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  • 1
    Electronic Resource
    Electronic Resource
    APPLICATION OF A NORMALIZATION METHOD FOR DETERMINING J-R CURVES IN GLASSY POLYMER PVC AT DIFFERENT CROSSHEAD SPEEDS (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 20 (1997), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— A new single-specimen testing method, the normalization method with the so-called LMN calibration function, based on the load separation principle and function calibrations from an individual test record, was used to construct J-R curves directly from load versus load-line displacement records without any additional on-line crack-length monitoring equipment. The research was done on CT-specimens of a glassy polymer PVC at different crosshead speeds ranging from 0.01 to 50 mm/min. The J-R curves evaluated from the normalization method are in good agreement with those from the conventional multiple-specimen testing method in the whole range of the tested crosshead speeds. The results demonstrated the applicability of the normalization method for developing J-R curves at different crosshead speeds in PVC. The crack initiation J-integral values, J0.2, showed a two-regime dependence on the crosshead speeds in the tested crosshead speed range.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1997.tb00272.x
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  • 2
    Electronic Resource
    Electronic Resource
    SIZE, THICKNESS AND GEOMETRY EFFECTS ON TRANSITION FRACTURE (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 16 (1993), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— Transition fracture toughness was studied to look at the effect of size, thickness and geometry. Size effects were studied on six sets of data collected from the literature in which proportionally sized compact specimens of various steels were tested. Thickness effects were studied on tests of compact specimens of constant thickness and varying planar dimensions. Tests were conducted on a pressure vessel steel at a constant thickness of 20 mm where planar dimensions were increased so that thickness constraint was decreased. Geometry effects were studied on tests from a center cracked tension specimen geometry. Initially all of the data from the tests were included in the study; none were eliminated due to a size or other validity requirement. Then two validity requirements, the KIc and the Anderson-Dodds size requirements, were imposed to study their effect on the data.The results showed that a smaller specimen size does not necessarily result in higher toughness. Rather, the smallest size often gave the lowest values of toughness. Loss of thickness constraint tended to increase toughness but not very much; it may not increase at all at the lower temperatures. The center cracked tension geometry appeared to have a lower constraint. These specimens showed an increase in toughness which is similar to that observed on a compact specimen for a change of temperature from −90°C to −60°C. Imposing a size validity requirement eliminated much of the fracture toughness data in the transition and influenced the distribution of data. Validity size criteria should be avoided if possible, especially for a scientific study.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1993.tb00729.x
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  • 3
    Electronic Resource
    Electronic Resource
    J-Q MODEL FOR PREDICTING FRACTURE IN THE DUCTILE-BRITTLE TRANSITION (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 19 (1996), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A model is proposed to predict cleavage failure of precracked bodies in the transition region for steels. It is based on the concept that the failure of a weak link triggers the failure of the entire body. The model is similar to that originally proposed by Heerens et al. which assumes that the weak link has a given level of stress labeled the cleavage stress needed to cause failure. This weak link is located at some characteristic but variable distance from the crack tip. The variation in distance from the crack tip to the weak link causes variation in the transition fracture toughness. The crack tip stress is given by the J-Q model of O'Dowd and Shih where Q characterizes the constraint level in the body.Given a set of input data, that is fracture toughness from a given specimen geometry at a known temperature, toughness values can be predicted from these inputs at a different temperature where the yield stress is known or for a different size or geometry where Q is known. The model is applied here for two steels; a DIN 20MnMoNi55 steel and a CrMoV steel. For the first steel fracture toughness values measured on compact specimens are used to predict cleavage fracture throughout the transition for the same geometry. For the second steel the transition trend is predicted for the same compact geometry. The results show that the model is good for predicting the sudden end of the transition that is often observed but does not predict the lower shelf or early transition very well. This is a region where a weak link mechanism may not be operating.〈section xml:id="abs1-2"〉〈title type="main"〉SUMMARYA model is proposed to predict the cleavage fracture toughness in the transition for steels. It is based on a weak link failure concept and a crack tip stress distribution that is influenced by the constraint level. The model uses measured fracture toughness data to predict a distance from the crack tip to the weak link. This distance is a variable that is used to account for all of the variability in the fracture toughness. For a new temperature or geometry the toughness can be predicted by assuming that the cleavage stress is fixed and the material has the same range of weak link distances. The magnitude of the crack tip stresses can change due to a change in yield stress or constraint.The model was used to predict the toughness trend in the transition and the end of the transition. It was applied to two steels, a 20MnMoNi55 steel and a CrMoV steel. For the 20MnMoNi55 steel the transition trend and the end of the transition that were predicted by the model compared well with experimental results. For the CrMoV steel the interesting part was that the lower shelf region of the transition was not predicted well. The prediction from the model overestimated the measured fracture toughness values. This suggests, as was previously believed, that a weak link mechanism may not operate near the lower shelf part of the transition. The model could also be used to predict the toughness for a new geometry such as a component model geometry. That will be reported in a later work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1996.tb01022.x
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  • 4
    Electronic Resource
    Electronic Resource
    THE BLUNTING LINE IN ELASTIC-PLASTIC FRACTURE (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 18 (1995), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The blunting line evaluation procedure used in the ESIS standard fracture toughness test method “Procedure for Determining the Fracture Behaviour of Materials” is re-evaluated to see if a simpler format can be developed. An equation based on the ultimate tensile strength was found to represent the blunting line in a simple manner. This equation is in error at most ±5% from the analytical representation and is as accurate as the graphical procedure used to determine the blunting line. It is recommended that this equation be used for fracture toughness test standards which use the ESIS blunting line. A comparison of the ESIS blunting line and the ASTM blunting line is made using some J-R curve data generated with an elastic unloading compliance test procedure. These data do not favor one line over the other. Microscopic evaluation of the blunting line reported in the literature using the stretch zone width measured on the fracture surface suggests that the ESIS blunting line better represents the physical blunting process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1995.tb00855.x
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  • 5
    Electronic Resource
    Electronic Resource
    A COMMON FORMAT APPROACH FOR THE DUCTILE FRACTURE METHOD USING A DISPLACEMENT-BASED NORMALIZATION PARAMETER (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Fatigue & fracture of engineering materials & structures 20 (1997), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract— The Ductile Fracture Method (DFM) proposed by Ernst and Landes and further developed by Landes and coworkers is examined in conjunction with the Common Format Equation (CFE) proposed by Donoso and Landes. The DFM can be used to predict the load versus displacement behavior for a structure from the load versus displacement record for a fracture toughness test specimen. This involves a calibration function transformation procedure which is often laborious. But, it will be shown here that using the CFE approach with an adequate normalizing parameter for the deformation function, H, the transformation procedure can be virtually eliminated. As a consequence, the predictions done by the DFM can be completed in a shorter time. The equations which originated the CFE approach are reviewed to show that the modification proposed in this paper is necessary for H to get closer to a unique representation, independent of the geometry. Some examples are presented to demonstrate the applicability of the approach.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-2695.1997.tb01489.x
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  • 6
    Electronic Resource
    Electronic Resource
    An application of the J-Q model for estimating cleavage stress in the brittle-to-ductile transition (2001)
    Oxford, UK : Blackwell Science Ltd
    Fatigue & fracture of engineering materials & structures 24 (2001), S. 0 
    Details
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A recent model was proposed by the authors to predict cleavage failure for steels based on a weak link mechanism and a crack tip stress field modified for planar constraint by the J–Q theory. The model uses the distribution of toughness results at a single temperature to predict a toughness distribution at a different temperature and/or geometry. In this model a material cleavage stress is needed to predict when the weak link fracture is triggered. This cleavage stress is a key input for the application of the model but it is not a property that is routinely measured and it is hence not available for most steel alloys. In this paper, a method to estimate the average value of the cleavage stress is presented, based on a characteristic of the model to predict cleavage failure. Examples of cleavage stress are given for several steels and these results are used to predict the toughness distributions for structural component models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-2695.2001.00403.x
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  • 7
    Electronic Resource
    Electronic Resource
    CEMS investigations of interfaces: magnetic interactions
    Amsterdam : Elsevier
    Journal of Magnetism and Magnetic Materials 113 (1992), S. 137-143 
    Details
    ISSN: 0304-8853
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0304-8853(92)91259-V
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  • 8
    Electronic Resource
    Electronic Resource
    Magnetic properties of amorphous Fe in Fe/Y layered structures
    Amsterdam : Elsevier
    Journal of Magnetism and Magnetic Materials 119 (1993), S. 254-260 
    Details
    ISSN: 0304-8853
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0304-8853(93)90409-U
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  • 9
    Electronic Resource
    Electronic Resource
    Magnetic hyperfine fields near the Fe / Cr (100, 110) interface studied by CEMS
    Amsterdam : Elsevier
    Journal of Magnetism and Magnetic Materials 86 (1990), S. 71-77 
    Details
    ISSN: 0304-8853
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0304-8853(90)90086-6
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  • 10
    Electronic Resource
    Electronic Resource
    Versorgung der per- bis subtrochantären Femurfraktur durch Gammanagel und modulare Hüftprothese Differentialindikation und Ergebnisse (2000)
    Springer
    Der Unfallchirurg 103 (2000), S. 444-451 
    Details
    ISSN: 1433-044X
    Keywords: Schlüsselwörter Gammanagel ; Modulare Hüftprothese ; Pertrochantäre Femurfraktur ; Koxarthrose ; Keywords Gamma nail ; Modular hip prostheses ; Trochanteric fracture ; Osteoarthrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary From January 1997 to August 1998 all stabel and nonstabel trochanteric femoral fractures (n=72) were treated routinely by gamma nail using the correct operative technique. Patients showing additional osteoarthritis of the hip in radiographs hip replacement was performed by a cementless modular femoral hip prostheses from January 1996 to August 1998 (n=28). Follow up period was 6 to 18 months. Operation time and blood loss were higher using the prostheses. However complications and letality (〈5%) were not different during postoperativ course. In each group three operative technical complications occured. Using a modified Harris Hip Score (without range of motion, contractions) the score was decreased non significant comparing both groups first of all in unstabel fractures until follow up. In each group one revision (loosening of prostheses, excessive shortening of femoral neck) was necessary. Using the correct operative technique, the gamma nail prooved to be a save device with good outcome. Outcome using modular prostheses is comparable to gamma nail. Therefore the use of modular prostheses is justified in case of osteoarthrosis and in some cases of very unstable fracture.
    Notes: Zusammenfassung In der Zeit vom 1.1.1997 bis 1.8.1998 wurden alle stabilen und instabilen per- bis subtrochantären Femurfrakturen (n=72) routinemäßig durch einen Gammanagel (GN) unter Anwendung der korrekten Operationstechnik stabilisiert. Ausgenommen waren Patienten, die radiologisch eindeutige Koxarthrosezeichen hatten. In dieser Vergleichsgruppe (n=28) wurde der Gelenkersatz durch eine zementfreie, modulare Hüftprothese (MHP) durchgeführt und die Patienten im Zeitraum vom 1.1.96 bis 1.8.98 ebenfalls prospektiv erfaßt. Die Nachuntersuchung erfolgte nach 6–18 Monaten. Trotz längerer Operationszeit und höherem Blutverlust in der MHP Gruppe bestand kein Unterschied an Komplikationen und Letalität (〈5%) während des stationären Aufenthalts. In jeder Gruppe waren drei operationstechnische Komplikationen nachweisbar. Unter Verwendung eines modifizierten Harris-Hip-Scores (ohne Bewegungsumfang, Deformität) zeigten beide Gruppen eine nicht signifikant unterschiedliche Abnahme der Punktzahl vor allem bei den instabilen Frakturen zum Zeitpunkt der Nachuntersuchung. In jeder Gruppe mußte ein Patient (Sinterung im Frakturbereich, Prothesenlockerung) revidiert werden. Unter Anwendung der korrekten Operationstechnik ist der GN ein sicheres Implantat. Die MHP zeigt gleich gute Ergebnisse mit gleicher Letalität, so daß der Einsatz bei Koxarthrose und in ausgewählten Fällen auch bei hochgradig instabilen Frakturen gerechtfertigt ist.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001130050564
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