Fused deposition modelling (FDM) has been one of the most widely used rapid prototyping (RP) technologies, which has been attracted increasing attentions in the world. However, existing literatures about energetic material flow inside the 3D printer nozzle are sparse. For plunger 3D printer, we summarized the experimental and related literatures, finding that viscosity, temperature, outlet velocity, pressure, and nozzle diameter are the main factors to affect the flow state in the nozzle. Based on the actual printer nozzle structure, in this paper, a finite element model was established by SOLIDWORKS software firstly, meanwhile, the flow channel model of the nozzle was extracted and simplified. Secondly, the factors influencing the printing results were researched and analysed. In the end, numerical simulation on velocity field and temperature field was carried out by FLUENT software. Moreover, the printing test of HMX/TNT was also carried out by using EAM-D-1 3D printer. The printed sample shows that 3D printing is more satisfactory than conventional melt-casting ways to prepare high viscocity and unconventional structure explosives
Fused deposition modelling (FDM) has been one of the most widely used rapid prototyping (RP) technologies, which has been attracted increasing attentions in the world. However, existing literatures about energetic material ow inside the 3D printer nozzle are sparse. For plunger 3D printer, we summarized the experimental and related literatures, nding that viscosity, temperature, outlet velocity, pressure, and nozzle diameter are the main factors to affect the ow state in the nozzle. Based on the actual printer nozzle structure, in this paper, a nite element model was established by SOLIDWORKS software rstly, meanwhile, the ow channel model of the nozzle was extracted and simpli ed. Secondly, the factors in uencing the printing results were researched and analysed. In the end, numerical simulation on velocity eld and temperature eld was carried out by FLUENT software. Moreover, the printing test of HMX/TNT was also carried out by using EAM-D-1 3D printer. The printed sample shows that 3D printing is more satisfactory than conventional melt-casting ways to prepare high viscocity and unconventional structure explosives
Room-temperature self-healing adhesives require more
flexible polymer
chains and weaker interactions, which are not conducive to good mechanical
properties. Therefore, an energetic self-healing adhesive containing
asymmetric alicyclic structures and multiple urea groups was designed.
The asymmetric alicyclic structures could form loosely packed hard
domains, and the irregular arrangement of multiple continuous urea
groups could strengthen the physical cross-linking and improve the
strengths of the hard domains. As a result, adhesives with improved
mechanical properties (tensile strength and toughness) were obtained,
and their dynamic adaptabilities and responsiveness required for self-healing
at room temperature were maintained. The glycidyl azide polymer-based
polyurethane (GPU) adhesive (GPU-3.0) exhibited excellent comprehensive
performance in terms of toughness, healing efficiency, adhesion strength,
and energy level. The maximum tensile strength and toughness of the
energetic composite material (ECM, GPU/Al) prepared using GPU-3.0
and Al were 2.52 MPa and 2.45 MJ m–3, respectively.
After 72 h at room temperature, the scratches on the GPU/Al surface
were no longer observed and the mechanical properties were completely
recovered. Therefore, the designed adhesive, which displays a high-efficiency
room-temperature self-healing capacity and good mechanical properties,
is applicable in self-healing ECM systems. This strategy should provide
insights for use in improving the stabilities and safety of ECMs.
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