scholarly journals Experimental Study on Statistic Failure Properties of Composite Considering Temperature Effect

2021 ◽  
Vol 2101 (1) ◽  
pp. 012062
Author(s):  
Zhun Liu ◽  
Xiaoning Zhao ◽  
Xuanxiu Liu ◽  
Lei Song ◽  
Qing Nie
Keyword(s):  
Mechanical Performance ◽  
Superposition Principle ◽  
Strength Properties ◽  
Shear Loading ◽  
Model Parameters ◽  
Loading Conditions ◽  
Plane Shear ◽  
Performance Requirements ◽  
Time Temperature Superposition Principle ◽  
Equivalent Strength

Abstract Advanced composite has been widely used in many fields with high mechanical performance requirements. Aim to characterize the reliability of composite, a statistic failure model was established based on Weibull distribution. Strength tests at various temperatures were conducted under tensile, compressive and in-plane shear loading conditions. As the temperature rises from 25 °C to 180°C, the strengths at different loading conditions reduces by nearly 60% except that the longitudinal tensile one reduces by only 16%. Equivalent strength at reference temperature was obtained based on time-temperature superposition principle. Then, the model parameters were determined with transferred test data using the median rank method, and statistic characterizations of different strength properties were further studied. Results show that the failure probability of composite is independent of temperature. Among all the strengths, the longitudinal compressive strength possesses the smallest shape parameter and correlation coefficient R of the fitting result, which means the strongest randomness of failure.

Asymptotic Crack-Tip Fields in Perfectly Plastic Solids Under Mixed Mode II/III Loading Conditions

2006 ◽  
Vol 129 (4) ◽  
pp. 664-669
Author(s):  
J. Pan ◽  
P.-C. Lin
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode Ii ◽  
Pure Mode ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and nonsingular crack-tip sectors in perfectly plastic materials are first summarized under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode II/III loading conditions are then investigated. An assembly of crack-tip sectors is adopted with stress discontinuities along the border of the two constant stress sectors. The solutions of the crack-tip fields under pure mode II, mixed mode II/III, and nearly pure mode III loading conditions are presented. The trends of the angular variations of the mixed mode II/III crack-tip stresses agree with those of the available computational analysis and the asymptotic analysis for low strain hardening materials. The pure mode II crack-tip stresses are similar to those of Hutchinson, and the nearly pure mode III stresses are similar to those of the pure mode III crack-tip field of Rice.

Asymptotic Crack-Tip Fields in Perfectly Plastic Solids Under Combined In-Plane and Out-of-Plane Shear Loading Conditions

2005 ◽  
Author(s):  
J. Pan
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode Ii ◽  
Pure Mode ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and non-singular crack-tip sectors in perfectly plastic materials are first summarized under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode II/III loading conditions are then investigated. An assembly of crack-tip sectors is adopted with stress discontinuities along the border of the two constant stress sectors. The solutions of the crack-tip fields under pure mode II, mixed mode II/III, and nearly pure mode III loading conditions are presented. The trends of the angular variations of the mixed mode II/III crack-tip stresses agree with those of the available computational analysis and the asymptotic analysis for low strain hardening materials. The pure mode II crack-tip stresses are similar to those of Hutchinson and the nearly pure mode III stresses are similar to those of the pure mode III crack-tip field of Rice.

Mixed Mode I/III Crack-Tip Fields for Perfectly Plastic Mises Materials

2007 ◽  
Author(s):  
J. Pan
Keyword(s):  
Mixed Mode ◽  
Crack Tip ◽  
Shear Loading ◽  
Mode I ◽  
Pure Mode ◽  
Loading Conditions ◽  
Plane Shear ◽  
Tensile Stresses ◽  
Crack Tip Fields ◽  
Perfectly Plastic

In this paper, governing equations and solutions for asymptotic singular and non-singular crack-tip sectors in perfectly plastic Mises materials are first reviewed under combined in-plane and out-of-plane shear loading conditions. The crack-tip fields under mixed mode I/III loading conditions are then investigated. One assembly of four crack-tip plastic sectors is adopted with stress discontinuities along the border of two constant stress sectors. The solutions of the crack-tip fields under pure mode I and mixed mode I/III loading conditions are presented. The crack-tip fields under pure mode I and mixed mode I/III loading conditions give fully-plastic solutions with various hydrostatic tensile stresses ahead of the crack tip. The characteristics of the mode I limits of fully plastic crack-tip fields with different hydrostatic tensile stresses ahead of the crack tip agree well the past computational results under pure mode I with different constraint conditions.

Computational Analysis of the AFM Specimen on Mixed-Mode II and III Fracture

2010 ◽  
Vol 452-453 ◽  
pp. 173-176 ◽  
Author(s):  
Qing Fen Li ◽  
Li Zhu ◽  
Friedrich G. Buchholz ◽  
Sheng Yuan Yan
Keyword(s):  
Mixed Mode ◽  
Strain Energy Release ◽  
Shear Loading ◽  
Mode Ii ◽  
Loading Conditions ◽  
Mode Iii ◽  
Plane Shear ◽  
Loading Mode ◽  
Out Of Plane ◽  
Global Deformation

Some results of 3D finite element analyses of the all fracture modes (AFM) specimen on mixed-mode II and III fracture are presented in this paper. The computational fracture analysis is based on the calculation of separated strain energy release rates (SERRs) along the crack front by the modified virtual crack closure integral (MVCCI)-method and the commercially available FE-code ANSYS. Calculation results show that under pure in-plane shear loading (mode II), not only the mode II, but also the mode III loading conditions, are generated owing to the Poission’s ratio effects. Similarly, under pure out-of-plane shear loading (mode III), besides the mode III, the mode II loading conditions are induced due to the global deformation. Nevertheless, once in-plane and out-of-plane shear loadings are superimposed, the fracture behavior appears more complex. Further discussion is given associate with some previous study.

scholarly journals The Master-Curve Band considering Measurement and Modeling Uncertainty for Bituminous Materials

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Quan Liu ◽  
Jiantao Wu ◽  
Pengfei Zhou ◽  
Markus Oeser
Keyword(s):  
Measurement Errors ◽  
Master Curve ◽  
Superposition Principle ◽  
Original Data ◽  
Model Parameters ◽  
Aging Effects ◽  
Rheological Models ◽  
Modeling Uncertainty ◽  
Sigmoidal Model ◽  
Time Temperature Superposition Principle

This paper proposes using the master-curve band (MCB) to incorporate the unavoidable measurement errors and modeling uncertainty into the bitumen master-curve construction. In general, the rheological property of bitumen within the linear viscoelastic region is characterized by the master curve of modulus and/or phase angle, provided that the bitumen complies with the time-temperature superposition principle (TTSP). However, the master-curve construction is essentially a mathematical fitting process regardless of whether or not the original data is perfect enough to fit. For this reason, the MCB was introduced to consider the uncertainty information instead of a single master curve. Rheological data of four kinds of bitumen including unaged and aged bitumen were used to construct the MCBs. The results indicated that the generalized sigmoidal model showed the widest master-curve band, followed by Christensen-Anderson-Marasteanu (CAM) and CAM ( G g ) models. The width of MCB was a useful tool to identify the sensitivity of bitumen to rheological models. The sensitivity of bitumen to rheological models is associated with the number of active parameters in rheological models and model parameters’ confidence intervals. The construction of an MCB was beneficial to select the rheological models. Accordingly, the CAM ( G g ) model is proved to be the best to analyze the aging effects.

Integration of Atomistic Simulation with Experiment Using Time−Temperature Superposition for a Cross-Linked Epoxy Network

2019 ◽  
Author(s):  
Ketan Khare ◽  
Frederick R. Phelan Jr.
Keyword(s):  
Master Curve ◽  
Glassy State ◽  
Superposition Principle ◽  
Quantitative Comparison ◽  
Time Shift ◽  
Data Sets ◽  
Epoxy Network ◽  
Temperature Superposition ◽  
Time Temperature Superposition ◽  
Time Temperature Superposition Principle

<a></a><a>Quantitative comparison of atomistic simulations with experiment for glass-forming materials is made difficult by the vast mismatch between computationally and experimentally accessible timescales. Recently, we presented results for an epoxy network showing that the computation of specific volume vs. temperature as a function of cooling rate in conjunction with the time–temperature superposition principle (TTSP) enables direct quantitative comparison of simulation with experiment. Here, we follow-up and present results for the translational dynamics of the same material over a temperature range from the rubbery to the glassy state. Using TTSP, we obtain results for translational dynamics out to 10<sup>9</sup> s in TTSP reduced time – a macroscopic timescale. Further, we show that the mean squared displacement (MSD) trends of the network atoms can be collapsed onto a master curve at a reference temperature. The computational master curve is compared with the experimental master curve of the creep compliance for the same network using literature data. We find that the temporal features of the two data sets can be quantitatively compared providing an integrated view relating molecular level dynamics to the macroscopic thermophysical measurement. The time-shift factors needed for the superposition also show excellent agreement with experiment further establishing the veracity of the approach</a>.

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