Dissemination DeliverablesD4.2

Deliverable 4.2

Abstract

This deliverable presents the Mechanical-Structural (MS) modelling framework developed to characterize the mechanical and structural behaviour of strut-based lattice elements fabricated using the Dot-by-Dot Wire Arc Additive Manufacturing (DbD WAAM) process. Two complementary modelling strategies are introduced: a phenomenological MS model and a Finite Element Analysis (FEA)-based MS model. The phenomenological MS model describes the material behaviour through a set of effective mechanical parameters calibrated at the batch level from tensile test data, enabling the definition of effective stress-strain curves and the prediction of key mechanical properties for structural assessment. The FEA-based MS model investigates the structural response numerically in order to capture the effects of geometrical irregularities characteristic of DbD WAAM elements and to calibrate a suitable material constitutive model. By explicitly representing the as-built geometric configuration, including diameter variability and nodal features, and by incorporating material nonlinearities, the model enables a consistent interpretation of the experimental results and of the structural behaviour.

The proposed methodology is applied to elements manufactured using DbD WAAM with ER70S-6 steel wire. First, single rods are analyzed to evaluate the influence of nominal diameter and idle time (time between the deposition of two subsequent droplets). The study is then extended to intersecting rods to assess the influence of the nodal region on the mechanical response. Finally, lattice-based unit cells are investigated to characterize the structural response under axial loading, comparing two lattice-based configurations.

By progressively moving from the single element to the intersecting ones and ultimately to the unit cell level, this deliverable presents a modelling approach applicable to DbD WAAM elements. The phenomenological model is validated through its application to single rods, intersecting rods, and unit cells.

Table of contents

ABSTRACT

1.     INTRODUCTION

2.     MODELING APPROACH

2.1        Modeling of single rods

2.1.1     Phenomenological MS model

2.1.2     Finite Element Analysis (FEA) MS model

2.2        Modeling of intersecting rods

2.2.1     Phenomenological MS model

2.2.2     Finite Element Analysis (FEA) MS Model

2.3        Modeling of unit cells

2.3.1     Phenomenological MS model

2.3.2     Finite Element Analysis (FEA) MS Model

3.     RESULTS

3.1        Single rods

3.1.1     Geometrical properties

3.1.2     Mechanical properties

3.2        Intersecting rods

3.2.1     Geometrical properties

3.2.2     Mechanical properties

3.3        Unit cells

3.3.1     Geometrical properties

3.3.2     Mechanical properties