scholarly journals On-Coupling Mechanical, Electrical and Thermal Behavior of Submarine Power Phases

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1009 ◽  
Author(s):  
Abdelghani MATINE ◽  
Monssef DRISSI-HABTI
Keyword(s):  
Thermal Behavior ◽  
Homogeneous Distribution ◽  
Plastic Behavior ◽  
Damage Mechanisms ◽  
Mechanical Study ◽  
Plastic Domain ◽  
Submarine Cables ◽  
Power Wave ◽  
Electrical Cables ◽  
The Impact

Floating offshore renewable energies (OREs), such as offshore floating wind turbines (wind energy) or wave power (wave and wave energy), are increasingly in demand. Submarine cables that transmit the energy produced from offshore farms all the way to onshore stations are critical structures that must be able to work perfectly over 20 years without any maintenance. In order to reduce the significant costs associated with electrical cables, it is important to optimize the dimensioning of the components of these cables, or to develop structural monitoring techniques that target zero and/or minimum maintenance over their lifespan. In this paper, we FEM of the impact of damage mechanisms of the conductor part of a submarine power phase on its mechanical, electrical, and thermal behavior. The main damage mechanisms are local plasticity and wire failure. The first mechanical study made it possible to obtain the elasto-plastic behavior of the conductor. The electrical study took into consideration the deformed geometry of the conductor in the elasto-plastic domain, as well as the non-homogeneous distribution of the electrical conductivity of the conductor. Their influence on the electrical resistance of the conductor was then analyzed. Finally, we studied the impact of plasticity and conductor failure on the thermal behavior of the phase. The temperature differences obtained in the numerical analysis of this work may be used further to help preventive and curative maintenance of the cables, for example, by using an optical fiber as sensor for structural health monitoring.

scholarly journals Advanced Constitutive Modeling of the Thixotropic Elasto-Visco-Plastic Behavior of Blood: Steady-State Blood Flow in Microtubes

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 367
Author(s):  
Konstantinos Giannokostas ◽  
Yannis Dimakopoulos ◽  
Andreas Anayiotos ◽  
John Tsamopoulos
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Constitutive Model ◽  
Blood Plasma ◽  
Constitutive Modeling ◽  
Flow Direction ◽  
Momentum Balance ◽  
Plastic Behavior ◽  
Flow Investigation ◽  
The Impact

The present work focuses on the in-silico investigation of the steady-state blood flow in straight microtubes, incorporating advanced constitutive modeling for human blood and blood plasma. The blood constitutive model accounts for the interplay between thixotropy and elasto-visco-plasticity via a scalar variable that describes the level of the local blood structure at any instance. The constitutive model is enhanced by the non-Newtonian modeling of the plasma phase, which features bulk viscoelasticity. Incorporating microcirculation phenomena such as the cell-free layer (CFL) formation or the Fåhraeus and the Fåhraeus-Lindqvist effects is an indispensable part of the blood flow investigation. The coupling between them and the momentum balance is achieved through correlations based on experimental observations. Notably, we propose a new simplified form for the dependence of the apparent viscosity on the hematocrit that predicts the CFL thickness correctly. Our investigation focuses on the impact of the microtube diameter and the pressure-gradient on velocity profiles, normal and shear viscoelastic stresses, and thixotropic properties. We demonstrate the microstructural configuration of blood in steady-state conditions, revealing that blood is highly aggregated in narrow tubes, promoting a flat velocity profile. Additionally, the proper accounting of the CFL thickness shows that for narrow microtubes, the reduction of discharged hematocrit is significant, which in some cases is up to 70%. At high pressure-gradients, the plasmatic proteins in both regions are extended in the flow direction, developing large axial normal stresses, which are more significant in the core region. We also provide normal stress predictions at both the blood/plasma interface (INS) and the tube wall (WNS), which are difficult to measure experimentally. Both decrease with the tube radius; however, they exhibit significant differences in magnitude and type of variation. INS varies linearly from 4.5 to 2 Pa, while WNS exhibits an exponential decrease taking values from 50 mPa to zero.

Dependency of Machine Efficiency on the Thermal Behavior of Induction Machines

Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 9
Author(s):  
Svenja Kalt ◽  
Karl Ludwig Stolle ◽  
Philipp Neuhaus ◽  
Thomas Herrmann ◽  
Alexander Koch ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Electric Vehicles ◽  
Thermal Load ◽  
Load Capacity ◽  
Maximum Load ◽  
Induction Machines ◽  
Electric Machines ◽  
Model Parameters ◽  
Dynamic Operating ◽  
The Impact

The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is caused due to the impact of temperature on the resulting loss types. This leads to a shift of efficiency areas in the efficiency diagram of electric machines and has a significant impact on the maximum load capability and an impact on the cycle efficiency during operation, resulting in a reduction in the overall range of the electric vehicle. Therefore, this article aims at analyzing the thermal load limits of induction machines in regard to actual operation using measured driving data of battery electric vehicles. For this, a thermal model is implemented using MATLAB® and investigations to the sensitivity of model parameters as well as analysis of the continuous load capacity, thermal load and efficiency in driving cycles under changing boundary conditions are conducted.

scholarly journals A Comprehensive Set of Impact Data for Common Aerospace Metals

2017 ◽  
Vol 12 (6) ◽  
Author(s):  
M. R. W. Brake ◽  
P. L. Reu ◽  
D. S. Aragon
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Model Development ◽  
Coefficient Of Restitution ◽  
Image Correlation ◽  
Plastic Behavior ◽  
Data Set ◽  
Force Resolution ◽  
Impact Data ◽  
The Impact

The results of two sets of impact experiments are reported within. To assist with model development using the impact data reported, the materials are mechanically characterized using a series of standard experiments. The first set of impact data comes from a series of coefficient of restitution (COR) experiments, in which a 2 m long pendulum is used to study “in-context” measurements of the coefficient of restitution for eight different materials (6061-T6 aluminum, phosphor bronze alloy 510, Hiperco, nitronic 60A, stainless steel 304, titanium, copper, and annealed copper). The coefficient of restitution is measured via two different techniques: digital image correlation (DIC) and laser Doppler vibrometry (LDV). Due to the strong agreement of the two different methods, only results from the digital image correlation are reported. The coefficient of restitution experiments are in context as the scales of the geometry and impact velocities are representative of common features in the motivating application for this research. Finally, a series of compliance measurements are detailed for the same set of materials. The compliance measurements are conducted using both nano-indentation and micro-indentation machines, providing sub-nm displacement resolution and μN force resolution. Good agreement is seen for load levels spanned by both machines. As the transition from elastic to plastic behavior occurs at contact displacements on the order of 30 nm, this data set provides a unique insight into the transitionary region.

The impact of graphene nanoparticle additives on the strength of simple and hybrid adhesively bonded joints

2018 ◽  
Vol 53 (23) ◽  
pp. 3335-3346 ◽  
Author(s):  
Hamid Reza Borghei ◽  
Bashir Behjat ◽  
Mojtaba Yazdani
Keyword(s):  
Joint Strength ◽  
Tensile Tests ◽  
Lap Joints ◽  
Homogeneous Distribution ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Single Lap Joints ◽  
Hybrid Joints ◽  
Graphene Nanoparticles ◽  
The Impact

In this paper, the effect of graphene nanoparticle additive on the strength of simple and hybrid (rivet-bonded) single-lap joints is studied using the experimental method. Two different types of graphene with different number of layer and thicknesses are used in adhesive-graphene nanoparticle composite construction. At first, tensile tests are done on bulk specimens of adhesive with different additives. It is found that adding 0.5 wt% of graphene to the neat adhesive leads to an increase in the ultimate tensile strength of bulk specimens almost 24% and 12% for two graphene types compared to the neat adhesive. Also, the shear strength of adhesive and hybrid lap joints incorporating two types of graphene nanoparticles (types I and II) is compared to that of adhesive and hybrid joints without graphene nanoparticles. SEM results of fracture surfaces show that the inclusion of graphene nanoparticle to the adhesive increases the roughness of surfaces. Experimental results reveal that graphene nanoparticle increases the strength of bonded and hybrid joints. It is observed that, graphene with a lower thickness and number of layers has a better influence on joint strength. In fact, graphene nanoparticle type II makes a homogeneous distribution in adhesive-graphene nanoparticle composite and causes a significant increase on joint strength.

scholarly journals Main parameters influencing the plastic behavior of clays used for traditional ceramics production

2021 ◽  
Author(s):  
Hicham El Boudour El Idrissi
Keyword(s):  
Mineral Composition ◽  
Ceramic Industry ◽  
Raw Material ◽  
Plastic Behavior ◽  
Different Types ◽  
The Impact ◽  
The City ◽  
Traditional Ceramics ◽  
Clayey Materials ◽  
Clay Mineral Composition

This paper investigates the main parameters influencing the plastic behavior of clays used for traditional ceramics production. For this, twenty-six clayey pastes were selected from twelve traditional ceramic plants around the city of Marrakech (Morocco). According to the lithology, six different types of materials are used as raw material in the ceramic industry of this region. Emphasis is placed on the impact of the characteristics of these clayey materials upon the plastic behavior of these clays. The pastes were characterized through their consistency using the Atterberg limits. It has been concluded that the gain size, the mineralogical and the clay mineral composition and content, the effect of diagenesis and the presence of talc-pyrophyllite association play the most important role in the control of the plasticity behavior.

scholarly journals Installation of submarine cables and pipes in shallow waters and connecting them to the shore by the method of horizontal directional drilling

2021 ◽  
Vol 286 ◽  
pp. 04007
Author(s):  
Valeriu-Florian Vasilescu ◽  
Dumitru Dinu
Keyword(s):  
Marine Environment ◽  
Offshore Wind ◽  
Shallow Waters ◽  
Directional Drilling ◽  
Horizontal Directional Drilling ◽  
Negative Effects ◽  
Subsea Tunnel ◽  
Submarine Cables ◽  
Wind Energy Systems ◽  
The Impact

This article presents the horizontal directional drilling (HDD) as one of the most suitable technique used to reduce the impact on the environment during the submarine pipe and cable installation process, especially in the coastal area and shallow waters. HDD is a technique used to drill a subsea tunnel or under other designated area with the goal to pull a pipe or other facility through the drilled underground tunnel. With the development of the offshore natural gas and wind industry, the demand for the construction of transfer pipeline and cables has also increased. The installation of submarine pipelines and cables can have negative effects on the marine environment. This is one of the main reasons that construction and operation of offshore wind energy systems has been and continues to be regarded with scepticism by environmental activists, despite the undeniable benefits of this renewable energy source. The main objectives of this article are to emphasize the importance of using this technique but also to highlight the benefits, in particular by significantly reducing the impact on the marine environment.

Experimental and Numerical Plastic Response and Failure of Laterally Impacted Rectangular Plates

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
B. Liu ◽  
R. Villavicencio ◽  
C. Guedes Soares
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Failure Modes ◽  
Mesh Size ◽  
Plastic Behavior ◽  
Finite Element Models ◽  
Rectangular Plates ◽  
Marine Structures ◽  
Fine Mesh ◽  
The Impact

Experimental and numerical results of drop weight impact test are presented on the plastic behavior and fracture of rectangular plates stuck laterally by a mass with a hemispherical indenter. Six specimens were tested in order to study the influence of the impact velocity and the diameter of the indenter. The impact scenarios could represent abnormal actions on marine structures, such as ship collision and grounding or dropped objects on deck structures. The tests are conducted on a fully instrumented impact tester machine. The obtained force-displacement response is compared with numerical simulations, performed by the LS-DYNA finite element solver. The simulations aim at proposing techniques for defining the material and restraints on finite element models which analyze the crashworthiness of marine structures. The mesh size and the critical failure strain are predicted by numerical simulations of the tensile tests used to obtain the mechanical properties of the material. The experimental boundary conditions are modeled in order to represent the reacting forces developed during the impact. The results show that the critical impact energy until failure is strongly sensitive to the diameter of the striker. The shape of the failure modes is well predicted by the finite element models when a relatively fine mesh is used. Comments on the process of initiation and propagation of fracture are presented.

A multiscale approach for modelling impact on woven composites under consideration of the fabric topology

2018 ◽  
Vol 52 (21) ◽  
pp. 2859-2874 ◽  
Author(s):  
Martin Schwab ◽  
Melanie Todt ◽  
Heinz E Pettermann
Keyword(s):  
Total Energy ◽  
Energy Absorption ◽  
Temporal Distribution ◽  
Woven Composites ◽  
Multiscale Approach ◽  
Stress Concentrations ◽  
Damage Mechanisms ◽  
Explicit Finite Element ◽  
Impact Behaviour ◽  
The Impact

A computationally efficient multiscale modelling approach for predicting impact damage within fabric reinforced laminated composites is presented. In contrast to common ply-level approaches, the topology of a multi-layered fabric reinforced laminate is resolved at tow-level for a sub-domain embedded in a shell layer with homogenised representation of the laminate. The detailed sub-domain is entirely modelled using shell elements, where material nonlinearities such as damage and plasticity-like behaviour of the tows, inelastic behaviour of unreinforced resin zones up to failure and delamination between plies are accounted for. To exemplify the capabilities of the approach, an explicit finite element simulation of a laminated plate consisting of eight carbon fabric reinforced epoxy plies with eight harness satin weaving style in a drop weight impact test setup is conducted. The spatial and temporal distribution of intra- and inter-ply damage is predicted and the total energy absorption by the plate, as well as the contributions of individual damage mechanisms are evaluated. The predictions show very good agreement with corresponding experimental data from the literature and give insight into the impact behaviour of the laminate beyond the capability of usual experiments. The new approach allows to resolve the stress concentrations due to fabric topology in detail. Compared to common ply-level approaches this is reflected in different predicted energy absorptions per mechanism although, the total energy absorption hardly differs. This is especially important when the post impact behaviour of laminates is predicted as it is strongly influenced by the extent of the individual damage mechanisms.

scholarly journals Falling Weight Impact Damage Characterisation of Flax and Flax Basalt Vinyl Ester Hybrid Composites

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 806 ◽  
Author(s):  
Hom Nath Dhakal ◽  
Elwan Le Méner ◽  
Marc Feldner ◽  
Chulin Jiang ◽  
Zhongyi Zhang
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Hybrid Composites ◽  
Impact Damage ◽  
Matrix Cracking ◽  
Damage Mechanisms ◽  
Pull Out ◽  
Weight Impact ◽  
Falling Weight ◽  
The Impact

Understanding the damage mechanisms of composite materials requires detailed mapping of the failure behaviour using reliable techniques. This research focuses on an evaluation of the low-velocity falling weight impact damage behaviour of flax-basalt/vinyl ester (VE) hybrid composites. Incident impact energies under three different energy levels (50, 60, and 70 Joules) were employed to cause complete perforation in order to characterise different impact damage parameters, such as energy absorption characteristics, and damage modes and mechanisms. In addition, the water absorption behaviour of flax and flax basalt hybrid composites and its effects on the impact damage performance were also investigated. All the samples subjected to different incident energies were characterised using non-destructive techniques, such as scanning electron microscopy (SEM) and X-ray computed micro-tomography (πCT), to assess the damage mechanisms of studied flax/VE and flax/basalt/VE hybrid composites. The experimental results showed that the basalt hybrid system had a high impact energy and peak load compared to the flax/VE composite without hybridisation, indicating that a hybrid approach is a promising strategy for enhancing the toughness properties of natural fibre composites. The πCT and SEM images revealed that the failure modes observed for flax and flax basalt hybrid composites were a combination of matrix cracking, delamination, fibre breakage, and fibre pull out.

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