Publications
5 results found
Quinteros L, García-Macías E, Martínez-Pañeda E, 2023, Electromechanical phase-field fracture modelling of piezoresistive CNT-based composites, Computer Methods in Applied Mechanics and Engineering, Vol: 407, Pages: 1-24, ISSN: 0045-7825
We present a novel computational framework to simulate the electromechanical response of self-sensing carbon nanotube (CNT)-based composites experiencing fracture. The computational framework combines electrical-deformation-fracture finite element modelling with a mixed micromechanics formulation. The latter is used to estimate the constitutive properties of CNT-based composites, including the elastic tensor, fracture energy, electrical conductivity, and linear piezoresistive coefficients. These properties are inputted into a coupled electro-structural finite element model, which simulates the evolution of cracks based upon phase-field fracture. The coupled physical problem is solved in a monolithic manner, exploiting the robustness and efficiency of a quasi-Newton algorithm. 2D and 3D boundary value problems are simulated to illustrate the potential of the modelling framework in assessing the influence of defects on the electromechanical response of meso- and macro-scale smart structures. Case studies aim at shedding light into the interplay between fracture and the electromechanical material response and include parametric analyses, validation against experiments and the simulation of complex cracking conditions (multiple defects, crack merging). The presented numerical results showcase the efficiency and robustness of the computational framework, as well as its ability to model a large variety of structural configurations and damage patterns. The deformation-electrical-fracture finite element code developed is made freely available to download.
Meruane V, Yanez SJ, Quinteros L, et al., 2022, Damage detection in steel–concrete composite structures by impact hammer modal testing and experimental validation, Sensors, Vol: 22, Pages: 3874-3874, ISSN: 1424-8220
Steel–concrete composite systems are an efficient alternative to mid- and high-rise building structures because of their high strength-to-weight ratio when compared to traditional concrete or steel constructive systems. Nevertheless, composite structural systems are susceptible to damage due to, for example, deficient construction processes, errors in design and detailing, steel corrosion, and the drying shrinkage of concrete. As a consequence, the overall strength of the structure may be significantly decreased. In view of the relevance of this subject, the present paper addresses the damage detection problem in a steel–concrete composite structure with an impact-hammer-based modal testing procedure. The mathematical formulation adopted in this work allows for the identification of regions where stiffness varies with respect to an initial virgin state without the need for theoretical models of the undamaged structure (such as finite element models). Since mode shape curvatures change due to the loss of stiffness at the presence of cracks, a change in curvature was adopted as a criterion to quantify stiffness reduction. A stiffness variability index based on two-dimensional mode shape curvatures is generated for several points on the structure, resulting in a damage distribution pattern. Our numerical predictions were compared with experimentally measured data in a full-scale steel–concrete composite beam subjected to bending and were successfully validated. The present damage detection strategy provides further insight into the failure mechanisms of steel–concrete composite structures, and promotes the future development of safer and more reliable infrastructures.
Quinteros L, García-Macías E, Martínez-Pañeda E, 2022, Micromechanics-based phase field fracture modelling of CNT composites, Composites Part B: Engineering, Vol: 236, ISSN: 0961-9526
We present a novel micromechanics-based phase field approach to model crack initiation and propagation in carbon nanotube (CNT) based composites. The constitutive mechanical and fracture properties of the nanocomposites are first estimated by a mean-field homogenisation approach. Inhomogeneous dispersion of CNTs is accounted for by means of equivalent inclusions representing agglomerated CNTs. Detailed parametric analyses are presented to assess the effect of the main micromechanical properties upon the fracture behaviour of CNT-based composites. The second step of the proposed approach incorporates the previously estimated constitutive properties into a phase field fracture model to simulate crack initiation and growth in CNT-based composites. The modelling capabilities of the framework presented is demonstrated through three paradigmatic case studies involving mode I and mixed mode fracture conditions.
Quinteros L, Meruane V, Lenz Cardoso E, et al., 2021, Phononic bandgap optimization in sandwich panels using cellular truss cores, Materials, Vol: 14, Pages: 1-19, ISSN: 1996-1944
The development of custom cellular materials has been driven by recent advances in additive manufacturing and structural topological optimization. These contemporary materials with complex topologies have better structural efficiency than traditional materials. Particularly, truss-like cellular structures exhibit considerable potential for application in lightweight structures owing to their excellent strength-to-mass ratio. Along with being light, these materials can exhibit unprecedented vibration properties, such as the phononic bandgap, which prohibits the propagation of mechanical waves over certain frequency ranges. Consequently, they have been extensively investigated over the last few years, being the cores for sandwich panels among the most important potential applications of lattice-based cellular structures. This study aims to develop a methodology for optimizing the topology of sandwich panels using cellular truss cores for bandgap maximization. In particular, a methodology is developed for designing lightweight composite panels with vibration absorption properties, which would bring significant benefits in applications such as satellites, spacecraft, aircraft, ships, automobiles, etc. The phononic bandgap of a periodic sandwich structure with a square core topology is maximized by varying the material and the geometrical properties of the core under different configurations. The proposed optimization methodology considers smooth approximations of the objective function to avoid non-differentiability problems and implements an optimization approach based on the globally convergent method of moving asymptotes. The results show that it is feasible to design a sandwich panel using a cellular core with large phononic bandgaps.
Quinteros L, Meruane V, Cardoso EL, 2021, Phononic band gap optimization in truss-like cellular structures using smooth P-norm approximations, Structural and Multidisciplinary Optimization, Vol: 64, Pages: 113-124, ISSN: 1615-147X
The emergence of additive manufacturing and the advances in structural optimization have boosted the development of tailored cellular materials. These modern materials with complex architectures show higher structural efficiency when compared to traditional materials. In particular, truss-like cellular structures show great potential to be applied in lightweight applications due to their large strength/stiffness to mass ratio. Besides lightweight, these materials may exhibit incredible vibration isolation properties known as phononic band gaps. The present investigation addresses the topology optimization of two-dimensional (2D) truss-like cellular structures. The formulation aims to find the optimal geometrical and mechanical properties of each truss element to create a material exhibiting outstanding vibration (elastic wave) isolation at a certain frequency range (band gap). A new method to handle the non-differentiation of repeated eigenvalues, as well as mode switching, is proposed, where P-norms are used to create continuous approximation for extreme frequency values for all wave vectors of the band diagram. Results show that the proposed formulation is effective and avoids convergence problems associated to mode switching and to repeated eigenvalues.
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