Post-fracture analysis

XPS is used to evaluate surfaces prior to bonding yielding information which may relate to bond performance, as well as to study failure surfaces. The added advantage in XPS is that more sample types can be analyzed, such as nonconductive adhesive surfaces without the problems of charging found with other techniques such as AES, SIMS, and ISS. For this reason XPS is often the method of choice in post-fracture analysis. 

Clinical trials on postmenopausal women with osteoporosis have demonstrated that raloxifene reduces bone turnover markers by 25-35% after 1 year of treatment and reduces the relative risk of the occurrence of new vertebral fractures by 30-50% after 3 years of treatment (Ettinger et al. 1999). A post hoc analysis in women at high risk for cardiovascular diseases also showed a reduction of 40% in the rate of new cardiovascular events (Barrett-Connor et al. 2002), with no observed reduction in the overall study population after 4 years of treatment in the MORE trial. 

With the initial aim of evaluating the applicability of the ISO 15024 standard for fracture toughness testing for non-unidirectional composite laminates, ESIS TC4 has conducted a number of round robin studies on cross-ply laminates with different stacking sequences. We report here the results of two test laboratories from the 3 round robin activity in which double cantilever beam (DCB) specimens made from unidirectional (0°/0°-interface) composite laminates were compared to DCB-specimens with 0°/90°- and 90790° interfaces. In the analysis, correlation with observations from the delamination growth (e.g., deviation from the mid-plane) and post-test (e.g., fracture surface) inspection was attempted. The results are compared with some results in the literature. 

The fracture toughness measurements, combined with the post-mortem surface analysis of the fracture surfaces, allow us to develop some simple micromechanical models to account for these three situations. 

The problem of secondary flexure in axial tensile tests is considered in view of the tension-softening process. The procedures aimed at elimination of that parasite effect were studied by Akita et al. (2001) and Novak et al. (2006) who have shown possibilities of nonlinear fracture mechanics simulation in analysis of the experimental data, including post-peak descending branch of the load-displacement curves, taking into consideration material imperfections and heterogeneities. 

Crossman FW, Warren WJ (1985) The infiuence of environment on matrix dominated composite fracture. Final report N60921-81-C-0157, Dec 1985 Crossman FW, Mauri RE, Warren WJ (1978) Moisture altered viscoelastic response of graphite/ epoxy composite. In Vinson JR (ed) Advanced Composite Materials - Environmental Effects, ASTM STP 658. American Society for Testing and Materials, Philadelpia, PA, pp 205-220 Ferry JD (1980) Viscoelastic Properties of Polymers. Wiley, New York Flaggs DL, Crossman FW (1981) Analysis of the Viscoelastic Response of Composite Laminates During Hygrothermal Exposure. Journal of Composite Materials 15(l) 21-40 Harper BD (1983) On the Effects of Post Cure Cool Down and Environmental Conditioning on Residual Stresses in Composite Laminates. Texas A M University Report MM-4665-83-11, Aug 1983... 

One of the most important areas in which EM has delivered significant contributions has been the investigation of deformation behaviors of polymer blends, in particular with insitu deformation tests. Post-mortem studies of specimens cJose to the fracture surface, or an evaluation of the deformed semi-thin section by means of TEM and an analysis of the fracture surfaces using SEM, may provide important clues as to the deformation micromecdianisms of polymer blends. 

Keywords— Ferrule effect. Post, Finite Element Analysis, Endodontically treated teeth, root fracture. 

Test Procedures - Generally, a displacement-control or strain-control test mode is used to avoid run-away tests that sometimes occur in force-control. A test mode rate is chosen so as to produce test specimen failure in 5-50 s. Failure within 1 minute or less should be sufficient to minimize slow-crack growth (SCG) effects in the tensile test. If slow crack growth is observed (e.g. under slow test mode rates), subsequent tests can be accelerated to reduce or eliminate slow crack growth. Extensometers and/or strain gages are used to determine gage length extension and/or local strain. The test specimen is tested in flexure to fracture. The test specimen is retained for failure analysis and post-test dimensional measurement. 

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