Issue 41

A. A. Ahmed et alii, Frattura ed Integrità Strutturale, 41 (2017) 252-259; DOI: 10.3221/IGF-ESIS.41.34 259  satisfactory results were obtained by forming the hypothesis that the mechanical behaviour of additively manufactured PLA follows a simple linear-elastic constitutive law;  more work has to be done in this area to systematically check the accuracy and reliability of the TCD when used to predict static failures in additively manufactured materials not only characterised by different elasto-plastic behaviours, but also failing by different mechanisms. R EFERENCES [1] Taylor, D. The Theory of Critical Distances: A new perspective in fracture mechanics. Elsevier, Oxford, UK (2007). [2] Taylor, D. Predicting the fracture strength of ceramic materials using the theory of critical distances. Engng. Fract. Mech. 71 (2004) 2407-2416. [3] Susmel, L., Taylor, D. The theory of critical distances to predict static strength of notched brittle components subjected to mixed-mode loading. Eng Frac Mech, 75 3-4 (2008) 534-550. [4] Susmel, L., Taylor, D. On the use of the Theory of Critical Distances to predict static failures in ductile metallic materials containing different geometrical features. Engng. Fract. Mech. 75 (2008) 4410-4421. [5] Susmel, L., Taylor, D. The Theory of Critical Distances to estimate the static strength of notched samples of Al6082 loaded in combined tension and torsion. Part I: Material cracking behaviour. Engng. Fract. Mech. 77 (2010) 452–469. [6] Susmel L., Taylor D. The Theory of Critical Distances to estimate the static strength of notched samples of Al6082 loaded in combined tension and torsion. Part II: Multiaxial static assessment. Engng. Fract. Mech. 77 (2010) 470–478. [7] Susmel, L., Askes, H. Material length scales in fracture analysis: from Gradient Elasticity to the Theory of Critical Distances. Computational Technology Reviews 6 (2012) 63-80. [8] Susmel, L., Askes, H., Bennett, T., Taylor, D. Theory of Critical Distances vs. Gradient Mechanics in modelling the transition from the short- to long-crack regime at the fatigue limit. Fatigue Fract Engng Mater Struct. (2013). [9] Askes, H., Livieri, P., Susmel, L., Taylor, D., Tovo R. Intrinsic material length, Theory of Critical Distances and Gradient Mechanics: analogies and differences in processing linear-elastic crack tip stress fields. Fatigue Fract Engng Mater Struct. 36 (2013) 39-55. [10] Hamad, K., Kaseem, M., Yang, H.W., Deri, F., Ko, Y.G.. Properties and medical applications of polylactic acid: a review. eXPRESS Polymer Letters 9 (2015) 435–455. [11] Whitney, J.M., Nuismer, R.J. Stress fracture criteria for laminated composites containing stress concentrations. J. Composite Mater. 8 (1974) 253-265. [12] Sheppard, S.D. Field effects in fatigue crack initiation: long life fatigue strength. Transactions of ASME, Journal of Mechanical Design 113 (1991) 188-194. [13] Bellett, D., Taylor, D., Marco, S., Mazzeo, E., Guillois, J., Pircher, T. The fatigue behaviour of three-dimensional stress concentrations. Int. J. Fatigue 27 (2005) 207-221. [14] Pilkey, W.D., Pilkey, D.F. Peterson's Stress Concentration Factors. Wiley, USA, (2008). [15] Anderson, T.L. Fracture Mechanics: Fundamentals and Applications, CRC Press, USA, (2005). [16] Tada, H., Paris, P.C., Irwin, G.R. Stress Analysis of Cracks Handbook, ASME Press, USA, (2000). [17] Taylor, D., Merlo, M., Pegley, R., Cavatorta, M.P. The effect of stress concentrations on the fracture strength of polymethylmethacrylate. Materials Science and Engineering A 382 (2004) 288-294. [18] Glinka, G., Newport, A. Universal features of elastic notch-tip stress fields. Int. J. Fatigue 9 (1987) 143-150.