FATIGUE OF MATERIALS AND STRUCTURES
EVENT DATE: July 8, 2020
16.00 – 16.30: Final Exam
Introduction to AM of polymer components
Additive manufacturing (AM) has gradually transformed industries and made work easier for scientists and engineers. Recent advances in AM of polymer components not only enable scientists develop novel materials with unusual mechanical properties, but also allow engineers fabricating load-bearing components instead of prototypes. Moreover, the cost of AM of polymer components is relatively low, leading to vast applications in industries such as marine, aerospace, and medicine.
This 1.5-hrs lectures provides learners with a fundamental understanding of AM of polymer components, especially for the fused deposition modeling (FDM) and Polyjet technology. The lecture includes:
1. Working principles of AM of polymer components. (i) Liquid polymer systems (Stereolithography process and Polyjet process); (ii) Molten material systems (FDM process).
2. Material properties and testing methods of 3D printed polymer components.
3. Mechanics of 3D printed polymer components.
4. Design principles and performance of 3D printed advanced materials.
Part 1 (10.00-10.45)
1. Introduction to AM of polymer components
2. Challenges to understand mechanical properties of 3D printed polymer parts.
Part 2 (11.00-11.45)
1. Case study: Mechanics of polymer fused deposition modeling (FDM) parts.
2. Case study: Bioinspired architectured materials
Mechanical properties of additive manufacturing materials
Most commonly used materials in Additive Manufacturing (AM) are polymers, in the form of thermoplastic materials, liquid resins or powders-depending on the technology of manufacturing, and metals. Their mechanical properties vary depending on additive process parameters, common to all technologies are part orientation on build platform and layer thickness. Depending on the technology, i.e. method of building a part, there are different issues which affect directly on mechanical properties of the final part. Different AM processes are available in order to print a polymeric component. In each of the above presented techniques different process parameters, whose variation have an influence on several aspects such as building time, component resolution, surface regularity, mechanical properties, are involved. A brief overview on the effects of the process parameters (layer thickness , raster orientation , building orientation) on the mechanical properties of polymeric materials is presented. Special attention will be on fracture mechanics properties, including static and dynamic crack growth resistance.
Introduction to AM of metallic materials
Additive manufacturing (AM) techniques offer the potential to economically fabricate customized parts with complex geometries in a rapid design-to-manufacture cycle. Before benefits can be explored in critical load bearing applications, the basic understanding of the mechanical and functional behavior of these materials must be substantially improved at all scales. In particular, a better understanding of fracture and fatigue performance is the key.
Part 1. (14.00-14.45)
An introduction to AM of metallic components will be given to the audience of the course. Different AM processes that are used for AM of metals would be discussed mentioning the advantages and drawbacks of each technique.
Part 2. (15.00-15.45)
Challenges with the structural integrity of AM parts will be discussed. The course will focus on the process-dependent mechanical properties and failure mechanisms of AM parts. Methods to evaluate the effect of surface and internal defects on mechanical properties (including tensile properties, fracture and fatigue) will be deeply discussed.