Investigation of Eigen-Values for Matrix Cracks of Two Materials

2011 ◽  
Vol 488-489 ◽  
pp. 170-173
Author(s):  
You Tang Li ◽  
Rui Feng Wang
Keyword(s):  
Stress Field ◽  
Displacement Field ◽  
Poisson Ratio ◽  
Matrix Material ◽  
Matrix Crack ◽  
Matrix Cracks ◽  
Eigen Values

The eigen-values problem of matrix cracks is studied in this paper. The stress field and displacement field of plane matrix crack is setup at first. The eigen-equation of matrix cracks is founded on the basis of the stress field and displacement field. The factors to affect the eigen-values are discussed. The effect of shearing modulus and Poisson ratio of matrix material and attaching material on eigen-values are analyzed. The results show that the bigger shearing modulus of material should be selected for attaching material and the shearing modulus of attaching material should bigger than that of matrix material in fracture design.

Investigation of Fracture Design for Bi-Steel Materials

2006 ◽  
Vol 324-325 ◽  
pp. 503-506 ◽  
Author(s):  
You Tang Li ◽  
Ping Ma ◽  
Chang Feng Yan
Keyword(s):  
Stress Intensity ◽  
Stress Field ◽  
Displacement Field ◽  
Stress Intensity Factors ◽  
Poisson’S Ratio ◽  
Matrix Material ◽  
Matrix Crack ◽  
Poisson's Ratio ◽  
Intensity Factors ◽  
Eigen Values

The eigen-equation of bi-materials cracks was founded on the basis of the stress field and displacement field. The influence of shearing modulus and Poisson’s ratio of matrix material and additive material to eigen-values were analyzed through the results of calculating. The stress intensity factors at the tip of matrix crack were calculated. The suitable parameters of bi-steel materials crack in fracture design were obtained. The results show that the effect of Poisson’s ratio on eigen-values is not obviously and the effect of shearing modulus is obviously. The shearing modulus of additive material should bigger than that of matrix material.

scholarly journals Evolution Pattern and Matching Mode of Precursor Information about Water Inrush in a Karst Tunnel

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1579
Author(s):  
Jie Song ◽  
Diyang Chen ◽  
Jing Wang ◽  
Yufeng Bi ◽  
Shang Liu ◽  
...  
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Displacement Field ◽  
Water Inrush ◽  
Seepage Field ◽  
Karst Tunnel ◽  
Rock Mass Structure ◽  
Evolution Pattern ◽  
Water Blocking ◽  
Precursor Information

The water inrush of the Shangjiawan karst tunnel is used to study the evolution pattern of precursor water inrush information in water-filled caves and to further reveal the matching mode of the information. The three-dimensional numerical method FLAC3D was used to simulate the evolution process of water inrush after damage to a water-blocking rock mass structure in a water-filled cave and to obtain the evolution pattern of precursor water-inrush information caused by the damage. The results show that the multifield response to the characteristic precursor information of the water-inrush pattern after the fracture of the water-blocking rock mass follows the order of stress-field displacement-field seepage-field. Further, the matching pattern of the information shows that the stress field increased first and then decreased, the displacement field always increased, and the seepage field increased first and then decreased.

General Solutions of the Equations of Elasticity and Consolidation for a Porous Material

1956 ◽  
Vol 23 (1) ◽  
pp. 91-96
Author(s):  
M. A. Biot
Keyword(s):  
Stress Field ◽  
Porous Material ◽  
Elastic Material ◽  
Displacement Field ◽  
Theory Of Elasticity ◽  
Isotropic Case ◽  
General Solutions ◽  
General Properties ◽  
Stress Functions

Abstract Equations of elasticity and consolidation for a porous elastic material containing a fluid have been previously established (1, 5). General solutions of these equations for the isotropic case are developed, giving directly the displacement field or the stress field in analogy with the Boussinesq-Papkovitch solution and the stress functions of the theory of elasticity. General properties of the solutions also are examined and the viewpoint of eigenfunctions in consolidation problems is introduced.

Finite Element Simulation of Molded Pulp Pallet in the Dropping Process

2013 ◽  
Vol 469 ◽  
pp. 209-212
Author(s):  
Xin Guo ◽  
Hong Wei Ji ◽  
Hai You Zheng
Keyword(s):  
Finite Element ◽  
Stress Field ◽  
Finite Element Simulation ◽  
Displacement Field ◽  
Green Material ◽  
Element Simulation ◽  
Development Prospects ◽  
Abaqus Software

Molded pulp pallet is a kind of new green material pallet which has a broad development prospects. In this paper, ABAQUS software was applied to simulate the situation that molded pulp pallet dropped from different heights in different ways. Stress field and displacement field of the pallet are obtained. Cushioning property and deformation of the molded pulp pallet were analyzed. The work of this paper could give a significant guide to design the molded pulp pallet.

Matrix and interface microcracking in carbon fiber/polymer structural micro-battery

2019 ◽  
Vol 53 (25) ◽  
pp. 3615-3628 ◽  
Author(s):  
Johanna Xu ◽  
Janis Varna
Keyword(s):  
Carbon Fiber ◽  
Energy Release ◽  
Crack Growth ◽  
Matrix Crack ◽  
Matrix Interface ◽  
Release Rates ◽  
Matrix Cracks ◽  
The Matrix ◽  
Energy Release Rates ◽  
Coating Matrix

In this paper, the propagation of radial matrix cracks and debond cracks at the coating/matrix interface in unidirectional carbon fiber structural micro-battery composite are studied numerically. The micro battery consists of a solid electrolyte-coated carbon fiber embedded in an electrochemically active polymer matrix. Stress analysis shows that high hoop stress in the matrix during charging may initiate radial matrix cracks at the coating/matrix interface. Several 2-D finite element models of the transverse plane with different arrangements of fibers and other matrix cracks were used to analyze the radial matrix crack growth from the coating/matrix interface of the central fiber in a composite with a square packing of fibers. Energy release rates of radial cracks along two potential propagation paths are calculated under pure electrochemical loading. The presence of a radial matrix crack imposes changes in the stress distribution along the coating/matrix interface, making debonding relevant for consideration. Results for energy release rates show that the debond crack growth is governed by mode II.

Modeling of subsurface ceramic inclusions in metallic matrices

2020 ◽  
Vol 55 (5-6) ◽  
pp. 134-144
Author(s):  
Andrew C Pickard ◽  
David E Mills
Keyword(s):  
Stress Field ◽  
Fatigue Cracks ◽  
Matrix Material ◽  
Metallic Matrix ◽  
Uniaxial Stress ◽  
Free State ◽  
Nickel Base Superalloy ◽  
Stress Free State ◽  
Nickel Base ◽  
The Impact

All engineering materials have the potential to contain inhomogeneities that can act as initiators for fatigue cracks during cyclic loading. One class of inhomogeneity that can occur as a result of the processes used to create metallic materials is a ceramic inclusion, typically resulting from the raw material contamination during the melting process. This article examines the predicted behavior of hard ceramic inclusions in a nickel-base superalloy metallic matrix. Compressive residual stresses are created in the inclusion during cool down from a stress-free state at high temperature. The influence of the proximity of the inclusion to the surface of the matrix material is examined, together with the impact of subsequent uniaxial loading on the stress field in the inclusion and in the surrounding material. The stress field in the ceramic inclusion is observed to transition from compressive to tensile as a function of the proximity of the inclusion to the surface of the material and the applied uniaxial stress field. For deep subsurface inclusions, the uniaxial stress field required to achieve a tensile stress in the inclusion is close to the yield stress of the material. The sensitivity of this critical stress to material cyclic hardening behavior and to the temperature difference between the stress-free state and the operating state is also explored. The significance of these modeling results is discussed in terms of the sensitivity of nickel-base superalloys to crack formation and growth from ceramic inclusions and hence the impact on probabilistic fatigue life assessments of the presence, location and size of the ceramic inclusions.

scholarly journals Modelling Cracked Cross-Ply Laminates with Delamination Buckling

2018 ◽  
Vol 774 ◽  
pp. 60-65 ◽  
Author(s):  
A. Köllner ◽  
Maria Kashtalyan ◽  
Igor Guz ◽  
C. Völlmecke
Keyword(s):  
Structural Stability ◽  
Analytical Framework ◽  
Matrix Crack ◽  
Stability Behavior ◽  
Matrix Cracks ◽  
Stiffness Properties ◽  
Delamination Buckling ◽  
Plane Compression ◽  
Constrained Model ◽  
Modelling Approach

The mechanical behavior of cross-ply laminates loaded under in-plane compression containing matrix cracks and delaminations is investigated in order to study their influence on the structural stability behavior. This is done by employing a semi-analytical modelling approach which comprises an analytical framework for a structural stability analysis of damageable structures and the Equivalent Constrained Model for deriving reduced stiffness properties of the cracked layers. Cross-ply laminates with varying delamination depths as well as varying matrix crack densities are studied.

Development of a Railway Track Displacement Monitoring by Using Digital Image Correlation Technique

2014 ◽  
Vol 548-549 ◽  
pp. 683-687 ◽  
Author(s):  
Lenny Iryani ◽  
Hery Setiawan ◽  
Tatacipta Dirgantara ◽  
Ichsan Setya Putra
Keyword(s):  
Digital Image Correlation ◽  
Stress Field ◽  
Digital Image ◽  
Displacement Field ◽  
Image Correlation ◽  
Railway Track ◽  
Remaining Life ◽  
Full Field ◽  
Field Displacement ◽  
Dic Technique

To avoid an unnecessary catastrophic accident due to a failure of a railway track, it is important to have a reliable condition monitoring system for the railway track. The integrity of the railway track can be assessed by monitoring the displacement field of the track, which can then be used to determine the strain and stress field. By knowing the stress history of the track and the S–N curves of the track material, the remaining life of the railway track can be predicted. In the present work, a simple system to monitor and record the displacement field of the railway track has been developed by using Digital Image Correlation (DIC) technique. The set–up to monitor the displacement field of the railway track was developed using a high speed video camera of Nikon J1 to capture the image of the railway track when the train passing through. The DIC technique was then employed off line to measure the displacement field of the 2D image captured. The results showed that the full field displacement measured by using DIC technique gives a good agreement compared to the finite element results. The full field displacement can be used to calculate the strain-stress field, and later on the remaining life assessment can be conducted based on the results.

FEM Analysis of the Unsteady Seepage during Excavation

2014 ◽  
Vol 638-640 ◽  
pp. 457-461 ◽  
Author(s):  
Ji Liang Fan ◽  
Yan Hua Ren ◽  
Yong Hong Wu ◽  
Xiu Feng Liu ◽  
Shi Chong Zhou
Keyword(s):  
Stress Field ◽  
Flow Field ◽  
Constitutive Model ◽  
Displacement Field ◽  
Fem Analysis ◽  
Field Stress ◽  
Field Displacement ◽  
Seepage Model ◽  
Stress And Deformation

The seepage is the main reason of many excavation accidents. Currently, most of the excavation designs ignore the seepage function or pay little attention on it. This paper focuses on the excavation’s stress and deformation influenced by the unsteady seepage, leading into the Van Genuchten seepage model and the Hardening-Soil constitutive model. And compare and analyze the different influences of flow field, stress field, displacement field and force caused by the steady and unsteady seepage

FRACTURE-PROCESS ZONE ANALYSIS OF REINFORCED BARS VERTICAL TO MATRIX CRACKS

2014 ◽  
Vol 1 (1) ◽  
Author(s):  
Shujin Duan ◽  
Yanlong Zhang ◽  
Ruimei An ◽  
Quanmin Guo
Keyword(s):  
Tensile Stress ◽  
Fracture Process ◽  
Tensile Strain ◽  
Fracture Process Zone ◽  
Strain Softening ◽  
Poisson Ratio ◽  
Process Zone ◽  
Power Exponent ◽  
Matrix Cracks ◽  
Steel Bar

This study focuses on a crack mechanics model—an infinite center-cracked concrete panel with a steel bar across a crack loaded by uniform tensile stress, under which the slip between reinforcement and concrete is neglected and the force produced by the reinforcement is regarded as a centralized force to close the upper and lower surface of the crack. The critical sizes of the fracture process zone (FPZ) are obtained by the use of a power-exponent tensile-strain softening model under the maximum tensile stress criterion and the maximum tensile strain criterion. The results show that the critical sizes of fracture process zone at both crack tips decrease with the increasing steel bar area, but the distance between the reinforcement and the crack tip or the decreasing Poisson ratio increase with the increasing of the tensile-strain softening index.

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