The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Wanghu Peng - One of the best experts on this subject based on the ideXlab platform.
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correction to an analytical Inverse Analysis to determine equi biaxial tensile properties of strain hardening uhpfrc from ringon ring test
Materials and Structures, 2021Co-Authors: Xiujiang Shen, Eugen Bruhwiler, E Denarie, Wanghu PengAbstract:The article “An analytical Inverse Analysis to determine equi-biaxial tensile properties of strain-hardening UHPFRC from ringon-ring test”, written by Xiujiang Shen, Eugen Bruhwiler, Emmanuel Denarie and Wanghu Peng was originally published electronically on the publisher’s.
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an analytical Inverse Analysis to determine equi biaxial tensile properties of strain hardening uhpfrc from ring on ring test
Materials and Structures, 2020Co-Authors: Xiujiang Shen, Eugen Bruhwiler, E Denarie, Wanghu PengAbstract:The equi-biaxial tensile properties of strain-hardening UHPFRC are determined and investigated based on an original analytical Inverse Analysis of results from ring-on-ring tests. First, the analytical Inverse Analysis method is developed based on the elastic slab bending and yield line theories. Using this method, a new objective criterion for the determination of the elastic limit stress of strain-hardening UHPFRC is provided, and a point-by-point Inverse Analysis is used to obtain the strain value at the end of hardening. This method reduces uncertainties regarding assumptions and avoids any iterative procedures. The Inverse Analysis results are put into perspective with experimental evidence, particularly based on DIC measurements. Moreover, the uniaxial tensile properties are also derived from the Inverse Analysis of 4PBT results and compared with the equi-biaxial tensile properties from the proposed Inverse Analysis. The Inverse Analysis results show a 18% lower elastic limit stress, and almost equivalent tensile strength of UHPFRC subjected to equi-biaxial stresses, compared with the corresponding values from uniaxial stress. Moreover, a relatively small equi-biaxial strain at the end of hardening is highlighted.
Xiujiang Shen - One of the best experts on this subject based on the ideXlab platform.
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correction to an analytical Inverse Analysis to determine equi biaxial tensile properties of strain hardening uhpfrc from ringon ring test
Materials and Structures, 2021Co-Authors: Xiujiang Shen, Eugen Bruhwiler, E Denarie, Wanghu PengAbstract:The article “An analytical Inverse Analysis to determine equi-biaxial tensile properties of strain-hardening UHPFRC from ringon-ring test”, written by Xiujiang Shen, Eugen Bruhwiler, Emmanuel Denarie and Wanghu Peng was originally published electronically on the publisher’s.
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an analytical Inverse Analysis to determine equi biaxial tensile properties of strain hardening uhpfrc from ring on ring test
Materials and Structures, 2020Co-Authors: Xiujiang Shen, Eugen Bruhwiler, E Denarie, Wanghu PengAbstract:The equi-biaxial tensile properties of strain-hardening UHPFRC are determined and investigated based on an original analytical Inverse Analysis of results from ring-on-ring tests. First, the analytical Inverse Analysis method is developed based on the elastic slab bending and yield line theories. Using this method, a new objective criterion for the determination of the elastic limit stress of strain-hardening UHPFRC is provided, and a point-by-point Inverse Analysis is used to obtain the strain value at the end of hardening. This method reduces uncertainties regarding assumptions and avoids any iterative procedures. The Inverse Analysis results are put into perspective with experimental evidence, particularly based on DIC measurements. Moreover, the uniaxial tensile properties are also derived from the Inverse Analysis of 4PBT results and compared with the equi-biaxial tensile properties from the proposed Inverse Analysis. The Inverse Analysis results show a 18% lower elastic limit stress, and almost equivalent tensile strength of UHPFRC subjected to equi-biaxial stresses, compared with the corresponding values from uniaxial stress. Moreover, a relatively small equi-biaxial strain at the end of hardening is highlighted.
G Maier - One of the best experts on this subject based on the ideXlab platform.
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flat jack tests and Inverse Analysis for the identification of stress states and elastic properties in concrete dams
Meccanica, 2007Co-Authors: Roberto Fedele, G MaierAbstract:In this paper an experimental-numerical method, centred on flat-jack tests, is presented for the identification of local stress states and possibly deteriorated elastic properties of concrete in existing dams. It is shown herein that the synergistic combination of new pattern of flat-jack experiment, computer simulation of the test (by conventional finite elements) and Inverse Analysis allows to exploit experimental data more effectively than by the traditional procedure, and to achieve more information on material properties. In fact, at suitably chosen locations on the free surface of the monitored dam, all the components of local (plane) stress state and the elastic moduli in two orthogonal directions (including shear stiffness) can be estimated by the proposed method. The Inverse problem in point is formulated as a sequence of two parameter identifications, i.e. as a bilevel (in the sense of Stackelberg) mathematical programming problem. The solution in a stochastic context is achieved by means of a modified Bayes technique, allowing to obtain, in a “batch” (non sequential) way, parameter estimates endowed with a covariance matrix which quantifies their degrees of confidence and correlations.
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material model calibration by indentation imprint mapping and Inverse Analysis
International Journal of Solids and Structures, 2004Co-Authors: Gabriella Bolzon, G Maier, Michele PanicoAbstract:Abstract The identification of elastic–plastic material parameters by means of indentation tests and their finite element simulation is considered in this paper with the innovative provision of measuring the imprint geometry besides the indentation curves. The Inverse Analysis is carried out by a deterministic approach using conventional algorithms. The proposed methodology is validated using “pseudo-experimental” (computer generated) data with and without noise. Also friction between the indenter tool and the indented specimen is dealt with by Inverse Analysis and investigated through a parametric study. Sensitivity with respect to the sought parameters is examined for measurable quantities, including residual displacements on the specimen surface.
Taylan Altan - One of the best experts on this subject based on the ideXlab platform.
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determination of flow stress and interface friction at elevated temperatures by Inverse Analysis technique
Journal of Materials Processing Technology, 2005Co-Authors: Hyunjoong Cho, Taylan AltanAbstract:Abstract An Inverse Analysis technique has been introduced to obtain the flow stress of the bulk and sheet materials at elevated temperatures. The Inverse problem is defined as the minimization of the differences between the experimental measurements and the corresponding FEM predictions. As reference material tests, the ring compression and the modified limiting dome height test (sheet blank with a hole at the center stretched with a hemispherical punch) at elevated isothermal conditions were selected. The friction condition at the tool/workpiece interface is identified from the geometrical changes that occur in deformed samples. It is shown that the developed Inverse Analysis technique is reliable and can determine the flow stress and friction factor simultaneously from one set of material tests.
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3d finite element Analysis of orbital forming and Inverse Analysis for determination of flow stress of the workpiece
MATERIALS PROCESSING AND DESIGN: Modeling Simulation and Applications - NUMIFORM 2004 - Proceedings of the 8th International Conference on Numerical M, 2004Co-Authors: Hyunjoong Cho, Gracious Ngaile, Taylan AltanAbstract:In this study, the effectiveness of recent 3D FEM simulations of orbital forming was investigated by (a) measuring the computation time and (b) by comparing the results of simulations with experiments. Commercial FEA software DEFORM™ 3D v4.0 that has an efficient computation numerical algorithm for simulating incremental forming process was used for the simulations and the amount of savings in computation time was shown. Two measurable quantities from experiments are (1) deformed tab geometry of the spindle and (2) maximum forming load. Therefore, the accuracy of 3D FEM simulation was evaluated by comparing the differences between the predicted and measured deformed tab geometry and maximum forming load. In order to provide reliable flow stress for the simulation, a finite element based Inverse Analysis technique was used to identify the parameters of the flow stress equation from upset test by minimizing a least‐square functional of differences between predicted and measured forming loads. Thank to a new...
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simultaneous determination of flow stress and interface friction by finite element based Inverse Analysis technique
CIRP Annals, 2003Co-Authors: Hyunjoong Cho, G Ngalle, Taylan AltanAbstract:Abstract A finite element based Inverse Analysis technique has been developed to determine the flow stress and friction at the tool/workplace interface simultaneously from one set of material tests. The Inverse problem is aimed at minimizing the error between experimental data and predictions made by rigid-plastic finite element simulations. The ring compression test and the modified limiting dome height test (sheet blank with a hole at center stretched with a hemispherical punch) were selected for evaluating the method for bulk forming and for sheet forming, respectively. The determined flow stress data were compared with corresponding data obtained Independently using the well-lubricated cylinder compression test and hydraulic bulge test. Results show that the method discussed In the study is efficient and accurate.
Hugo Coll - One of the best experts on this subject based on the ideXlab platform.
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a simplified five point Inverse Analysis method to determine the tensile properties of uhpfrc from unnotched four point bending tests
Composites Part B-engineering, 2016Co-Authors: J Lopez, Pedro Serna, Juan Navarrogregori, Hugo CollAbstract:Abstract Characterisation of the tensile behaviour of UHPFRC remains a challenge for researchers, and an agreement on the standard test set-up and advisability of notch is yet to be reached. Bending tests are easier to conduct if compared to direct tensile tests, but require a sophisticated post-process to obtain the uniaxial tensile behaviour of specimens. Unlike notched tests, unnotched tests allow the determination of strain-hardening behaviour, which characterises UHPFRC tensile behaviour. However, post-cracking behaviour is more difficult to analyse. This work focuses on the development of a new simplified Inverse Analysis method applied to unnotched four-point bending tests which improves current simplified methods, but maintains the accuracy of more complex ones. For this purpose, an analytical model based on a quadrilinear assumption of tensile behaviour in tension was assumed. A statistical Analysis of theoretical flexural strength vs. displacement on mid-span analytical curves was conducted to link the assumed tensile behaviour to the analytical flexural behaviour that derived from it. After this process, a simplified method to obtain not only the stress–strain behaviour prior to crack localisation, but also the stress–crack opening relationship after that point is proposed. The new method is based on the determination of only five key points in experimental bending strength vs. displacement at mid-span curves and in the application of a back-of-the-envelope calculation. The analytical basis on which the method is based, justification of key point selection, and the process followed to achieve the simplified formulation, which allows dispensing with the use of a computer, are presented. An application example on a UHPFRC unnotched four-point bending test specimen, and its comparison with a point-by-point Inverse Analysis, are included.
