A Numerical Approach for Simulation of Rock Fracturing in Engineering Blasting

2012 ◽  
pp. 203-224
Author(s):  
Mani Ram Saharan ◽  
Hani Mitri
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modelling ◽  
Knowledge Base ◽  
Plane Stress ◽  
Numerical Approach ◽  
The Other ◽  
Brittle Rock ◽  
Rock Fracturing ◽  
Element Elimination

An approach for simulation of rock fracturing as a result of engineering blasting is presented in this paper. The approach uses element elimination technique within the framework of finite element method to capture the physics of engineering blasting. The approach does not require pre-placement of fracture paths which is the severe drawback of the other existing methodologies and approaches. Results of plane stress modelling for isotropic brittle rock behaviour are presented in this paper and these results are in good agreement with the existing knowledge base. The authors also review the existing approaches of numerical modelling to compare the efficacy of the element elimination technique. It is anticipated that the further developments with this approach can prove to be good experimental tool to improve engineering blasting operations.

A Numerical Approach for Simulation of Rock Fracturing in Engineering Blasting

2010 ◽  
Vol 1 (2) ◽  
pp. 38-58
Author(s):  
Mani Ram Saharan ◽  
Hani S. Mitri
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modelling ◽  
Plane Stress ◽  
Numerical Approach ◽  
The Other ◽  
Rock Fracturing ◽  
Experimental Tool ◽  
Element Elimination ◽  
Good Agreement

An approach for simulation of rock fracturing as a result of engineering blasting is presented in this paper. The approach uses element elimination technique within the framework of finite element method to capture the physics of engineering blasting. The approach does not require pre-placement of fracture paths which is the severe drawback of the other existing methodologies and approaches. Results of plane stress modelling for isotropic brittle rock behaviour are presented in this paper and these results are in good agreement with the existing knowledge base. The authors also review the existing approaches of numerical modelling to compare the efficacy of the element elimination technique. It is anticipated that the further developments with this approach can prove to be good experimental tool to improve engineering blasting operations.

A numerical approach based on finite element method for the wrinkling analysis of dielectric elastomer membranes

2021 ◽  
pp. 1-37
Author(s):  
Guoyong Mao ◽  
Wei Hong ◽  
Martin Kaltenbrunner ◽  
Shaoxing Qu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thickness Distribution ◽  
Numerical Approach ◽  
Dielectric Elastomer ◽  
Equivalent Model ◽  
Maxwell Stress ◽  
Buckling Mode ◽  
Post Buckling ◽  
Element Method

Abstract Dielectric elastomer (DE) actuators are deformable capacitors capable of a muscle-like actuation when charged. When subjected to voltage, DE membranes coated with compliant electrodes may form wrinkles due to the Maxwell stress. Here, we develop a numerical approach based on the finite element method (FEM) to predict the morphology of wrinkled DE membranes mounted on a rigid frame. The approach includes two steps, I) pre-buckling and II) post-buckling. In step I, the first buckling mode of the DE membrane is investigated by substituting the Maxwell stress with thermal stress in the built-in function of the FEM platform SIMULIA Abaqus. In step II, we use this first buckling mode as an artificial geometric imperfection to conduct the post-buckling analysis. For this purpose, we develop an equivalent model to simulate the mechanical behavior of DEs. Based on our approach, the thickness distribution and the thinnest site of the wrinkled DE membranes subjected to voltage are investigated. The simulations reveal that the crests/troughs of the wrinkles are the thinnest sites around the center of the membrane and corroborate these findings experimentally. Finally, we successfully predict the wrinkles of DE membranes mounted on an isosceles right triangle frame with various sizes of wrinkles generated simultaneously. These results shed light on the fundamental understanding of wrinkled dielectric elastomers but may also trigger new applications such as programmable wrinkles for optical devices or their prevention in DE actuators.

scholarly journals Influence of the Mechanical Properties of Elastoplastic Materials on the Nanoindentation Loading Response

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 4842
Author(s):  
Huanping Yang ◽  
Wei Zhuang ◽  
Wenbin Yan ◽  
Yaomian Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
The Other ◽  
Equivalent Model ◽  
Strain Hardening Exponent ◽  
Mechanical Parameters ◽  
The Finite Element Method ◽  
Fem Simulations ◽  
Elastoplastic Materials

The nanoindentation loading response of elastoplastic materials was simulated by the finite element method (FEM). The influence of the Young’s modulus E, yield stress σy, strain hardening exponent n and Poisson’s ratio ν on the loading response was investigated. Based on an equivalent model, an equation with physical meaning was proposed to quantitatively describe the influence. The calculations agree well with the FEM simulations and experimental results in literature. Comparisons with the predictions using equations in the literature also show the reliability of the proposed equation. The investigations show that the loading curvature C increases with increasing E, σy, n and ν. The increase rates of C with E, σy, n and ν are different for their different influences on the flow stress after yielding. It is also found that the influence of one of the four mechanical parameters on C can be affected by the other mechanical parameters.

scholarly journals Selected aspects of numerical modelling in prediction of building vibrations due to traffic

2018 ◽  
Vol 196 ◽  
pp. 01055
Author(s):  
Sławomir Dudziak ◽  
Zofia Kozyra
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modelling ◽  
The Finite Element Method ◽  
Frequency Range ◽  
Mass Estimation ◽  
Structure Response ◽  
Dynamic Analyses ◽  
Transportation Routes ◽  
The Impact

Dynamic analyses play an important role in the process of designing buildings in the vicinity of transportation routes. The Finite Element Method is the most popular modelling technique, because it allows to simulate the structure response in the higher frequency range properly. However, the results of such analyses depend on many factors and can differ a lot. This paper discusses the impact of the building mass estimation and neglecting or including damping in the analysis on the assessment of influence of vibrations due to traffic on people.

Numerical investigation of nonlinear fluid–structure interaction dynamic behaviors under a general Immersed Boundary-Lattice Boltzmann-Finite Element method

2018 ◽  
Vol 29 (04) ◽  
pp. 1850038 ◽  
Author(s):  
Chun-Lin Gong ◽  
Zhe Fang ◽  
Gang Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Lattice Boltzmann ◽  
Fluid Structure Interaction ◽  
Numerical Approach ◽  
Immersed Boundary ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Flexible Objects ◽  
Element Method

A numerical approach based on the immersed boundary (IB), lattice Boltzmann and nonlinear finite element method (FEM) is proposed to simulate hydrodynamic interactions of very flexible objects. In the present simulation framework, the motion of fluid is obtained by solving the discrete lattice Boltzmann equations on Eulerian grid, the behaviors of flexible objects are calculated through nonlinear dynamic finite element method, and the interactive forces between them are implicitly obtained using velocity correction IB method which satisfies the no-slip conditions well at the boundary points. The efficiency and accuracy of the proposed Immersed Boundary-Lattice Boltzmann-Finite Element method is first validated by a fluid–structure interaction (F-SI) benchmark case, in which a flexible filament flaps behind a cylinder in channel flow, then the nonlinear vibration mechanism of the cylinder-filament system is investigated by altering the Reynolds number of flow and the material properties of filament. The interactions between two tandem and side-by-side identical objects in a uniform flow are also investigated, and the in-phase and out-of-phase flapping behaviors are captured by the proposed method.

Spectral Fatigue Analysis of Plate Surface Hot-Spots: A Practical Solution to the Stress Direction Issue

2020 ◽  
Author(s):  
Fabien Bigot ◽  
Stéphanie Mougin
Keyword(s):  
Finite Element ◽  
Spectral Analysis ◽  
Fatigue Strength ◽  
Plane Stress ◽  
Hot Spots ◽  
Fatigue Analysis ◽  
Multiaxial Fatigue ◽  
The Other ◽  
Plate Surface ◽  
Practical Solution

Abstract Spectral Fatigue Analysis using coupled hydrodynamics and finite element models has now become a common practice for the fatigue strength assessment of offshore units, with established procedures given in Classification Rules. However, users are facing a practical issue that is almost never mentioned in the procedures. Indeed, many fatigue hot-spots are located on a plate surface, as opposed to plate edges. For such hot-spots, the finite element model results are the three components of the plane-stress stress tensor. Therefore, the outcome of the Spectral Fatigue Analysis is a set of three transfer functions (RAOs). On the other hand, our industry’s practice regarding the fatigue strength model is still the proven « design S-N curve » approach in combination with the Palmgren-Miner’s damage summation. As a consequence, today the engineer is left with no clear instruction about the proper way how to close this gap between the three stress RAOs on the one hand, and the single stress S-N curve on the other hand. If any advice is given, it is most often to consider the principal stresses, tentatively extending to spectral analysis the classification rule load cases approach. However, principal stress determination is a non-linear procedure that is not compatible with spectral analysis in frequency domain. Turning the spectral results into time domain to overcome this limitation is extremely costly and is not straightforward. Of course, a rational solution to this issue would be the adoption of a multiaxial fatigue damage criteria in lieu of the uniaxial S-N curve. But until such a multiaxial fatigue criteria is widely accepted in our industry, users have to square the circle, and force their stress tensor RAOs into the existing rule criteria. In this paper, a practical solution to reconcile plane stress results and conventional S-N curve criterion in spectral fatigue is proposed: the “facet approach “.

Development of Stacked-Type Electrostatic Actuator Using Two Ribbon Films

2013 ◽  
Vol 25 (2) ◽  
pp. 324-332 ◽  
Author(s):  
Kazuo Okuda ◽  
◽  
Keiji Saneyoshi ◽  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Reduction Rate ◽  
Measured Data ◽  
The Other ◽  
Artificial Muscles ◽  
Electrostatic Actuator ◽  
The Finite Element Method ◽  
Nonlinear Structural Analysis ◽  
Working Region

A new stacked-type electrostatic actuator with two ribbon films has been developed to be applied to artificial muscles. In this paper, spring characteristics of the actuator have been simulated and compared to measured data. There are two regions in spring characteristics of the actuator: one is the working region where the actuator contracts easily, and the other is the overload region where the actuator is extended only negligibly by the load. Spring characteristics of the actuator have been simulated by nonlinear structural analysis including the contact problem using the finite element method. It is understood that spring characteristics of working and overload regions can be improved by thinning the hinge and by thickening the electrode. The stroke of the actuator can be controlled, furthermore, by changing the length of the hinge. When the size of the actuator is reduced and actuators are integrated until they become the same volume, voltage applied to the actuator to generate the same force is reduced in proportion to the reduction rate while the actuator keeps the same spring characteristics and stroke.

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