scholarly journals Finite Element Simulation for Structural Response of U7Mo Dispersion Fuel Plates via Fluid-Thermal-Structural Interaction

Author(s):  
Hakan Ozaltun ◽  
Herman Shen ◽  
Pavel Medvedev

This article presents numerical simulation of dispersion fuel mini plates via fluid-thermal-structural interaction performed by commercial finite element solver COMSOL Multiphysics to identify initial mechanical response under actual operating conditions. Since fuel particles are dispersed in Aluminum matrix, and temperatures during the fabrication process reach to the melting temperature of the Aluminum matrix, stress/strain characteristics of the domain cannot be reproduced by using simplified models and assumptions. Therefore, fabrication induced stresses were considered and simulated via image based modeling techniques with the consideration of the high temperature material data. In order to identify the residuals over the U7Mo particles and the Aluminum matrix, a representative SEM image was employed to construct a microstructure based thermo-elasto-plastic FE model. Once residuals and plastic strains were identified in micro-scale, solution was used as initial condition for subsequent multiphysics simulations at the continuum level. Furthermore, since solid, thermal and fluid properties are temperature dependent and temperature field is a function of the velocity field of the coolant, coupled multi-physics simulations were considered. First, velocity and pressure fields of the coolant were computed via fluid-structural interaction. Computed solution for velocity fields were used to identify the temperature distribution on the coolant and on the fuel plate via fluid-thermal interaction. Finally, temperature fields and residual stresses were used to obtain the stress field of the plates via fluid-thermal-structural interaction.

Author(s):  
Dong-Feng Li ◽  
Noel P. O’Dowd ◽  
Catrin M. Davies ◽  
Shu-Yan Zhang

In this study, the deformation behavior of an austenitic stainless steel is investigated at the microscale by means of in-situ neutron diffraction (ND) measurements in conjunction with finite-element (FE) simulations. Results are presented in terms of (elastic) lattice strains for selected grain (crystallite) families. The FE model is based on a crystallographic (slip system based) representation of the deformation at the microscale. The present study indicates that combined in-situ ND measurement and micromechanical modelling provides an enhanced understanding of the mechanical response at the microscale in engineering steels.


2014 ◽  
Vol 695 ◽  
pp. 588-591
Author(s):  
Khairul Salleh Basaruddin ◽  
Ruslizam Daud

This study aims to investigate the influence of trabecular bone in human mandible bone on the mechanical response under implant load. Three dimensional voxel finite element (FE) model of mandible bone was reconstructed from micro-computed tomography (CT) images that were captured from bone specimen. Two FE models were developed where the first consists of cortical bone, trabecular bone and implants, and trabecular bone part was excluded in the second model. A static analysis was conducted on both models using commercial software Voxelcon. The results suggest that trabecular bone contributed to the strength of human mandible bone and to the effectiveness of load distribution under implant load.


Author(s):  
Vladimir Panchenko ◽  
Sergey Chirskiy ◽  
Valeriy Vladimirovich Kharchenko

The chapter discusses the simulation of thermal operating conditions and the optimization of the design of solar photovoltaic thermal modules. As a realization of the developed method, two photovoltaic thermal modules with one-sided solar cells with one-sided heat removal and two-sided solar cells with two-sided heat removal are presented. The components of the developed models of solar modules must be optimized on the basis of the required indicators of the thermal mode of operation of the modules. For this task, a method has been developed for visualizing thermal processes using the Ansys system of finite element analysis, which has been used to research thermal modes of operation and to optimize the design of the modules created. With the help of the developed method, the temperature fields of the module components, coolant velocity and its flow lines in the developed models of a planar photovoltaic thermal roofing panel and a concentrator photovoltaic thermal two-sided module are visualized.


2019 ◽  
Vol 43 (4) ◽  
pp. 443-453
Author(s):  
Stephen M. Handrigan ◽  
Sam Nakhla

An investigation to determine the effect of porosity concentration and location on elastic modulus is performed. Due to advancements in testing methods, the manufacturing and testing of microbeams to obtain mechanical response is possible through the use of focused ion beam technology. Meanwhile, rigorous analysis is required to enable accurate extraction of the elastic modulus from test data. First, a one-dimensional investigation with beam theory, Euler–Bernoulli and Timoshenko, was performed to estimate the modulus based on load-deflection curve. Second, a three-dimensional finite element (FE) model in Abaqus was developed to identify the effect of porosity concentration. Furthermore, the current work provided an accurate procedure to enable accurate extraction of the elastic modulus from load-deflection data. The use of macromodels such as beam theory and three-dimensional FE model enabled enhanced understanding of the effect of porosity on modulus.


Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2198 ◽  
Author(s):  
Liping Tang ◽  
Wei He ◽  
Xiaohua Zhu ◽  
Yunlai Zhou

End fittings are essential components in marine flexible pipe systems, performing the two main functions of connecting and sealing. To investigate the sealing principle and the influence of the temperature on the sealing performance, a hydraulic-thermal finite element (FE) model for the end fitting sealing structure was developed. The sealing mechanism of the end fitting was revealed by simulating the sealing behavior under the pressure penetration criteria. To investigate the effect of temperature, the sealing behavior of the sealing ring under different temperature fields was analyzed and discussed. The results showed that the contact pressure of path 1 (i.e., metal-to-polymer seal) was 31.7 MPa, which was much lower than that of path 2 (metal-to-metal seal) at 195.6 MPa. It was indicated that the sealing capacities were different for the two leak paths, and that the sealing performance of the metal-to-polymer interface had more complicated characteristics. Results also showed that the finite element analysis can be used in conjunction with pressure penetration criteria to evaluate the sealing capacity. According to the model, when the fluid pressures are 20 and 30 MPa, no leakage occurs in the sealing structure, while the sealing structure fails at the fluid pressure of 40 MPa. In addition, it was shown that temperature plays a significant role in the thermal deformation of a sealing structure under a temperature field and that an appropriately high temperature can increase the sealing capacity.


2011 ◽  
Vol 223 ◽  
pp. 733-742 ◽  
Author(s):  
Barbara Linke ◽  
Michael Duscha ◽  
Anh Tuan Vu ◽  
Fritz Klocke

The grinding process is one of the most important finishing processes to obtain high surface quality. Nowadays, grinding is also considered as a high performance process with high material removal rates. Nevertheless, to avoid thermally-induced structural changes poses a major challenge for this manufacturing technology. Until now, the Finite Element Method (FEM) has been widely applied as a proper numerical technique to predict workpiece properties in machining processes. However, actual models in grinding are limited to conventional grinding processes with simple workpiece profiles and low table speeds. In this paper, finite element simulations are expanded to 3-dimensional (3D) models with temperature-dependent material properties and heat source profiles derived from experimental results, i.e. tangential forces. Both temperature simulation and measurement were conducted for deep grinding, pendulum grinding and speed stroke grinding in the table speed range of vw= 12 m/min to 180 m/min and specific material removal rates of Q’w= 40 mm³/mms. Overall, the simulation results show a good agreement with the measured temperature and surface integrity after grinding. This research indicates that a 3D FE model with temperature dependent material properties can predict realistic temperature fields in speed stroke grinding. Therefore, the experiment and measurement costs and time can be reduced by FEM simulation.


Author(s):  
Jean de Cazenove ◽  
Scott Cogan ◽  
Moustapha Mbaye

Integrally bladed rotors dynamic properties are known to be particularly sensitive to small geometric discrepancies due to the machining process or in-service wear. In this context, it is straightforward that setting up accurate numerical models which take into account real mistuning patterns is a key issue in the prediction of forced response amplitudes under operating conditions. The present study focuses on an experimental bladed disk. Due to strong inter-blade coupling, the geometric mistuning is supposed to result in severe mode localization for the studied bladed disk, thus emphasizing the need of a realistic, predictive finite-element model. This paper describes the procedure which leads to the development and validation of a high-fidelity FE model for a realistic bladed disk, based on coordinate measurements by means of fringe projection. After giving an overview of the coordinate measurement and model building for the studied bladed disk, the comparison of cantilevered-blade and full disk calculated eigenfrequencies to individual blade and full disk in quasi-vacuum measurements are presented.


2014 ◽  
Vol 17 (11) ◽  
pp. 1601-1621 ◽  
Author(s):  
Nima Khorsandnia ◽  
Hamid Valipour ◽  
Keith Crews

This paper presents the structural response of timber-concrete composite (TCC) beams predicted by finite element models (i.e. continuum-based and 1D frame) and manual calculations. Details of constitutive laws adopted for modelling timber and concrete are provided and application of the Hashin damage model in conjunction with continuum-based FE for capturing failure of timber under bi-axial stress state is discussed. A simplified strategy for modelling the TCC connection is proposed in which the connection is modelled by a nonlinear spring and the full load-slip behaviour of each TCC connection is expressed with a formula that can be directly implemented in the general purpose FE codes and used for nonlinear analysis of TCC beams. The developed FE models are verified by examples taken from the literature. Furthermore, the load-displacement response and ultimate loading capacity of the TCC beams are determined according to Eurocode 5 method and compared with FE model predictions.


Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2041 ◽  
Author(s):  
Wenke Huang ◽  
Hao Wang ◽  
Yingmei Yin ◽  
Xiaoning Zhang ◽  
Jie Yuan

In this paper, an image-based micromechanical model for an asphalt mixture’s rheological mechanical response is introduced. Detailed information on finite element (FE) modeling based on X-ray computed tomography (X-ray CT) is presented. An improved morphological multiscale algorithm was developed to segment the adhesive coarse aggregate images. A classification method to recognize the different classifications of the elemental area for a confining pressure purpose is proposed in this study. Then, the numerical viscoelastic constitutive formulation of asphalt mortar in an FE code was implemented using the simulation software ABAQUS user material subroutine (UMAT). To avoid complex experiments in determining the time-dependent Poisson’s ratio directly, numerous attempts were made to indirectly obtain all material properties in the viscoelastic constitutive model. Finally, the image-based FE model incorporated with the viscoelastic asphalt mortar phase and elastic aggregates was used for triaxial compressive test simulations, and a triaxial creep experiment under different working conditions was conducted to identify and validate the proposed finite element approach. The numerical simulation and experimental results indicate that the three-dimensional microstructural numerical model established can effectively analyze the material’s rheological mechanical response under the effect of triaxial load within the linear viscoelastic range.


2012 ◽  
Vol 19 (5) ◽  
pp. 1051-1059 ◽  
Author(s):  
A. Devin ◽  
P.J. Fanning

Structures include elements designated as load bearing and non-load bearing. While non-load bearing elements, such as facades and internal partitions, are acknowledged to add mass to the system, the structural stiffness and strength is generally attributed to load bearing elements only. This paper investigates the contribution of non-load bearing elements to the dynamic response of a new structure, the Charles Institute, in the grounds of University College Dublin (UCD) Ireland. The vertical vibration response of the first floor and the lateral response at each floor level were recorded at different construction stages. The evolution of the structural response as well as the generation of a finite element (FE) model is discussed. It was found that the addition of the non-load bearing facades increased the first floor natural frequency from 10.7 Hz to 11.4?Hz, a change of approximately +6.5%. Similarly these external facades resulted in the first sway mode having its frequency increased by 6%. The subsequent addition of internal partitions, mechanical services and furnishings resulted in the floor natural frequency reducing to 9.2 Hz. It is concluded that external facades have the net effect of adding stiffness and the effect of internal partitions and furnishings is to add mass. In the context of finite element modelling of structures there is a significant challenge to represent these non-structural elements correctly so as to enable the generation of truly predictive FE models.


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