Abstract

Abstract

Abstract

The methodology proposed in this research work explores the use of the strain injection concept in a combination of classical strain localization methods and
embedded strong discontinuities, to remove the flaws (stress locking and mesh
bias dependence) of the former, and simultaneously abdicate of the global tracking
algorithms usually required by the later. The basic idea is to use, after the
bifurcation instant, i.e. after the time that elements are amenable to develop discontinuities,
a mixed continuous displacements - discontinuous constant strains
condensable finite element formulation (Q1/e0 ) for quadrilaterals in 2D. This
formulation provides improved behavior results, specially, in avoiding mesh bias
dependence. In a first, very short, stage after the bifurcation the concept of strong
discontinuity is then left aside, and the apparent displacement jump is captured
across the finite element length (smeared) like in classical strain localization settings.
Immediately after, in a second stage, the kinematics of those finite elements
that have developed deep enough strain localization is enriched with the injection
of a weak/strong discontinuity mode that minimizes the stress locking defects.
The necessary data to inject the discontinuity (the discontinuity direction and its
position inside the finite element) is obtained by a post process of the strain-like
internal variable field obtained in the first stage, this giving rise to a local (elemental
based) tracking algorithm (the crack propagation problem) that can be
locally and straightforwardly implemented in a finite element code in a non invasive
manner. The obtained approach enjoys the benefits of embedded strong discontinuity
methods (stress locking free, mesh bias independence and low computational
cost), at a complexity similar to the classical, and simpler, though less
accurate, strain localization methods. Moreover, the methodology is applicable to
any constitutive model (damage, elasto-plasticity, etc.) without apparent limitations.
Representative numerical simulations validate the proposed approach.

Abstract

Abstract

In course of this work, we examine the process of plastic profile extrusion, where a polymer melt is shaped inside the so-called extrusion die and fixed in its shape by solidification in the downstream calibration unit. More precise, we focus on the development of a data-driven reduced order model (ROM) for the purpose of predicting temperature distributions within the extruded profiles inside the calibration unit. Therein, the ROM functions as a first step to our overall goal of prediction based process control in order to avoid undesired warpage and damages of the final product.

Abstract

This paper aims at investigating the in-plane shear response of FRCM-strengthened masonry walls. To this end, available results of experimental tests are collected, accounting for the masonry substrate made with bricks and mortar joints and several FRCM materials applied with different strengthening configurations. The contribution of the composite material to the masonry wall shear capacity is evaluated. The influence of some geometrical and mechanical parameters on the shear strength of the retrofitted walls is assessed. Available analytical design formulations are implemented to the database and commented.

Abstract