scholarly journals Dynamic Behaviour Adaptation of Lightweight Structures by Compressible Constrained Layer Damping with Embedded Polymeric Foams and Nonwovens

2019 ◽  
Vol 9 (17) ◽  
pp. 3490 ◽  
Author(s):  
Tom Ehrig ◽  
Klaudiusz Holeczek ◽  
Niels Modler ◽  
Pawel Kostka
Keyword(s):  
Intermediate Layer ◽  
Dynamic Behaviour ◽  
Constrained Layer Damping ◽  
Polymeric Foams ◽  
Lightweight Structures ◽  
Crucial Component ◽  
Theoretical Assumptions ◽  
Original Concept ◽  
Better Than ◽  
Modelling Approach

Evanescent morphing in combination with an original concept of Compressible Constrained Layer Damping (CCLD) is a novel and promising approach for dynamic behaviour adaptation. The crucial component of the CCLD is a compressible intermediate layer with its thickness and material properties controlled by fluid actuation, enabling the adjustment of the damping and stiffness of the overall system. To estimate the potential of the CCLD, an analytical model was developed which describes the vibration behaviour of the overall structure, taking into account the compression-driven properties of the intermediate layer. The results confirm the principal correctness of the initial theoretical assumptions regarding the adaptive dynamic behaviour of structures with CCLD treatment. A significant vibration mitigation as well as a high adaptability of dynamic behaviour were observed, however, they show a complex dependence on the system configuration. Nevertheless, the developed analytical modelling approach can already be used for a preliminary system design. Besides the analysed polymer-based foams as the intermediate layer, nonwovens also exhibit compression-dependent shear properties and can therefore be used in CCLD. First preliminary investigations show that the damping performance is on average about ten times better than that of the polymeric foams.

Theoretical Bioevaluation of 1,2,4-Thiadiazole-1,2,4-triazole Derivatives via Molecular Modelling Approach

2021 ◽  
Vol 6 (1) ◽  
pp. 40-46
Author(s):  
Oyebamiji Abel Kolawole ◽  
Akintelu Sunday Adewale ◽  
Simon N. Odoemene ◽  
Oyeneyin Oluwatoba Emmanuel ◽  
Semire Banjo
Keyword(s):  
Breast Cancer ◽  
Docking Study ◽  
Qsar Model ◽  
Qsar Study ◽  
Triazole Derivatives ◽  
Discovery Studio ◽  
Artificial Neural Network Ann ◽  
Type 3 ◽  
Better Than ◽  
Modelling Approach

Breast cancer still remains one of the precarious ailments among humans globally. The vulnerability of this ailment in homeopathic world remains colossal and this has drawn the attention of seasoned researchers to find lasting solution to this hazard. Therefore, 10 novel 1,2,4-thiadiazole-1,2,4-triazole derivatives were studied so as to explore their anti-breast cancer activities. The studied compounds were optimized using Spartan 14 and the QSAR study was executed by using Gretl and MATLAB. Also, docking study was observed using Pymol (for treating downloaded protein), Autodock Tool (for locating binding site in the downloaded protein and for converting ligand and receptor to .pdbqt format from .pdb format), Auto dock vina (for docking calculation) and discovery studio (for viewing the nonbonding interaction between the docked complexes). The selected descriptors were used to developed effective QSAR model and it was observed that the developed QSAR model using artificial neural network (ANN) predicted better than the prediction made by multiple linear regression (MLR). More so, the calculated binding affinity revealed that compound g (-11.4 kcal/mol) possess ability to inhibit 3α-hydroxysteroid dehydrogenase type 3 (PDB ID: 4xo6) than other studied compounds as well as etoposide (Standard).

Long-term Macroeconomic Dynamics of Competition in the Russian Economy using Agent- based Modelling

2017 ◽  
Vol 6 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Tatyana Eftonova ◽  
Mariam Kiran ◽  
Mike Stannett
Keyword(s):  
Dynamic Behaviour ◽  
Economic Modelling ◽  
Macroeconomic Dynamics ◽  
Agent Based ◽  
Economic Agents ◽  
Agent Based Modelling ◽  
Russian Economy ◽  
Modelling Techniques ◽  
Modelling Approach

Agent-based economic modelling techniques are increasingly being used to complement standard economic simulations. This paper re-models a standard equation-based simulation model of the Russian macroeconomy in an agent-based setup, and uses it to investigate the effect that antimonopoly legislation can be expected to have upon long-term dynamic behaviour. The results reveal various potential outcomes which would have not been visible using traditional equation-based modelling techniques. While the number of economic agents has been kept deliberately small in the work presented here, the modelling approach is scalable to systems incorporating many millions of agents.

Modelling of a Hybrid Constrained Layer/Piezoceramic Approach to Active Damping

1997 ◽  
Vol 119 (1) ◽  
pp. 120-130 ◽  
Author(s):  
J. A. Rongong ◽  
J. R. Wright ◽  
R. J. Wynne ◽  
G. R. Tomlinson
Keyword(s):  
Active Control ◽  
Laboratory Experiments ◽  
Dynamic Behaviour ◽  
Flexural Vibration ◽  
Open Loop ◽  
Structural Vibration ◽  
Constrained Layer Damping ◽  
Element Analysis ◽  
Cantilevered Beam ◽  
And Performance

It has been shown that significant reductions in structural vibration levels can be achieved using a hybrid system involving constrained layer damping and active control with piezoceramics. In this paper, mathematical models based on the Rayleigh Ritz approach, are developed to describe the longitudinal and flexural vibration behaviour of a cantilevered beam when excited using piezoceramic patches bonded to a constrained layer damping treatment. Predictions of static and steady state dynamic behaviour, obtained using the models are validated by comparison with results from finite element analysis and laboratory experiments. The models are then used in open loop and closed loop velocity feedback control simulations to demonstrate the improvements in stability and performance achieved using this method over that achieved using conventional active control.

scholarly journals Dimensionless quantification of small radial turbine transient performance

2020 ◽  
Vol 235 (1) ◽  
pp. 188-198
Author(s):  
Qiyou Deng ◽  
Andrew Pennycott ◽  
Qingning Zhang ◽  
Calogero Avola ◽  
Ludek Pohorelsky ◽  
...  
Keyword(s):  
Dynamic Behaviour ◽  
Internal Flow ◽  
Simulation Studies ◽  
Dimensionless Parameters ◽  
Transient Behaviour ◽  
Response Characteristics ◽  
Radial Turbine ◽  
Housing Temperature ◽  
Turbine Housing ◽  
Modelling Approach

Turbochargers are inherently dynamic devices, comprising internal flow volumes, mechanical inertias and thermal masses. When operating under transient conditions within an engine system, these dynamics need to be better understood. In this paper, a new non-dimensional modelling approach to characterise the turbocharger is proposed. Two new dimensionless quantities are defined with respect to mechanical and thermal transient behaviour, which are used in conjunction with the Strouhal number for flow transients. The modelling approach is applied to a small wastegated turbocharger and validated against experimental results. The model is used to simulate the turbocharger mass flow rate, turbine housing temperature and shaft speed responses to different excitation frequencies for different sizes of turbine. The results highlight the influence of turbocharger size on the dynamic behaviour of the system, which is particularly marked for the turbine housing temperature. At certain frequency ranges, the system behaviour is quasi-steady, allowing modelling through static maps in these operating regions. Outside these ranges, however, transient elements play a more important role. The simulation study shows that the proposed dimensionless parameters can be used to normalise the influence of turbine size on the dynamic response characteristics of the system. The model and corresponding dimensionless parameters can be applied in future simulation studies as well as for turbocharger matching in industry.

Decrease of CO2 exchange in Scots pine after naturally occurring or artificial low temperatures

1977 ◽  
Vol 7 (3) ◽  
pp. 462-468 ◽  
Author(s):  
Paavo Pelkonen ◽  
Pertti Hari ◽  
Olavi Luukkanen
Keyword(s):  
Low Temperatures ◽  
Laboratory Experiments ◽  
Co2 Exchange ◽  
Additional Parameter ◽  
Naturally Occurring ◽  
Pine Seedlings ◽  
Measuring Period ◽  
Infrared Gas Analyzer ◽  
Better Than ◽  
Modelling Approach

A decrease in the net photosynthetic rate was recorded using an infrared gas analyzer after subjecting pine seedlings to naturally occurring or artificial low temperature pulses in field and laboratory experiments. Mathematical models were developed to quantify the depression in CO2 exchange observed when autumn measurements taken in the field were analyzed. A model which included a mathematically determined additional parameter gave values more closely correlated with CO2 exchange at the end of the measuring period better than one which included only temperature and light as independent variables. This modelling approach was similar to one used earlier to quantify the effect of water stress on photosynthesis. The same kind of effect was found in a laboratory experiment after artificial low temperatures, as shown in this paper.

An electrodynamic shaker with an integral force gauge for high-frequency measurements on lightweight structures

2000 ◽  
Vol 214 (10) ◽  
pp. 1285-1297 ◽  
Author(s):  
R M Grice ◽  
R J Pinnington
Keyword(s):  
Frequency Response ◽  
Piezoelectric Material ◽  
Response Function ◽  
High Frequency ◽  
Frequency Response Function ◽  
Dynamic Behaviour ◽  
High Frequencies ◽  
Lightweight Structures ◽  
Electrodynamic Shaker ◽  
Design Construction

The design, construction and calibration of a purpose-built electrodynamic shaker for making frequency response function measurements on lightweight structures at high frequencies (i.e. many kHz) are described. The shaker uses a conventional wire-wound coil onto which is assembled a force gauge. The force gauge is constructed using little more than just a miniature piece of piezoelectric material. The dimensions of the components used to manufacture the shaker are determined by comparing their estimated dynamic behaviour with the estimated mobility of a lightweight perspex test structure. Although such an electrodynamic shaker is not entirely novel, it demonstrates how careful use of basic materials can produce a device that overcomes some limitations of commercial devices at very little cost.

scholarly journals Size selectivity and length-dependent escape behaviour of haddock in a sorting device combining a grid and a square mesh panel

2019 ◽  
Vol 76 (8) ◽  
pp. 1350-1361 ◽  
Author(s):  
Bent Herrmann ◽  
Manu Sistiaga ◽  
Eduardo Grimaldo ◽  
Roger B. Larsen ◽  
Leonore Olsen ◽  
...  
Keyword(s):  
Barents Sea ◽  
Selection Process ◽  
Species Selection ◽  
Melanogrammus Aeglefinus ◽  
Size Selectivity ◽  
Escape Behaviour ◽  
Trawl Fishery ◽  
Haddock Melanogrammus Aeglefinus ◽  
Better Than ◽  
Modelling Approach

Size selectivity of a new sorting section combining a sorting grid and a square mesh panel was tested for haddock (Melanogrammus aeglefinus) in the Barents Sea demersal trawl fishery. Sampling data for a wide size range enabled investigating the selection process for this species in detail, both for the grid and the square mesh panel. Contrary to earlier studies modelling size selectivity for grids and square mesh panels, which assume that the escape behaviour of all sizes of fish is equal, we applied a model that accounted for haddock of different sizes showing different escape behaviours. Our results demonstrated that this model could describe the experimental data collected better than existing models. Specifically, our results showed that the likelihood for smaller haddock to seek escape through the grid and the square mesh panel was higher than that for bigger haddock that still would manage to escape through the devices if they attempted. The new modelling approach presented in this study may be applicable to other species, selection devices, and fisheries.

scholarly journals A Comparative Study on the Modelling of Soybean Particles Based on the Discrete Element Method

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 286
Author(s):  
Dongxu Yan ◽  
Jianqun Yu ◽  
Liusuo Liang ◽  
Yang Wang ◽  
Yajun Yu ◽  
...  
Keyword(s):  
Soybean Seeds ◽  
Test Results ◽  
Dem Simulation ◽  
Equation Modelling ◽  
Multiple Contacts ◽  
Simulation Results ◽  
Related Machines ◽  
Better Than ◽  
Modelling Approach ◽  
Modelling Approaches

To solve the poor universality in the existing modelling approaches of soybean particles, we proposed a soybean particle modelling approach by combining five, nine, and 13 balls. The soybean seeds from three varieties (Suinong42, Jidou17, and Zhongdou39 with a sphericity of 94.78%, 86.86%, and 80.6%, respectively) are chosen as the study objects. By the comparisons between the simulation results and the test results in the “self-flow screening” and “piling angle” tests, it is concluded that the soybean particle modelling approach we presented in this paper is a universal modelling approach appropriate for soybean particles with different sphericities. The five-ball model is appropriate for the soybean particles with high sphericity, and the nine- or 13-ball models are applicable to those with low sphericity. The soybean particle modelling approach we presented is also compared with the ellipsoidal equation modelling approach for soybean particles and with the modelling approaches presented by other researchers. From an overall perspective, the soybean particle modelling approach we presented is better than the ellipsoidal equation modelling approach and those modelling approaches presented by other researchers. Additionally, it is shown that the multiple contacts issue in the multi-ball model has a little influence on the simulation results of soybean particle models. The study in this paper provides a new modelling approach for soybean particles in the DEM simulation of the contacts between soybean particles and the related machines.

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