Multiaxial Fatigue Life Assessment of Integral Concrete Bridge with a Real-Scale and Complicated Geometry Due to the Simultaneous Effects of Temperature Variations and Sea Waves Clash

Abstract

In the present study, the authors attempted to predict the fatigue lifetime of a real-scale integral concrete bridge with H-shaped steel piles resulting from working and environmental conditions. In this regard, various types of nonproportional variable amplitude loads were applied on the bridge, such as temperature variations and sea waves clash. To this end, CATIA software was used to model the real-scale bridge with its accessories, such as a concrete deck, concrete anchors (walls), I-shaped concrete beams (Ribs), and steel piles. Subsequently, stress analysis was performed to determine the critical area apt to fail. The results showed that steel piles are the most critical bridge components. As a result, in future analysis, the purpose will be to study this critical area, and the effect of relative humidity on the fatigue properties of concrete was ignored. Subsequently, the time history of stress tensor components in the critical area was obtained by performing transient dynamic analysis. Various well-known equivalent stress fatigue theories (von Mises, Findley, Dang Van, McDiarmid, Carpinteri–Spagnoli, Modified Findley, Modified McDiarmid, and Liu–Zenner) were utilized to calculate the equivalent stress caused by the simultaneous effect of temperature variations and sea waves clash. Eventually, the fatigue life of the structure was predicted by employing the rainflow counting algorithm and the Palmgren–Miner damage accumulation rule. The results indicated a reduction in the multiaxial fatigue life of the structure under the simultaneous effects of two phenomena, the daily temperature variations and the sea waves clash, of approximately 87% and 66%, respectively, compared with the fatigue life of the structure under either the effect of temperature changes or the effect of sea waves clash, separately. Therefore, it was necessary to consider all the cyclic loads in the structural design step to estimate the fatigue life of the structure. Moreover, the findings of this case study revealed that the lowest value of multiaxial fatigue lifetime is related to the application of the Liu-Zenner criterion. In other words, this criterion is more conservative than the other used criteria.

XFEM-Based Study of Fatigue Crack Propagation in Rocket Deflector Troughs under Coupled High-Temperature and Impact Conditions

“…It is crucial to note that the increase in temperature not only diminishes the elastic modulus of the metal material but also attenuates its yield strength [18]. Consequently, both these material properties are dynamically adjusted with temperature variations [19], as comprehensively outlined in Table 1 [20]. The temperature referenced for the fracture mechanics properties of the deflector metal material is above 200 °C.…”

“…It is crucial to note that the increase in temperature not only diminishes the elastic modulus of the metal material but also attenuates its yield strength [18]. Consequently, both these material properties are dynamically adjusted with temperature variations [19], as comprehensively outlined in Table 1 [20]. The temperature referenced for the fracture mechanics properties of the deflector metal material is above 200 • C. In comparison, this study's maximum temperature on the lower surface was 132.2 • C. The actual temperature of the metal is lower than this, because this study measured the temperature on the backside of the insulation material.…”

Common Failures in Hydraulic Kaplan Turbine Blades and Practical Solutions

“…A crack's "lifecycle", which culminates in fatigue failure of a cyclically loaded component, is divided into five stages: crack initiation, microstructurally short crack propagation, mechanically/physically short crack propagation, protracted crack propagation, and final structure fracture [122]. Since most industrial parts are under the effect of dynamic and repeating loads, the occurrence of fatigue phenomenon in the industry is inevitable [123][124][125][126][127][128]. In this regard, large industries such as petrochemical and power plants are not excluded.…”

Influence of Conventional Shot Peening Treatment on the Service Life Improvement of Bridge Steel Piles Subjected to Sea Wave Impact

“…The most important achievement obtained in this research is the insight that the use of conical caps improves the fatigue life of a bridge by 45% compared to the use of vertical caps. Abdollahnia et al investigated the simultaneous influence of temperature changes and sea wave impact on the fatigue life of steel piles in integrated bridges [16]. They reported that in both loading modes, the critical zone, which is prone to failure, is the intermediate steel piles at approximately 1.5 m height from the floor.…”