Numerical Simulation of Fracture Saturation in Multilayer Materials in Symmetric Case

2011 ◽  
Vol 704-705 ◽  
pp. 641-644
Author(s):  
Feg Shan Han
Keyword(s):  
Numerical Simulation ◽  
Layer Thickness ◽  
Process Analysis ◽  
Failure Process ◽  
Bottom Layer ◽  
Symmetric Case ◽  
Thickness Ratio ◽  
Central Layer ◽  
Layer Thickness Ratio ◽  
Multilayer Materials

Using Realistic Failure Process Analysis Code RFPA2D, a three layer materials model with a central layer and with the same thickness top and bottom layer, progressive formation of fracture saturation in multilayer materials is simulated in all case by numerical simulation. Our numerical simulation recurrence the phenomenon of fracture saturation in multilayer materials. numerical simulation shown that for the symmetric case the spacing of these fractures at fracture saturation are approximately the same and lineally related to thickness of the fractured layer. We investigate that the critical fracture spacing to layer thickness ratio is function of the thickness ratio of the top and bottom layers to central layer at fracture saturation. numerical simulation shown that for the symmetric case the critical spacing of fractures to layer thickness ratio decreases rapidly and tends to a constant value.

Numerical Investigation for Fracture Saturation in Multilayer Sedimentary Rock in Unsymmetrical Case

2013 ◽  
Vol 690-693 ◽  
pp. 3050-3053
Author(s):  
Feng Shan Han ◽  
Li Song
Keyword(s):  
Numerical Simulation ◽  
Layer Thickness ◽  
Sedimentary Rock ◽  
Process Analysis ◽  
Failure Process ◽  
Bottom Layer ◽  
Thickness Ratio ◽  
Fracture Spacing ◽  
Layer Thickness Ratio ◽  
Rock Failure Process

Opening mode fractures in multilayer sedimentary rock often are periodically distributed with fracture spacing scaled to the thickness of the fractured layer. In this paper, based on Rock Failure Process Analysis Code RFPA2D, a three layer model with a central layer and with the different thickness top and bottom layer, progressive formation in multilayer sedimentary rock at fracture saturation in unsymmetrical case is simulated. We investigate the change of the critical fracture spacing to layer thickness ratio as a function of the thickness of the top layer where the bottom layers is much thicker (5 times) than the fractured layer called the unsymmetrical case, in this unsymmetrical case, fracture saturation is simulated. By numerical simulation of RFPA2D, the critical spacing to layer thickness ratio decreases and tend to the same constant value as the thickness of the top layer increases. Numerical simulation shown that for the unsymmetrical case, if the adjacent layers are thicker than 1.5 times the thickness of the fractured layer, the multilayer sedimentary rock can be treated approximately as a system with infinitely thick top and bottom layers at fracture saturation.That should be useful in the design of engineering systems and in the prediction of fracture spacing in hydrocarbon reservoirs and groundwater aquifers.

Numerical Approach to Fracture Spacing in Two Layered Material

2005 ◽  
Vol 297-300 ◽  
pp. 750-755
Author(s):  
Xu Chang ◽  
Junjie Liu ◽  
Chun An Tang ◽  
Yong Bin Zhang ◽  
Juan Xia Zhang
Keyword(s):  
Layer Thickness ◽  
Process Analysis ◽  
Failure Process ◽  
Fracture Initiation ◽  
Horizontal Stress ◽  
Numerical Approach ◽  
Thickness Ratio ◽  
Fracture Spacing ◽  
Layer Thickness Ratio ◽  
Constant State

Equally spaced opening-mode fractures always evolve in top layer attached to underlying layer. With a newly developed Material Failure Process Analysis code (MFPA2D), we have firstly investigated the stress distribution between two adjacent fractures as a function of the fracture-spacing-to-layer-thickness ratio using a two-layer model with a fractured top layer. The numerical results indicate the horizontal stress perpendicular to the fractures near the top surface changes from tensile to compressive when the fracture-spacing-to-layer-thickness ratio changes from greater than to less than a critical value. Then, the process from fracture initiation to fracture saturation is numerically modeled. The modeling of fracture process shows that the fractures initiate at the top surface and propagate to the interface between the two layers in the first stage. In the following stage, new fractures can infill between the earlier formed fractures and they always initiate at the interface and propagate to the top surface. Numerical simulation clearly demonstrates that the stress state transition precludes further infilling of fractures and the fracture spacing reaches a constant state, i.e. the so-called fracture saturation.

Tuning Negative Capacitance in PbZr0.2Ti0.8O3/SrTiO3 Heterostructures via Layer Thickness Ratio

2021 ◽  
Vol 16 (3) ◽  
Author(s):  
Yifei Hao ◽  
Tianlin Li ◽  
Yu Yun ◽  
Xin Li ◽  
Xuegang Chen ◽  
...  
Keyword(s):  
Layer Thickness ◽  
Thickness Ratio ◽  
Negative Capacitance ◽  
Layer Thickness Ratio

Influence of Layer-Thickness Ratio on Magnetic Properties in F-La2/3Ca1/3MnO3/AF-La1/3Ca2/3MnO3 Bilayers

2012 ◽  
Vol 25 (7) ◽  
pp. 2193-2198 ◽  
Author(s):  
P. Prieto ◽  
L. Marín ◽  
S. M. Diez ◽  
J.-G. Ramirez ◽  
M. E. Gómez
Keyword(s):  
Magnetic Properties ◽  
Layer Thickness ◽  
Thickness Ratio ◽  
Layer Thickness Ratio

Experimental Study of Wave Loading by Internal Solitary Waves on a Submerged Slender Body

2020 ◽  
Author(s):  
Meng Ji ◽  
Ke Chen ◽  
Yunxiang You ◽  
Ruirui Zhang
Keyword(s):  
Layer Thickness ◽  
Solitary Waves ◽  
Wave Amplitude ◽  
Prediction Method ◽  
Thickness Ratio ◽  
Experimental Results ◽  
Slender Body ◽  
Internal Solitary Waves ◽  
Wave Loads ◽  
Layer Thickness Ratio

Abstract Although ocean structures are complex, they all can be disassembled into a number of simple-shaped parts. One common shape is the slender body mentioned in this paper, and we focus on studying the mechanism of this shape. Experiments were carried out to study features of wave loads exerted by internal solitary waves (ISWs) on a submerged slender body. ISWs were generated by a piston-type wave maker in a large-type density stratified two-layer fluid wave flume. Using a three-component force transducer, the force variation of three degree of freedom (DOF) on the model was recorded. A satisfactory prediction method is established for ISWs on a submerged slender body based on internal solitary wave theory, Morison equation and pressure integral. Calculations based on this new prediction method are in good agreement with the experimental results. The experimental results and calculations show that, different incident angles, wave amplitude and layer thickness ratio have great effects on the wave loads, especially transverse incident waves bring much more severely influence. Besides the forces increase linearly with the wave amplitude becoming larger, and the maximums of the horizontal forces increase with the layer thickness ratio increasing.

Numerical Simulation on Fracture Formation on Surfaces of Bi-Layered Materials

2007 ◽  
Vol 353-358 ◽  
pp. 993-996
Author(s):  
Tian Hui Ma ◽  
Ju Ying Yang ◽  
Zheng Zhao Liang ◽  
Yong Bin Zhang ◽  
Tao Xu
Keyword(s):  
Numerical Simulation ◽  
Numerical Solutions ◽  
Process Analysis ◽  
Failure Process ◽  
Layered Materials ◽  
Numerical Code ◽  
Material Layer ◽  
Fracture Formation ◽  
Constant State ◽  
The Individual

Fracture formation on surfaces of bi-layered materials is studied numerically. A simplified two-layered materials model like growing tree trunk is present. This work is focused on patterns of fractures and fracture saturation. We consider the formation of crack pattern in bark as an example of pattern formation due to expansion of one material layer with respect to another. As a result of this expansion, the bark stretches until it reaches its limit of deformation and cracks. A novel numerical code, 3D Realistic Failure Process Analysis code (abbreviated as RFPA3D) is used to obtain numerical solutions. In this numerical code, the heterogeneity of materials is taken into account by assigning different properties to the individual elements according to statistical distribution function. Elastic-brittle constitutive relation with residual strength for elements and a Mohr-Coulomb criterion with a tensile cut-off are adopted so that the elements may fail either in shear or in tension. The discontinuity feature of the initiated crack is automatically induced by using degraded stiffness approach when the tensile strain of the failed elements reaching a certain value. The different patterns are obtained by varying simulation parameters, the thickness of the material layer. Numerical simulation clearly demonstrates that the stress state transition precludes further infilling of fractures and the fracture spacing reaches constant state,i.e. the socalled fracture saturation. It also indicates that RFPA code is a viable tool for modeling fracture formation and studying fracture patterns.

Hygrothermal Effects on Dynamic Instability of Hybrid Composite Plates

2017 ◽  
Vol 17 (01) ◽  
pp. 1750001 ◽  
Author(s):  
Chun-Sheng Chen ◽  
An-Hung Tan ◽  
Jin-Yih Kao ◽  
Wei-Ren Chen
Keyword(s):  
Layer Thickness ◽  
Hybrid Composite ◽  
Volume Fraction ◽  
Dynamic Instability ◽  
Composite Plates ◽  
Thickness Ratio ◽  
Fiber Volume ◽  
Periodic Load ◽  
Moisture Concentration ◽  
Layer Thickness Ratio

The dynamic characteristics of hybrid composite plates under an arbitrary periodic load in hygrothermal environments are investigated. The material properties of the plate are assumed to be dependent on the temperature and moisture. The governing equations of motion of the Mathieu-type are established based on the Galerkin method with reduced eigenfunction transforms. The periodic stress is taken to be a combination of the pulsating axial and bending stress in the example problems. Based on Bolotin’s method, the dynamic instability behaviors of hybrid composite plates are determined. The effects of layer thickness ratio, fiber volume fraction, temperature rise, moisture concentration and dynamic load on the instability regions of hybrid composite plates are studied, along with the dynamic instability index discussed. The results reveal that the layer thickness ratio and hygrothermal conditions have a significant impact on the dynamic instability of hybrid composite plates.

Sign in / Sign up

Export Citation Format

Share Document