Nonlinear fatigue crack propagation in a baffle module of Wendelstein 7‐X under cyclic bending loads

Lepore, Marcello Antonio; Berto, Filippo; Maligno, Angelo; Fellinger, J.

doi:10.1111/ffe.13013

Cited by 3 publications

(4 citation statements)

References 32 publications

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“…Furthermore, all the simulations have been carried out in constant amplitude loading condition to calculate the maximum Stress Intensity Factor (SIF) and then ΔK, using an R ‐ratio equal to 0.1. The main advantage of the non‐linear approaches is related to their intrinsic ability to consider the energy dissipated within a small area surrounding the crack front by means of the Low Cycle Fatigue (LCF) properties . Hence, the material chosen for the composite matrix is modelled with either a linear or a non‐linear behaviour according to the Ramberg‐Osgood Equation ,

ε = \frac{σ}{E} + 0.002 {(\frac{σ}{σ_{0}})}^{\frac{1}{n}},

where n = 0.178 is the strain hardening coefficient, E = 74 000 MPa is the Young modulus, σ 0 = 314 MPa is the tensile yielding strength of the material, while the ultimate strength is σ ult = 487 MPa .…”

Section: Methodsmentioning

confidence: 99%

“…The main advantage of the non-linear approaches is related to their intrinsic ability to consider the energy dissipated within a small area surrounding the crack front by means of the Low Cycle Fatigue (LCF) properties. 11 Hence, the material chosen for the composite matrix is modelled with either a linear or a non-linear behaviour according to the Ramberg-Osgood Equation (1),…”

Section: Methodsmentioning

confidence: 99%

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Non‐linear fatigue propagation of multiple cracks in an aluminium metal matrix composite (AlMMC) with silicon‐carbide fibre reinforcement

Lepore

Sanguigno

Zamani

et al. 2019

Mat Design & Process Comms

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The fatigue crack growth (FCG) in a mesoscale metal matrix composite (MMC) sample has been simulated by the analyses of a 3D finite elements (FEs) model of a sample volume cell of the composite. Several FCG numerical simulations have been performed on MMC specimens made of aluminium (Al) alloy and silicon carbide (SiC). First, in the microscale, the homogenization of the single MMC unit cell has been performed in order to find the crack initiation sites. Subsequently, in the mesoscale, a tensile remote load with appropriate boundary conditions has been applied on the MMC unit volume. Simulation of FCG has been carried out using the Paris law and two non‐linear laws for small‐scale yielding (SSY), namely, the modified Kujawski‐Ellyin (KE) and UniGrow laws. Finally, the FCG rates provided by numerical simulations have been compared with each other.

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ε = \frac{σ}{E} + 0.002 {(\frac{σ}{σ_{0}})}^{\frac{1}{n}},

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Non‐linear fatigue propagation of multiple cracks in an aluminium metal matrix composite (AlMMC) with silicon‐carbide fibre reinforcement

Lepore

Sanguigno

Zamani

et al. 2019

Mat Design & Process Comms

Self Cite

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“…Kuna (1998) early presented three-dimensional finite element techniques to calculate the singular coupled electrostatic and anisotropic elastic fields at the crack front tips and confirm the fracture controlling parameters like stress intensity factors and energy release rates. Recently, the fatigue crack behavior was investigated by FEM-based numerical simulations and experimental fatigue tests under different cyclic loading Lepore et al, 2019aLepore et al, , 2019b.…”

Section: Introductionmentioning

confidence: 99%

Finite element analysis of the three-dimensional crack and defects in piezoelectric materials under the electro-mechanical coupling field

Zhu

Liu

2021

Journal of Intelligent Material Systems and Structures

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This paper presents three-dimensional planar crack and non-planar defects analysis of piezoelectric materials by the finite element method (FEM). Based on practical engineering, a series of reasonable three-dimensional defects models are established. Different from the usual two-dimensional plane as a three-dimensional defect form, the present paper takes into account the different causes, concrete position, and various shapes of typically three-dimensional non-planar defects in practical engineering. By changing the geometric size of the defect and the electro-mechanical boundary conditions, the effects of three-dimensional defect geometry and different electro-mechanical coupling boundary conditions on the distribution of stress, electric field strength, and electric displacement around the defect are investigated. The calculation results show that the electro-mechanical parameters are strongly affected by the geometry of defect and boundary conditions. Furthermore, the distribution of electro-mechanical parameters in the detailed position of the different three-dimensional defect model is also studied, which can accurately assess the location where the defect is prone to fracture. It is concluded that this paper can be used as a reference of three-dimensional defects and the service life of piezoelectric materials in practical engineering structures.

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“…Crack initiation under compressive loading has been explained by tensile residual stresses at the weld. Compressive residual stresses have been shown to slow down crack propagation in Tateishi et al 12 Recently, crack propagation under the influence of residual stresses has been studied in numerical and experimental investigations on brazed pipe specimens 13 and friction stir welded specimens 14 …”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on the influence of welding residual stresses on fatigue for two different weld geometries

Friedrich

2020

Fatigue Fract Eng Mat Struct

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Fatigue tests on welded small-scale specimens often do not show a distinct residual stress influence. An exception is longitudinal stiffeners, which are therefore frequently used to study the influence of welding residual stresses on fatigue. The results are not directly transferable to other weld geometries because the residual stress distribution depends on the weld geometries. In the presented investigation, fatigue tests on multilayer K-butt weld and longitudinal stiffener specimens were performed. The tests were carried out in the as-welded and stress-relieved conditions at different load ratios. Initiation of macroscopic cracks was detected using digital image correlation. This allowed determining the influence of welding residual stresses on the initiation of macroscopic cracks, crack propagation and total fatigue life for both investigated weld geometries.

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Nonlinear fatigue crack propagation in a baffle module of Wendelstein 7‐X under cyclic bending loads

Cited by 3 publications

References 32 publications

Non‐linear fatigue propagation of multiple cracks in an aluminium metal matrix composite (AlMMC) with silicon‐carbide fibre reinforcement

Non‐linear fatigue propagation of multiple cracks in an aluminium metal matrix composite (AlMMC) with silicon‐carbide fibre reinforcement

Finite element analysis of the three-dimensional crack and defects in piezoelectric materials under the electro-mechanical coupling field

Experimental investigation on the influence of welding residual stresses on fatigue for two different weld geometries

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