Mechanical and physical properties of slate from Britannia Cove, Newfoundland

2008 ◽  
Vol 35 (7) ◽  
pp. 751-755 ◽  
Author(s):  
M.R. Alam ◽  
A.S.J. Swamidas ◽  
J. Gale ◽  
K. Munaswamy
Keyword(s):  
Fracture Toughness ◽  
Physical And Mechanical Properties ◽  
Test Results ◽  
Direct Tension ◽  
Element Analysis ◽  
Tension Tests ◽  
Strain Fracture ◽  
Indirect Tension ◽  
American Society ◽  
Experimental Values

The experimental investigation described in this study was carried out to determine the physical and mechanical properties (elastic moduli, Poisson’s ratio, compressive and tensile strengths, hardness and plane strain fracture toughness) of slate quarried from Britannia Cove, Bonavista, Newfoundland, Canada. Microscopic observations were carried out to determine layers’ orientation and thickness and the grain boundaries. All tests were carried out according to American Society for Testing and Materials (ASTM) and International Society for Rock Mechanics (ISRM) procedures. The results obtained from this investigation were compared with those obtained from other published results for slate, mined from different parts of the world. It is seen that the present test results are compatible with other published results except for fracture toughness and direct tension tests. In fracture toughness tests, the calculated values using accepted empirical equations were much higher than the numerically computed values using finite element analysis (FEA). For the case of direct and indirect tension tests, the differences between our experimental values and previously published results were quite large.

scholarly journals Tensile behaviour identification in Ultra-High Performance Fibre Reinforced Cementitious Composites: indirect tension tests and back analysis of flexural test results

2020 ◽  
Vol 53 (6) ◽  
Author(s):  
Francesco Lo Monte ◽  
Liberato Ferrara
Keyword(s):  
High Performance ◽  
Tensile Behaviour ◽  
Cementitious Composites ◽  
Test Results ◽  
Direct Tension ◽  
Identification Procedure ◽  
Horizon 2020 ◽  
Tension Tests ◽  
Indirect Tension ◽  
High Performance Fibre

AbstractWithin the framework of the European Programme Horizon 2020, the Research Project ReSHEALience is currently running with the objective of developing a new approach for the design of structures exposed to extremely aggressive environments, based on Durability Assessment based Design and Life Cycle Analysis. To this aim, new advanced Ultra-High Performance Fibre Reinforced Cementitious Composites with improved durability, called Ultra-High Durability Concretes, are under investigation to characterize their tensile response in both ordinary and very aggressive conditions. In this context, the first step is to develop an effective approach for identifying the main parameters describing the overall behaviour in tension. In the present study, indirect tension tests have been performed via two techniques, based on Double Edge Wedge Splitting and 4-Point Bending Tests. Starting from the test results, a combined experimental-numerical identification procedure has been implemented in order to evaluate the effective material behaviour in direct tension in terms of stress–strain law. In the paper, the mechanical characterization for the reference mix is reported so to describe the identification procedure adopted.

Watertightness, cracking resistance, and self-healing of asphalt concrete used as a water barrier in dams

2013 ◽  
Vol 50 (3) ◽  
pp. 275-287 ◽  
Author(s):  
Yingbo Zhang ◽  
Kaare Höeg ◽  
Weibiao Wang ◽  
Yue Zhu
Keyword(s):  
Asphalt Concrete ◽  
Leakage Rate ◽  
Strain Rates ◽  
Self Healing ◽  
Test Results ◽  
Direct Tension ◽  
Coefficient Of Permeability ◽  
Tension Tests ◽  
Laboratory Test Results ◽  
Cracked Specimens

The coefficient of permeability of hydraulic asphalt concrete is in the range 10−8–10−10 cm/s. Laboratory test results show that triaxial specimens in axial compression can undergo axial strains up to 18% without any significant increase in permeability until approaching the compressive strength. For temperatures between 5 and 20 °C and strain rates between 2 × 10−3%/s and 5 × 10−3%/s, conventional hydraulic asphalt concrete can tolerate 1%–3% tensile strains before cracking in direct tension tests and strains up to 3%–4% in bending. At 20 °C the tensile and bending strains at cracking are 2–4 times higher than those at 0 °C, and at −20 °C they are approximately 0.2% and 0.8%, respectively. Asphalt concrete possesses pronounced crack self-healing properties. In the experiments, the crack leakage rate dropped 1–4 orders of magnitude within a few hours and the cracked specimens regained 55% of the intact tensile strength after only 1 day of self-healing. In summary, the comprehensive series of laboratory tests documents that asphalt concrete has characteristics that make the material extremely well suited for use in impervious barriers in dams, and the test results reported herein can be of great use in barrier design.

Finite Element Analysis of Dry Shrinkage of Fiber Cement Mortar

2014 ◽  
Vol 590 ◽  
pp. 312-315
Author(s):  
Wei Hong Xuan ◽  
Pan Xiu Wang ◽  
Yu Zhi Chen ◽  
Xiao Hong Chen
Keyword(s):  
Fracture Toughness ◽  
Cement Mortar ◽  
Polypropylene Fiber ◽  
Polypropylene Fibers ◽  
Test Results ◽  
Ansys Software ◽  
Element Analysis ◽  
Cement Based Materials ◽  
Dry Shrinkage ◽  
Good Agreement

The dry shrinkage deformation of polypropylene fiber mortar was analyzed by ANSYS software and compared with experiment value in this paper. The error of the calculated and experimental results in the 14 days and 28 days are 7.8% and 10.5%. It can be found that the calculated results are in good agreement with test results. The results indicate that the dry shrinkage value of polypropylene fiber mortar is lower than ordinary mortar. Adding polypropylene fibers can inhibit the process of cracking and improve the fracture toughness of cement-based materials.

scholarly journals The Influence of Loading Rate on Direct and Indirect Tensile Strengths: Laboratory and Numerical Methods

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jie Liu ◽  
Gangyuan Jiang ◽  
Taoying Liu ◽  
Qiao Liang
Keyword(s):  
Tensile Strength ◽  
Tensile Stress ◽  
Crack Propagation ◽  
Large Scale ◽  
Loading Rate ◽  
Peak Stress ◽  
Direct Tension ◽  
Tension Tests ◽  
Indirect Tension ◽  
Indirect Tensile

To investigate different responses of direct and indirect tensile strengths to loading rate, direct and indirect tension tests were performed on sandstone, rust stone, and granite specimens. Typical load curves indicate that a peak tensile stress frequently appears before the second peak stress, used to calculate the tensile strength in indirect tension tests. As expected, increase in the loading rate increases the tensile strength. In addition, the calculated tensile strengths of the indirect tension tests are frequently higher. Interestingly, the increase ratio of the tensile strength with the increase in the loading rate in indirect tension tests is higher. To verify the above results, crack propagation and stress evolution in direct and indirect tension tests were dynamically monitored using PFC 3D. For direct tension tests, specimens fail at the peak tension point, corresponding to the tensile strength. However, for indirect tension tests, minor cracks, composing of continuous microcracks, form before the peak stress and accompany with the decreased slope of the compression curve. At the peak point, tensile stresses significantly concentrate at the crack tips and further cause large-scale crack propagation. In addition, the initiation stress instead of the peak tensile stress is closer to the tensile strength, obtained from the direct tests for the same loading rate.

Evaluation of Fracture Toughness (JIC) Using Single Specimen Fracture Test Augmented by Finite Element Analysis

1983 ◽  
Vol 105 (1) ◽  
pp. 8-12 ◽  
Author(s):  
R. D. Streit
Keyword(s):  
Fracture Toughness ◽  
Crack Length ◽  
Compact Tension ◽  
Test Results ◽  
Single Specimen ◽  
Fracture Test ◽  
Flow Properties ◽  
Element Analysis ◽  
Extension Curve ◽  
Tension Fracture

Fracture toughness is evaluated using the combination of results from a single compact tension fracture test and computationally developed key-curves. The key-curves—a family of load-deflection curves for the test specimen with different length cracks—were developed using the tensile flow properties of the material. By overlaying the experimental test results on these curves the crack length and crack growth during the test can be deduced. The value of J for each crack length is then evaluated from the experimental load-deflection data. The J versus crack extension curve is plotted and JIC evaluated. The method is applied to the evaluation of the toughness of depleted uranium and is shown to substantially reduce the scatter often observed in the J versus Δa data.

Evaluation of the Minimum Temperature Requirements for the RPV Closure Head Flange Region in 10 CFR 50 Appendix G

2011 ◽  
Author(s):  
Eric M. Focht
Keyword(s):  
Fracture Toughness ◽  
Minimum Temperature ◽  
Normal Operation ◽  
Reference Temperature ◽  
Operating Pressure ◽  
Water Power ◽  
Strain Fracture ◽  
Temperature Requirements ◽  
Potential Alternative ◽  
American Society

Title 10 of the Code of Federal Regulations, Part 50 Appendix G (10CFR50 App. G) prescribes the pressure-temperature (P-T) limits for light water power reactors by incorporating American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel Code, Section XI, Appendix G (ASME App. G) by reference. The P-T limits in ASME App. G are based on the fracture toughness of the vessel limiting material accounting for irradiation effects. The fracture toughness of the limiting material is determined based on the plane strain fracture toughness, KIc, indexed to the material reference temperature, RT NDT. Prior to the 2000 Addenda of ASME App. G, fracture toughness was based on the arrest fracture toughness, KIa, but the approval of Code Case N-640 [1] in 1998 changed the fracture toughness basis to KIc. In addition to the P-T limits determined by ASME App. G, 10CFR50 App. G sets additional minimum temperature requirements that limit the operating pressure based on other factors such as the minimum unirradiated reference temperature, RTNDT(u), of the material in the closure head flange region. This paper presents an analysis of the closure head flange region minimum temperature requirements based on both KIa and KIc. Recommendations for potential alternative minimum temperature requirements are made for normal operation and hydrostatic test conditions.

scholarly journals Analysis of Equibiaxial Tension Tests for Hyperelastic EAP Film

2021 ◽  
Author(s):  
huaan luo ◽  
Yin-Long Zhu ◽  
Hai-Feng Zhao ◽  
Jing-Jing Zhang
Keyword(s):  
Simulation Analysis ◽  
Tension Test ◽  
Contour Error ◽  
Bulge Test ◽  
Material Strength ◽  
Model Parameters ◽  
Test Results ◽  
Element Analysis ◽  
Tension Tests ◽  
Radial Tension

Abstract Equibiaxial tension tests for hyperelastic electroactive polymers (EAPs) are important means to obtain the mechanical properties. There are three main methods: equibiaxial planar tension, radial tension and bulge test. The finite element analysis software is used to model and analyze the influence of testing apparatus, specimen geometric parameters on the test results and accuracy. The results show that the uniformity of the deformation of the square film can be effectively improved by using single corner point fixed tension in equibiaxial planar tension test, and the force error also decreased; the number of the cuts and the size of punched holes should be appropriate in radial tension test of circular diaphragm specimen to avoid the material strength failure caused by excessive tension along the edge of transition arc between grips and excessive deformation of tensile belt between the cuts; in bulge test, the sampled deformation data should be near the spherical pole to obtain more accurate stress-strain relationship owing to contour error and non-uniform deformation, a certain range of model parameters will limit the scope of simulation analysis. This paper proposed research provides guidance for the design of equibiaxial tension test apparatus and method to obtain more accurate test results.

A Three-Dimensional Constitutive Model for the Dynamic Response of Rubber3

2009 ◽  
Vol 37 (4) ◽  
pp. 226-253 ◽  
Author(s):  
M. Liu ◽  
M. S. Hoo Fatt
Keyword(s):  
Constitutive Model ◽  
Dynamic Response ◽  
Three Dimensional ◽  
Central Hole ◽  
Test Results ◽  
Rubber Compound ◽  
Element Analysis ◽  
Cyclic Tension ◽  
Tension Tests ◽  
Finite Element Analysis Simulation

Abstract REFERENCE: Liu, M. and Hoo Fatt, M. S., "A Three-Dimensional Constitutive Model for the Dynamic Response of Rubber," Tire Science and Technology, TSTCA, Vol. 37, No. 4, October - December 2009, pp. 226-253. The development of a constitutive model to describe the dynamic response of a filled rubber compound is presented in this paper. A series of cyclic tension tests were done on the rubber compound with mean strains ranging from 0.2 to 0.5, strain amplitudes ranging from 0.05 to 0.2, and strain rates ranging from 0.1 to 10 s−1. The cyclic strain-controlled test results showed material rate dependence and hysteresis, and this motivated the development of a phenomenological-based, hyper-viscoelastic constitutive model. A Zener model, i.e., a spring in parallel with a Maxwell element, was assumed. The total stress was decomposed into a rate-independent equilibrium stress and a rate-dependent overstress. The springs were modeled as neo-Hookean, while the damper was defined by a nonlinear viscosity function. Material constants for the constitutive model were calculated from the cyclic tension test results. Cyclic tension tests were also performed on a sheet with central hole to check the accuracy of the constitutive model. The constitutive model was implemented into ABAQUS Standard with a user-defined material subroutine. The finite element analysis simulation of the rubber sheet with a central hole demonstrated relatively good agreement with the experimental data.

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