scholarly journals Experimental and numerical study of the failure process and energy mechanisms of rock-like materials containing cross un-persistent joints under uniaxial compression

PLoS ONE ◽  
2017 ◽  
Vol 12 (12) ◽  
pp. e0188646 ◽  
Author(s):  
Rihong Cao ◽  
Ping Cao ◽  
Hang Lin ◽  
Xiang Fan
Keyword(s):  
Uniaxial Compression ◽  
Numerical Study ◽  
Failure Process

Numerical Study of Effect of Joint Tip Distance from Sample End on Rock Failure

2014 ◽  
Vol 501-504 ◽  
pp. 244-247
Author(s):  
Yun Jie Zhang ◽  
Cheng Fan
Keyword(s):  
Uniaxial Compression ◽  
Numerical Study ◽  
Process Analysis ◽  
Rock Fracture ◽  
Failure Process ◽  
Strain Curve ◽  
Peak Stress ◽  
Rock Failure ◽  
Peak Strain ◽  
Failure Patterns

In this paper,the mechanical properties of rock experiencing the variation of joint tip distance from sample end under uniaxial compression condition were simulated.Numerical simulation for the different rock sample in the uniaxial compression have been conducted to evaluate the effects of joint tip distance from sample end on the overall mechanical behaviour of jointed rock masses. It was done using the Rock Failure Process Analysis program RFPA2D. Numerically simulated stress-strain curve, peak stress, peak strain and failure patterns were compared with the corresponding physical tests. We found that specimen joint tip distance from sample end corresponding value (distance from the crack tip to the compression surface) linear relationship with the compressive strength values .Numerical simulations agree well with physical results, it is shown that RFPA2D is suitable for the analysis of joint tip distance from sample end effect on rock fracture.

Numerical Study on Uniaxial Compression Failure of Brittle Material with a Single Flaw

2015 ◽  
Vol 1119 ◽  
pp. 683-687
Author(s):  
Jia Shen Tian ◽  
Cheng Zhao
Keyword(s):  
Uniaxial Compression ◽  
Numerical Study ◽  
Failure Process ◽  
Fracture Analysis ◽  
Two Dimensions ◽  
Analysis Software ◽  
Numerical Investigations ◽  
Compression Failure ◽  
Single Flaw ◽  
Good Agreement

Numerical investigations on failure process of rock-like materials with a single flaw were carried out under uniaxial compression based on the fracture analysis software: Fracture Analysis Code in Two Dimensions (FRANC2D/L). The change of the displacements and stress distribution were recorded around the crack. Comparative analysis is made among samples containing different angled flaw, which has great influnce on the process of crack initiation and propagetion, and with the increase of flaw angle from 30° to 75°, peak strength of the specimen increases linearly, basically. Which are in good agreement with those of experiments.

Failure Process of Rock Sample Observed by AE Source Locating Technique under Uniaxial Compression

2006 ◽  
Vol 324-325 ◽  
pp. 567-570
Author(s):  
Yuan Hui Li ◽  
Rui Fu Yuan ◽  
Xing Dong Zhao
Keyword(s):  
Uniaxial Compression ◽  
High Speed ◽  
Failure Process ◽  
Compression Tests ◽  
Temporal And Spatial Distribution ◽  
Primary Stage ◽  
Brewing Process ◽  
Ae Signal ◽  
Failure Location ◽  
Low Amplitude

A series of uniaxial-compression tests were conducted on some representative brittle rock specimens, such as granite, marble and dolerite. A multi-channel, high-speed AE signal acquiring and analyzing system was employed to acquire and record the characteristics of AE events and demonstrate the temporal and spatial distribution of these events during the rupture-brewing process. The test result showed that in the primary stage, many low amplitude AE events were developed rapidly and distributed randomly throughout the entire specimens. In the second stage, the number of AE increased much slower than that in the first stage, while the amplitude of most AE events became greater. Contrarily to the primary stage, AE events clustered in the middle area of the specimen and distributed vertically conformed to the orientation of compression. The most distinct characteristic of this stage was a vacant gap formed approximately in the central part of the specimen. In the last stage, the number of AE events increased sharply and their magnitude increased accordingly. The final failure location coincidently inhabited the aforementioned gap. The main conclusion is that most macrocracks are developed from the surrounding microcracks existed earlier and their positions occupy the earlier formed gaps, and the AE activity usually becomes quite acute before the main rupture occurs.

Numerical Study on Influence of Joint Characters on Rock Mechanical Parameters

2011 ◽  
Vol 201-203 ◽  
pp. 2909-2912
Author(s):  
Yan Feng Feng ◽  
Tian Hong Yang ◽  
Hua Wei ◽  
Hua Guo Gao ◽  
Jiu Hong Wei
Keyword(s):  
Rock Mass ◽  
Compression Strength ◽  
Numerical Study ◽  
Process Analysis ◽  
Failure Process ◽  
Deformation Modulus ◽  
Rock Joints ◽  
Structured Surfaces ◽  
Trace Length ◽  
The Impact

Rock mass is the syntheses composed of kinds of structure and structured surfaces. The joint characters is influencing and controlling the rock mass strength, deformation characteristics and rock mass engineering instability failure in a great degree. Through using the RFPA2D software, which is a kind of material failure process analysis numerical methods based on finite element stress analysis and statistical damage theory, the uniaxial compression tests on numerical model are carried, the impact of the trace length of rock joints and the fault throws on rock mechanics parameters are studied. The results showed that with the gradual increase of trace length,compression strength decreased gradually and its rate of variation getting smaller and smaller, the deformation modulus decreased but the rate of variation larger and larger; with the fault throws increasing, the compression strength first increases and then decreases, when the fault throw is equal to the trace length, the deformation modulus is the largest. When the joint trace length is less than the fault throw, the rate of the deformation modulus is greater than that of trace length, but the deformation modulus was not of regular change.

Analytical and Numerical Study of Crushing of Syntactic Foams Under Uniaxial Compression

2008 ◽  
Author(s):  
Prabhakar Marur
Keyword(s):  
Finite Element ◽  
Uniaxial Compression ◽  
Numerical Study ◽  
Bulk Material ◽  
Hollow Spheres ◽  
Syntactic Foam ◽  
Particulate Composites ◽  
Syntactic Foams ◽  
The Matrix ◽  
Crushing Behavior

Syntactic foams are a class of particulate composites made with hollow microspheres dispersed uniformly in a matrix. By the inclusion of hollow spheres in the matrix, the bulk mechanical properties are improved by limiting the bending of cell edges and localization of inelastic deformation, which is the cause of failure in the case of low-density foams. For the general class of cellular materials, several analytical and experimental methods are available in the literature to characterize the material. In the case of syntactic foams, relatively few methods exist for the computation of effective elastic properties and methods for analyzing the crush behavior of the syntactic foams are rather limited. In this research, the quasi-static crushing behavior of syntactic foam under uniaxial compression is investigated using analytical and numerical methods. To better understand the bulk behavior of syntactic foam, a micromechanical study is conducted to analyze the crushing of hollow spheres in dilute concentration. Initially the stress fields around dilute concentration are derived using continuum mechanics principles and subsequently a limit analysis is performed. To gain further insight into the deformation fields and deformations of cell walls leading to densification, a finite element (FE) analysis is performed. Assuming a periodic repetition of a representative volume of the material would correspond to the bulk material, axisymmetric and 3D finite element models are developed. The numerical computations are compared with the analytical results obtained in this study, and with experimental data reported in the literature. Using the FE models, a parametric study is conducted to investigate the influence of microsphere strength and elastic mismatch between the matrix and the inclusions on the crush behavior of syntactic foam.

scholarly journals A Numerical Study of the Effect of Component Dimensions on the Critical Buckling Load of a GFRP Composite Strut under Uniaxial Compression

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 931 ◽  
Author(s):  
Quoc Hoan Doan ◽  
Duc-Kien Thai ◽  
Ngoc Long Tran
Keyword(s):  
Uniaxial Compression ◽  
Cross Section ◽  
Numerical Study ◽  
Slenderness Ratio ◽  
Thickness Ratio ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
Channel Section ◽  
Gfrp Composite ◽  
Thin Walled

In the practical design of thin-walled composite columns, component dimensions should be wisely designed to meet the buckling resistance and economic requirements. This paper provides a novel and useful investigation based on a numerical study of the effects of the section dimensions, thickness ratio, and slenderness ratio on the critical buckling load of a thin-walled composite strut under uniaxial compression. The strut was a channel-section-shaped strut and was made of glass fiber-reinforced polymer (GFRP) composite material by stacking symmetrical quasi-isotropic layups using the autoclave technique. For the purpose of this study, a numerical finite element model was developed for the investigation by using ABAQUS software. The linear and post-buckling behavior analysis was performed to verify the results of the numerical model with the obtained buckling load from the experiment. Then, the effects of the cross-section dimensions, thickness ratio, and slenderness ratio on the critical buckling load of the composite strut, which is determined using an eigenvalue buckling analysis, were investigated. The implementation results revealed an insightful interaction between cross-section dimensions and thickness ratio and the buckling load. Based on this result, a cost-effective design was recommended as a useful result of this study. Moreover, a demarcation point between global and local buckling of the composite strut was also determined. Especially, a new design curve for the channel-section GFRP strut, which is governed by the proposed constitutive equations, was introduced to estimate the critical buckling load based on the input component dimension.

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