The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Saman Salari - One of the best experts on this subject based on the ideXlab platform.

Wei Cao - One of the best experts on this subject based on the ideXlab platform.

G. A. Gogotsi - One of the best experts on this subject based on the ideXlab platform.

  • Crack Resistance of modern ceramics and ceramic composites. II. EF method
    Powder Metallurgy and Metal Ceramics, 2006
    Co-Authors: G. A. Gogotsi
    Abstract:

    The procedure and test results are for Crack Resistance are presented for various monolithic and composite oxide and nonoxide ceramics by chipping the rectangular edge of a polished specimen. The main difference of the test method suggested (EF method) with an arbitrary point of fracture for a specimen edge from the well-known similar method with a fixed point of fracture is demonstrated. Tests are performed with Rockwell, Vickers and Knoop indenters, and the Rockwell indenter is chosen as the optimum. On the basis of statistically reliable experimental data a direct relationship is established between edge toughness and critical fracture toughness determined in the same ceramic specimens based on scandium oxide, aluminum oxide, zirconium dioxide, silicon carbide and silicon nitride. The EF method, whose use does not require special equipment, may be used effectively in a normal metallurgy test laboratory, particularly when specimens for evaluating ceramic breaking Resistance may only be prepared in smaller sizes than those required for standard Crack Resistance tests.

  • Crack Resistance of ceramics and composites with ceramic matrix (SEVNB method)
    Refractories and Industrial Ceramics, 1998
    Co-Authors: G. A. Gogotsi
    Abstract:

    The SEVNB method for studying Crack Resistance of ceramics and composites with a ceramic matrix is considered. Novel data on the Crack Resistance of various ceramics are presented. The special features of the SEVNB method which make it an optimum instrument for determining the Crack Resistance of ceramics and some composites with a ceramic matrix are described.

  • Problem of evaluating the Crack Resistance in ceramics of Si_3N_4 and ZrO_2
    Refractories and Industrial Ceramics, 1996
    Co-Authors: G. A. Gogotsi, V. I. Galenko, V. P. Zavada, B. A. Ozerskii, D. Yu. Ostrovoi, Toshiro Kobayashi
    Abstract:

    The mechanical behavior of silicon nitride and zirconium dioxide ceramics is investigated in a wide temperature range. Much attention is paid to Crack Resistance under the conditions of the ambient. Data obtained by different methods used for evaluating Crack Resistance are analyzed, and it is shown that the best results have been obtained in tests in which the concentrator was an indentation of a Vickers pyramid. The analysis was conducted using fractographic investigations of the materials and data of tests of a model material of zirconium dioxide.

Pedro P. Camanho - One of the best experts on this subject based on the ideXlab platform.

  • determination of the mode i Crack Resistance curve of polymer composites using the size effect law
    Engineering Fracture Mechanics, 2014
    Co-Authors: Giuseppe Catalanotti, A Arteiro, M Hayati, Pedro P. Camanho
    Abstract:

    Abstract This paper presents a new method to measure the Crack Resistance curve associated with the longitudinal failure of polymer composites reinforced by unidirectional fibres. Rather than using compact tension test specimens, the identification of the size-effect law of double edge notched specimens is used to obtain the Crack Resistance curve. Special emphasis is placed on the appropriate calculation of the stress intensity factor of the specimens when using quasi-isotropic or cross-ply laminates. For this purpose, both analytical closed-form solutions and numerical methods are investigated. Four different carbon-epoxy material systems, T800/M21, IM7/8552, T700/AR-2527, and T700/ACE are tested and the corresponding size effect laws and R-curves are measured. A good correlation between the Crack Resistance curve obtained using the size effect law and that previously measured for one of the material systems using the compact tension test is obtained. The highest value of the longitudinal fracture toughness was obtained for the T800/M21 material.

  • Measurement of the compressive Crack Resistance curve of composites using the size effect law
    Composites Part A: Applied Science and Manufacturing, 2014
    Co-Authors: Giuseppe Catalanotti, José Xavier, Pedro P. Camanho
    Abstract:

    Abstract This paper presents a new methodology to measure the compressive Crack Resistance curve of the longitudinal plies of carbon–epoxy laminates. The methodology is based on three main steps: the first one corresponds to the determination of the energy release rate of cross-ply laminates with two edge Cracks using a parametric finite element model. The energy release rate is used in the definition of a relation between the Crack Resistance curve and the size effect. Finally, experimental tests are performed in scaled double-edge notched specimens to quantify the size effect law, thus proving the last piece of information required to define the Crack Resistance curve. The full Crack Resistance curve is obtained for the IM7-8552 carbon epoxy composite material. The methodology proposed in this paper overcomes the inherent limitations of the existing test methods, and it serves as the basis for the identification of cohesive laws used in some analysis models.

R Deblieck - One of the best experts on this subject based on the ideXlab platform.

  • strain hardening modulus as a measure of environmental stress Crack Resistance of high density polyethylene
    Polymer, 2005
    Co-Authors: Lada Kurelec, M. Teeuwen, H. Schoffeleers, R Deblieck
    Abstract:

    In this paper it is shown that the Resistance to slow Crack propagation in polyethylene can be predicted from a simple tensile measurement performed at 80 °C. It is shown that for different types of polyethylene homopolymers and copolymers the slope of a tensile curve above its natural draw ratio (i.e. strain hardening) correlates well with the measured stress Crack Resistance. The data presented in this paper confirm that the slow Crack Resistance in polyethylene is determined by the failure of the fibrils within the craze, which is shown to be determined by the strain hardening of a tensile curve. A material with a strong strain hardening will reduce the strain rate and consequently the time to failure will be strongly increased. Considering the fact that the slow Crack Resistance of polyethylene is usually assessed by tedious and time consuming testing methods performed on the notched samples in contact with specific fluids, the findings reported in this publication offer a possibility to assess the information on slow Crack propagation in much simpler and faster way.