scholarly journals Numerical Evaluation for Roads Considering the Addition of Geogrids in Karst Geohazards Zones

2021 ◽  
Vol 6 (9) ◽  
pp. 120
Author(s):  
Alain Leonel Conrado-Palafox ◽  
Luisa Nicte Equihua-Anguiano ◽  
Victor Alfonso Hernández-Hernández
Keyword(s):  
Finite Element ◽  
Numerical Evaluation ◽  
Factor Of Safety ◽  
Numerical Study ◽  
Constitutive Models ◽  
Finite Element Models ◽  
Karst Terrain ◽  
The Road ◽  
Heavy Truck ◽  
Truck Load

Design of road infrastructure in karst terrain is a challenge for any geotechnical condition caused by the weathering of the subsoil. Previous investigations pointed out the efficiency of the roads with geogrids, however there are few studies analyzing road reinforced under karst geohazards. This paper presents a numerical study of the geogrid additions in a typical Mexican road and considering 19 cavities in the subsoil due to failures of the roads in these terrains. The rocks and the soil were simulated by Hoek–Brown and Mohr–Coulomb constitutive models, considering specific characteristics of karstic materials. Hence, it was carried out in different two-dimension finite element models to analyze the geogrid behavior and its benefits. First, the geogrid position was varied inside of the road structure and applying a heavy truck load in its surface and finally, underground cavities were sequentially opened in the numerical model. It was established the best combination of the road-geogrid structure construction and the influence when cavities are developed underground analyzing the stress paths in the medium. From this study, it is found, that when the geogrid layer is embedded between bedrock and subgrade, the failure is mitigated, observing an increase in the factor of safety even with 19 voids presence in the model. Concluding that the geogrid is an adequate solution of reinforcement of roads.

SEISMIC PERFORMANCE OF MASONRY-INFILLED RC FRAMES WITH AND WITHOUT RETROFIT

2013 ◽  
Vol 07 (03) ◽  
pp. 1350023 ◽  
Author(s):  
P. BENSON SHING ◽  
IOANNIS KOUTROMANOS ◽  
ANDREAS STAVRIDIS
Keyword(s):  
Finite Element ◽  
Seismic Performance ◽  
Numerical Study ◽  
Critical Role ◽  
Finite Element Models ◽  
Shake Table ◽  
Shake Table Tests ◽  
Rc Frames ◽  
Infilled Rc Frames ◽  
Masonry Infilled Rc Frames

This paper presents the findings of a research that focused on the seismic performance of masonry-infilled, nonductile, RC frames. This research has resulted in improved analytical methods and effective retrofit techniques to assess and enhance the performance of these structures. The methods were validated by a series of quasi-static tests conducted on one-story frame specimens as well as shake-table tests conducted on two 2/3-scale, three-story, two-bay, masonry-infilled, RC frames. This paper focuses on the observations from the shake-table tests and the further insight gained from a numerical study conducted with finite element models. The first shake-table test specimen had no retrofit measures, and the second had infill walls in the first and second stories strengthened with Engineered Cementitious Composite (ECC) and Fiber Reinforced Polymeric (FRP) overlays, respectively. The tests demonstrated the effectiveness of the retrofit measures. Finite element models that combine smeared and discrete cracks have been used in a numerical study to examine the benefits of the ECC retrofit and the influence of the capacity of the shear dowels that connect an ECC overlay to the RC beams on structural performance. It has been shown that these shear dowels play a critical role in enhancing both the strength and ductility of a retrofitted structure.

Analysis of Collisions of Vehicle and Concrete Barrier on Rural Highways

2011 ◽  
Vol 415-417 ◽  
pp. 2304-2307
Author(s):  
Yu Juan Sun ◽  
Jian Rong ◽  
Yong Gang Tai
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Road Safety ◽  
Finite Element Models ◽  
Collision Process ◽  
Rural Highways ◽  
The Road ◽  
Safety Barrier ◽  
Nonlinear Performance ◽  
Concrete Barrier

A concrete barrier used on rural highways of China was proposed. The crashworthiness of the concrete barrier was analyzed using the non-linear explicit dynamics FE code LS-DYNA. The finite element models of car, bus and concrete barrier were developed and validated using experimental results. These models can be used to simulate the dynamic collision process and evaluate the performance of the road safety barrier on rural highways. The nonlinear performance of materials as well as the boundary conditions was considered. The results show that the concrete barrier could contain and redirect the car and bus in the collision.

scholarly journals Numerical Analyses of Locomotive Impacts on a Spent Fuel Truck Cask and Trailer

2005 ◽  
Author(s):  
Doug Ammerman ◽  
Dave Stevens ◽  
Matt Barsotti
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Applied Research ◽  
Spent Nuclear Fuel ◽  
Numerical Study ◽  
Numerical Approach ◽  
Finite Element Models ◽  
Spent Fuel ◽  
Physical Test ◽  
Grade Crossing

During the transportation of spent nuclear fuel by truck, the possibility exists that a train could run into the spent fuel cask at a grade crossing. Sandia National Laboratories has conducted a numerical study to assess the possibility of cask breach or material release in the event of a high-speed, broadside locomotive collision. A numerical approach has the advantage over conducting a physical test as was done in the 1970s [1] in that varying parameters can be examined. For example, one of the criticisms of the 1970s test was the height of the cask. In the test, the centerline of the cask was above the main frame-rails of the locomotive. In this study the position of the cask with respect to the locomotive was varied. The response of the cask and trailer in different collision scenarios was modeled numerically with LS-DYNA [2]. The simulations were performed as a collaborative endeavor between Sandia National Laboratories (SNL), Applied Research Associates, Inc. (ARA) and Foster-Miller, Inc (FMI). ARA developed the GA-4 Spent Fuel Cask and Cask Transporter models described in this report. These models were then combined with two existing FMI heavy freight locomotive finite element models to create the overall simulation scenarios. The modeling effort, results, and conclusions are presented in this paper.

Integration of Microstructural Architecture of the Mitral Valve Into an Anatomically Accurate Finite Element Mesh

2012 ◽  
Author(s):  
Rouzbeh Amini ◽  
Inge van Loosdregt ◽  
Kevin Koomalsingh ◽  
Robert C. Gorman ◽  
Joseph H. Gorman ◽  
...  
Keyword(s):  
Finite Element ◽  
Mitral Valve ◽  
Constitutive Models ◽  
Geometrical Model ◽  
Finite Element Models ◽  
Element Mesh ◽  
Microstructural Alterations ◽  
Organ Level ◽  
Collagenous Tissues

Although mitral valve (MV) repair initially restores normal leaflets coaptation and stops MV regurgitation, in long term it can also dramatically change the leaflet geometry and stress distribution that may be in part responsible for limited repair durability. As shown for other collagenous tissues, such changes in geometry and loading reorganize the fiber architecture. In addition, MV interstitial cells respond to the altered stress by undergoing alterations in biosynthetic function, which would affect the load-bearing capabilities of MV and its long-term durability. Thus, investigating the repair-induced MV stress and the concomitant microstructural alterations is a key step in assessing the repaired valve durability. Finite element models have been widely used for stress analysis of the mitral valve [1–3]. Most of these models, however, have employed only basic constitutive models and utilized simplified valve geometry. Above all, they have ignored the complex microstructure of the MV, which is the critical physical link between organ level stresses and cellular function. Thus, in this work we developed an initial method to develop an accurate geometrical model of the ovine MV and map the fiber structure for the purposes of developing high fidelity computational meshes of the MV.

Improving finite element results in modeling heart valve mechanics

2018 ◽  
Vol 232 (7) ◽  
pp. 718-725 ◽  
Author(s):  
Emily Earl ◽  
Hadi Mohammadi
Keyword(s):  
Finite Element ◽  
Heart Valve ◽  
Numerical Technique ◽  
Strain Tensor ◽  
Computational Cost ◽  
Constitutive Models ◽  
Least Square ◽  
Computational Time ◽  
Finite Element Models ◽  
Fine Mesh

Finite element analysis is a well-established computational tool which can be used for the analysis of soft tissue mechanics. Due to the structural complexity of the leaflet tissue of the heart valve, the currently available finite element models do not adequately represent the leaflet tissue. A method of addressing this issue is to implement computationally expensive finite element models, characterized by precise constitutive models including high-order and high-density mesh techniques. In this study, we introduce a novel numerical technique that enhances the results obtained from coarse mesh finite element models to provide accuracy comparable to that of fine mesh finite element models while maintaining a relatively low computational cost. Introduced in this study is a method by which the computational expense required to solve linear and nonlinear constitutive models, commonly used in heart valve mechanics simulations, is reduced while continuing to account for large and infinitesimal deformations. This continuum model is developed based on the least square algorithm procedure coupled with the finite difference method adhering to the assumption that the components of the strain tensor are available at all nodes of the finite element mesh model. The suggested numerical technique is easy to implement, practically efficient, and requires less computational time compared to currently available commercial finite element packages such as ANSYS and/or ABAQUS.

Simulation of the Head-On Collision between Heavy Truck and Rigid Guardrail

2013 ◽  
Vol 409-410 ◽  
pp. 1085-1088
Author(s):  
Si Yang Wang ◽  
Yap Ping Zhang ◽  
Yu Wei ◽  
Yong Li Zhang
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Finite Element Models ◽  
Vehicle Speed ◽  
Regular Pattern ◽  
Whole Process ◽  
Collision Safety ◽  
Heavy Truck ◽  
The Finite Element Model ◽  
Setting Parameters

This paper mainly studied the collision between heavy truck and rigid guardrail. The integral finite element models were established via respectively building the finite element model of truck and rigid guardrail and setting parameters of head-on collision. Then the paper did relative simulation and calculation, and analyzed the curves of vehicle speed, accelerated speed and energy in collision process. The whole process above used LS-DYNA to calculate, ANSYS to do pretreatment and LSPREPOST to do post-treatment in order to test collision safety. Compared with relative documents, the established model is basically correct and accords with the regular pattern of collision simulation.

scholarly journals Numerical evaluation on steep soil-nailed slope using finite element method

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Panyabot Kaothon ◽  
Kean Thai Chhun ◽  
Chan-Young Yune
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Evaluation ◽  
Factor Of Safety ◽  
Slope Angle ◽  
The Finite Element Method ◽  
Conventional Design ◽  
Two Parameters ◽  
Element Method

AbstractIn conventional design of soil-nailed slope, the nail parameters such as nail spacing (1–2 m), and nail inclination (10º–20º) have been recommended without considering any specific slope angle. Henceforth, this paper presents a numerical evaluation on the soil-nailed slope with flexible facing based on the finite element method in order to investigate the range of those two parameters with any size of nail head in various slope angles (45º, 55º, 65º, and 75º). Based on a minimum factor of safety (FSmin  =  1.5), the analysis results indicated that the suggested range of those parameters in the conventional specification was applicable in the slope angle of 45º and 55º with any sizes of nail head. Nevertheless, it was not practical for slope angle of 65º and 75º, which required the size of nail head at least 400  ×  400  ×  250 mm, with nail spacing less than or equal to 1.5 m, and nail inclination from 5º to 10º.

scholarly journals Numerical Study of the Geometry Effect of Notched Connections in Mass Timber Panel-Concrete Composite Floors

2019 ◽  
pp. 587-596
Author(s):  
Lei Zhang ◽  
Y H Chui
Keyword(s):  
Finite Element ◽  
Numerical Study ◽  
Design Method ◽  
Element Model ◽  
Finite Element Models ◽  
Strut And Tie ◽  
Strut And Tie Model ◽  
Mass Timber ◽  
Gamma Method ◽  
Composite Floors

A mass timber panel-concrete (MTPC) composite floor system consists of a timber panel in the tensile zone, a concrete layer in the compression zone, and shear connectors between timber and concrete. The notched connections that are cut in timber and connected with concrete by the interlocking effect are often classified as the best type of connection system in terms of stiffness and load-carrying capacity. To study the effect of notch geometry to the performance of notched connections and composite beams, 2D finite element models are built in ABAQUS in this study. The concrete portion is modelled with concrete damaged plasticity model while the timber portion is modelled with Hashin’s failure criteria. The effective bending stiffness and ultimate bending capacity of the composite beam under uniformly distributed load are obtained from the finite element models and are compared with the well-known Gamma method in Eurocode 5 and strut-and-tie model. Good agreement between finite element model in the elastic range and strut-and-tie model was achieved. However, due to the assumptions made in the Gamma method, it was found that this simplified design method is not capable of describing MTPC composite floors with discrete notched connections.

scholarly journals Non-Linear Analysis of Plated T-Subjected to Negative Bending Moment

2013 ◽  
Vol 6 (1) ◽  
pp. 90-104
Author(s):  
Ahmed Abdullah Mansor
Keyword(s):  
Finite Element ◽  
Constitutive Models ◽  
Bending Moment ◽  
Plain Concrete ◽  
Steel Plates ◽  
Finite Element Models ◽  
Finite Element Program ◽  
Linear Behavior ◽  
Element Program ◽  
Negative Bending

This paper present a numerical analysis using ANSYS finite element program to simulate the reinforced concrete T- beams strengthened with external bonded steel plates when subjected to negative bending. Eight beams with length 2.0m and simply supported were modeled. Nonlinear materials behavior, as it relates to steel reinforcing bars and plain concrete, and linear behavior for plate is simulated using appropriate constitutive models. The results showed that the general behavior of the finite element models represented by the load-deflection curves at midspanappear well agreement with the test data from the previous researches. Also the crack patterns at the final loads from the finite models are discussed . The finite element models represented by this search can be used to carry out parametric study for the strengthening of plated T-beams.

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