scholarly journals Determination of Thermomechanical Stresses in Elements of Vehicles’ Braking Systems

2022 ◽  
Vol 24 (1) ◽  
pp. B1-B8
Author(s):  
Oleksii Grevtsev ◽  
Ninel Selivanova ◽  
Pavlo Popovych ◽  
Liubomyr Poberezhny ◽  
Yurii Rudyak ◽  
...  
Keyword(s):  
High Efficiency ◽  
Three Dimensional ◽  
Metal Structure ◽  
Theory Of Elasticity ◽  
Temperature Fields ◽  
Proposed Model ◽  
Simulation Strategy ◽  
Final Length ◽  
Thermomechanical Processes

The main objective of the study was to develop a model and analyze the thermomechanical behavior of the hub material of the vehicle brake disk. The simulation strategy was based on the solution of the three-dimensional problem of the theory of elasticity for the case of effect of external loads and temperature fields on the metal structure element of the vehicle brakes. To solve this type of task of the theory of elasticity, the differential equations of the second order were used for the first time. Adaptation of the proposed model, completed in the article, has proved the correctness of use of these equations in modeling the thermomechanical processes with determination of stresses and displacements in unevenly heated rotary cylinders of the final length. The proposed method can be applied with high efficiency in stress strain state simulation of individual parts of vehicles.

High-Efficiency Three-Dimensional Visualization of Complex Microstructures via Multidimensional STEM Acquisition and Reconstruction

2020 ◽  
Vol 26 (2) ◽  
pp. 240-246 ◽  
Author(s):  
Kevin G. Field ◽  
Benjamin P. Eftink ◽  
Chad M. Parish ◽  
Stuart A. Maloy
Keyword(s):  
High Efficiency ◽  
3D Visualization ◽  
Accurate Determination ◽  
Three Dimensional ◽  
High Energy ◽  
Scanning Transmission Electron Microscope ◽  
Chromium Steel ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractComplex material systems in which microstructure and microchemistry are nonuniformly dispersed require three-dimensional (3D) rendering(s) to provide an accurate determination of the physio-chemical nature of the system. Current scanning transmission electron microscope (STEM)-based tomography techniques enable 3D visualization but can be time-consuming, so only select systems or regions are analyzed in this manner. Here, it is presented that through high-efficiency multidimensional STEM acquisition and reconstruction, complex point cloud-like microstructural features can quickly and effectively be reconstructed in 3D. The proposed set of techniques is demonstrated, analyzed, and verified for a high-chromium steel with heterogeneously situated features induced using high-energy neutron bombardment.

Three-Dimensional Kinematic Modelling of the Human Shoulder Complex—Part I: Physical Model and Determination of Joint Sinus Cones

1989 ◽  
Vol 111 (2) ◽  
pp. 107-112 ◽  
Author(s):  
A. E. Engin ◽  
S. T. Tu¨mer
Keyword(s):  
Kinematic Model ◽  
Quantitative Description ◽  
Three Dimensional ◽  
Direct Methods ◽  
Composite Joint ◽  
Proposed Model ◽  
Shoulder Complex ◽  
Unit Vectors

Modelling of the human shoulder complex is essential for the multi-segmented mathematical models as well as design of the shoulder mechanism of anthropometric dummies. In Part I of this paper a three-dimensional kinematic model is proposed by utilizing the concepts of kinematic links, joints, and joint sinuses. By assigning appropriate coordinate systems, parameters required for complete quantitative description of the proposed model are identified. The statistical in-vivo data base established by Engin and Chen (1986) is cast in a form compatible with the model by obtaining a set of unit vectors describing circumductory motion of the upper arm in a torso-fixed coordinate system. This set of unit vectors is then employed in determining the parameters of a composite shoulder complex sinus of a simplified version of the proposed model. Two methods, namely the flexible tolerance and the direct methods, are formulated and tested for the determination of an elliptical cone surface for a given set of generating unit vectors. Numerical results are presented for the apex angles and orientation of the composite joint sinus cone with respect to the anatomical directions.

Entropy-Based Design of Liquid-Repellent Nanochannels Destined to Energy Absorption Systems (EAS)

2009 ◽  
Author(s):  
Claudiu Valentin Suciu
Keyword(s):  
Entropy Production ◽  
Energy Absorption ◽  
High Efficiency ◽  
Test Chamber ◽  
Heat Sources ◽  
Engineering Systems ◽  
External Work ◽  
Proposed Model ◽  
Nanoporous Solids

Entropy production is a key parameter to evaluate the maximal efficiency of engineering systems. Recently, liquid penetration/exudation in/from non-wetted nanoporous solids was employed to develop ecological energy absorption systems (EAS). Dissipation is based on the well-known fact that external work must be done to spread a liquid on a lyophobic surface. Minimization of the entropy production is usually required to obtain high-efficiency engineering systems. However, enhancement of the EAS nano-damping ability requires oppositely maximization of the entropy generated through interfacial, frictional and thermal instabilities. A model of the entropy production during water flow inside of a liquid-repellent silica nanopore is proposed. A mixture of hydrophobized nanoporous silica and water is introduced inside of a compression-decompression chamber. Using a thermo-camera, the temperature distribution on the external surface of the test chamber is recorded versus the working time and the positions of main heat sources are identified. Such experiments allow determination of the overall dissipation, generated heat, and the heat flux at the wall of silica nanochannel. Then, the test rig is introduced inside of an incubator that allows temperature adjustment in the range 0∼50 °C and the thermal effects on the hysteresis and damping performances are evaluated. From such tests one determines the variation of the solid surface tension on the nanochannel wall versus temperature. Entropy (heat) production in the nanochannel is estimated and compared with experimental data to validate the proposed model.

Effect of the Nozzle Radiation on the Fused Filament Fabrication Process: Three-Dimensional Numerical Simulations and Experimental Investigation

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Benoît Cosson ◽  
André Chateau Akué Asséko
Keyword(s):  
Temperature Field ◽  
Numerical Simulations ◽  
Source Term ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Experimental Investigations ◽  
Fused Filament Fabrication ◽  
Proposed Model ◽  
The Heat Balance ◽  
Good Agreement

This paper addresses heat distribution issues in fused filament fabrication (FFF) process. Three-dimensional (3D) numerical simulations and experimental investigations are performed during additive manufacturing of parts by FFF process. The transient numerical simulations of the filament temperature field are based on the finite difference method. Experimental measurements of the temperature field are carried out using infrared thermography. The proposed model mainly highlights the contribution of heat exchange from the nozzle to the fabricated part and from filament to filament. Optimum adhesion of filaments deposited by FFF requires control of the thermal history. The nozzle radiation is taken into account as a source term in the heat balance equation. The temperature fields of the printed parts computed by numerical simulations are in very good agreement with the temperature fields measured by infrared thermograph. The 3D numerical model provides information on how the nozzle affects the temperature field of the printed part. This source term must be taken into account for the optimization of the FFF process.

Application of Three-Dimensional Fluorescence Spectroscopy Coupled with ATLD in Rapid Determination of Triazophos Content in Duck Meat

2014 ◽  
Vol 651-653 ◽  
pp. 362-366
Author(s):  
Jin Hui Zhao ◽  
Hai Bin Xiao ◽  
Hai Chao Yuan ◽  
Qian Hong ◽  
Mu Hua Liu
Keyword(s):  
Fluorescence Spectroscopy ◽  
Mean Squared Error ◽  
Rapid Determination ◽  
Organic Phosphorus ◽  
Three Dimensional ◽  
Meat Extract ◽  
Trilinear Decomposition ◽  
Proposed Model ◽  
Standard Solution

The triazophos is a kind of organic phosphorus pesticide, the quantitative determination model based on three-dimensional fluorescence spectroscopy coupled with alternating trilinear decomposition (ATLD) was explored for realizing the rapid determination of triazophos content in duck meat. Firstly, three-dimensional fluorescence spectra of duck meat extract, triazophos standard solution and duck meat extract containing triazophos were explored, respectively. Secondly, the fluorescence quenching phenomenon of the triazophos in duck meat extract was analyzed. Lastly, the number of components for three linear decomposition of ATLD was set as 2 by using the core consistency diagnostic, and the calibration curve between the relative fluorescence intensity and the actual concentration of the triazophos was established by using ATLD. The experimental results showed that the determination coefficient (R2) and the root mean squared error of prediction (RMSEP) for the proposed model in this paper were 0.9741 and 0.764 respectively, and it was feasible to predict the triazophos content in duck meat combining with three-demensional fluorescence spectroscopy and ATLD.

Determination of Stator Temperature Distribution for a Synchronous Machine

2013 ◽  
Vol 300-301 ◽  
pp. 1018-1021
Author(s):  
Bo Qiang Yuan ◽  
Xin Zhen Wu
Keyword(s):  
Cooling System ◽  
Three Dimensional ◽  
Synchronous Machine ◽  
Temperature Fields ◽  
Operation Condition ◽  
Analysis And Design ◽  
Ventilation Ducts ◽  
Set Up ◽  
The Mathematical Model

For studying the influence of the stator ventilation structure on the thermal performance of a synchronous machine, the mathematical model of the stator three-dimensional temperature fields is set up and the corresponding equations solved. The calculated results of the stator temperature are compared between different number of the radial ventilation ducts, which provides a theory foundation for the analysis and design of the cooling system and improves the safe operation condition of large synchronous machine.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

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