Reference no: EM132462219

KB7008 - Advanced Stress and Structural Analysis - Northumbria University

Nonlinear analysis of PLA

Learning Outcomes

LO1: Analyse the theoretical and practical aspects of material nonlinearity and its influence on material behaviour.

LO2: Defend your engineering solution, design rationale or analysis.

Assessment Task

Polylactic acid (PLA) is a material commonly used in 3D printing. One feature of the 3D printing process is the ability to control the infill density and pattern of a part (figure 1).

PLA has a relatively low yield stress and demonstrates plasticity for much of the stress-strain curve. The internal structure of the printed part effectively alters the material properties giving a range of stress- strain plots for different infill density and pattern.

Figure 1. Various infill patterns and densities of 3D printed parts

A new area of research aims to investigate the effect of varying the infill pattern and density locally within a printed structure (example in figure 2). The hypothesis is that areas subject to high stresses would have a higher local density and areas subject to low stresses a lower local density. This has the potential to offer weight, cost and time savings.

You will be provided with tensile test data for two different configurations of PLA infill. These two datasets will be for a low and high density infill of a particular pattern (e.g. 30 and 80% infill, tri- hexagonal pattern).

Figure 2. Example of localised infill density

Your task has two aspects:

• analyse the non-linear behaviour of these two configurations separately using finite element analysis and compare numerical predictions with the provided experimental data for a tensile test coupon (BS EN ISO 527).

• design and analyse the internal structure of an open-hole tensile test coupon (ASTM D5766) to maximise the strength-to-weight ratio by varying the local infill (you may only use the densities and pattern provided)

Technical Poster (A1 size)

This task will be assessed through the submission of a technical poster. A template is provided for you to use. This poster should be aimed at an audience who are engineering graduates but non-experts in 3D printing.

Attachment:- Advanced Stress and Structural Analysis.rar