Reference : A quasicontinuum approach towards mechanical simulations of periodic lattice structures
Dissertations and theses : Doctoral thesis
Engineering, computing & technology : Mechanical engineering
Computational Sciences
A quasicontinuum approach towards mechanical simulations of periodic lattice structures
Chen, Li mailto [University of Luxembourg > Faculty of Science, Technology and Medicine (FSTM) > Department of Engineering (DoE) >]
University of Luxembourg, ​Esch-sur-Alzette, ​​Luxembourg
Docteur en Sciences de l'Ingénieur
Bordas, Stéphane mailto
Massart, Thierry mailto
Zilian, Andreas mailto
Francois, Francois mailto
Ortiz, Michael mailto
Dendievel, Rémy mailto
[en] quasicontinuum method ; periodic lattice structures ; mechanical simulation
[en] Thanks to the advancement of additive manufacturing, periodic metallic lattice structures are gaining more and more attention. A major attraction of them is that their design can be tailored to specific applications by changing the basic repetitive pattern of the lattice, called the unit cell. This may involve the selection of optimal strut diameters and orientations, as well as the connectivity and strut lengths.
Numerical simulation plays a vital role in understanding the mechanical behavior of metallic lattices and it enables the optimization of design parameters. However, conventional numerical modeling strategies in which each strut is represented by one or more beam finite elements yield prohibitively time­consuming simulations for metallic lattices in engineering­scale applications. The reasons are that millions of struts are involved, as well as that geometrical and material nonlinearities at the strut level need to be incorporated.
The aim of this thesis is the development of multi­scale quasicontinuum (QC) frameworks to substantially reduce the simulation time of nonlinear mechanical models of metallic lattices. For this purpose, this thesis generalizes the QC method by a multi­field interpolation enabling amongst others the representation of varying diameters in the struts’ axial directions (as a consequence of the manufacturing process). The efficiency is further increased by a new adaptive scheme that automatically adjusts the model reduction whilst controlling the (elastic or elastoplastic) model’s accuracy.
The capabilities of the proposed methodology are demonstrated using numerical examples, such as indentation tests and scratch tests, in which the lattice is modeled using geometrically nonlinear elastic and elastoplastic beam finite elements. They show that the multi­scale framework combines a high accuracy with substantial model reduction that are out of reach of direct numerical simulations.
University of Luxembourg: Computational Sciences
Fonds de la Recherche Scientifique Begium
Multiscale modelling of lightweight metallic materials accounting for variability of geometrical and material properties
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