Failure behavior and failure criterion of conductive cracks (deep notches) in piezoelectric ceramics II: experimental verification

A rock failure criterion is very important for the prediction of the failure of rocks or rock masses in rock mechanics and engineering. Least squares support vector machines (LSSVM) are a powerful tool for addressing complex nonlinear problems. This paper describes a LSSVM-based rock failure criterion for analyzing the deformation of a circular tunnel under differentin situstresses without assuming a function form. First, LSSVM was used to represent the nonlinear relationship between the mechanical properties of rock and the failure behavior of the rock in order to construct a rock failure criterion based on experimental data. Then, this was used in a hypothetical numerical analysis of a circular tunnel to analyze the mechanical behavior of the rock mass surrounding the tunnel. The Mohr-Coulomb and Hoek-Brown failure criteria were also used to analyze the same case, and the results were compared; these clearly indicate that LSSVM can be used to establish a rock failure criterion and to predict the failure of a rock mass during excavation of a circular tunnel.

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A Structurally Based Stress-Stretch Relationship for Tendon and Ligament

Journal of Biomechanical Engineering ◽

10.1115/1.2798284 ◽

1997 ◽

Vol 119 (4) ◽

pp. 392-399 ◽

Cited By ~ 127

Author(s):

C. Hurschler ◽

B. Loitz-Ramage ◽

R. Vanderby

Keyword(s):

Distribution Function ◽

Probability Distribution ◽

Failure Criterion ◽

Probability Distribution Function ◽

Mechanical Response ◽

Elastic Fiber ◽

Tissue Level ◽

Constitutive Law ◽

Failure Behavior ◽

Simplified Form

We propose a mechanical model for tendon or ligament stress–stretch behavior that includes both microstructural and tissue level aspects of the structural hierarchy in its formulation. At the microstructural scale, a constitutive law for collagen fibers is derived based on a strain-energy formulation. The three-dimensional orientation and deformation of the collagen fibrils that aggregate to form fibers are taken into consideration. Fibril orientation is represented by a probability distribution function that is axisymmetric with respect to the fiber. Fiber deformation is assumed to be incompressible and axisymmetric. The matrix is assumed to contribute to stress only through a constant hydrostatic pressure term. At the tissue level, an average stress versus stretch relation is computed by assuming a statistical distribution for fiber straightening during tissue loading. Fiber straightening stretch is assumed to be distributed according to a Weibull probability distribution function. The resulting comprehensive stress–stretch law includes seven parameters, which represent structural and microstructural organization, fibril elasticity, as well as a failure criterion. The failure criterion is stretch based. It is applied at the fibril level for disorganized tissues but can be applied more simply at a fiber level for well-organized tissues with effectively parallel fibrils. The influence of these seven parameters on tissue stress–stretch response is discussed and a simplified form of the model is shown to characterize the nonlinear experimentally determined response of healing medial collateral ligaments. In addition, microstructural fibril organizational data (Frank et al., 1991, 1992) are used to demonstrate how fibril organization affects material stiffness according to the formulation. A simplified form, assuming a linearly elastic fiber stress versus stretch relationship, is shown to be useful for quantifying experimentally determined nonlinear toe-in and failure behavior of tendons and ligaments. We believe this ligament and tendon stress–stretch law can be useful in the elucidation of the complex relationships between collagen structure, fibril elasticity, and mechanical response.

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Investigation of Failure Behavior of Polyethylene Pipe Reinforced by Winding Steel Wires Subject to Inner Pressure and Bending

Volume 6: Materials and Fabrication ◽

10.1115/pvp2020-21625 ◽

2020 ◽

Author(s):

Jun Shi ◽

Yuzhuo Miao ◽

Xiang Li ◽

Guangzhong Li ◽

Yu Wan ◽

...

Keyword(s):

Failure Criterion ◽

Chemical Engineering ◽

Volume Ratio ◽

Failure Behavior ◽

Polyethylene Pipes ◽

Four Point Bending ◽

Combined Loads ◽

Inner Pressure ◽

Steel Wires ◽

Bending Load

Abstract Polyethylene pipes reinforced by winding steel wires (PSP) have been widely used in many fields such as chemical engineering, pulp conveying, water supply, etc. The combined loads of inner pressure and bending sometimes leads to the failure of PSP, and for engineering projects it is still not proposed that the failure criterion of PSP subject to combined loads. In this paper, full-size finite element models (FEM) of PSP under inner pressure and bending were established to investigate the engineering failure criterion. In the FEM the steel wires and HDPE matrix were modeled separately. The freedom degrees of steel wires and HDPE were coupled together as the interface between these two constituents were considered intact. The investigation contains two parts: firstly, a FEM was established in reference to the details of an existing experiment, including the pipe specimen and relative boundary condition. The validation of the FEM was carried out and the simulation result agreed well with test result indeed. Subsequently, the model was optimized to undertake four-point bending under inner pressure, to analyze the failure behavior of PSP under this kind of condition, with three factors such as varied ratio of diameters to thickness, inner pressure and volume ratio of steel wires. In the end, the curvature of failed PSP was considered as the failure criterion, and the relationship of curvature and the three factors were discussed. This paper is useful for the safety of PSP subject to inner pressure and bending load.

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Application of the Tsai–Wu Quadratic Multiaxial Failure Criterion to Bovine Trabecular Bone

Journal of Biomechanical Engineering ◽

10.1115/1.2798051 ◽

1999 ◽

Vol 121 (1) ◽

pp. 99-107 ◽

Cited By ~ 48

Author(s):

T. M. Keaveny ◽

E. F. Wachtel ◽

S. P. Zadesky ◽

Y. P. Arramon

Keyword(s):

Trabecular Bone ◽

Apparent Density ◽

Failure Criterion ◽

Radial Pressure ◽

Nonlinear Dependence ◽

Triaxial Tests ◽

Failure Behavior ◽

Transverse Loading ◽

Trabecular Network ◽

Stress States

As a first step toward development of a multiaxial failure criterion for human trabecular bone, the Tsai–Wu quadratic failure criterion was modified as a function of apparent density and applied to bovine tibial trabecular bone. Previous data from uniaxial compressive, tensile, and torsion tests (n = 139 total) were combined with those from new triaxial tests (n = 17) to calibrate and then verify the criterion. Combinations of axial compression and radial pressure were used to produce the triaxial compressive stress states. All tests were performed with minimal end artifacts in the principal material coordinate system of the trabecular network. Results indicated that the stress interaction term F12 exhibited a strong nonlinear dependence on apparent density (r2 > 0.99), ranging from −0.126 MPa−2 at low densities (0.29 g/cm3) to 0.005 MPa−2 at high densities (0.63 g/cm3). After calibration and when used to predict behavior of new specimens without any curve-fitting, the Tsai–Wu criterion had a mean (± SD) error of −32.6 ± 10.6 percent. Except for the highest density triaxial specimens, most (15/17 specimens) failed at axial stresses close to their predicted uniaxial values, and some reinforcement for transverse loading was observed. We conclude that the Tsai–Wu quadratic criterion, as formulated here, is at best only a reasonable predictor of the multiaxial failure behavior of trabecular bone, and further work is required before it can be confidently applied to human bone.

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Revisiting the Cattaneo-Mindlin Concept of Interfacial Slip in Tangentially Loaded Compliant Bodies

ASME/STLE 2009 International Joint Tribology Conference ◽

10.1115/ijtc2009-15054 ◽

2009 ◽

Cited By ~ 1

Author(s):

Izhak Etsion

Keyword(s):

Failure Mode ◽

Experimental Verification ◽

Failure Criterion ◽

Basic Problem ◽

Theoretical Models ◽

Interfacial Slip ◽

Numerical Techniques ◽

Plastic Yield ◽

Alternative Approach ◽

Simplifying Assumptions

The Cattaneo-Mindlin concept of interfacial slip in tangentially loaded compliant bodies is revisited and its basic simplifying assumptions are critically examined. It is shown that these assumptions, which, in the absence of modern numerical techniques, were essential in 1949 to enable an elegant quantitative solution of the basic problem of presliding between contacting bodies, are actually non physical. An alternative approach to the same problem that is based on treating sliding inception as a failure mode involving material plastic yield is discussed. This alternative approach was suggested even before 1949 but for the same lack of modern numerical techniques could only be promoted qualitatively. Some recent theoretical models, that are based on this earlier alternative approach, and in which the simplifying assumptions of the Cattaneo-Mindlin concept were completely relaxed are described along with their experimental verification. It is shown that the pre-sliding problem between contacting bodies can be accurately solved by these models using realistic physical assumptions and failure criterion.

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Failure behavior and failure criterion of conductive cracks (deep notches) in thermally depoled PZT-4 ceramics

Acta Materialia ◽

10.1016/s1359-6454(03)00331-8 ◽

2003 ◽

Vol 51 (16) ◽

pp. 4881-4895 ◽

Cited By ~ 36

Author(s):

Tong-Yi Zhang ◽

Tianhong Wang ◽

Minghao Zhao

Keyword(s):

Failure Criterion ◽

Failure Behavior

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Revisiting the Cattaneo–Mindlin Concept of Interfacial Slip in Tangentially Loaded Compliant Bodies

Journal of Tribology ◽

10.1115/1.4001238 ◽

2010 ◽

Vol 132 (2) ◽

Cited By ~ 51

Author(s):

Izhak Etsion

Keyword(s):

Failure Mode ◽

Experimental Verification ◽

Failure Criterion ◽

Basic Problem ◽

Theoretical Models ◽

Interfacial Slip ◽

Numerical Techniques ◽

Plastic Yield ◽

Alternative Approach ◽

Simplifying Assumptions

The Cattaneo–Mindlin concept of interfacial slip in tangentially loaded compliant bodies is revisited and its basic simplifying assumptions are critically examined. It is shown that these assumptions, which, in the absence of modern numerical techniques, were essential in 1949 to enable an elegant quantitative solution of the basic problem of presliding between contacting bodies, may be nonphysical. An alternative approach to the same problem that is based on treating sliding inception as a failure mode involving material plastic yield is discussed. This alternative approach was suggested even before 1949 but for the same lack of modern numerical techniques could only be promoted qualitatively. Some recent theoretical models, which are based on this earlier alternative approach, and in which the simplifying assumptions of the Cattaneo–Mindlin concept were completely relaxed, are described along with their experimental verification. It is shown that the presliding problem between contacting bodies can be accurately solved by these models using realistic physical assumptions and failure criterion.

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Crystallographic Analysis of Specimens Used for Calibrate a Failure Model for an Al 6061 – T6 Alloy

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.488-489.89 ◽

2011 ◽

Vol 488-489 ◽

pp. 89-92 ◽

Cited By ~ 1

Author(s):

Marco Giglio ◽

Andrea Manes ◽

Carlo Mapelli ◽

Davide Mombelli ◽

Claudio Baldizzone ◽

...

Keyword(s):

Failure Criterion ◽

Structural Integrity ◽

Constitutive Relations ◽

Stress Triaxiality ◽

Failure Criteria ◽

Crystallographic Analysis ◽

Failure Behavior ◽

Al 6061 ◽

Extreme Loads ◽

Full Scale Tests

Calibration and exploitation of failure criterion is at present a challenging field in the structural integrity scenario. Calibrated failure criteria allow the simulation/reproduction of damages using virtual approach and eventually further assessment of the residual integrity of the components. Therefore the increase of awareness in failure issues makes the numerical simulation an actual, useful and reliable tool for the analysis of complex structures under extreme loads, especially in aerospace field where full scale tests are often very expensive and difficult to carry out. With this aim, the constitutive relations of an Aluminium Al 6061-T6 alloy have been calibrated with dedicated focus on failure criterion. The results obtained have been discussed considering the crystallographic measurements that permit to point out the dissipative behavior on the basis of texture formation as a function of the load type. The final aim is to confirm and explain the different failure behavior depending on the different stress triaxiality.

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