Fatigue and Fracture of the 767 Graphite Torsion Spring

Anisotropy of mechanical properties, fatigue and fracture resistance of precipitation hardened CuCrZr alloy ultrafine (UFG) grained by equal-channel angular pressing (ECAP) is in focus of the present communication. Fracture toughness was estimated in terms of J-integral and the fatigue crack growth rate was quantified. It was found that although the estimated JIC-value appeared lower than that reported in the literature for a reference alloy, the ductility, fracture and crack growth resistance remained satisfactory after ECAP while the tensile strength and fatigue limit improved considerably. The stable crack growth rate did not differ very much for ECAP and reference conventional CuCrZr and no remarkable anisotropy in the stable crack growth was noticed.

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Current challenges in modelling vibrational fatigue and fracture of structures: a review

Journal of the Brazilian Society of Mechanical Sciences and Engineering ◽

10.1007/s40430-020-02777-6 ◽

2021 ◽

Vol 43 (2) ◽

Author(s):

Khangamlung Kamei ◽

Muhammad A. Khan

Keyword(s):

Fatigue Damage ◽

Thermal Environment ◽

Research Work ◽

Working Life ◽

Stochastic Response ◽

Metal Structures ◽

Life Estimation ◽

The Past ◽

New Directions ◽

Fatigue And Fracture

AbstractFatigue damage is a concern in the engineering applications particularly for metal structures. The design phase of a structure considers factors that can prevent or delay the fatigue and fracture failures and increase its working life. This paper compiled some of the past efforts to share the modelling challenges. It provides an overview on the existing research complexities in the area of fatigue and fracture modelling. This paper reviews the previous research work under five prominent challenges: assessing fatigue damage accurately under the vibration-based loads, complications in fatigue and fracture life estimation, intricacy in fatigue crack propagation, quantification of cracks and stochastic response of structure under thermal environment. In the conclusion, the authors have suggested new directions of work that still require comprehensive research efforts to bridge the existing gap in the current academic domain due to the highlighted challenges.

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Image-based multiscale modeling with spatially varying microstructures from experiments: Demonstration with additively manufactured metal in fatigue and fracture

Journal of the Mechanics and Physics of Solids ◽

10.1016/j.jmps.2021.104350 ◽

2021 ◽

Vol 150 ◽

pp. 104350

Author(s):

Orion L. Kafka ◽

Kevontrez K. Jones ◽

Cheng Yu ◽

Puikei Cheng ◽

Wing Kam Liu

Keyword(s):

Multiscale Modeling ◽

Fatigue And Fracture ◽

Spatially Varying

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Shear Behavior of a Reinforced Concrete Frame Retrofitted with a Hinged Steel Damping System

Sustainability ◽

10.3390/su122410360 ◽

2020 ◽

Vol 12 (24) ◽

pp. 10360

Author(s):

Hyun-Do Yun ◽

Sun-Woong Kim ◽

Wan-Shin Park ◽

Sun-Woo Kim

Keyword(s):

Reinforced Concrete ◽

Shear Behavior ◽

Seismic Retrofitting ◽

Reinforced Concrete Frame ◽

Main Research ◽

Torsion Spring ◽

Concrete Frame ◽

Energy Dissipation Capacity ◽

Research Questions ◽

Torsion Springs

The purpose of this study was to experimentally evaluate the effect of a hinged steel damping system on the shear behavior of a nonductile reinforced concrete frame with an opening. For the experimental test, a total of three full-scale reinforced concrete frame specimens were planned, based on the “no retrofitting” (NR) specimens with non-seismic details. The main research questions were whether the hinged steel damping system is reinforced and whether torsion springs are installed in the hinged steel damping system. From the results of the experiment, the hinged steel damping system (DR specimen) was found to be effective in seismic retrofitting, while isolating the opening of the reinforced concrete (RC) frame, and the torsion spring installed at the hinged connection (DSR specimen) was evaluated to be effective in controlling the amount of deformation of the upper and lower dampers. The strength, stiffness, and energy dissipation capacity of the DSR specimen were slightly improved compared to the DR specimen, and it was confirmed that stress redistribution was induced by the rotational stiffness of the torsion spring installed in the hinge connection between the upper and lower frames.

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ECA Methodology for Fatigue Design of Risers and Flowlines

Volume 3: Pipeline and Riser Technology; CFD and VIV ◽

10.1115/omae2007-29066 ◽

2007 ◽

Author(s):

C. H. Luk ◽

T. J. Wang

Keyword(s):

Fracture Mechanics ◽

Design Method ◽

Steel Catenary Riser ◽

Fatigue Design ◽

Wide Range ◽

Fatigue And Fracture ◽

Level 3 ◽

Fatigue Loads ◽

Vessel Motion ◽

Level 2

Engineering Criticality Assessment (ECA) is a procedure based on fracture mechanics that may be used to supplement the traditional S-N approach and determine the flaw acceptance and inspection criteria in fatigue and fracture design of risers and flowlines. A number of design codes provide guidance for this procedure, e.g. BS-7910:2005 [1]. However, more investigations and example studies are still needed to address the design implications for riser and flowline applications. This paper provides a review of the existing ECA methodology, presents a fracture mechanics design method for a wide range of riser and flowline fatigue problems, and shows flaw size results from steel catenary riser (SCR) and flowline (FL) examples. The first example is a deepwater SCR subjected to fatigue loads due to vessel motion and riser VIV. The second example is a subsea flowline subjected to thermal fatigue loads. The effects of crack re-characterization and material plasticity on the Level-2 and Level-3 ECA results of the SCR and flowline examples are illustrated.

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