Explicit Solver Applied to Nonlocal Material Problems

2009 ◽  
Author(s):  
P. Rericha
Keyword(s):  
Explicit Solver

Advanced Approaches for Coupled Deformation-Seepage-Analyses of Suction Caisson Installation

2017 ◽  
Author(s):  
Marc Stapelfeldt ◽  
Britta Bienen ◽  
Jürgen Grabe
Keyword(s):  
Deformation Analysis ◽  
Numerical Techniques ◽  
Suction Caisson ◽  
Large Deformation Analysis ◽  
Centrifuge Tests ◽  
Calculation Results ◽  
Modelling Techniques ◽  
Explicit Solver ◽  
Excess Pore Pressures ◽  
Numerical Approaches

In this paper the installation procedure of suction caissons is investigated by means of coupled seepage large deformation analysis performed with finite element methods. The modelling techniques employed to enable simulations of the penetration of a caisson into the soil under offshore conditions, i. e. several tens of meters below the water level. The numerical model includes a u-p-formulation, which is used to calculate the excess pore pressures and effective stresses from the total stresses. The Coupled-Eulerian-Lagrangian (CEL) approach available in conjunction with the Abaqus/Explicit solver is used. The calculation results are compared to centrifuge tests that were carried out recently at the Centre for Offshore Foundation Systems (COFS). This sheds light on the potential and the limitations of the presented numerical techniques. This paper concludes with a brief discussion of alternative numerical approaches that could be capable of the simulation of caisson installation.

scholarly journals An Investigation of Turbulence Modelling in Transonic Fans Including a Novel Implementation of an Implicit κ–ϵ Turbulence Model

1992 ◽  
Author(s):  
Mark G. Turner ◽  
Ian K. Jennions
Keyword(s):  
Turbulence Models ◽  
Algebraic Model ◽  
Turbulence Modelling ◽  
Experimental Results ◽  
Navier Stokes ◽  
Multiple Time Scales ◽  
Multiple Time ◽  
Wall Functions ◽  
Solution Methods ◽  
Explicit Solver

An explicit Navier-Stokes solver has been written with the option of using one of two types of turbulence models. One is the Baldwin-Lomax algebraic model and the other is an implicit k-ϵ model which has been coupled with the explicit Navier-Stokes solver in a novel way. This type of coupling, which uses two different solution methods, is unique and combines the overall robustness of the implicit k-ϵ solver with the simplicity of the explicit solver. The resulting code has been applied to the solution of the flow in a transonic fan rotor which has been experimentally investigated by Wennerstrom. Five separate solutions, each identical except for the turbulence modelling details, have been obtained and compared with the experimental results. The five different turbulence models run were: the standard Baldwin-Lomax model both with and without wall functions, the Baldwin-Lomax model with modified constants and wall functions, a standard k-ϵ model and an extended k-ϵ model which accounts for multiple time scales by adding an extra term to the dissipation equation. In general, as the model includes more of the physics, the computed shock position becomes closer to the experimental results.

A Cartesian Explicit Solver for Complex Hydrodynamic Applications

2014 ◽  
Author(s):  
P. Bigay ◽  
A. Bardin ◽  
G. Oger ◽  
D. Le Touzé
Keyword(s):  
Level Set ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Simulation Method ◽  
Navier Stokes ◽  
Viscous Effects ◽  
Navier Stokes Equations ◽  
Eddy Simulation ◽  
Flow Past A Cylinder ◽  
Explicit Solver

In order to efficiently address complex problems in hydrodynamics, the advances in the development of a new method are presented here. This method aims at finding a good compromise between computational efficiency, accuracy, and easy handling of complex geometries. The chosen method is an Explicit Cartesian Finite Volume method for Hydrodynamics (ECFVH) based on a compressible (hyperbolic) solver, with a ghost-cell method for geometry handling and a Level-set method for the treatment of biphase-flows. The explicit nature of the solver is obtained through a weakly-compressible approach chosen to simulate nearly-incompressible flows. The explicit cell-centered resolution allows for an efficient solving of very large simulations together with a straightforward handling of multi-physics. A characteristic flux method for solving the hyperbolic part of the Navier-Stokes equations is used. The treatment of arbitrary geometries is addressed in the hyperbolic and viscous framework. Viscous effects are computed via a finite difference computation of viscous fluxes and turbulent effects are addressed via a Large-Eddy Simulation method (LES). The Level-Set solver used to handle biphase flows is also presented. The solver is validated on 2-D test cases (flow past a cylinder, 2-D dam break) and future improvements are discussed.

scholarly journals Improving the Blast Resistance of Large Steel Gates—Numerical Study

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2121 ◽  
Author(s):  
Hasan Al-Rifaie ◽  
Wojciech Sumelka
Keyword(s):  
Positive Impact ◽  
Numerical Study ◽  
Blast Resistance ◽  
Critical Factor ◽  
Induced Response ◽  
Dissipation Energy ◽  
Auxetic Structures ◽  
Explicit Solver ◽  
Supporting Frame ◽  
Energy Absorbing

Blast resistant gates/doors are essential for sensitive infrastructure, such as embassies, ministries, or parliaments. Lightweight gates equipped with ‘energy absorbing systems’ have better operational performance than the traditional costly and bulky design. Graded auxetic structures have not yet been used as potential passive damping systems in the supporting frame of blast resistant gates. Consequently, this study tries to test if a uniaxial graded auxetic damper (UGAD) proposed by the authors in a recent article, namely the development of a new shock absorbing UGAD, could maintain a 3000 mm × 4500 mm steel gate operable after high blast peak reflected overpressure of 6.6 MPa, from 100 kg TNT at 5 m stand-off distance. The blast-induced response of the gate was assessed, with and without the proposed UGAD, using Abaqus/Explicit solver. Results showed that the attachment of the proposed UGAD to the gate led to a dramatic decrease in permanent deformations (a critical factor for gate operability after a blast event). Hence, a lighter, more economical gate (with 50% reduction in mass) was required to satisfy the operability condition. In addition, 49% of peak reaction forces were diminished, that have a direct impact on the supporting frame. Moreover, the results revealed that, in the numerical model, 56% of the achieved plastic dissipation energy was from the UGADs, and 44% from the gate. The outcomes of this research may have a positive impact on other sectors beyond academia, such as industry, economy, and public safety.

Numerical Study on Explosion Cutting Process of PMMA Plate and Key Factors Influence on Cutting Performance

2018 ◽  
Author(s):  
Lei Ge ◽  
Yantao Wang ◽  
Huipeng Hu ◽  
Lijun Li ◽  
Yiben Zhang
Keyword(s):  
Numerical Study ◽  
Engineering Application ◽  
Material Model ◽  
Cutting Performance ◽  
Cutting Process ◽  
Transient Pressure ◽  
Key Factors ◽  
Explicit Solver ◽  
The Relationship ◽  
Selection Of

Polymethylmethacrylate (PMMA) has been widely utilized to manufacture the covers of aircraft cockpits, naval vessels, car windows and so on, due to their high transmittance, low density, easy processing formability, high corrosion resistance and excellent mechanical properties. Under special conditions such as ejection lifesaving, the PMMA plate needs to be split precisely by explosion cutting technology. Hence, an accurate numerical simulation of PMMA structures is significantly important in engineering application. This paper aims to study the cutting behavior of PMMA plate numerically and investigate the influencing factors on cutting performance of PMMA plates. First of all, the simulation of explosion cutting process of PMMA plate is carried out by a non-linear explicit solver in LS-DYNA software using the fluid-solid coupling method. Jones-Wilkins-Lee (JWL) equation of state is used to simulate the relationship between the transient pressure and specific volume of explosives during explosion. The material model considering failure behaviors is used in the simulation. Additionally, the influence of explosive dosage as well as explosive type on the cutting performance of PMMA plate is investigated. Furthermore, the effect of PMMA geometry size on cutting performance is discussed. This study contributes to the knowledge for the design of PMMA structures which needs explosion cutting and the selection of explosive dosage and explosive type.

A Design Practice for Subsea Pipeline Subjected to UXO Hazards

2019 ◽  
Author(s):  
Zhenhui Liu ◽  
Ragnar Igland ◽  
Sindre Bruaseth ◽  
Luca Ercoli-Malacari ◽  
Odd Arne Lillebø
Keyword(s):  
Survey Methods ◽  
Oil Field ◽  
Charge Weight ◽  
Unexploded Ordnance ◽  
Design Practice ◽  
Project Schedule ◽  
Original Design ◽  
Safety Distance ◽  
Oil Export ◽  
Explicit Solver

Abstract This paper presents a design practice for the oil export pipeline (OEP) of Johan Sverdrup Oil Field subjected to unexploded ordnance (UXO) hazards during the pipeline installation period. The UXO (unexploded ordnance) is a potential risk to the oil export pipeline due to its significant impulsive pressure load in a short time. Present paper discusses an unfavorable scenario in which the UXOs are identified during the pre-lay survey stage. It may (and it does) happen due to the survey methods chosen between the initial preliminary and the pre-lay survey. Consequently the original design pipeline routing has to be updated in order to minimize the UXOs’ potential damage to the pipeline. A safety distance between pipeline and UXOs shall be established and maintained. To achieve this, advanced numerical simulation was used for assessing the damage of pipeline under UXO explosion loads. The damage is sensitive to the charge weight and the distance between charge and pipeline. The pipeline route was updated accordingly based on the safety distance and actual locations of UXOs. The new route shall also fulfill all design checks. With the updated pipeline routing, the installation could continue without interruption of the project schedule. The identified UXOs will be subject to later removal before startup of production to further ensure the safety of installed pipeline. The overall design process is presented. Some simulation results from Abaqus Explicit solver are shown in the paper. Conclusions and discussions are included, which may be useful for similar projects in the future.

3D Numerical Simulation of Aluminum Foams Behavior in Large Deformation

2015 ◽  
Vol 749 ◽  
pp. 3-7
Author(s):  
Abel Cherouat ◽  
Shi Jie Zhu ◽  
Houman Borouchaki ◽  
Xiao Lu Gong
Keyword(s):  
Metal Foam ◽  
Deformable Body ◽  
Mechanical Parameters ◽  
Aluminum Foams ◽  
Absorbed Energy ◽  
3D Numerical Simulation ◽  
Open Cell ◽  
Program Transfer ◽  
Explicit Solver ◽  
Compression Characteristics

The compression characteristics of open-cell aluminum foams were experimentally and numerically investigated. It is found that the mechanical parameters, such as collapse stress and absorbed energy, are dependent on the porosity of aluminum foams material. During simulation of metal foam compression, the finite elements distort severely at the local regions with high gradient of physical field. The procedure integrates Explicit solver of Abaqus FEA, 3D Optiformmesher and Python script program transfer to execute step by step the incremental deformation of deformable body.

Folding and Deployment of a New Thin-Walled Tube Flexible Hinge

2014 ◽  
Vol 635-637 ◽  
pp. 365-369 ◽  
Author(s):  
Hui Yang ◽  
Rong Qiang Liu ◽  
Hong Wei Guo ◽  
Jian Guo Tao
Keyword(s):  
Finite Element Analysis ◽  
Strain Curve ◽  
Tension Test ◽  
Slot Width ◽  
Stress Strain Curve ◽  
Element Analysis ◽  
Flexible Hinge ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Explicit Solver

A new thin-walled tube flexible hinge with six slots is proposed. The slot geometry is parameterized in terms of slot width, length and distance between two adjacent slots. The experiment for tension test of the thin-walled tube hinge with six-slots is conducted by INSTRON and the tensile stress-strain curve is measured. Finite element analysis to investigate the quasi-static folding and deployment of the new hinges by ABAQUS/Explicit solver are employed to perform a series of parameter studies for the slots longitude lengthl0, the slot widthwand the distancedbetween two adjacent slots.

scholarly journals RKC: An explicit solver for parabolic PDEs

1998 ◽  
Vol 88 (2) ◽  
pp. 315-326 ◽  
Author(s):  
B.P. Sommeijer ◽  
L.F. Shampine ◽  
J.G. Verwer
Keyword(s):  
Parabolic Pdes ◽  
Explicit Solver
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