## 1 Introduction
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Category** & **Focus Area** & **Gaps Identified** & **Ref.** \\ \hline Materials & PLA, ABS, LW-PLA, PA6, & Lack of performance & [6; 9; 10; 11; 12; 13; 14; 15] \\  & PC, PETG * & knowledge of LW materials & [6; 9; 10; 11; 12; 13; 14; 15] \\ \hline Optimizing mechanical performance & Stress–strain behavior, energy & & \\  & absorption, and & Lack of real-world & \\  & failure mechanisms & collision/impact analysis & [9; 11; 14; 15; 16] \\ \hline Design issues (DfAM) & Internal structure, infill patterns, & Lack of standardized DfAM & \\  & and lattice design & frameworks for drones & [2; 14; 17; 18; 19; 20] \\ \hline Weight reduction & Foam cores, porous plastics, and & Mechanical compromise and & \\  & internal structure optimization & fabrication repeatability issues & [6; 11; 12; 13; 14; 15; 16] \\ \hline Hybrid materials and structures & Integral structures and & Few holistic studies & \\  & materials’ compatibility & integrating geometry & [6; 13; 22] \\  & & and materials & \\ \hline \hline \end{tabular}  
* PLA = polylactic acid; ABS = acrylonitrile butadiene styrene; LW = lightweight; PA6 = polyamide 6; PC = polycarbonate; PETG = polyethylene terephthalate glycol.  
\end{table} 
Table 1: Current research trends in AM for drone applications. [PERSON] and [PERSON] [13] highlights the potential of low-density polymers for energy-dissipative applications. [PERSON] et al. [21] identified the outstanding performance of LW-PLA under dynamic loads. However, challenges remain regarding the mechanical strength and dimensional stability of the porous materials [7]. Still, this strategy aligns with the growing goals of sustainability and cost-effectiveness, particularly within the consumer drone industry, where economical and easily repairable components are crucial [2]. A combination of materials further enhances the mechanical performance of AM objects [6; 13; 22], but it also raises concerns about material compatibility and durability [7; 23]. Therefore, this study employs the internal structure hybridization approach, which combines different stiffness and density parts of the same material to achieve a desired mechanical performance, forming metastructures, as discussed in [24]. [PERSON] et al. [25] demonstrated that such internal architectures can significantly improve energy absorption, stiffness-to-weight ratios, and failure resistance in polymer-based components. For instance, topology optimization and lattice-based infill strategies have been employed to create functionally graded structures that outperform uniform infill designs in both static and dynamic scenarios [26; 27; 28]. Despite these promising developments, the practical implementation of metastructures in drone applications remains limited, particularly when considering the constraints of consumer-grade 3D printers and accessible materials. To evaluate the effectiveness of these advanced designs, mechanical testing protocols must go beyond traditional strength metrics and incorporate energy-based assessments. Deformation energy--quantified as the area under the load-displacement curve--has emerged as a reliable indicator of a structure's ability to absorb impact or collision energy [28; 29; 30]. However, standardized methods for such evaluations are still lacking, especially for lightweight AM components. Due to the limited tension resistance of polymeric components, compression tests are typically used to estimate the mechanical performance of AM parts [25; 27; 29; 30]. This gap is particularly relevant in the context of drone fuselage design, where both weight and crashworthiness are critical [2]. The present study addresses this need by experimentally validating the compression deformation energy absorption of FFF components made from PLA and LW-PLA. The latter material, known for its foamed microstructure and reduced density, presents a compelling alternative to conventional PLA, particularly in applications where weight savings are crucial without compromising mechanical resilience [21].