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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.

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.

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.

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.

Notes: Summary The development and clinical indications of a new modular femoral endoprosthesis consisting of a head and shaft component is discribed. Components are available in different lengths and diameters and therefore can be joined individually depending on the patients anatomy and surgery required. Both parts are joined by a unique optimized taper socket with a groove, avoiding fretting and corosion. Fatigue tests showed no loosening of the tapered connection and no prosthesis fracture. The advantage of this new modular prosthesis is diaphyseal stabilization, if necessairy by two distal interlocking screwes. Indications are revisions, pertrochanteric femoral and neoplastic fractures if cementless bridging of boney defects in the calcar region must be achieved. Further indications are femoral neck fraktures and coxarthrosis if stable diaphyseal fixation is required. The material and surface structure as well as the philosophie of the distal fixation are discussed.