Material Parameters Identification for Modelling of Carbon Rod Structures Delamination

The aim of the present work is to compare the interlaminar shear strength and fracture toughness of glued carbon fiber rods obtained using different experimental approaches and provide the effective way to characterise the interlaminar properties for reliable simulation of the delamination. Five different test methods (tension, single shear test, and double shear test, mode I and mode II delamination tests) were performed. Using the explicit LS-DYNA code the finite element model capable of simulating the damage process of bonded connection was developed. The interlaminar connection and delamination criteria were calibrated using the parameter identification methodology implemented in LS-OPT optimization tool.

Material Parameters Identification of Historic Lighthouse Based on Operational Modal Analysis

In the present paper, the identification of the material parameters of a masonry lighthouse is discussed. A fully non-invasive method was selected, in which the material properties were determined via numerical model validation applied to the first pair of natural frequencies and their related mode shapes, determined experimentally. The exact structural model was built by means of the finite element method. To obtain experimental data for the inverse analysis, operational modal analysis was applied to the structure. Three methods were considered: peak picking (PP), eigensystem realization algorithm (ERA) and natural excitation technique with ERA (NExT-ERA). The acceleration’s responses to environmental excitations, enhanced in some periods of time by sheet piling hammering or by sudden interruptions like wind stroke, were assumed within the analysis input. Different combinations of the input were considered in the PP and NExT-ERA analysis to find the most reasonable modal forms. A number of time periods of a free-decay character were considered in the ERA technique to finally calculate the averaged modal forms. Finally, the elastic modulus, Poisson’s ratio and material density of brick, sandstone and granite masonry were determined. The obtained values supplement the state of the art database concerning historic building materials. In addition, the numerical model obtained in the analysis may be used in further cases of structural analysis.

Effect of Foam’s Heterogeneity on the Behaviour of Sandwich Panels

This study aimed to develop a knowledge about material parameters identification of the foam core and numerical modelling of the sandwich panels to accurately predict the behaviour of this kind of structures. The polyisocyanurate foam (PIR) with low density used in sandwich panels dedicated to civil engineering is examined in the paper. A series of experiments (tensile, compression and bending tests) were carried out to identify its mechanical parameters. To determine the heterogeneity of analysed foam a Digital Image Correlation (DIC) technique, named Aramis, is applied in the paper. The results obtained from FE analyses are compared with the experimental results on full-size plates carried out by the author and proper conclusions are drawn.

Characterization of the Hot Anode Paste Compaction Process: A Computational and Experimental Study

The aim of this work is to model and characterize green anode paste compaction behavior. For this purpose, a nonlinear viscoplastic constitutive law for compressible materials, based on the finite strain theory and the thermodynamic framework, was used. An experimental study was carried out to characterize axial and radial behaviors of the anode paste. To this end, simple compaction tests using a thin steel instrumented mold were performed at a temperature of 150 °C. Results of these experiments brought out the nonlinear mechanical behavior of the anode paste. Furthermore, they showed the importance of its radial behavior. The constitutive law was implemented in Abaqus software through the user’s material subroutine VUMAT for explicit dynamic analysis. An inverse analysis procedure for material parameters identification showed that the model predicts compaction tests results with a good agreement. In order to assess the constitutive law predictive potential in situations involving density gradients, compaction tests using complex geometries such as slots and stub holes were carried out. Finite element simulation results showed the ability of the model to successfully predict density profiles measured by the X-ray tomography.

Accuracy and Robustness Analysis of Geometric Finite Element Model Updating Approach for Material Parameters Identification in Transient Dynamic

We study the accuracy and the robustness of the Geometrical Finite Element Model Updating method proposed in Touzeau et al. [Touzeau, C., Magnain, B., Emile, B., Laurent, H. and Florentin, E. (2016) “Identification in transient dynamic using a geometry-based cost function in finite element model updating method,” Finite Elements Anal. Des. 122, 49–60]. In this work, the method is applied to transient dynamic in finite transformations to identify mechanical material parameters. A stochastic approach is performed to determine accuracy and robustness. The method is illustrated on numerical test cases and compared to a classical FEMU method. Uncertainties on the loading are taken into account in the identification using an original approach.