Overview of the geometrical influence on the fatigue strength of steel butt welds by a nonlocal approach

Abstract

The paper deals with the high-cycle fatigue behaviour of steel butt-welded joints in the as-welded condition, under constant amplitude loading. It tackles the problem of strength assessment by changing the geometrical shape and features of the weldment. This investigation considers the recommendations available in design standards, particularly referring to the Eurocodes, and it reanalyses experimental data where a clear profile of the actual weld shape is available. For the available weld profiles, numerical investigations are shown by applying the Implicit Gradient approach for the evaluation of the nonlocal effective stress in the fatigue strength assessment. The results are very promising since the nonlocal approach significantly agrees with design standard recommendations in conventional cases, but it is also able to provide specific indications on the influence of the geometrical features, as well as the tip radius and opening angles, specifying their influence when no explicitly detailed indications are available in the design standards.

A two-scale finite element model for the fatigue design of large welded structures

“…Hence, as the volume approach does not require this information, it is preferred here. The efficiency of this approach for notched components has been demonstrated by Taylor [23], Taylor [24] and Livieri and Tovo [25]. Also, to account for the influence of a multiaxial stress field, this approach can easily be coupled with a multiaxial criterion [26,27].…”

A Review on Nonlocal Theories in Fatigue Assessment of Solids

“…Meanwhile, Livieri and Tovo [ 42 ] provided an overview of the geometrical effect on the fatigue strength of steel welded joints by considering nonlocal approaches such as the nonlocal implicit gradient approach. Then, in 2021 [ 43 ], they exploited the implicit gradient approach, as mentioned in Equation (14), to study aluminum welded joints numerically.…”

Smoothed peridynamics for the extremely large deformation and cracking problems: Unification of peridynamics and smoothed particle hydrodynamics

“…However, in the microscale cases it may rule out some effects which exist in the atomic theory and other scaled physics phenomenon, such as long‐range force, cohesive force and their effect on the dispersion of elastic wave 2 . To remedy this situation, a number of theories have been proposed to investigate the granular nature of materials 3–6 …”

“…2 To remedy this situation, a number of theories have been proposed to investigate the granular nature of materials. [3][4][5][6] One of these theories is Eringen's nonlocal theories which was proposed to reconsider classical continuum mechanics more carefully in terms of long-range force effects. The earliest concept of nonlocality in continuum mechanics dates back to the late 19th century in 1893, Duhem pointed out that the stress at one point is related to the strain state of the whole object.…”