Damage models for the micromorphic continuum

• Autor(a) principal: Pâmela Daniela Nogueira Reges
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Institucional da UFMG
• Texto Completo: http://hdl.handle.net/1843/44064; https://orcid.org/ 0000-0003-2203-6138
• topic: Micromorphic continuum theory; Continuum damage mechanics; Elasticdegrading constitutive models; Heterogeneous media; Quasi-brittle materials; INSANE system; Engenharia de estruturas; Mecânica do dano continuo

Numerous materials, although they appear macroscopically homogeneous, usually presents a heterogeneous microstructure that directly influences the structural behavior. The phenomenological approach pursued in the classical continuum mechanics does not individually accounts for this influence, specially in cases where the structure or the specimen under analysis is small compared to its microstructure. Within the framework of continuum mechanics, so-called generalized continuum theories are particularly suited to deal with the above issues incorporating the microstructural behavior on the formulation. The micromorphic theory is included in this general class of generalized continua and, more specifically, in the group that incorporates additional degrees of freedom to the material particles. Another aspect of generalized continua is its ability to address the issue of localization in quasi-brittle material modeled as elastic-degrading media as a result of its nonlocal character. In order to allow the representation of quasi-brittle media with the micromorphic continuum theory, this work formulates scalar-isotropic damage models for a micromorphic continuum in the constitutive models framework of the INSANE system, initially conceived for classic media and later expanded for the micropolar continuum. In order to represent heterogeneous media, the take-and-place algorithm for the microstructure generation associated to a homogenization strategy is proposed. The computational implementations are based on a tensorial format of a unified constitutive models formulation applying a compact tensorial representation for the micromorphic continuum, and a homogenization technique to obtain the micromorphic constitutive relations. Simulations were conducted in order to attest the implemented constitutive models as well as for studying the influence on the material and structural behavior of the heterogeneity introduction. The obtained results verify the proposed hypotheses and the conducted implementations, providing the basis for non-linear analysis of homogeneous and inhomogeneous micromorphic media and allowing possible further research on the topic.