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The widespread use of Additive Manufacturing (AM) has been extensively progressed in the past decade due to the convenience provided by AM in rapid and reliable part production. Fused Deposition Modeling (FDM) has witnessed even faster growth of application as its equipment is environmentally-friendly and easily adaptable. This increased use of FDM to manufacture prototypes and nished parts is accompanied by concerns that 3D printed parts do not perform the same as relatively homogeneous parts produced by molding or machining. As the interface between two faces of bonded material may be modeled by stress elements, in theory by modeling 3D printed layers subjected to tension at varying angles as transformed stress elements, the stress required to break the layer bonds can be determined. To evaluate such a relationship, in this study, the stresses calculated from stress transformation were compared with the behavior of 3D printed specimens subjected to tensile loads. The maximum principal stress was found to be constant relative to the layer angle, regardless of whether the specimen experienced failure at the layer interface or within the layer material, although the specimens with layers 75° relative to the load were notable exceptions to this nding. This failure at much lower stresses for the samples used in the 75° tests may be attributed to a possible environmental factor, such as temperature or humidity change, degrading the samples' structural integrity.

Additive Manufacturing (AM) can be deployed for space exploration purposes, such as fabricating different components of robots’ bodies. The produced AM parts should have desirable thermal and mechanical properties to withstand the extreme environmental conditions, including the severe temperature variations on moon or other planets which cause changes in parts’ strengths and may fail their operation. Therefore, the correlation between operational temperature and mechanical properties of AM fabricated parts should be evaluated. In this study, three different types of polymers, including polylactic acid (PLA), polyethylene terephthalate glycol (PETG), and acrylonitrile butadiene styrene (ABS), were used in Fused Deposition Modeling (FDM) process to fabricate several parts. The mechanical properties of produced parts were then investigated at various temperatures to generate knowledge on the correlation between temperature and type of material. When varying the operational temperature during tensile tests, the material’s glass transition temperature was found influential in determining the type of material failure. Among the materials used, ABS showed the best mechanical properties at all temperatures due to its highest glass transmission temperatures. The results of statistical analysis indicated the temperature as the significant factor on tensile strength while the change in material did not show a significant effect.

Fourier's Law is a tool utilized within heat transfer theory to predict heat flow through a system. Fourier's Law can be applied to establish an analogy for heat energy flow, much like Ohm's Law for electrical voltage flow through a system. The various materials within layers act as resistors, preventing heat flow. With such analog, a heating circuit is established, it is possible to predict heat flow, thermal gradients, or thermal resistivity throughout a system, given the system parameters and sources of heat gain or loss. This study utilized an established ASTM standard to validate the model. An enclosed, guarded heat-flow technique following the ASTM E1225 was created. The heat was provided to the system as the temperature was tracked throughout the system, helping to validate the model and thermal resistivity analog. Overall, the results show that the physical lab setup demonstrated an acceptable accuracy compared to the theoretical model. Suggesting further that the model for thermal resistivity to predict the temperature and thermal resistivity is indeed valid and may be utilized in some select scenarios where the environment, materials, power flow, and insulating devices are well-controlled and well-monitored.