Neshani, Roozbeh
Recent technological advances rendered additive manufacturing (AM) a disruptive technology for the development and manufacturing of next generation complex parts and lightweight structures. AM of polymeric parts is widely applicable to structural parts ranging from load bearing components to impact absorbing structures. Digital Light Synthesis (DLS) is a recently developed technique that enables the reliable, fast and accurate AM of a wide range of polymeric materials. DLS is especially effective in producing lattice parts – three-dimensional open-cell structures composed of repeating unit cells. This thesis investigates elastomeric polyurethane (EPU) lattice parts produced by DLS and characterizes their mechanical properties. Initial characterization of fully dense EPU demonstrated the nonlinear hyperelastic behavior of this material combined with high elongation at fracture and excellent recovery. A combination of Ogden model and Prony series successfully described the visco-hyperelastic behavior. Next, octet-truss, BCC+CP, and cubic type lattice structures were produced and their energy absorption performances under quasi-static compression were characterized. In general, Octet-truss structures provided a more reliable and effective architecture for absorbing energy due to the balancing effects of buckling and stretching. Accurate control of the truss diameter provided means for tuning the peak stress and energy absorbance capacity of the lattice geometries for the requirements of a wide range of applications. Overall, the findings demonstrated the great potential of the EPU and the DLS technique for the design and implementation of energy-absorbing structures. Additionally, through combining the excellent capabilities of DLS 3D printing method and another type of resin, namely the rigid polyurethane RPU 70, with a novel approach of depositing NiCo (Nickel, Cobalt) metallic alloy, the feasibility of hybrid production of metal-polymer lattice structures was demonstrated. Metal plated polymer honeycomb structure exhibited orders of magnitude increase in compression strength.


Mechanical properties comparison of strut-based and TPMS lattice structures produced by EBM
Sokollu, Barış; Konukseven, Erhan İlhan; Gülcan, Orhan; Department of Mechanical Engineering (2022-4-28)
Additive manufacturing is a relatively old but rapidly emerging innovative technology that enables various shapes and designs to be realized which are almost not possible with conventional manufacturing. Lattice structures are one of the most unique applications of utilizing additive manufacturing technology due to weight-to-strength ratios they offer, high impact absorption capabilities, and difficult to produce with conventional approaches. Studies in the literature are mainly focusing on the strut-based ...
Effect of annealing on the mechanical properties of pla parts produced by fused filament fabrication
Aydın, Sencer; Özerinç, Sezer; Department of Micro and Nanotechnology (2021-9-01)
Additive manufacturing has become a disruptive technology for the production of load bearing components in a wide range of applications. Fused filament fabrication (FFF) is among the most effective and economical techniques for the printing of polymeric parts. There are numerous thermoplastic materials suitable for FFF. Among these, Polylactic acid (PLA) is a renewable, sustainable and cost-effective alternative. For better utilization of PLA parts produced by FFF, there is a need to understand the structur...
Simulator of an additive and subtractive type of hybrid manufacturing system
Dilberoğlu, Mecid Uğur; Yaman, Ulaş; Dölen, Melik (2019-06-24)
Additive Manufacturing (AM) facilitates the production of intricate objects despite its weakness in attainable part quality and fabrication speed compared to the conventional manufacturing methods. To alleviate the problems arising as a natural outcome of AM methods, hybrid technologies become viable options by employing concurrent manufacturing procedures, e.g. synergetic additive and subtractive manufacturing (SM) actions. Hybrid workstations have recently opened up new dimensions to 3D-printing industry,...
An intelligent design approach trained by fabrication techniques
Sönmez, Ayça; Sorguç, Arzu; Department of Aerospace Engineering (2021-2-15)
The developments in recent technologies through Industry 4.0 lead to the integration of digital design and manufacturing processes. While manufacturing is becoming an essential input of the design, it is usually considered at the last stages of the design process. This misconception creates a gap between digital design and fabrication, resulting in fabricated outcome being different from initial design in the context of architectural tectonics. This thesis aims to provide a basis to bridge digital design an...
Taymaz, Erol (1991-12-01)
The changes in manufacturing systems and industrial structure brought about by the development of new, computer-based flexible technologies has been a subject of growing debate during the last decade. There is a lack of solid empirical support for almost all hypotheses developed in this debate since data on the relative use of various manufacturing systems are not available for an econometric analysis of the subject. The objective of this paper is to determine the major manufacturing systems and their distr...
Citation Formats
R. Neshani, “IMPACT ABSORBING LATTICE STRUCTURES PRODUCED BY ADDITIVE MANUFACTURING,” M.S. - Master of Science, Middle East Technical University, 2022.