Three-dimensional effects at the tip of rounded notches subjected to mode-I loading under cyclic plasticity

Abstract

In this work, a comprehensive theoretical and numerical study on the cyclic elastic-plastic notch stress and strain distributions is carried out. In more detail, the incremental cyclic plasticity theory, already proposed by other authors to determine the actual stress and strain state arising in two-dimensional or axisymmetric notched components, is extended to the study of three-dimensional effects at the tip of rounded notches in plates of finite thickness. The analytical frame is initially validated considering a number of plane problems and later modified to consider three-dimensional effects. Different notch geometries are investigated, such as plane specimens with finite thickness weakened by circular holes, U-notches and rounded V-notches subjected to cyclic mode-I loading. Theoretical results based on the incremental cyclic plasticity theory are compared with time-consuming elastic-plastic finite element analyses carried out with a commercial finite element code showing a very satisfactory agreement. Finally, a link between the averaged strain energy density criterion and the area subtended by the hysteresis loops tied to the different stress and strain components acting at the notch tip has been investigated

Coupled fracture modes of discs and plates under anti‐plane loading and a disc under in‐plane shear loading

“…The advantage of the SED parameter if compared with other local parameters is that it is not sensitive to the size of the finite elements so that it can be directly evaluated using coarse meshes. 4,5,36,37 With the aim of providing some numerical assessment of the contribution of the three-dimensional effects, because of the induced fracture mode, K II , the local energy has been employed in previous works. 4,5,36,37 With the aim of providing some numerical assessment of the contribution of the three-dimensional effects, because of the induced fracture mode, K II , the local energy has been employed in previous works.…”

Fatigue strength of steel rollers with failure occurring at the weld root based on the local strain energy values: modelling and fatigue assessment

“…As opposed to the direct evaluation of the NSIFs, which needs very refined meshes, the mean value of the elastic SED on the control volume can be determined with high accuracy by using coarse meshes [42][43][44] and directly takes into account the three-dimensional effects well described in [45][46][47][48]. Very refined meshes are necessary to directly determined the NSIFs from the local stress distributions.…”

Effect of corrosion and fatigue on the remaining life of structures and its implication to additive manufacturing

“…As an important factor in failure assessments under fatigue and static loading, 3D effect has been studied in numerous researches and 3D effects in the form of stress state have been investigated for wide variety of notch geometries under various in-plane and out of plane loading conditions by considering stress concentration factors and constraint factors throughout the thickness of the specimen [48,49]. As a representative of stress state in cracked and notched components, the variations of the stress concentration factor as a function of the thickness have been studied in some recent researches by Berto and co-researchers [50][51][52][53][54][55][56]. As an interesting and effective fact, the same concept can be considered for fatigue crack growth assessment in metallic components of steel bridges with presence of natural corrosion in the material.…”