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Seismic damage behaviour of aeolian sand reinforced concrete columns with I-shaped structural steel

Wang Y. H., Wang H. Y., Wang Y. P., Zhao M., Qi J., Huo G. Z., Liu P. Q.

Archives of Civil Engineering

2020

Vol. 66, nr 4

633--650

To promote the application of aeolian sand resources for steel-concrete composite structures, an aeolian sand reinforced concrete column with I-shaped structural steel is proposed in this study. Four specimens are designed and manufactured with different replacement rates of aeolian sand. The seismic behaviour and damage evolution process of the specimens are studied by low-cycle repeated loading tests. Based on the test results, the mechanical characteristics, failure modes, hysteresis curves, skeleton curves, energy dissipation capacity, displacement ductility, and stiffness degradation of the specimens with different replacement rates of aeolian sand are analysed. In addition, the effects of the design parameters on the seismic behaviour of the specimens are also studied. The results show that the indexes of the seismic behaviour can be significantly improved by adding steel. Moreover, a revised damage model is proposed, to better reflect the evolution law of seismic damage of aeolian sand reinforced concrete columns with steel. The proposed model can provide an important reference for seismic damage assessment of the columns.

On prediction of the compressive strength and failure patterns of human vertebrae using a quasi-brittle continuum damage finite element model

Nakhli Zahira, Hatira Fafa Ben, Pithioux Martine, Chabrand Patrick, Saanouni Khemais

Acta of Bioengineering and Biomechanics

2019

Vol. 21, no. 2

143--151

Damage of bone structures is mainly conditioned by bone quality related to the bone strength. The purpose of this work was to present a simple and reliable numerical treatment of a quasi-brittle damage constitutive model coupled with two different elastic modulus and to compare the numerical results with the experimental ones. Methods: To achieve this goal, a QCT based finite element model was developed within the framework of CDM (Continuum Damage Mechanics) and implemented in the FE code (ABAQUS). It described the propagation of brittle cracks which will help to predict the ultimate load fracture of a human vertebra by reproducing the experimental failure under quasi-static compressive loading paths of nineteen cadaveric lumbar vertebral bodies. Results: The numerical computations delivered by the proposed method showed a better agreement with the available experimental results when bone volume fraction related Young’s modulus (E(BV/TV)) is used instead of density related Young’s modulus (E(ρ)). Also, the study showed that the maximum relative error (%) in failure was 8.47% when E(BV/TV) was used, whereas the highest relative error (%) was 68.56% when E(ρ) was adopted. Finally, a mesh sensitivity analysis revealed that the element size has a weak incidence on the computed load magnitude. Conclusions: The numerical results provided by the proposed quasi-brittle damage model combined with E(BV/TV) are a reliable tool for the vertebrae fracture prediction.

Crack identification in composite elements with non-linear geometry using spatial wavelet transform

Katunin A., Holewik F.

Archives of Civil and Mechanical Engineering

2013

Vol. 13, no. 3

287--296

A great popularity of constructional polymer composites in industrial applications requires the development of appropriate diagnostic methods for the elements made of these materials. These methods should provide damage detection and identification in possible early stages of its development. A large group of such methods is based on vibration testing and modal analysis. One of the promising techniques of processing vibration data for damage identification is a wavelet transform. Considering the practical needs the method should be applicable for plane structures with non-linear geometry. Results presented in this paper consider numerous analyses including the application of different types of wavelet transforms, different types of wavelet functions and other factors, which have an influence on the accuracy of damage identification. The proposed method shows good effectiveness in damage identification problems and could be applied in industrial conditions as well.