SteBLife – The Enhanced Short-Time Evaluation Procedure for Materials Fatigue Data Generation

Abstract:

The availability of reliable fatigue data is of continuous and often urgent need. The paper to be presented therefore intends to show how the potential of non-destructive testing methods, digitisation in metrology as well as signal processing can be combined in order to achieve a significant gain in information concerning the fatigue behaviour combined with a reduction of required experimental effort and cost. The new SteBLife approach is an enhanced short-time calculation method developed at the Chair of Non-Destructive Testing and Quality Assurance at Saarland University, which takes into account that a material’s elastic-plastic reaction and hence relationship is non-linear. With respect to a test strategy, the number of fatigue experiments required to determine a material’s complete S-N-curve can be limited to three to five tests only (SteBLife_mtc, mtc: multiple tests, trend curve and SteBLife_msb, msb: multiple tests, scatter bands) in cases that mean values and/or complete scatter bands of S-N-curves are required. If a trend S-N-curve is sufficient, the effort can be reduced to one single test only (SteBLife_stc, stc: single test, trend curve) with a special step-shaped specimen. This leads to a significant improvement in efficiency when compared to the conventional way an S-N-curve is determined where a minimum of 15 fatigue tests is required. Within the work to be presented the SteBLife method is demonstrated for normalized SAE 1045 (C45E) steel.

• Periodical: Materials Science Forum (Volume 941)
• Pages: 2395-2400
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.941.2395
• Online since: December 2018
• Authors: Peter Starke*, Haoran Wu, Christian Boller
• Keywords: Fatigue Life Evaluation, Non-Destructive Testing, SteBLife, Thermography

References

[1] R.W. Landgraf, J. Morrow, T. Endo, Determination of the cyclic stress-strain curve J. Mater. 4 (1) (1969) 176–188.

[2] G. Meneghetti, Analysis of the fatigue strength of a stainless steel based on the energy dissipation, Int J Fatigue 29;1 (2007) 81–94.

DOI: 10.1016/j.ijfatigue.2006.02.043

[3] O. Plekhov, T. Palin-Luc, N. Saintier, S. Uvarov, O. Naimark, Fatigue crack initiation and growth in a 35CrMo4 steel investigated by infrared thermography, Fatigue Fract Eng M 28;1-2(2005) 169–178.

DOI: 10.1111/j.1460-2695.2005.00856.x

[4] B. Sun, L. Yang, Y. Guo, A high-cycle fatigue accumulation model based on electrical resistance for structural steels, Fatigue Fract Eng M 30;11 (2007) 1052–1062.

DOI: 10.1111/j.1460-2695.2007.01175.x

[5] I. Altpeter, R. Tschuncky, K. Hällen, G. Dobmann, C. Boller, M. Smaga, A. Sorich, D. Eifler, Early detection of damage in thermo-cyclically loaded austenitic materials, 16th Int. Workshop on Electromagnetic Non-destructive Evaluation (ENDE), 10.-12. March, India, (2011) 130-139.

[6] P. Starke, D. Eifler, C Boller, Fatigue assessment of metallic materials beyond strain measurement, Int. J. Fat. 82 (2015) 274-279.

DOI: 10.1016/j.ijfatigue.2015.03.018

[7] P. Starke, A. Bäumchen, H. Wu H, SteBLife – A new short-time procedure for the calculation of S-N curves and failure probabilities. Mater Test 60 (2018) 1–7.

DOI: 10.3139/120.111139

[8] P. Starke, H. Wu, C Boller, Advanced Evaluation of Fatigue Phenomena Using Non-Destructive Testing Methods. Adv. Mater. Proc. THERMEC 2016 (2016), 1841–1847.

DOI: 10.4028/www.scientific.net/msf.879.1841

[9] JD. Morrow, Cyclic plastic strain energy and fatigue of metals. Internal friction, damping and cyclic plasticity, Philadelphia, PA: American Society for Testing and Materials (1964) 45–87.

DOI: 10.1520/stp43764s

[10] OH. Basquin, The exponential law on endurance tests, Proc ASTM 10 (1910) 625–630.

[11] W.J. Dixon, F. Jr. Massey, Introduction to statistical analysis, The Maple Press Company, York (1969).