimens treated by LSP have higher heat dissipation during fatigue loading. This fact can be explained by generation of plastic deformation with such defect structure relaxation which increases heat generation. The results of Armco-iron tests show that laser shock peening procedure can change scenario of fracture initiation and evolution. At the final stage of the test in LSP treated specimen multi cracking with the major crack propagation is observed. In opposite to that, the specimen in the initial state has a one crack during the test. The tests for Titanium Grade 2 show that the heat dissipation is higher for specimens with LSP treatment at the beginning of crack initiation and during the entire test. The character of heat generation during fatigue loading is the same in both cases but for LSP-treated specimens it is more rapid. Acknowledgements The paper was prepared in the framework of the program for the creation and development of the world-class scientific center "Supersonic" for 2020-2025 with the financial support of the Ministry of Education and Science of the Russian Federation (Agreement No. 075-15-2020-925 of November 16, 2020). References Liu, Q., Baburamani, P., and Loader, C., Effect of High Temperature Exposure on the Mechanical Properties of Cold Expanded Open Holes in 7050- T7451 Aluminium Alloy. Air Vehicles Division, DSTO Defence Science and Technology Organisation, Report No. DSTO-TN-0844. 2008, McClung, R.C. A literature survay on the stability and significance of residual stresses during fatigue. Fatigue Fract. Eng. Mater. Struct. 2007, 30, 173-205. LAMBDA Technology Group, Low Plasticity Burnishing August 23, 2013, http://www.lambdatechs.com/low-plasticity-burnishing-LPB.html Jayaraman, N., Hornbach, D. J., and Prev ey, P. S. Mitigation of Fatigue and Pre-Cracking Damage in Aircraft Structures Through Low Plasticity Burnishing (LPB). Proceedings of ASIP, Palm Springs, CA, 2007, December 4 – 6. Ding, K.; Ye, L. Laser Shock Peening: Performance and Process Simulation; Woodhead Publishing Ltd.: Cambridge, UK, 2006 Peyre P, Fabbro R, Merrien P, Lieurade H. Laser shock processing of aluminium alloys. Application to high cycle fatigue behaviour. Mater Sci Eng 1996. V. 210 pp. 102 – 13. Fabbro, R., Peyre, P., Berthe, L., Scherpereel, X., Physics and applications of laser-shock processing. J. Laser Appl. 1998. V. 10, pp. 265 – 279.