Rapid characterization of the fatigue limit of additive-manufactured maraging steels using infrared measurements

Douellou, Corentin; Balandraud, Xavier; Duc, Emmanuel; Verquin, Benoît; Lefèbvre, Fabien; Sar, Frédéric

doi:10.1016/j.addma.2020.101310

Cited by 11 publications

(15 citation statements)

References 38 publications

(74 reference statements)

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“…• Classical LayerWise Approach: ∼ 9 2 (𝑁 𝑧 .𝐷 𝑧 ) 3 .𝑁𝐷 𝑥 .𝑁 𝑡 • PGD approach computation time for the 𝑇 𝑡 problem: ∼ 1 2 𝑁 3 4𝑢𝑝 𝑁 𝑡 • PGD approach computation time for the 𝑇 𝑧 problem:…”

Section: Comments About Computational Costmentioning

confidence: 99%

“…Heat sources study is also important for investigation of new fabrication processes such as additive manufacturing (AM). Douellou et al [9] evaluates the mechanical dissipation in AM materials during fatigue loading. Additive manufacturing can also produce functional or multifunctional materials in which heat sources have a functional role.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Multi-resolution approach based on a variables separation method in unsteady thermal problem for composites

Vidal

Ibouroi

Gallimard

et al. 2021

Composite Structures

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Section: Comments About Computational Costmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multi-resolution approach based on a variables separation method in unsteady thermal problem for composites

Vidal

Ibouroi

Gallimard

et al. 2021

Composite Structures

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“…Snow et al 14) summarized the current understanding of formation mechanisms for gas porosity, lack-of-fusion and flaws related to melt pool instabilities, and described their impact on mechanical properties including fatigue life showing large scattering. Douellow et al 16) proposed a statistical model to identify the fatigue limit, and wrote that it leads to the rapid optimization of AM process with respect to the fatigue performance.…”

Section: Introductionmentioning

confidence: 99%

Probabilistic finite element analysis of fatigue life of additively manufactured clasp

et al. 2022

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The present study was aimed to develop a probabilistic finite element method (FEM) that predicts the variability in the fatigue life of additively manufactured clasp so that it can be used as a virtual test in the design phase before manufacturing. Titanium alloy (Ti-6Al-4V) clasp with integrated chucking part, which was designed for experimental fatigue test to validate the computational method, was investigated. To predict the lower bound, an initial spherical defect was assumed in the region where stress concentration was predicted. The Smith-Watson-Topper (SWT) method, Bäumel & Seeger rule, elasto-plastic FEM, and zooming FEM were used. The influence of assumed initial defect on the fatigue life was significant, and the large variability in the fatigue life was predicted. This study demonstrated that the proposed practical computational method can simulate the large variability in the fatigue life of titanium alloy clasp, which is useful in its design before manufacturing.

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“…Finally, some defects like lack of fusion or gas pores are formed depending on the process parameters and matter input [12,13]. For most metal AM technologies, pores are found to have a first-order influence on fatigue life, inducing large scatter of fatigue data of machined specimens [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

A probabilistic approach for high cycle fatigue of Wire and Arc Additive Manufactured parts taking into account process-induced pores

Bercelli

Moyne

D’Hondt

et al. 2021

Additive Manufacturing

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Wire and Arc Additive Manufacturing (WAAM) is a direct-energy deposition technique (unlike SLM or EBM) that builds up a part in a layer-by-layer fashion, each layer being constituted of interlaced weld beads. It is the best suited Additive Manufacturing (AM) technique for large structures thanks to its high deposition rate (5kg/h). The resulting material shows a rough surface, strong residual stress induced by its complex thermal history, a heterogeneous microstructure marked by the different weld passes as well as defects formed by gas pockets. Despite their rarity, pores are found to have a first-order influence on the fatigue life of machined specimens. The discrepancy in their size (> 100µm) and position is responsible for a considerable scatter that makes classical fatigue tests ineffective. The aim of this study is to propose a novel approach to take into account the effect of rare WAAM-induced defects in high cycle fatigue. To achieve this, numerical porous structures are generated from the knowledge of the real pore population determined by tomography. Their fatigue performances are predicted via a two-scale probabilistic model identified on experimental self-heating results, on which pores have no influence. In that sense, the probabilistic model describes the behaviour of a virtually healthy material. Then, by computing a database of representative pore cases, the whole bundle of Wöhler curves for each numerical porous structure is determined. Finally, the numerical fatigue scatter is in close agreement with experimental data, and it is shown that the ranking in pore criticality according to the model matches the fractography observations. Keywords: Wire and Arc Additive Manufacturing (WAAM) ; High cycle fatigue ; Pores ; Self-heating ; Poisson point process Draft articleIRDL fatigue life of the position of an isolated pore over its size. From this observation a novel approach is proposed in [16], where the total plastic zone in the vicinity of a defect is considered from Finite Element Analysis (FEA). Although gas pores found in WAAM parts have much larger dimensions (>100µm) and have smooth near-spherical shapes [23][24][25], to which notch fatigue and crack initiation approaches are best suited [26,27].In the case of WAAM, a low density of defects can be achieved using the Cold Metal Transfer (CMT) technology [28,29]. Typical WAAM defects are round smooth pores, with sizes ranging from a few micrometers to more than half a millimeter [23,30]. Fatigue samples extracted from optmized WAAM blocks show rare isolated pores with an important discrepancy in size and distance to free surface. As a result, a considerable scatter in fatigue data is observed [31] (for example compared to casting materials), posing quite a challenge to the assessment of fatigue properties by conventional methods (ASTM E466-15 standard [32], the staircase method [33]). These samples do not constitute a Representative Volume Element (RVE) of the material's fatigue behaviour: each sample can be seen as a unique structure. This is t...

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Rapid characterization of the fatigue limit of additive-manufactured maraging steels using infrared measurements

Cited by 11 publications

References 38 publications

Multi-resolution approach based on a variables separation method in unsteady thermal problem for composites

Multi-resolution approach based on a variables separation method in unsteady thermal problem for composites

Probabilistic finite element analysis of fatigue life of additively manufactured clasp

A probabilistic approach for high cycle fatigue of Wire and Arc Additive Manufactured parts taking into account process-induced pores

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