Size independent fracture energy from fracture energy release rate in plain concrete beams

2013 ◽  
Vol 98 ◽  
pp. 284-295 ◽  
Author(s):  
S. Muralidhara ◽  
B.K. Raghu Prasad ◽  
R.K. Singh
Keyword(s):  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Release Rate ◽  
Concrete Beams ◽  
Plain Concrete

Test Study of Fracture Mechanical Properties of Reactive Powder Concrete with Additives

2014 ◽  
Vol 904 ◽  
pp. 3-6 ◽  
Author(s):  
Zhi Gang Yin
Keyword(s):  
Mechanical Properties ◽  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Release Rate ◽  
Fracture Behavior ◽  
Fracture Model ◽  
Reactive Powder Concrete ◽  
Critical Crack Length ◽  
Reactive Powder

The different influencing regular of fly-ash fractiontype of fibre (steel fibre and polypropylene fibre) and fibre fraction on the mechanical property and fracture behavior of Reactive Powder Concrete (PRC) are studied. Fracture mechanical properties of RPC is researched in double-K fracture model and fracture energy release rate G . Test results show that the crack propagation of RPC with steel fibers is limited. Its fracture toughness and pre-critical crack length is largely enhanced. Double-K fracture model and fracture energy release rate G are consistent with describing the fracture behavior of RPC.

The Laboratorial Study of Fracture Energy Release Rate of the Reservoir Ice Layer

2011 ◽  
Vol 250-253 ◽  
pp. 3802-3806
Author(s):  
Xiao Zhou Liu ◽  
Peng Liu
Keyword(s):  
Energy Balance ◽  
Fracture Mechanics ◽  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Release Rate ◽  
Calculation Model ◽  
Energy Balance Method ◽  
Pressure Calculation ◽  
Ice Pressure

The fracture energy release rate , which is the important parameter of ice pressure calculation model that is built on energy balance method, is the fracture mechanics performance of ice material. It is related with these factors such as ice material temperature T, which must be measured by experiment. It is the experimental method of fracture mechanics used in this paper. These ice specimens on the different thickness T were tested with fracture mechanics method at low-temperature testing machine, to obtain the fracture flexibility change rate of ice body which contains pre-crack and the values of under different conditions of T, which could determine fracture energy release rate of ice body during the ice pressure generated, which provide the necessary experimental data to establish ice layer pressure calculation model for the application of energy balance method.

Fracture Toughness Measurement of Asphalt Concrete by Nanoindentation

2017 ◽  
Author(s):  
Zafrul Khan ◽  
Hasan M. Faisal ◽  
Rafiqul Tarefder
Keyword(s):  
Fracture Toughness ◽  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Release Rate ◽  
Asphalt Concrete ◽  
Nanoindentation Test ◽  
Displacement Curve ◽  
Macro Scale ◽  
Load Displacement

Fracture toughness and fracture energy release rate are two important parameters to understand the crack propagation within any material. Fracture toughness of asphalt concrete (AC) is vital to explain the fatigue cracking and low temperature cracking of asphalt pavement. These two types of distresses are still unsolved issues for asphalt researchers. Measuring fracture toughness of AC is not a new phenomenon. Recently, researchers have used several techniques to measure the fracture toughness of AC. Tests like semi-circular bending (SCB) and disk-shaped compact specimen (DCT) testing have been used to measure the fracture toughness of the AC. From the SCB or DCT tests, past researchers have shown that crack in AC propagates through mainly binder and mastic phase. All these conventional tests are carried out in macro scale. It is important to understand that before propagation of these macro scale cracks, the cracks initiates at the nano/micro scale level. With the increment of the loads these nanoscale cracks become macro scale cracks and propagates through the sample. Therefore, it is important to understand the cracks at nanoscale. In this study, nanoindentation test was introduced to measure the fracture toughness of the asphalt concrete. In a nanoindentation test, the sample surface is indented with a loaded indenter. For this test, Berkovich indenter with load control method was used. A field cored asphalt concrete sample was used for this study. The sample was collected by coring at interstate 40 (I-40) near Albuquerque, New Mexico. The sample was field aged for four years. The maximum load applied in this study was 5-mn and the unloading was done at a faster rate than the loading rate. From the load-displacement curves of the nanoindentation tests, fracture toughness of the samples was measured. The unloading curve of the nanoindentation test was further used to obtain reduced modulus of the asphalt concrete using Oliver-Pharr method. In this study, fracture energy is thought of as a portion of irreversible energy. This irreversible energy is comprised of plastic energy and energy required for propagation of crack. By analyzing the load displacement curve along with the maximum indentation depth, energy release rate and mode I fracture toughness of asphalt concrete was measured.

Adhesion Thin Ductile Films Using Stressed Overlayers and Nanoindentation

2002 ◽  
Vol 750 ◽  
Author(s):  
M. J. Cordill ◽  
N. R. Moody ◽  
D. F. Bahr
Keyword(s):  
Fracture Toughness ◽  
Silicon Dioxide ◽  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Release Rate ◽  
Pure Shear ◽  
Interfacial Fracture ◽  
Shear Mode ◽  
Interfacial Fracture Toughness

ABSTRACTDifferently stressed films of tungsten on silicon dioxide have been studied to determine the interfacial fracture toughness and the Mode I fracture energy release rate of tungsten on glass. Tungsten films with a low compressive stress (less than 1GPa) had nanoindentation tests performed on them to induce buckling. Using mechanics based models and the dimensions of the buckles the fracture energy release rate and the phase angle of loading (Ψ) were calculated to be between 3.8 and 13 J/m2. By varying the residual stress in the film it was possible to examine regions of pure shear (Mode II) interfacial fracture as well as mixed mode interfacial fracture toughness of this system. A similar tungsten film was then used as stressed overlayer on sputtered Pt films on silicon dioxide to determine the fracture energy release rate. Nanoindentation was required to induce buckling, as the overlayer alone did not cause spontaneous buckling. The stressed overlayer method and nanoindentation were used to determine the interfacial toughness of the Pt/silica system to be 1.4 J/m2.

Dynamic Shear Fracture at Subsonic and Transonic Speeds in a Compressible Neo-Hookean Material Under Compressive Prestress

2002 ◽  
Vol 69 (5) ◽  
pp. 663-670 ◽  
Author(s):  
L. M. Brock
Keyword(s):  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Release Rate ◽  
Shear Fracture ◽  
Uniform Compression ◽  
Wave Speeds ◽  
Dilatational Wave ◽  
Infinitesimal Deformations ◽  
Small Deformations

A crack driven by shear forces translating on its surfaces grows in an isotropic compressible neo-Hookean material that is initially in uniform compression. The material replicates a linear isotropic solid at small deformations, and preserves as a limit case for all deformations the incompressibility that occurs in the linear case when Poisson’s ratio becomes 1/2. A plane-strain steady state is assumed such that the crack and surface forces move at the same constant speed, whether subsonic, transonic, or supersonic. An exact analysis is performed based on superposition of infinitesimal deformations upon large, both for frictionless crack surface slip, and slip resisted by friction. The pre-stress induces anisotropy and increases the Rayleigh, rotational and dilatational wave speeds from their classical values. A positive finite fracture energy release rate arises for crack speeds below the Rayleight value and at two transonic speeds. In contrast, the transonic range in a purely linear analysis exhibits only one speed. It is found that friction enhances fracture energy release rate, and that compressive pre-stress enhances the rates for small crack speeds, but decreases it for speeds near the Rayleigh value.

scholarly journals Parameter interdependence of dynamic self-similar crack with distance-weakening friction

2020 ◽  
Vol 223 (3) ◽  
pp. 1584-1596
Author(s):  
Shiro Hirano ◽  
Hiromichi Itou
Keyword(s):  
Energy Release Rate ◽  
Fracture Energy ◽  
Energy Release ◽  
Crack Growth ◽  
Release Rate ◽  
Process Zone ◽  
Slip Rate ◽  
Zone Size ◽  
Rupture Velocity ◽  
Self Similar

SUMMARY In several analytical and numerical studies, the slip rate function and energy release rate for dynamic self-similar crack growth have been investigated, and the results obtained have contributed to a theoretical understanding and estimation of on-fault energetics. However, the relationships among physical parameters, including stress state, process zone size, rupture velocity, peak slip rate and energy release rate, are still unclear. Therefore, the aim of this study is to derive an analytical solution of the slip rate distribution of antiplane self-similar crack growth under distance-weakening friction that mimics slip-weakening friction. To satisfy the condition that the slip rate starts from zero at the rupture front, a trade-off relationship among rupture velocity, process zone size and breakdown stress-to-stress drop ratio is proposed. The peak slip rate, slip-weakening distance and fracture energy obtained using the proposed model provide a possible mechanism for the determination of the rupture velocity and the estimation of the fracture energy of the self-similar crack growth, based on the seismic observables.

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