scholarly journals Compression Test of a Single Carbon Fiber in a Scanning Electron Microscope and Its Evaluation via Finite Element Analysis

2018 ◽  
Vol 44 (3) ◽  
pp. 100-106
Author(s):  
Masahito UEDA ◽  
Masanori AKIYAMA
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Electron Microscope ◽  
Carbon Fiber ◽  
Scanning Electron Microscope ◽  
Compression Test ◽  
Element Analysis ◽  
Scanning Electron

A Study on the Effects of Covered Stents on Tissue Prolapse

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Jason D. Weaver ◽  
D. N. Ku
Keyword(s):  
Finite Element ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Wall Stress ◽  
Environmental Scanning Electron Microscope ◽  
Environmental Scanning ◽  
Covered Stents ◽  
Artery Wall ◽  
Element Analysis ◽  
Scanning Electron

Polyvinyl alcohol (PVA) cryogel covered stents may reduce complications from thrombosis and restenosis by decreasing tissue prolapse. Finite element analysis was employed to evaluate the effects of PVA cryogel layers of varying thickness on tissue prolapse and artery wall stress for two common stent geometries and two vessel diameters. Additionally, several PVA cryogel covered stents were fabricated and imaged with an environmental scanning electron microscope. Finite element results showed that covered stents reduced tissue prolapse up to 13% and artery wall stress up to 29% with the size of the reduction depending on the stent geometry, vessel diameter, and PVA cryogel layer thickness. Environmental scanning electron microscope images of expanded covered stents showed the PVA cryogel to completely cover the area between struts without gaps or tears. Overall, this work provides both computational and experimental evidence for the use of PVA cryogels in covered stents.

scholarly journals Vacuum Preconsolidation Settlement Characteristics and Microstructural Evolution of Marine Dredger-Filled Silt

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Keping Chen ◽  
Xinkai Ren ◽  
Yong He ◽  
Muyuan Gan ◽  
Danwei Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Levels ◽  
Equivalent Diameter ◽  
Vacuum Preloading ◽  
Element Analysis ◽  
Scanning Electron

The method of vacuum preloading for foundation treatments is used in the construction of the Fangchenggang coastal area in Guangxi province, China. The thick marine dredger-filled silt has a considerable impact on the treatment effort. In this study, the mineral composition and grain size distribution of these silts were analyzed to investigate their consolidation settlement property and microstructures. The scanning electron microscope and finite element method were adopted. The results reveal that the dredger-filled silt in this area is composed mainly of sand with particle size mostly smaller than 0.075 mm. To replicate the construction process, the process of drainage by the vacuum preloading method was simulated by setting different water levels in the finite element analysis. The displacement and the dissipation of the pore water pressure obtained by simulations were reasonably consistent with the field monitoring data. In addition, the results obtained using the scanning electron microscope indicate that the equivalent diameter of the structural unit and that of the pore unit decrease with the silt depth. However, the value of the structural abundance approaches one, whereas the pore abundance is significantly different from one.

scholarly journals Finite Element Analysis for Nonlinear Unbonded Circular Fiber-Reinforced Elastomeric Bearings

2021 ◽  
Vol 5 (7) ◽  
pp. 170
Author(s):  
Pablo Castillo Ruano ◽  
Alfred Strauss
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carbon Fiber ◽  
Seismic Isolation ◽  
Nonlinear Viscoelasticity ◽  
Fiber Reinforcement ◽  
Special Focus ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Elastomeric Bearings

In recent years, interest in low-cost seismic isolation systems has increased. The replacement of the steel reinforcement in conventional elastomeric bearings for a carbon fiber reinforcement is a possible solution and has garnered increasing attention. To investigate the response of fiber-reinforced elastomeric bearings (FREBs) under seismic loads, it is fundamental to understand its mechanical behavior under combined vertical and horizontal loads. An experimental investigation of the components presents complexities due to the high loads and displacements tested. The use of a finite element analysis can save time and resources by avoiding partially expensive experimental campaigns and by extending the number of geometries and topologies to be analyzed. In this work, a numerical model for carbon fiber-reinforced bearings is implemented, calibrated, and validated and a set of virtual experiments is designed to investigate the behavior of the bearings under combined compressive and lateral loading. Special focus is paid to detailed modeling of the constituent materials. The elastomeric matrix is modeled using a phenomenological rheological model based on the hyperelastic formulation developed by Yeoh and nonlinear viscoelasticity. The model aims to account for the hysteretic nonlinear hyper-viscoelastic behavior using a rheological formulation that takes into consideration hyperelasticity and nonlinear viscoelasticity and is calibrated using a series of experiments, including uniaxial tension tests, planar tests, and relaxation tests. Special interest is paid to capturing the energy dissipated in the unbonded fiber-reinforced elastomeric bearing in an accurate manner. The agreement between the numerical results and the experimental data is assessed, and the influence of parameters such as shape factor, aspect ratio, vertical pressure, and fiber reinforcement orientation on stress distribution in the bearings as well as in the mechanical properties is discussed.

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