scholarly journals A computational fluid–structure interaction model to predict the biomechanical properties of the artificial functionally graded aorta

2016 ◽  
Vol 36 (6) ◽  
Author(s):  
Arezoo Khosravi ◽  
Milad Salimi Bani ◽  
Hossein Bahreinizade ◽  
Alireza Karimi

In the present study, three layers of the ascending aorta in respect to the time and space at various blood pressures have been simulated. Two well-known commercial finite element (FE) software have used to be able to provide a range of reliable numerical results while independent on the software type. The radial displacement compared with the time as well as the peripheral stress and von Mises stress of the aorta have calculated. The aorta model was validated using the differential quadrature method (DQM) solution and, then, in order to design functionally graded materials (FGMs) with different heterogeneous indexes for the artificial vessel, two different materials have been employed. Fluid–structure interaction (FSI) simulation has been carried out on the FGM and a natural vessel of the human body. The heterogeneous index defines the variation of the length in a function. The blood pressure was considered to be a function of both the time and location. Finally, the response characteristics of functionally graded biomaterials (FGBMs) models with different values of heterogeneous material parameters were determined and compared with the behaviour of a natural vessel. The results showed a very good agreement between the numerical findings of the FGM materials and that of the natural vessel. The findings of the present study may have implications not only to understand the performance of different FGMs in bearing the stress and deformation in comparison with the natural human vessels, but also to provide information for the biomaterials expert to be able to select a suitable material as an implant for the aorta.

Author(s):  
Minyan Yin ◽  
Jun Li ◽  
Liming Song ◽  
Zhenping Feng

The aerodynamic and mechanical performance of the last stage was numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) solution and Finite Element Analysis (FEA) coupled with the one-way and two-way fluid-structure interaction models in this work. The part-span damping snubber and tip damping shroud of the rotor blade and aerodynamic pressure on rotor blade mechanical performance was considered in the one-way model. The two-way fluid-structure interaction model coupled with the mesh deformation technology was conducted to analyze the aerodynamic and mechanical performance of the last stage rotor blade. One-way fluid-structure interaction model numerical results show that the location of nodal maximum displacement moves from leading edge of 85% blade span to the trailing edge of 85% blade span. The position of nodal maximum Von Mises stress is still located at the first tooth upper surface near the leading edge at the blade root of pressure side. The two-way fluid-structure interaction model results show that the variation of static pressure distribution on long blade surface is mostly concentrated at upper region, absolute outflow angle of long blade between the 40% span and 95% span reduces, the location of nodal maximum displacement appears at the trailing edge of 85% blade span. Furthermore, the position of nodal maximum Von Mises stress remains the same and the value decreases compared to the oneway fluid-structure model results.


2021 ◽  
Vol 143 (8) ◽  
Author(s):  
Harry J. Carpenter ◽  
Alireza Gholipour ◽  
Mergen H. Ghayesh ◽  
Anthony C. Zander ◽  
Peter J. Psaltis

Abstract A fluid–structure interaction-based biomechanical model of the entire left anterior descending coronary artery is developed from in vivo imaging via the finite element method in this paper. Included in this investigation is ventricle contraction, three-dimensional motion, all angiographically visible side branches, hyper/viscoelastic artery layers, non-Newtonian and pulsatile blood flow, and the out-of-phase nature of blood velocity and pressure. The fluid–structure interaction model is based on in vivo angiography of an elite athlete's entire left anterior descending coronary artery where the influence of including all alternating side branches and the dynamical contraction of the ventricle is investigated for the first time. Results show the omission of side branches result in a 350% increase in peak wall shear stress and a 54% decrease in von Mises stress. Peak von Mises stress is underestimated by up to 80% when excluding ventricle contraction and further alterations in oscillatory shear indices are seen, which provide an indication of flow reversal and has been linked to atherosclerosis localization. Animations of key results are also provided within a video abstract. We anticipate that this model and results can be used as a basis for our understanding of the interaction between coronary and myocardium biomechanics. It is hoped that further investigations could include the passive and active components of the myocardium to further replicate in vivo mechanics and lead to an understanding of the influence of cardiac abnormalities, such as arrythmia, on coronary biomechanical responses.


Author(s):  
Ziyi Su ◽  
Kazuaki Inaba ◽  
Amit Karmakar ◽  
Apurba Das

Abstract Functionally graded materials (FGMs) are advanced class of composite materials which can be used as the thermal barrier to protect inner components from the outside high temperature environment. In FGMs, the volume fraction of each constituent can be tailored made across the thickness for desired applications. In this work, the simulation of FGMs in pipes is considered. Despite the wide application of pipes in machinery, those pipes would suffer from many safety problems, such as thermal stress, cavitation, fracture etc. Application of FGMs to the piping systems could lead to some new solutions accounting for safety measures and higher service life. However, the complex phenomena within the fluid structure interaction are hard to describe with the theoretical solution. The visualization of results from simulation will be helpful in understanding the distribution of kinds of physical quantities within the concerned model. For the simulation, FGMs are modeled as the layered structure in the standard finite element method (FEM) package based on FGM constituent law. The free vibration of the FG pipe is simulated and the accuracy of layered model is verified by numerical calculations. Further, based on the layered model, conjugate heat transfer simulations in a heat exchanger with FGMs are conducted.


Author(s):  
Mohammad Khairul Habib Pulok ◽  
Uttam K. Chakravarty

Abstract Rotary-wing aircrafts are the best-suited option in many cases for its vertical take-off and landing capacity, especially in any congested area, where a fixed-wing aircraft cannot perform. Rotor aerodynamic loading is the major reason behind helicopter vibration, therefore, determining the aerodynamic loadings are important. Coupling among aerodynamics and structural dynamics is involved in rotor blade design where the unsteady aerodynamic analysis is also imperative. In this study, a Bo 105 helicopter rotor blade is considered for computational aerodynamic analysis. A fluid-structure interaction model of the rotor blade with surrounding air is considered where the finite element model of the blade is coupled with the computational fluid dynamics model of the surrounding air. Aerodynamic coefficients, velocity profiles, and pressure profiles are analyzed from the fluid-structure interaction model. The resonance frequencies and mode shapes are also obtained by the computational method. A small-scale model of the rotor blade is manufactured, and experimental analysis of similar contemplation is conducted for the validation of the numerical results. Wind tunnel and vibration testing arrangements are used for the experimental validation of the aerodynamic and vibration characteristics by the small-scale rotor blade. The computational results show that the aerodynamic properties of the rotor blade vary with the change of angle of attack and natural frequency changes with mode number.


2018 ◽  
Vol 9 (4) ◽  
pp. 739-751 ◽  
Author(s):  
Anna Maria Tango ◽  
Jacob Salmonsmith ◽  
Andrea Ducci ◽  
Gaetano Burriesci

2018 ◽  
Vol 21 (16) ◽  
pp. 813-823 ◽  
Author(s):  
John T. Wilson ◽  
Lowell T. Edgar ◽  
Saurabh Prabhakar ◽  
Marc Horner ◽  
Raoul van Loon ◽  
...  

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