Numerical Predictions of Absolutely Unstable Round Hot Jet

This article presents an overview of the recent developments at Instituto Superior Técnico and Maritime Research Institute Netherlands in applying computational methods for the hydrodynamic analysis of ducted propellers. The developments focus on the propeller performance prediction in open water conditions using boundary element methods and Reynolds-averaged Navier-Stokes solvers. The article starts with an estimation of the numerical errors involved in both methods. Then, the different viscous mechanisms involved in the ducted propeller flow are discussed and numerical procedures for the potential flow solution proposed. Finally, the numerical predictions are compared with experimental measurements.

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A Novel Finite Element Method Approach in the Modelling of Edge Trimming of CFRP Laminates

Applied Sciences ◽

10.3390/app11114743 ◽

2021 ◽

Vol 11 (11) ◽

pp. 4743

Author(s):

Fernando Cepero-Mejias ◽

Nicolas Duboust ◽

Vaibhav A. Phadnis ◽

Kevin Kerrigan ◽

Jose L. Curiel-Sosa

Keyword(s):

Finite Element ◽

Tool Wear ◽

Cutting Tool ◽

Machining Process ◽

Machining Forces ◽

General Terms ◽

Numerical Predictions ◽

Composite Damage ◽

Edge Trimming ◽

Optimal Cutting Parameters

Nowadays, the development of robust finite element models is vital to research cost-effectively the optimal cutting parameters of a composite machining process. However, various factors, such as the high computational cost or the complicated nature of the interaction between the workpiece and the cutting tool significantly hinder the modelling of these types of processes. For these reasons, the numerical study of common machining operations, especially in composite machining, is still minimal. This paper presents a novel approach comprising a mixed multidirectional composite damage mode with composite edge trimming operation. An ingenious finite element framework which infer the cutting edge tool wear assessing the incremental change of the machining forces is developed. This information is essential to replace tool inserts before the tool wear could cause severe damage in the machined parts. Two unidirectional carbon fibre specimens with fibre orientations of 45∘ and 90∘ manufactured by pre-preg layup and cured in an autoclave were tested. Excellent machining force predictions were obtained with errors below 10% from the experimental trials. A consistent 2D FE composite damage model previously performed in composite machining was implemented to mimic the material failure during the machining process. The simulation of the spring back effect was shown to notably increase the accuracy of the numerical predictions in comparison to similar investigations. Global cutting forces simulated were analysed together with the cutting tool tooth forces to extract interesting conclusions regarding the forces received by the spindle axis and the cutting tool tooth, respectively. In general terms, vertical and normal forces steadily increase with tool wear, while tangential to the cutting tool, tooth and horizontal machining forces do not undergo a notable variation.

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Erratum to: NNLO QCD corrections to jet production in deep inelastic scattering

Journal of High Energy Physics ◽

10.1007/jhep12(2020)042 ◽

2020 ◽

Vol 2020 (12) ◽

Author(s):

James Currie ◽

Thomas Gehrmann ◽

Alexander Huss ◽

Jan Niehues

Keyword(s):

Inelastic Scattering ◽

Deep Inelastic Scattering ◽

Jet Production ◽

Numerical Predictions

We correct an error in the implementation of specific integrated initial-final antenna functions that impact the numerical predictions for the DIS process.

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Bending Response of 3D-Printed Titanium Alloy Sandwich Panels with Corrugated Channel Cores

Materials ◽

10.3390/ma14030556 ◽

2021 ◽

Vol 14 (3) ◽

pp. 556

Author(s):

Zhenyu Zhao ◽

Jianwei Ren ◽

Shaofeng Du ◽

Xin Wang ◽

Zihan Wei ◽

...

Keyword(s):

Titanium Alloy ◽

Heat Dissipation ◽

Sandwich Panels ◽

Face Sheet ◽

Collapse Mechanism ◽

Corrugated Channel ◽

Four Point Bending ◽

Numerical Predictions ◽

Load Carrying ◽

3D Printed

Ultralight sandwich constructions with corrugated channel cores (i.e., periodic fluid-through wavy passages) are envisioned to possess multifunctional attributes: simultaneous load-carrying and heat dissipation via active cooling. Titanium alloy (Ti-6Al-4V) corrugated-channel-cored sandwich panels (3CSPs) with thin face sheets and core webs were fabricated via the technique of selective laser melting (SLM) for enhanced shear resistance relative to other fabrication processes such as vacuum brazing. Four-point bending responses of as-fabricated 3CSP specimens, including bending resistance and initial collapse modes, were experimentally measured. The bending characteristics of the 3CSP structure were further explored using a combined approach of analytical modeling and numerical simulation based on the method of finite elements (FE). Both the analytical and numerical predictions were validated against experimental measurements. Collapse mechanism maps of the 3CSP structure were subsequently constructed using the analytical model, with four collapse modes considered (face-sheet yielding, face-sheet buckling, core yielding, and core buckling), which were used to evaluate how its structural geometry affects its collapse initiation mode.

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