Experimental database with full field measurements for mixed-mode crack propagation in concrete: comparison between experimental and numerical results

International audienceno abstrac

"Drawing with a crack in concrete": A hybrid test to control mixed-mode crack propagation

International audienceno abstrac

Comparison between experimental and numerical results of mixed-mode crack propagation in concrete: Influence of boundary conditions choice

International audienceno abstrac

Innovative tests for characterizing mixed-mode concrete fracture

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A complex mixed-mode crack propagation test performed with a 6-axis testing machine and full-field measurements propagation

International audienceA new type of mixed mode crack propagation test is proposed. A single crack is initiated and propagates in a stable way up to complete failure. A combination of tensile, shear and in-plane rotation performed by a 6-axis testing machine is prescribed. The rotation creates a tension/compression gradient in the sample ensuring the stability, while the shear direction is closely related to the orientation of the crack and the tensile load is responsible for the actual propagation. The experiment is performed in an interactive manner, namely, depending on the crack tip position estimated by Digital Image Correlation (DIC) during the test, the loading is changed to bifurcate the crack. The displacements of the sample surfaces are assessed using multiple DIC measurements and displacement sensors. The displacement fields on each face of the sample give access to the crack pattern, and also to the actual boundary conditions that are crucial for a faithful numerical analysis of the test. Last, the 6 load components are recorded enabling for a complete description of the 3D mechanical behavior of the specimen

: article lié au prix de thèse discerné au congrès TINCE 2016

article lié au prix de thèse discerné au congrès TINCE 2016International audienceThe knowledge of the concrete behavior is essential when analyzing the aging and leakage phenomena of production facilities. On the industrial level the concrete fracture characterization is currently performed through standard experimental tests that are not sufficiently rich to determine in an optimized manner all the corresponding characteristics. First there is a general lack of mixed mode loading experiments that produce non trivial crack paths. Moreover, even for some well defined material properties (as for example critical shear stress) the corresponding loading tests are not sufficiently developed, as the results are too dependent on aggregate distribution and specimen sizes. It means that we are still not able to locally reproduce some specific me-chanical stresses distribution and repeatedly check it in order to attain necessary accuracy. Therefore an improvement in corresponding measurement technique is still needed.When studying concrete fracture behavior the main difficulty is related to instable crack propagation. In the past some relevant works in mixed mode fracture were conducted by Nooru-Mohamed. More recently the work was extended employing an up-to-date full-field measurement technique.In this work, we develop a stable crack path control technique that allows “customized” cracking tests creation for the characterization of various materials. Using this technique well instrumented and discriminating mixed–mode crack propagation tests performed on VERCORS concrete samples are presented. Finally we discuss the relevance of these tests for various pa-rameters identification and some possible extension of stable crack path control technique

Indirect comparisons of second-generation tyrosine kinase inhibitors in CML: case study using baseline population characteristics.

The use of indirect comparisons to evaluate the relative effectiveness between two or more treatments is widespread in the literature and continues to grow each year. Appropriate methodologies will be essential for integrating data from various published clinical trials into a systematic framework as part of the increasing emphasis on comparative effectiveness research. This article provides a case study example for clinicians using the baseline study population characteristics and response rates of the tyrosine kinase inhibitors in imatinibresistant or imatinib-intolerant chronic myelogenous leukemia followed by a discussion of indirect comparison methods that are being increasingly implemented to address challenges with these types of comparison

"Drawing with a crack in concrete": a hybrid test to control mixed-mode crack propagation

International audienceno abstrac