Fatigue crack growth behavior of cables and steel wires for the cable-stayed portion of Runyang bridge: Disproportionate loosening and/or tightening of cables

Experimental analyses on the structural response caused by local fatigue damage accumulation in welded details are accomplished to perform failure process and nonlinear effect analysis at different structural levels. The experiment is carried out by using welded compact tension (CT) specimens and a scaled truss specimen, and all of them have a notch at the weld toe to facilitate damage initiation. Cyclic loads are applied to those specimens to generate accumulative fatigue damage, respectively. The process of fatigue accumulation including initiation and propagation of fatigue cracks in the welded detail and resultant structural responses of CT specimens and the truss are measured with integration of multiple testing techniques. Multi‐scale experimental results show that microscopic‐/mesoscopic‐concentrated strain and extension of plastic zone in the vicinity of notch tip are both affected significantly by the fatigue damage accumulation and present appreciable nonlinear behaviour; however, the macroscopic response such as the frequency and stiffness parameters of the welded truss specimen are less sensitive to the low‐level fatigue damage. It is concluded that the fatigue failure of the welded truss is a multi‐scale progressive process due to fatigue damage trans‐scale evolving, in which the local meso‐damage firstly affects local strain of plastic zone in the vicinity of the notch tip, and then fatigue damage evolving from meso‐ to macro‐scale affects nonlinear responses of the damaged components; lastly, the fatigue failure could be expected as the results of the propagation of macroscopic fatigue cracks.

Section: Analyses On the Effect Of Mesoscopic Fatigue Damage On Macromentioning

confidence: 72%

“…This was a damage‐oriented model that accounts for the major effects of the damage, local deterioration processes and nonlinear influence on structural response. Pommier et al 30–33 . proposed their respective multi‐scale models to discuss the fatigue failure behaviour in the crack tip region or in the pre‐tensioned bridge cables.…”

Section: Introductionmentioning

confidence: 99%

Multi‐scale experimental study on fatigue damage behaviour and its effect on structural nonlinear response

Huaming

et al. 2012

“…Over the last decade, there has been a rapid growth in the diversity of steel cable products to meet the market requirements for developing modern long‐span rope bridges (LSRBs). As it is well known, the durability of bridge wire ropes is very important for the continuing interest in this area 1–4 . Steel cables have great flexibility and strength associated with light weight as well as beautiful appearance, which are suitable for structures of special architectural.…”

Section: Introductionmentioning

confidence: 99%

Corrosion fatigue performance of pre‐split steel wires for high strength bridge cables

Jiang

Weng

et al. 2009

A B S T R A C TThe first parametric investigation about corrosion fatigue (CF) behaviour of pre-split high-strength galvanized steel wires was conducted for perfecting the design and maintenance of modern bridge cable structures. Counting the cycle number to failure presents that lower fatigue endurance always correlates with higher stress amplitude, while decrease in load ratio and/or increase in cyclic load frequency significantly prolongs the CF life. Electron fractography indicates that the fatigue crack growth rate of the steel wires is lower in air with the presence of tyre tracks on the fracture surface, and faster in aggressive media resulting from anodic dissolution and crack opening displacement at the crack tips. Longer CF endurance of bridge cable steel wires can be expected through ideal thermo-mechanical treatment after the successive cold drawing, for a significant benefit on corrosion resistance and microstructure improvement.

“…Strain energy density is the energy stored either in macroscopic scale or microscopic scale, in contrast to the stress criterion for the Δ K model. The volume energy density (VED) factor S naturally can be treated as the released energy at the initiation of instability and serve a better choice for multiscaling fatigue solution . Recent work on the applications of energy density criterion is included in Lazzarin et al ., Lazzarin and Berto, Berto and Lazzarin and Berto and Lazzarin…”

Section: Introductionmentioning

confidence: 99%

Interactive creep–fatigue crack growth of 2024‐T3 Al sheets: selective transitional functions

Tang

2014

Interactive creep–fatigue on aeronautical materials has been of a great concern to engineers and researchers. There are still more fundamental issues to be addressed. In this regard, 2024‐T3 Al sheets are considered to study the transitional behaviours that incorporatematerial, loading and geometry effects in the interactive creep–fatigue process. A dual‐scale fatigue crack growth da/dN‐ΔS model that includes microscale, macroscale and large scales is proposed based on the volume energy density criterion. The model generates the transitionalised crack length (TCL) compared with the fictitious crack length (FCL) yielded from the da/dN‐ΔK model that is only restricted to monoscaling. Crossover points are observed across TCL and FCL curves. With stress amplitude being fixed, three levels of mean stress are employed to discuss the variational effects of transitional functions (TFs). Applied loading conditions have an appreciable effect on the fatigue life cycles of 2024‐T3 Al sheets. Variation of R ratios leads to the interactive creep–fatigue behaviour and further enforces the selective TFs in the inherent multiscaling process. TCLs and FCLs are compared with test data of the 2024‐T3 Al sheet. Rationality and superiority of the dual‐scale crack growth model are validated.