Evaluation of the Fracture Parameters in a Cracked Plate Using the Crack Opening Displacements

2006 ◽  
Author(s):  
V.N. Maksimenko ◽  
A.V. Tyagnii
Keyword(s):  
Crack Opening ◽  
Cracked Plate ◽  
Fracture Parameters

Effect of polypropylene fiber on fracture properties of high-performance concrete composites

2012 ◽  
Vol 19 (4) ◽  
pp. 407-414 ◽  
Author(s):  
Peng Zhang ◽  
Qing-fu Li
Keyword(s):  
Fly Ash ◽  
Silica Fume ◽  
Fiber Volume Fraction ◽  
High Performance Concrete ◽  
Volume Fraction ◽  
Crack Opening ◽  
Polypropylene Fiber ◽  
Fiber Volume ◽  
Opening Displacement ◽  
Fracture Parameters

AbstractA parametric experimental study has been conducted to investigate the effect of polypropylene fiber on the workability and fracture properties of high-performance concrete (HPC) composites containing fly ash and silica fume, with the five fiber volume fractions (0.04%, 0.06%, 0.08%, 0.1%, and 0.12%) used. The results indicate that the addition of polypropylene fiber decreases the workability of the HPC composites containing fly ash and silica fume. With the increase in the fiber volume fraction, both of the slump and the slump flow decrease gradually. Furthermore, the addition of polypropylene fiber has greatly improved the fracture parameters of concrete composite containing 15% fly ash and 6% silica fume, such as fracture toughness, fracture energy, effective crack length, maximum midspan deflection, the critical crack opening displacement, and the maximum crack opening displacement of the three-point bending beam specimens. When the fiber volume fraction increases from 0% to 0.12%, the fracture parameters increase gradually. The variation rules of the fracture parameters indicate that the capability of the polypropylene fiber to resist the crack propagation of the concrete composite containing 15% fly ash and 6% silica fume is becoming stronger and stronger with the increase in fiber volume fraction with the fiber volume fraction not above 0.12%.

Fracture properties of high-performance concrete containing fly ash

2012 ◽  
Vol 226 (2) ◽  
pp. 170-176 ◽  
Author(s):  
P Zhang ◽  
Q Li ◽  
H Zhang
Keyword(s):  
Fly Ash ◽  
Crack Opening Displacement ◽  
High Performance ◽  
High Performance Concrete ◽  
Crack Opening ◽  
Ash Content ◽  
Crack Mouth Opening Displacement ◽  
Opening Displacement ◽  
Fracture Properties ◽  
Fracture Parameters

A parametric experimental study has been conducted to investigate the effect of fly ash on the fracture properties of high-performance concrete (HPC), with four fly ash contents used. By means of three-point bending method, the fracture toughness, fracture energy, effective crack length, critical crack opening displacement, and maximum crack opening displacement of the specimen were measured, respectively. The results indicate that fly ash has great improvement on the fracture parameters, and these fracture parameters gradually increase when the content of fly ash increases from 10 per cent to 20 per cent. However, these fracture parameters begin to decrease after the fly ash content exceeds 20 per cent. Besides, as the fly ash content increases from 10 per cent to 20 per cent, the relational curves between the vertical load and the mid-span deflection ( PV– δ), crack mouth opening displacement ( PV– CMOD), and crack tip opening displacement ( PV– CTOD) become plumper and plumper, which indicates that the capability of HPC containing fly ash to resist crack propagation is becoming stronger and stronger, while the curves become shriveled after the fly ash content exceeds 20 per cent. The contribution of fly ash on the fracture properties of HPC containing fly ash seems to be performed only when the fly ash content does not exceed 20 per cent.

A Study of Crack-Face Boundary Conditions for Piezoelectric Strip Cut Along Two Equal Collinear Cracks

2016 ◽  
Vol 8 (4) ◽  
pp. 573-587 ◽  
Author(s):  
R. R. Bhargava ◽  
Pooja Raj Verma
Keyword(s):  
Boundary Conditions ◽  
Crack Opening ◽  
Electric Displacement ◽  
Potential Drop ◽  
Collinear Cracks ◽  
Crack Face ◽  
Plane Shear ◽  
Fracture Parameters ◽  
Analytic Expressions ◽  
Piezoelectric Strip

AbstractA problem of two equal, semi-permeable, collinear cracks, situated normal to the edges of an infinitely long piezoelectric strip is considered. Piezoelectric strip being prescribed out-of-plane shear stress and in-plane electric-displacement. The Fourier series and integral equation methods are adopted to obtain analytical solution of the problem. Closed-form analytic expressions are derived for various fracture parameters viz. crack-sliding displacement, crack opening potential drop, field intensity factors and energy release rate. An numerical case study is considered for poled PZT–5H, BaTiO3 and PZT–6B piezoelectric ceramics to study the effect of applied electro-mechanical loadings, crack-face boundary conditions as well as inter-crack distance on fracture parameters. The obtained results are presented graphically, discussed and concluded.

Boundary Element Analysis of Stiffened Panels with Repair Patches

2015 ◽  
Vol 665 ◽  
pp. 45-48
Author(s):  
Corrado Di Pisa ◽  
M.H. Ferri Aliabadi
Keyword(s):  
Boundary Element ◽  
Crack Opening ◽  
J Integral ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Fracture Parameters ◽  
Boundary Element Analysis

In this paper BEM for analysis of fractured stiffened panels repaired with riveted patches is presented. Several boundary element formulations involving the membrane and bending of displacement, and, stress resultants are coupled together to analyse the model. The Crack Opening Displacements (COD) method and the J-integral are implemented to evaluate the required fracture parameters.

Inverse Analysis to Estimate Critical Crack Propagation Parameters for Elastic-Plastic and Graded Materials

2004 ◽  
Vol 261-263 ◽  
pp. 117-122
Author(s):  
Toshio Nakamura ◽  
Zi Qiang Wang
Keyword(s):  
Crack Propagation ◽  
Inverse Analysis ◽  
Crack Opening ◽  
Reaction Force ◽  
Accurate Estimation ◽  
Crack Advance ◽  
Inhomogeneous Materials ◽  
Graded Materials ◽  
Elastic Plastic ◽  
Fracture Parameters

Accurate crack propagation simulation requires critical fracture parameters to be known a priori. For elastic-plastic materials, two fundamental parameters are the separation energy and the peak stress required to generate new crack surfaces. In general, both are difficult to quantify since direct determinations are not possible in experiments. For inhomogeneous materials, such as graded materials, determination is even more complex since these parameters vary spatially. In this paper, a novel method based on an inverse analysis technique is proposed to estimate the fracture parameters of elastic-plastic and graded media. The method utilizes the Kalman filter to process measured data and extract best estimates of the unknown parameters. The accuracy of the method is examined in a verification study where a dynamically propagating crack in double cantilever beam type specimen is modeled. In the study, time variation records of crack opening displacement, opening strain, crack advance distance, and load point reaction force are used as possible measurements. Despite large noises in data, the results confirm accurate estimation. The estimates improve when multiple measurements are supplied to the inverse technique.

Fracture Parameters and Post-Peak Behavior Evaluation under LEFM on Bonded Cement-Based Materials

2006 ◽  
Vol 324-325 ◽  
pp. 587-590
Author(s):  
Cheol Woo Park ◽  
David A. Lange
Keyword(s):  
Process Zone ◽  
Crack Opening ◽  
Opening Angle ◽  
Fracture Parameter ◽  
Crack Tip Opening Displacement ◽  
Critical Crack ◽  
Mechanical Fracture ◽  
Critical Crack Length ◽  
Fracture Parameters ◽  
Cement Based Materials

Fracture of bonded cement based materials is complicated due to not only bonding itself but also heterogeneous genuine nature of cement-based materials. This study investigates the fracture parameters that obtained from the mechanical fracture tests and the post-peak behavior of bonded cement-based materials. Fracture parameters were analyzed such as the critical stress intensity factor, the critical crack length and the critical crack tip opening displacement. In addition, this study defines a new fracture parameter, the critical crack opening angle, which describes a crack opening resistance. In order to evaluate the fracture energy of quasi-brittle materials, it is typical to use the non-linear elastic fracture mechanics approaches. From the test results, however, it is known that the toughening action at the fracture process zone of the bonded interface has been significantly diminished because of the brittle fracture and the pre-determined weak crack path. Therefore, the post-peak behavior could be successfully estimated by using the suggested model that considered only the elastic deformations.

Riemann–Hilbert approach-based analytical solutions for strip saturated two unequal collinear cracks in piezoelectric media

2021 ◽  
Vol 13 (4) ◽  
pp. 177-195
Author(s):  
Sandeep Singh ◽  
Kuldeep Sharma
Keyword(s):  
Analytical Solutions ◽  
Complex Potential ◽  
Crack Opening ◽  
Electric Displacement ◽  
Potential Functions ◽  
Collinear Cracks ◽  
Crack Face ◽  
Piezoelectric Media ◽  
Fracture Parameters ◽  
Poling Direction

The objective of the work is to derive analytical solutions based on the Riemann–Hilbert (R–H) approach for semipermeable strip saturated two unequal collinear cracks in arbitrary polarized piezoelectric media. We particularly consider the influence of far field electromechanical loadings, poling direction and different crack-face boundary conditions. The problem is mathematically formulated into a set of non-homogeneous R–H problems in terms of complex potential functions (related to field components) using complex variable and extended Stroh formalism approach. After solving these equations, explicit solutions are obtained for the involved unknown complex potential functions and hence, the stress and electric displacement components at any point within the domain. Furthermore, after employing standard limiting conditions, explicit expressions for some conventional fracture parameters such as saturated zone lengths (in terms of nonlinear equations), local stress intensity factors and crack opening displacement are obtained. Numerical studies are presented for the PZT-4H material to analyze the effects of prescribed electromechanical loadings, inter-cracks distance, crack-face conditions and poling direction on the defined fracture parameters.

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