Issue 46

M. Hack et alii, Frattura ed Integrità Strutturale, 46 (2018) 54-61; DOI: 10.3221/IGF-ESIS.46.06 61 Further validation cases on component like (i.e. flat and V-shaped components) have been conducted. In these cases the overall stiffness degradation contribution from the fatigue loading were quite small. The comparison of the predicted and measured stiffness reduction showed good coincidence. As the failures in these examples were not initiated from fatigue failure due to intra-ply damage but due to the inter-laminar delamination from the edge, the examples were not sufficient to fully validate the methodology. So the authors decided that additional validation cases are needed and under investigation. C ONCLUSION new methodology to efficiently analyse the fatigue damage by stiffness reduction under variable amplitude was introduced. It combines the efficiency of the N-Jump algorithm with complex load scenarios under variable and non-proportional loading. First validations show good coincidence between simulated and measured global stiffness behaviour. Further investigation are needed that also include the inter-ply behaviour and the initiation of delamination. This introduces new challenges to extend this methodology to a complete intra-laminar and inter-laminar fatigue damage solution for variable amplitude and multi-axial loadings. The first steps have been already done but further validation of these extensions is still needed. R EFERENCES [1] Van Paepegem, W. (2002). Development and finite element implementation of a damage. PhD Thesis, 2002, U Gent. [2] Siemens PLM Software: Wikipedia [3] Sevenois, R.B. and Van Paepegem, W. (2015). Fatigue Damage Modeling Techniques for Textile Composites: Review and Comparison With Unidirectional Composite Modeling Techniques. ASME. Appl. Mech. Rev. 67(2), 020802- 020802-12. DOI: 10.1115/1.4029691. [4] Xu, J., Lomov, S.V., Verpoest, I. Daggumati, I., Paepegem, W. Van and Degrieck, J. (2009). Meso-scale modeling of static and fatigue damage in woven composite materials with finite element method.” presented in 17th International Conference on Composite Materials (ICCM-17). [5] Xu, J. (2011). Meso Finite Element Fatigue Modelling of Textile Composites, Ph. D. thesis, Dept MTM, Katholieke Universiteit Leuven, Belgium. [6] Miner, M.A. (1945). Cumulative Damage in Fatigue, Journal of Applied Mechanics 67, pp. A159-A164. [7] Matsuishi, M. and Endo, T. (1968). Fatigue of metals subjected to varying stresses, Japanese Society of Mech. Eng., Fukuoka, Japan. [8] Brokate, M. and Sprekels, J. (1996). Hysteresis and Phase Transitions, Series Applied Mathematical Sciences, 121. [9] Brokate, M., Dressler, K. and Krejci, P. (1996). Rainflow counting and energy dissipation for hysteresis models in elastoplasticity, Eur. J. Mech. A/Solids 15, pp. 705-737. [10] Hack, M. (1998). Schädigungsbasierte Hysteresefilter, PhD Thesis, TU Kaiserslautern. [11] Nagode, M. and Hack, M. (2011). The Damage Operator Approach: Fatigue, Creep and Viscoplasticity Modeling in Thermo-Mechanical Fatigue, SAE Int. J. of Mat. & Manuf., 4(1), pp. 632-637, 2011, DOI:10.4271/2011-01-0485. [12] Nagode, M., Hack, M. and Fajida, M. (2010). Low cycle thermo ‐ mechanical fatigue: damage operator approach, Fat. Fract Mat. Struct. 33(3), pp. 149-160. DOI: 10.1111/j.1460-2695.2009.01424.x. [13] Nagode, M., Hack, M. and Fajida, M. (2009). High cycle thermo ‐ mechanical fatigue: damage operator approach, Fat. Fract Mat. Struct. 32(6), pp. 505-514. DOI: 10.1111/j.1460-2695.2009.01353.x. [14] Šeruga, D., Hack, M. and Nagode, M. (2016). Thermomechanical Fatigue Life Predictions of Exhaust System Components, MTZ Worldwide, 77(3), pp. 44-49. DOI:10.1007/s38313-015-0102-y. [15] Brune, M., Fiedler, B., Köttgen, V.B. and Reißel, M. (1998). FEM based Durability analysis of the Knuckle of the 5 Series BMW, Fatigue Design’98, Helsinki. [16] Hack M., Korte W., Straesser S. and Teschner M. (2018). Fatigue simulation of a short fiber reinforced oil-filter under high temperature and pressure loads, Procedia Engineering 213C, pp. 207-214. DOI: 10.1016/j.proeng.2018.02.022. [17] ASTM D3479, Tension Fatigue Testing of Polymer Matrix Composite Materials, Space Simulation, composite mat., 15.03, 2015. A