TY - JOUR AU - Campagnolo, A. AU - Berto, F. AU - Pook, L. P. PY - 2015/09/28 Y2 - 2024/03/28 TI - Three-dimensional effects on cracked discs and plates under nominal Mode III loading JF - Frattura ed Integrità Strutturale JA - Fra&IntStrut VL - 9 IS - 34 SE - Miscellanea DO - 10.3221/IGF-ESIS.34.20 UR - https://www.fracturae.com/index.php/fis/article/view/1571 SP - AB - <p>The existence of three-dimensional effects at cracks has been known for many years, but<br>understanding has been limited, and for some situations still is. Understanding improved when the existence of<br>corner point singularities and their implications became known. Increasingly powerful computers made it<br>possible to investigate three-dimensional effects numerically in detail. Despite increased understanding, threedimensional<br>effects are sometimes ignored in situations where they may be important. The purpose of the<br>present contribution is to review the study carried out by the same authors in some recent investigations, in<br>which a coupled fracture mode generated by anti-plane loading of a straight through-the-thickness crack in<br>linear elastic discs and plates has been analysed by means of accurate 3D finite element (FE) models.<br>The results obtained from the highly accurate finite element analyses have improved understanding of the<br>behaviour of through cracked components under anti-plane loading. The influence of plate bending is<br>increasingly important as the thickness decreases. It appears that a new field parameter, probably a singularity, is<br>needed to describe the stresses at the free surfaces. Discussion on whether KIII tends to zero or infinity as a<br>corner point is approached is futile because KIII is meaningless at a corner point.<br>The intensity of the local stress and strain state through the thickness of the cracked components has been<br>evaluated by using the strain energy density (SED) averaged over a control volume embracing the crack tip. The<br>SED has been considered as a parameter able to control fracture in some previous contributions and can easily<br>take into account also coupled three-dimensional effects. Calculation of the SED shows that the position of the<br>maximum SED in the discs case is a function of the thickness. In the plates case instead the position of the<br>maximum SED is independent of plate thickness, contrary to disc results.</p> ER -