Investigation on the effect of the thermal dynamic, evaporation, and alternative material properties in a laser melt pool with a developed 2D model based on the VOSET method

This paper presents the performance quantification of different green-grey infrastructures, including rainfall-runoff and infiltration processes, on the overland flow and its connection with a sewer system. The present study suggests three main components to form the structure of the proposed model-based assessment. The first two components provide the optimal number of green infrastructure (GI) practices allocated in an urban catchment and optimal grey infrastructures, such as pipe and storage tank sizing. The third component evaluates selected combined green-grey infrastructures based on rainfall-runoff and infiltration computation in a 2D model domain. This framework was applied in an urban catchment in Dhaka City (Bangladesh) where different green-grey infrastructures were evaluated in relation to flood damage and investment costs. These practices implemented separately have an impact on the reduction of damage and investment costs. However, their combination has been shown to be the best action to follow. Finally, it was proved that including rainfall-runoff and infiltration processes, along with the representation of GI within a 2D model domain, enhances the analysis of the optimal combination of infrastructures, which in turn allows the drainage system to be assessed holistically.

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A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽

10.3390/ma14112784 ◽

2021 ◽

Vol 14 (11) ◽

pp. 2784

Author(s):

Georgios Maliaris ◽

Christos Gakias ◽

Michail Malikoutsakis ◽

Georgios Savaidis

Keyword(s):

Process Parameters ◽

Material Properties ◽

Shot Peening ◽

Qualitative Assessment ◽

Experimental Investigations ◽

Elastoplastic Material ◽

Size Distributions ◽

User Friendly ◽

The Impact ◽

2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

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A robust parallel implementation of 2D model-based recognition

Proceedings CVPR '88: The Computer Society Conference on Computer Vision and Pattern Recognition ◽

10.1109/cvpr.1988.196336 ◽

2003 ◽

Cited By ~ 12

Author(s):

T.A. Cass

Keyword(s):

Parallel Implementation ◽

Model Based ◽

2D Model

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Effect of Time Spacing and Hatch Spacing on Thermal Material Properties and Melt Pool Geometry in Additive Manufacturing of S316L

Volume 1: Additive Manufacturing; Manufacturing Equipment and Systems; Bio and Sustainable Manufacturing ◽

10.1115/msec2019-2741 ◽

2019 ◽

Cited By ~ 2

Author(s):

Elham Mirkoohi ◽

Daniel E. Sievers ◽

Steven Y. Liang

Keyword(s):

Heat Transfer ◽

Additive Manufacturing ◽

Material Properties ◽

Metal Additive Manufacturing ◽

Melt Pool ◽

Experimental Values ◽

Melt Pool Size ◽

Transfer Mechanisms ◽

Hatch Spacing ◽

Metal Additive

Abstract A physics-based analytical solution is proposed in order to investigate the effect of hatch spacing and time spacing (which is the time delay between two consecutive irradiations) on thermal material properties and melt pool geometry in metal additive manufacturing processes. A three-dimensional moving point heat source approach is used in order to predict the thermal behavior of the material in additive manufacturing process. The thermal material properties are considered to be temperature dependent since the existence of the steep temperature gradient has a substantial influence on the magnitude of the thermal conductivity and specific heat, and as a result, it has an influence on the heat transfer mechanisms. Moreover, the melting/solidification phase change is considered using the modified heat capacity since it has an influence on melt pool geometry. The proposed analytical model also considers the multi-layer aspect of metal additive manufacturing since the thermal interaction of the successive layers has an influence on heat transfer mechanisms. Temperature modeling in metal additive manufacturing is one of the most important predictions since the presence of the temperature gradient inside the build part affect the melt pool size and geometry, thermal stress, residual stress, and part distortion. In this paper, the effect of time spacing and hatch spacing on thermal material properties and melt pool geometry is investigated. Both factors are found statistically significant with regard to their influence on thermal material properties and melt pool geometry. The predicted melt pool size is compared to experimental values from independent reports. Good agreement is achieved between the proposed physics-based analytical model and experimental values.

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Model-based extraction of material properties in multifrequency atomic force microscopy

Physical Review B ◽

10.1103/physrevb.85.195449 ◽

2012 ◽

Vol 85 (19) ◽

Cited By ~ 49

Author(s):

Daniel Forchheimer ◽

Daniel Platz ◽

Erik A. Tholén ◽

David B. Haviland

Keyword(s):

Atomic Force Microscopy ◽

Material Properties ◽

Force Microscopy ◽

Model Based ◽

Atomic Force

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Computational model-based probabilistic analysis of in vivo material properties for ligament stiffness using the laxity test and computed tomography

Journal of Materials Science Materials in Medicine ◽

10.1007/s10856-016-5797-z ◽

2016 ◽

Vol 27 (12) ◽

Cited By ~ 30

Author(s):

Kyoung-Tak Kang ◽

Sung-Hwan Kim ◽

Juhyun Son ◽

Young Han Lee ◽

Heoung-Jae Chun

Keyword(s):

Computed Tomography ◽

Computational Model ◽

Probabilistic Analysis ◽

Material Properties ◽

Model Based ◽

Ligament Stiffness

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Model-Based Feedforward Control of Part Height in Directed Energy Deposition

Materials ◽

10.3390/ma14020337 ◽

2021 ◽

Vol 14 (2) ◽

pp. 337

Author(s):

Qian Wang ◽

Jianyi Li ◽

Abdalla R. Nassar ◽

Edward W. Reutzel ◽

Wesley F. Mitchell

Keyword(s):

Laser Power ◽

Energy Deposition ◽

Inverse Dynamics ◽

Feedforward Control ◽

Layer By Layer ◽

Model Based ◽

Melt Pool ◽

Directed Energy Deposition ◽

Proposed Model ◽

Directed Energy

Control of the geometric accuracy of a metal deposit is critical in the repair and fabrication of complex components through Directed Energy Deposition (DED). This paper developed and experimentally evaluated a model-based feedforward control of laser power with the objective of achieving the targeted part height in DED. Specifically, based on the dynamic model of melt-pool geometry derived from our prior work, a nonlinear inverse-dynamics controller was derived in a hatch-by-hatch, layer-by-layer manner to modulate the laser power such that the melt-pool height was regulated during the simulated build process. Then, the laser power trajectory from the simulated closed-loop control under the nonlinear inverse-dynamics controller was implemented as a feedforward control in an Optomec Laser-Engineered Net Shape (LENS) MR-7 system. This paper considered the deposition of L-shaped structures of Ti-6AL-4V as a case study to illustrate the proposed model-based controller. Experimental validation showed that by applying the proposed model-based feed-forward control for laser power, the resulting build had 24–42% reduction in the average build height error with respect to the target build height compared to applying a constant laser power through the entire build or applying a hatch-dependent laser power strategy, for which the laser power values were obtained from experimental trial and error.

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