Papers

@article{espinoza_numerical_2026,

title = {Numerical analysis of the integrated hydrology of a hillslope regulated river basin},

author = {Jesús E. Espinoza and Francisco Padilla and Pablo Rodríguez-Vellando-Fernández-Carvajal},

url = {https://doi.org/10.1007/s12665-026-13056-3},

doi = {10.1007/s12665-026-13056-3},

issn = {1866-6299},

year  = {2026},

date = {2026-07-01},

urldate = {2026-08-18},

journal = {Environmental Earth Sciences},

volume = {85},

number = {13},

pages = {311},

abstract = {The limited availability of hydrometeorological records in mountainous regions severely constrains the technical management of water resources in river basins. In response to this limitation, this study presents a methodological framework for estimating both surface and groundwater discharges in scarce-data basins, applying an integrated hydrological numerical model, based on the finite element method, to the Casacay River catchment in south-western Ecuador. The MELEF-FSW model was employed to simulate the coupled flows of groundwater and surface water under transient conditions, incorporating processes of overland flow, infiltration, soil water content, groundwater recharge, actual evapotranspiration and water management. The Casacay catchment is characterised by steep topography, pronounced seasonal variability, and intensive water abstraction facilities for human consumption. Given the dispersed nature of the available data, multiple information sources were integrated, including field observations, satellite-derived, hydromorphological analyses, and GIS-based tools. The model configuration involved the definition of high-resolution meshes in critical zones, assigning calibrated hydrogeological parameters, and applying realistic boundary conditions and scenarios of water consumption extraction and recharge, during a 3 years calibration period. No validation period was performed due to the scarcity of actual observed data. The local analysis of the results indicates a limited soil water storage capacity, a cumulative decline in groundwater reserves, and a strong seasonal variability in streamflow. Therefore, the proposed methodology demonstrates technical robustness and potential replicability in hydrological catchments with similar characteristics, providing a valid alternative for local water resource assessment in the absence of conventional monitoring networks.},

keywords = {Casacay River Basin, Finite element method, Integrated hydrological modelling, MELEF-FSW, Mountainous catchments, Scarce-data catchments, Surface–groundwater interaction},

pubstate = {published},

tppubtype = {article}

}

@article{miguel_first_2025,

title = {A first order FEM-based formulation for the analysis of molecular structures with bonded interactions},

author = {Andrés Fernández-San-Miguel and Luis Ramírez-Palacios and Iván Couceiro-Aguiar and Fermín Navarrina-Martínez},

url = {https://doi.org/10.1007/s00366-024-02085-w},

doi = {10.1007/s00366-024-02085-w},

issn = {1435-5663},

year  = {2025},

date = {2025-08-01},

urldate = {2025-08-01},

journal = {Engineering with Computers},

volume = {41},

number = {4},

pages = {2093–2118},

abstract = {In this paper we present a formulation, denoted as the Molecular Element Method, that allows, given a certain force field, the possibility of performing a first order analysis as is common in structural mechanics. The stiffness matrices have been obtained in an exact way, without the need to resort to any assumptions other than those used to define the force field. Obtaining these matrices analytically allows the exploitation of algorithms and techniques typical of finite elements, being able to perform both static and vibration mode analysis independently of the molecular geometry. In this aspect, the formulation has been validated by studying the frequencies and vibration modes of several molecules, comparing with both theoretical and experimental results. Values of the modulus of elasticity of both graphene sheets and carbon nanotubes have also been obtained in accordance with the values present in the literature. Finally, the formulation shows its potential allowing to obtain the flexural wave dispersion in nanotubes compared to results using Tersoff-Brenner potentials and non-local elasticity models.},

keywords = {Computational molecular mechanics, Finite element method, Molecular element method, Molecular vibrations, Structural analysis},

pubstate = {published},

tppubtype = {article}

}

@article{villalba_topology_2022,

title = {Topology optimization of structures considering minimum weight and stress constraints by using the Overweight Approach},

author = {Diego Villalba and José París-López and Iván Couceiro-Aguiar and Ignasi Colominas-Ezponda and Fermín Navarrina-Martínez},

url = {https://www.sciencedirect.com/science/article/pii/S0141029622011476},

doi = {10.1016/j.engstruct.2022.115071},

issn = {0141-0296},

year  = {2022},

date = {2022-12-01},

urldate = {2026-08-07},

journal = {Engineering Structures},

volume = {273},

pages = {115071},

abstract = {In this paper, a new method for structural topology optimization considering minimum weight and local stress constraints is proposed. For this purpose, the Overweight Approach, an improvement of the so-called Damage Approach, is used. In this method, a virtual relative density is defined as a function of the violation of the local stress constraints. The virtual relative density is increased as stresses exceed the maximum allowable value. The optimization algorithm will provide a design with a minimal variation of the relative density. The structural analysis is performed by means of the Finite Element Method (FEM) and the distribution of material is modelled in terms of a uniform relative density within each element. Moreover, the optimization is addressed by means of the Sequential Linear Programming algorithm (SLP). Finally, the proposed methodology is tested by means of some benchmark problems, and the results show that the Overweight Approach is a feasible alternative for the Damage Approach and the stress constraint aggregation techniques.},

keywords = {Aggregation techniques, Finite element method, overweight approach, Stress constraint, Structural topology optimization},

pubstate = {published},

tppubtype = {article}

}