A new procedure for implementing the modified inherent strain method with improved accuracy in predicting both residual stress and deformation for laser powder bed fusion

Dong, Wenxia; Liang, Xuan; Chen, Qian; Hinnebusch, Shawn; Zhou, Zekai; To, Albert C.

doi:10.1016/j.addma.2021.102345

Cited by 20 publications

(12 citation statements)

References 45 publications

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“…This further creates material wastage and drives up the overall cost of production or research. However, numerical simulation offers a more cost-effective alternative and can be applied in the design phase to achieve rapid evaluation [ 21 – 23 ]. The simulation-based analysis provides information for users to identify residual stress distribution and distortion during a product design stage.…”

Section: Introductionmentioning

confidence: 99%

“…percentage error between simulated and experimental values) are the temperature-dependent material properties, flow softening, and microstructure evolution is neglected in the simulation model. Notwithstanding, the general trend (location and/or distribution) remains unchanged [ 23 , 34 , 35 ]. Despite this limitation and the associated difficulty of predicting absolute values, such models can be used to determine the trend of stress/strain change between input conditions.…”

Section: Introductionmentioning

confidence: 99%

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Bi-directional Scan Pattern Effects on Residual Stresses and Distortion in As-built Nitinol Parts: A Trend Analysis Simulation Study

Monu

Afkham

Chekotu

et al. 2023

Integr Mater Manuf Innov

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In this paper, a part-scale simulation study on the effects of bi-directional scanning patterns (BDSP) on residual stress and distortion formation in additively manufactured Nitinol (NiTi) parts is presented. The additive manufacturing technique of focus is powder bed fusion using a laser beam (PBF-LB), and simulation was performed using Ansys Additive Print software. The numerical approach adopted in the simulation was based on the isotropic inherent strain model, due to prohibitive material property requirements and computational limitations of full-fledged part-scale 3D thermomechanical finite element approaches. In this work, reconstructed 2D and 3D thermograms (heat maps) from in situ melt pool thermal radiation data, the predicted residual stresses, and distortions from the simulation study were correlated for PBF-LB processed NiTi samples using selected BDSPs. The distortion and residual stress distribution were found to vary greatly between BDSPs with no laser scan vector rotations per new layer, whereas negligible variations were observed for BDSPs with laser scan vector rotations per new layer. The striking similarities between the reconstructed thermograms of the first few layers and the simulated stress contours of the first lumped layer provide a practical understanding of the temperature gradient mechanism of residual stress formation in PBF-LB processed NiTi. This study provides a qualitative, yet practical insight towards understanding the trends of formation and evolution of residual stress and distortion, due to scanning patterns.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bi-directional Scan Pattern Effects on Residual Stresses and Distortion in As-built Nitinol Parts: A Trend Analysis Simulation Study

Monu

Afkham

Chekotu

et al. 2023

Integr Mater Manuf Innov

View full text Add to dashboard Cite

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“…Many researches have been done to control and reduce residual stresses in additive manufacturing (AM) [26][27][28][29][30][31][32]. Preheating the substrate is a commonly used in-situ method [24].…”

Section: Introductionmentioning

confidence: 99%

“…Later in late 80s, Mura [50] described this inelastic strain as "eigenstrain", he presented that eigenstrain is any kind of permanent strain due to inelastic process such as plastic deformation, crystallographic transformation, thermal expansion mismatch between different parts of assembly which causes incompatibility in the material, leading to the occurrence of residual stress distribution. In recent years, inherent strain theory has also been applied to analyze metal AM processes as they share similar characteristics with metal welding processes in which the materials will experience a cycle of heating and cooling and left with inherent strains [20,28,29,31,32,51,52]. In the AM built parts and heat-affected zone of welding pass, when the metal cools down to ambient temperature, there will be in-plane compressive inherent strains (usually inherent strain equals to plastic strain in this case if phase transformation is not considered) left, which are formed due to the constraint of the surrounding area during contraction.…”

Section: Introductionmentioning

confidence: 99%

Laser shock forging—a novel in situ method designed towards controlling residual stresses in laser metal deposition

Zhang

Cai

Yang

et al. 2023

Int J Adv Manuf Technol

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This paper presents a novel hybrid in-situ additive manufacturing (AM) method -Laser Shock Forging (LSF), which combines laser shock peening (LSP) with laser melting deposition (LMD). Based on the classical Bar-frame model and inherent strain theory, the mechanisms of the effects of pretreatment and post-treatment on AM process has been rstly elaborated. Towards controlling tensile residual stress (TRS) in the as-built (AB) state of AM parts which has a detrimental effect on their fatigue life, we then developed LSF to introduce tensile inherent strains in LMD built parts in an in-situ manner, which will convert TRS to compressive residual stress (CRS). The laser beam used for shock peening can be adjusted to move synchronously with the laser beam used for metal deposition at a certain distance, ensuring the laser shock peening to act on the region where the material temperature cools down to the forging temperature range. Then experimental works have been conducted on 316L stainless steel, residual stress distributions of the AB, LSP and LSF treated specimens were compared, results show that LSF increases both the magnitude and depth of CRS compared with conventional LSP treatment, thus providing a promising application in enhancing fatigue life in AM process.

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“…Therefore, only the final geometric distortion of the printed component is needed as input. Thanks to the advantages that the method offers, it is more suitable for the simulation of large and complex components in the industry and has been widely adapted in [ 17 , 18 , 19 , 20 ].…”

Section: Introductionmentioning

confidence: 99%

Residual Stress Build-Up in Aluminum Parts Fabricated with SLM Technology Using the Bridge Curvature Method

Měsíček

Fojtík

et al. 2022

Materials

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In metal 3D printing with Selective Laser Melting (SLM) technology, due to large thermal gradients, the residual stress (RS) distribution is complicated to predict and control. RS can distort the shape of the components, causing severe failures in fabrication or functionality. Thus, several research papers have attempted to quantify the RS by designing geometries that distort in a predictable manner, including the Bridge Curvature Method (BCM). Being different from the existing literature, this paper provides a new perspective of the RS build-up in aluminum parts produced with SLM using a combination of experiments and simulations. In particular, the bridge samples are printed with AlSi10Mg, of which the printing process and the RS distribution are experimentally assessed with the Hole Drilling Method (HDM) and simulated using ANSYS and Simufact Additive. Subsequently, on the basis of the findings, suggestions for improvements to the BCM are made. Throughout the assessment of BCM, readers can gain insights on how RS is built-up in metallic 3D-printed components, some available tools, and their suitability for RS prediction. These are essential for practitioners to improve the precision and functionality of SLM parts should any post-subtractive or additive manufacturing processes be employed.

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A new procedure for implementing the modified inherent strain method with improved accuracy in predicting both residual stress and deformation for laser powder bed fusion

Cited by 20 publications

References 45 publications

Bi-directional Scan Pattern Effects on Residual Stresses and Distortion in As-built Nitinol Parts: A Trend Analysis Simulation Study

Bi-directional Scan Pattern Effects on Residual Stresses and Distortion in As-built Nitinol Parts: A Trend Analysis Simulation Study

Laser shock forging—a novel in situ method designed towards controlling residual stresses in laser metal deposition

Residual Stress Build-Up in Aluminum Parts Fabricated with SLM Technology Using the Bridge Curvature Method

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