A Method Based on Virtual Strain-Energy Parameters for Multiaxial Fatigue Life Prediction

Abstract

A new method is proposed for multiaxial fatigue life prediction using correlation parameters based on virtual strain energy as a measure of fatigue damage on critical planes of fracture. The virtual strain-energy parameters are physically associated with two different modes of fatigue fracture planes. The critical plane leading to Mode I fracture is driven by the principal stress and strain, and the other, leading to Mode II fracture, is driven by the maximum shear stress and strain. The mode of crack initiation and propagation depends on material, temperature, strain range, and stress and strain histories, but not on the relative magnitude of the virtual strain-energy parameters. Biaxial fatigue data obtained from the literature were analyzed for Type 304 stainless steel tested at room and elevated temperatures and for SAE 1045 steel tested at room temperature under in-phase and 90° out-of-phase loading conditions. Comparisons are made between experimental data and theoretical predictions to show the effectiveness of the proposed method.

Fatigue Life Estimation Based on Continuum Mechanics Theory With Application of Genetic Algorithm

“…Liu [27] presented a virtual strain energy (VSE) model which is a critical plane model, as work quantities are defined for specific planes within the material. For multiaxial loading, VSE considers two possible failure modes: a mode for tensile failure and a mode for shear failure.…”

On the multiaxial fatigue assessment of complex three-dimensional stress concentrators

“…2a). As to definition (9), it is worth observing here also that L is recommended to be always estimated through fatigue properties (i.e., Dr 0 and DK th ) experimentally determined under fully-reversed loading, the mean stress effect being directly taken into account by the MWCM itself [33]. The MWCM can be applied together with the PM also to estimate finite lifetime, provided that the critical distance increases as the number of cycles to failure, N f , decreases, i.e.…”

“…As to the multiaxial fatigue issue, it is worth observing here that, starting from the pioneering work done by Gough back in the 1940s [6], a tremendous effort has been made by the scientific community to propose reliable criteria suitable for estimating fatigue damage under multiaxial fatigue loading. Amongst the different methods which have been proposed and experimentally validated so far certainly the criteria formalised by Dang Van et al [7], Papadopoulos [8], Liu [9], Fatemi and Socie [10], and Brown and Miller [11] deserve to be mentioned explicitly.…”

Critical plane concept and energy approach in multiaxial fatigue

“…In 1993, Liu proposed to predict the multiaxial fatigue strength of materials under proportional and non-proportional loadings by using the virtual strain energy (VSE) ∆W VSE = ∆W VSE, n + ∆W VSE,γ = ∆σ∆ε + ∆τ∆γ /2 computed on the critical fracture plane. This critical plane is depending on the cracking mode of the material (mode I or II) and on the crack orientation in mode II (type A or B) [14]. Glinka et al [15] used the normal and shear parts of energy in the critical plane: W* = (∆σ/2) (∆ε/2) + (∆τ /2) (∆γ /2) .…”