scholarly journals Multi‐scale simulation of rock compaction through breakage models with microstructure evolution

2020 ◽  
Vol 382 ◽  
pp. 421-425
Author(s):  
Giuseppe Buscarnera ◽  
Yanni Chen ◽  
José Lizárraga ◽  
Ruiguo Zhang
Keyword(s):  
Hydraulic Conductivity ◽  
Constitutive Law ◽  
Pore Collapse ◽  
Physical Processes ◽  
Linear Processes ◽  
Element Analysis ◽  
Multi Scale ◽  
Reservoir Compaction ◽  
Proposed Model ◽  
Rock Microstructure

Abstract. Regional subsidence due to fluid depletion includes the interaction among multiple physical processes. Specifically, rock compaction is governed by coupled hydro-mechanical feedbacks involving fluid flow, effective stress change and pore collapse. Although poroelastic models are often used to explain the delay between depletion and subsidence, recent evidence indicates that inelastic effects could alter the rock microstructure, thus exacerbating coupling effects. Here, a constitutive law built within the framework of Breakage Mechanics is proposed to account for the inherent connection between rock microstructure, hydraulic conductivity, and pore compaction. Furthermore, it is embedded into a 1-D hydromechanical coupled finite element analysis (FEA) to explore the effects of micro-structure rearrangement on the development of reservoir compaction. Numerical examples with the proposed model are compared with simulations under constant hydraulic conductivity to illustrate the model capability to capture the non-linear processes of reservoir compaction induced by fluid depletion.

scholarly journals Finite element modelling of air cavities effect on GnP/epoxy nanocomposite thermal response and its full-field validation

2018 ◽  
Vol 188 ◽  
pp. 01014
Author(s):  
Asimina Manta ◽  
Matthieu Gresil ◽  
Constantinos Soutis
Keyword(s):  
Finite Element ◽  
Thermal Response ◽  
Field Validation ◽  
Element Analysis ◽  
Full Field ◽  
Multi Scale ◽  
Proposed Model ◽  
Air Cavities ◽  
Induced Defects ◽  
Scale Scheme

The manufacturing process of GnP/polymer nanocomposites exhibits important challenges regarding the material quality and how to reduce or eliminate fabrication induced defects. In this work, the effect of air cavities (voids) on the thermal response of nanocomposites is studied by means of finite element analysis on a multi-scale scheme. The proposed model is validated with experimental data by performing generic and full-field comparisons.

A novel continuum model for the reduction of numerical errors of finite-element analysis

2011 ◽  
Vol 225 (4) ◽  
pp. 817-825 ◽  
Author(s):  
H Mohammadi ◽  
F Bahramian ◽  
W Herzog
Keyword(s):  
Finite Element ◽  
Continuum Model ◽  
Constitutive Models ◽  
Least Square ◽  
Constitutive Law ◽  
Element Analysis ◽  
Element Mesh ◽  
Numerical Errors ◽  
Proposed Model ◽  
Numerical Formulation

The authors developed a novel numerical formulation that reduces the computational expense of solving linear and non-linear constitutive models. A finite-element constitutive law followed by a novel continuum model is discussed. The proposed approach is employed to reduce numerical errors obtained from the standard finite-element method. The continuum model is based on the Lagrange multipliers strategy along with the finite-difference method and a least-square algorithm. It is crucial to this approach that the components of either the strain or the stress tensor are known at the nodes of the finite-element mesh. The proposed model is independent of element topology which can be strongly and arbitrarily distorted.

Optimization of Sheet Metal Process Parameters of a Shield Case Piece Using Computer Simulation

2006 ◽  
Vol 510-511 ◽  
pp. 330-333
Author(s):  
M.C. Curiel ◽  
Ho Sung Aum ◽  
Joaquín Lira-Olivares
Keyword(s):  
Sheet Metal ◽  
Thickness Distribution ◽  
Forming Limit Diagram ◽  
Forming Limit ◽  
Physical Processes ◽  
Forming Process ◽  
Element Analysis ◽  
One Step ◽  
Range Of Values ◽  
Principal Strains

Numerical simulations based on Finite Element Analysis (FEA) are widely used to predict and evaluate the forming parameters before performing the physical processes. In the sheet metal industry, there are basically two types of FE programs: the inverse (one-step) programs and the incremental programs. In the present paper, the forming process of the shield case piece (LTA260W1-L05) was optimized by performing simulations with both types of software. The main analyzed parameter was the blankholding force while the rest of the parameters were kept constant. The criteria used to determine the optimum value was based on the Forming Limit Diagram (FLD), fracture and wrinkling of the material, thickness distribution, and the principal strains obtained. It was found that the holding force during the forming process deeply affects the results, and a range of values was established in which the process is assumed to give a good quality piece.

scholarly journals Topology Optimization and Performance Calculation for Control Arms of a Suspension

2014 ◽  
Vol 6 ◽  
pp. 734568 ◽  
Author(s):  
Liang Tang ◽  
Jie Wu ◽  
Jinhao Liu ◽  
Cuicui Jiang ◽  
Wen-Bin Shangguan
Keyword(s):  
Topology Optimization ◽  
Ride Comfort ◽  
Constitutive Law ◽  
Fea Model ◽  
Proposed Model ◽  
Rubber Bushing ◽  
And Performance ◽  
Motion Characteristics ◽  
Ball Joints ◽  
Performance Calculation

Control Arm (CA) of a suspension plays an important role in the automotive ride comfort and handling stability. In this paper, the topology optimization model including ball joints and bushing for topology optimization of an aluminium CA is established, where a ball joint is simplified as rigid elements and the elastic properties of a rubber bushing are estimated using Mooney-Rivlin constitutive law. A method for treating with multiple loads in topology optimization of CA is presented. Inertia relief theory is employed in the FEA model of the CA in order to simulate the large displacement motion characteristics of the CA. A CA is designed based on the topology optimization results, and the strength, natural frequency, and rigidity of the optimized CA are calculated. The calculated results show that the performances of the optimized CA with the proposed model meet the predetermined requirements.

LOAD SEQUENCE ANALYSIS IN FATIGUE LIFE PREDICTION

2015 ◽  
Vol 39 (4) ◽  
pp. 819-828 ◽  
Author(s):  
Moises Jimenez ◽  
Jose Martinez ◽  
Ulises Figueroa
Keyword(s):  
Life Prediction ◽  
Rear Axle ◽  
Element Analysis ◽  
Proposed Model ◽  
Damage Process ◽  
Load Sequence ◽  
Number Of Cycles ◽  
Total Damage ◽  
Damage Rule

In this work, the load sequence effect is analyzed in fatigue test. One of the assumptions of the Miner’s rule is that the total damage is equal to the sum of the damages absorbed; however, different models have been proposed to take the effect of the load sequences under two load levels into account. To analyze this effect, a case study of a rear axle mounting bracket has been performed, analyzing six different sequences of three load levels, defined as Low, Medium and High. A Finite Element Analysis was also performed using MSC Tools. With these results and a series of test at constant amplitude, the component S-N curve was made. 24 tests at room temperature were performed in order to evaluate the damage process. It was found that, under a block of three load levels, the sequence of each block has an effect in the total amount of damage under the same number of cycles. With this information it is possible to improve the life prediction through the modification of the damage rule. The proposed model uses a factor which depends on the ultimate strength and yield point. This is an advantage over other approaches, as the other models need additional dynamic tests to obtain coefficients to perform the life prediction.

J-Integral Analysis of Surface Cracks in Round Bars under Bending Moments

2011 ◽  
Vol 52-54 ◽  
pp. 43-48 ◽  
Author(s):  
Al Emran Ismail ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Mariyam Jameelah Ghazali ◽  
Ruslizam Daud
Keyword(s):  
Finite Element ◽  
Crack Depth ◽  
Crack Tip ◽  
Bending Moment ◽  
Limit Load ◽  
Fe Model ◽  
Surface Cracks ◽  
Element Analysis ◽  
Reference Stress ◽  
Proposed Model

This paper presents a non-linear numerical investigation of surface cracks in round bars under bending moment by using ANSYS finite element analysis (FEA). Due to the symmetrical analysis, only quarter finite element (FE) model was constructed and special attention was given at the crack tip of the cracks. The surface cracks were characterized by the dimensionless crack aspect ratio, a/b = 0.6, 0.8, 1.0 and 1.2, while the dimensionless relative crack depth, a/D = 0.1, 0.2 and 0.3. The square-root singularity of stresses and strains was modeled by shifting the mid-point nodes to the quarter-point locations close to the crack tip. The proposed model was validated with the existing model before any further analysis. The elastic-plastic analysis under remotely applied bending moment was assumed to follow the Ramberg-Osgood relation with n = 5 and 10. J values were determined for all positions along the crack front and then, the limit load was predicted using the J values obtained from FEA through the reference stress method.

scholarly journals A nonlinear multi-scale model for blood circulation in a realistic vascular system

2021 ◽  
Vol 8 (12) ◽  
Author(s):  
Ulin Nuha A. Qohar ◽  
Antonella Zanna Munthe-Kaas ◽  
Jan Martin Nordbotten ◽  
Erik Andreas Hanson
Keyword(s):  
Blood Flow ◽  
Blood Circulation ◽  
Vascular System ◽  
Scale Model ◽  
Model Framework ◽  
Fluid Exchange ◽  
Multi Scale ◽  
Proposed Model ◽  
Porous Media Model ◽  
Capillary Bed

In the last decade, numerical models have become an increasingly important tool in biological and medical science. Numerical simulations contribute to a deeper understanding of physiology and are a powerful tool for better diagnostics and treatment. In this paper, a nonlinear multi-scale model framework is developed for blood flow distribution in the full vascular system of an organ. We couple a quasi one-dimensional vascular graph model to represent blood flow in larger vessels and a porous media model to describe flow in smaller vessels and capillary bed. The vascular model is based on Poiseuille’s Law, with pressure correction by elasticity and pressure drop estimation at vessels' junctions. The porous capillary bed is modelled as a two-compartment domain (artery and venous) using Darcy’s Law. The fluid exchange between the artery and venous capillary bed compartments is defined as blood perfusion. The numerical experiments show that the proposed model for blood circulation: (i) is closely dependent on the structure and parameters of both the larger vessels and of the capillary bed, and (ii) provides a realistic blood circulation in the organ. The advantage of the proposed model is that it is complex enough to reliably capture the main underlying physiological function, yet highly flexible as it offers the possibility of incorporating various local effects. Furthermore, the numerical implementation of the model is straightforward and allows for simulations on a regular desktop computer.

scholarly journals Macro-meso scale simulations of 3D woven composite reinforcements during the forming process

2021 ◽  
Author(s):  
Jie Wang ◽  
Peng Wang ◽  
Nahiène Hamila ◽  
Philippe Boisse
Keyword(s):  
Computational Cost ◽  
Constitutive Law ◽  
Forming Process ◽  
Multi Scale ◽  
Rtm Process ◽  
Macroscopic Simulation ◽  
Deformations And Orientations ◽  
High Computational Cost ◽  
Meso Scale ◽  
Composite Reinforcements

During the forming stage in the RTM process, deformations and orientations of yarns at the mesoscopic scale are essential to evaluate mechanical behaviors of final composite products and calculate the permeability of the reinforcement. However, due to the high computational cost, it is very difficult to carry out a mesoscopic draping simulation for the entire reinforcement. In this paper, a macro-meso scale simulation of composite reinforcements is presented in order to predict mesoscopic deformations of the fabric in a reasonable calculation time. The proposed multi-scale method allows linking the macroscopic simulation of the reinforcement with the mesoscopic modelling of the RVE through a macromeso embedded analysis. On the base of macroscopic simulations using a hyperelastic constitutive law of the reinforcement, an embedded mesoscopic geometry is first deduced from the macroscopic simulation of the draping. To overcome the inconvenience of the macro-meso embedded solution which leads to unreal excessive yarn extensions, local mesoscopic simulations based on the embedded analysis are carried out on a single RVE by defining specific boundary conditions. Finally, the multi-scale forming simulations are investigated in comparison with the experimental results, illustrating the efficiency of the proposed approach, in terms of accuracy and CPU time.

scholarly journals Dependence structure analysis of multisite river inflow data using vine copula-CEEMDAN based hybrid model

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10285
Author(s):  
Hafiza Mamona Nazir ◽  
Ijaz Hussain ◽  
Muhammad Faisal ◽  
Alaa Mohamd Shoukry ◽  
Mohammed Abdel Wahab Sharkawy ◽  
...  
Keyword(s):  
River Basin ◽  
Hybrid Model ◽  
Moving Average ◽  
Ensemble Empirical Mode Decomposition ◽  
Dependence Structure ◽  
Absolute Deviation ◽  
River Inflow ◽  
Multi Scale ◽  
Proposed Model ◽  
Vine Copula

Several data-driven and hybrid models are univariate and not considered the dependance structure of multivariate random variables, especially the multi-site river inflow data, which requires the joint distribution of the same river basin system. In this paper, we proposed a Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) Vine copula-based approach to address this issue. The proposed hybrid model comprised on two stages: In the first stage, the CEEMDAN is used to extract the high dimensional multi-scale features. Further, the multiple models are used to predict multi-scale components and residuals. In the second stage, the residuals obtained from the first stage are used to model the joint uncertainty of multi-site river inflow data by using Canonical Vine. For the application of the proposed two-step architecture, daily river inflow data of the Indus River Basin is used. The proposed two-stage methodology is compared with only the first stage proposed model, Vector Autoregressive and copula-based Autoregressive Integrated Moving Average models. The four evaluation measures, that is, Mean Absolute Relative Error (MARE), Mean Absolute Deviation (MAD), Nash-Sutcliffe Efficiency (NSE) and Mean Square Error (MSE), are used to observe the prediction performance. The results demonstrated that the proposed model outperforms significantly with minimum MARE, MAD, NSE, and MSE for two case studies having significant joint dependance. Therefore, it is concluded that the prediction can be improved by appropriately modeling the dependance structure of the multi-site river inflow data.

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