In the family of smart materials termed as “self-healing materials”, there is a prominent number of them sharing many similarities in the way that healing is affecting their post-damaged mechanical response. In this work, a generic and multi-material phenomenological-based healing formulation is proposed to investigate and characterize the self-healing effect in the mechanical response of materials exhibiting strong nonlinearities like rate-dependent plasticity, visco-damage initiation and evolution. The proposed healing formulation uses objective experimental measures such as resting time, loading rate and damage level. This formulation is integrated in a combined computational–experimental procedure, the so-called Generic Healing-Oriented Multi-Material Modeling Framework (GHOM ³) that facilitates (i) the understanding of a strongly nonlinear response, (ii) a robust material characterization and (iii) the predictive simulation via the finite element analysis. As study case, the intrinsic self-healable mechanical response of a highly nonlinear asphalt-based composite matrix is characterized at room temperature using the proposed framework. As additional novelty in the framework, an ultra-fast optimization-based material parameter identification process is developed using a master–slave parallelization paradigm that leads to save up to 90% of data processing time. The framework is put into practice to virtually predict the mechanical response influenced by the healing process of the validated material in a dog-bone specimen under Load–Unload–Resting–Reload at multiple loading rates and damage levels. The implemented approach gives direct access to the entire damage and healing histories, which are experimentally inaccessible, as well as providing an alternative definition of the healing indices commonly used in experimentation.

@en

This research presents an experimental and numerical approach to study the mechanics of asphalt matrix, a crucial component in asphalt concrete. Understanding its response is essential to guide the new designs in advanced asphalt concrete. The dynamic mechanical analysis (DMA) is used to execute a variety of quasi-static and dynamic tests under tension and compression. Uniaxial tests reveal a remarkable rate-dependent compression-tension (C-T) asymmetry of the asphalt matrix in terms of stiffness and strength. The creep rupture envelop is derived by performing creep tests at different stress levels. Amplitude and frequency sweep tests and fatigue-recovery test are performed to explore the fatigue response. A user-material visco-elasto-plastic-damageable (VEPD) model is developed to simulate the asphalt via finite element method (FEM).@en

Smart asphaltic, cementitious and composite materials are drawing great attention in civil engineering and material science. The aim of smart material is to extend the lifespan and improve the mechanical performance of structures. These materials have in common complex behaviors like visco-elasticity, visco-plasticity, progressive damage and fracture. A good understanding of these phenomena is required to improve and extend the capabilities of smart materials. To do that, constitutive laws are needed to describe the non-linear mechanisms where the crucial parameters must be identified. The development of a mathematical and simulation framework is the key to predict and investigate new developments in smart materials. In this paper, a three-dimensional visco-elasto-plastic-damageable constitutive model is proposed, consisting of three basic modules: visco-elasticity, plasticity and damage, which can provide rate-dependency on stiffness and strength, and describe progressive degradation and failure. An efficient gradient-less optimization algorithm with user-defined constraints is developed to identify the material parameters. This methodology can solve a highly non-linear function with multiple variables, where the physical meaning and the effect of each variable are understood. The model and the optimization approach are implemented using the finite element code ABAQUS via user-defined material subroutines (V)UMAT. The proposed constitutive model is thoroughly validated and verified with experimental results. This numerical framework will allow for adding additional features like the effect of temperature on the mechanical properties and the self-healing capability in further research.@en

The results of a low-velocity impact programme on both carbon/epoxy and glass/polyamide-6 composite laminates are compared to the results of quasi-static indentation. Cross-ply and quasi-isotropic stacking sequences are impacted and quasi-static indentation tests are performed up to the same maximum displacement. The response of the laminates to both test methods is compared in terms of force-displacement behaviour, dissipated energy and resulting damage. Significant differences between low-velocity impact and quasi-static indentation are found for both material systems. It is therefore concluded that the test methods cannot be interchanged for material characterisation.

@en