High Energy Absorption Capability Research Articles

Mechanical, thermal, and microstructure analysis of 3D printed polyolefin elastomer-acrylonitrile butadiene styrene blends for tunable mechanical properties

Fused Deposition Modeling (FDM) has emerged as a cost-effective and user-friendly technique that has garnered significant attention in recent years. However, challenges persist when printing soft materials using FDM technology. This study proposes a solution by blending a soft polyolefin elastomer (POE) with a stiffer material, acrylonitrile butadiene styrene (ABS). A comprehensive experimental investigation utilizing a direct pellet printing method was conducted to 3D print POE-ABS blends in various ratios (10%, 30%, and 50% ABS content). The study encompassed material preparation, 3D printing, SEM (Scanning Electron Microscopy) analysis, Dynamic Mechanical Thermal Analysis (DMTA), uniaxial tensile testing, and compression testing to assess the mechanical properties and energy absorption capabilities of the 3D printed blends. The results of the DMTA showed that the blends with a higher amount of ABS have a larger area under the Tan δ curve, indicating their ability to absorb more energy. The SEM images revealed that as the proportion of ABS increases, the gaps between layers and beads become smaller. The mechanical properties of the pure printed POE, such as its elongation at break and tensile strength, were 2138% and 2.83 MPa, respectively. However, as the ABS content increased, the samples exhibited more rigid behavior, with a final transition to 50/50 ratio resulting in 9.4 MPa tensile strength and 160% elongation at break. The energy absorption test demonstrated that the sample with 30% ABS content has the highest energy absorption capability among all the tested samples. This research underscores the potential of blending soft and stiff materials to tailor properties for additive manufacturing applications, emphasizing the significance of material composition in achieving desired mechanical performance, printability, and functionality in printed objects.

Computer Simulation of Deformation characteristics of Hybrid Orthotropic Composite Sandwich Beams Under Bending and Axial Loading

This study focuses on the deformation characteristics of hybrid orthotropic composite sandwich beams under axial and bending loading. The homogeneous cores of the hybrid orthotropic sandwich beams affect different parameters on structures. We followed by analytically determining effective material properties to study response of the hybrid sandwich beam under axial and bending loading. Ensuing, we programmed all steps and procedures of solution algorithm into commercially available MATLABTM 2020 code to simulate practical scenarios. Subsequently, we collected and processed data in tabular and graphical forms to facilitate analyses. We compared simulation generated results to the data results available in the literature and found to be within the acceptable range of (±6%) deviations. We observed that the hybrid structure beams had undergone less deformation that confirmed that the hybrid structure beams have comprehensive mechanical advantages as well as has high strength and specific energy absorption capabilities. Based on comparison of the results, the hybrid beams are more damage resistant and tolerant than beams made of the other type of materials. Since hybrid sandwich beams are relatively light, economical, and perform better under axial and bending deformations. Therefore, this study could also be extended to investigate performance of the orthotropic sandwich beam structures under multiple loading directions as well as proposes that the usage of the hybrid sandwich beam components will be useful in global structures.

A Comparative Blast Mitigation Performance Evaluation of Metallic Sandwich Panels with Honeycomb, Corrugated, Auxetic, and Foam Cores

Due to the high energy absorption capability and excellent bending strength of the sandwich panels, they are mostly preferred as protective structures against explosive blast attacks. The evaluation of their blast-mitigation characteristics through experiments is highly dangerous, costly, time-consuming, and polluting for the environment. Therefore, in this presented work, a series of numerical analyses were performed to evaluate the blast mitigation of the outstanding sandwich panels with honeycomb, corrugated, auxetic, and foam cores. The masses of sandwich panels were kept constant, and their areal densities were maintained constant throughout the study to effectively compare their performance under identical air blast loading conditions. To apply the air blast loads to the designed sandwiches, 1–3[Formula: see text]kg of spherical-shaped trinitrotoluene charges were used for a 100[Formula: see text]mm stand-off distance. The sandwiches are made of high-strength AL-6XN steel and crushable aluminum foam. The rate-dependent Johnson–Cook constitutive model of plasticity and the crushable foam model with volumetric hardening were used for the evaluation of sandwich panels’ plastic deformations. The findings of the work depicted that the honeycomb core is more efficient than the other core structures of the same masses because the sandwich panels with honeycomb core provide smaller back skin deflections, globalized core crushing, and higher core energy absorption than the other sandwich panels for extreme conditions of air blast loading.

Investigating the impact of cross-sectional area on the crushing characteristics of axially-loaded hemispherical composite shells

The research focus has shifted towards lightweight structures with high energy absorption capabilities due to advancements in automotive safety technology. This study specifically investigates the impact of cross-sectional area on the energy absorption characteristics of hemispherical composite shells. The experimental phase involves characterizing a glass fiber epoxy composite, followed by the manufacture of hemispherical composite shell specimens with varying cross-sectional areas. These specimens undergo quasi-static axial compressive loading, and the energy absorption parameters are analyzed. The results indicate a significant influence of the composite cross-sectional area on the crushing behavior of hemispherical shells, with a observed decrease in specific energy absorption as the cross-sectional area increases. Additionally, a 3D Finite Element (FE) model is created using ABAQUS FE code to numerically simulate the crushing process. The model’s predictions are compared and validated against experimentally measured values, demonstrating a satisfactory correlation.

Analysis of deformation and failure mechanism of sandwich beams with lattice core under three-point bending load

This paper investigates sandwich beams with lattice cores under quasi-static bending, owing to their lightweight nature and high energy absorption capabilities. Utilizing analytical methods governing beams, an investigation into their failure mechanisms is conducted, incorporating experimental and numerical results. The influence of thickness and core cell sizes on energy absorption are examined. The analysis delves into the elastic and plastic behavior of the beam, which is refined and validated against the numerical and experimental tests and failure modes of sandwich panel beams. The alignment of analytical predictions with both experimental and numerical results in terms of mean forces, and energy absorptions was remarkably precise. Moreover, evidence has been presented that the face yield and core shear failure regions are significantly impacted by variances in core dimensions. Additionally, the thickness of core cell strands was found to be pivotal in influencing the compressive and shear strengths of sandwich panel beams.

4D printing of biobased shape memory sandwich structures

Lightweight sandwich structures already have many applications in the aerospace, automotive, and construction sectors due to their high strength-to-weight ratio, enhanced stiffness and rigidity, and high energy and shock absorption capabilities. Additive manufacturing (AM) can provide great freedom and flexibility in the fabrication of complex sandwich structures that cannot be made by other conventional processes. The application of smart materials, like shape memory polymers (SMP), can offer the capability of dynamic transformation so that the deformed structure can recover its original shape using external stimuli, such as temperature. This study exploits the potential of this technology in the design and manufacturing of biobased smart sandwich structures with energy absorption capability and shape recovery performance. For that, a combination of recycled poly(lactic acid) (PLA)/poly(butylene succinate) (PBS) biopolymers are developed as printing filaments with shape memory properties. The designed sandwich samples are fabricated by Fused Filament Fabrication (FFF) technology. The mechanical and functional properties of the printed samples are also evaluated. The results show PLA/PBS filaments have good printability and the fabricated parts have acceptable dimensional accuracy, mechanical strength, and functional performance.

Dynamic mechanical properties of selective laser-melted AlSi10Mg lattice structures: experimental and numerical analysis with emphasis on Johnson-Cook model parameters

Additively manufactured lattice structures are extensively utilized because of their unique characteristics, including lightweight design, high energy absorption capabilities, and exceptional specific strength. This study focuses on accurately simulating the dynamic mechanical behavior of AlSi10Mg lattice structures produced using selective laser melting (SLM). A series of experimental studies has been conducted to establish the parameters of the J–C hardening and damage model for additively manufactured AlSi10Mg alloys. The lattice structures, featuring face-centered cubic (FCC) and diamond topologies with a 25% designed relative density, underwent scanning electron microscopy (SEM) for geometrical precision assessment. Dynamic compressive behavior was investigated via split Hopkinson pressure bar (SHPB) tests. Numerical simulations in Ls-Dyna, utilizing the identified J–C parameters, were employed to replicate SHPB tests. Findings indicate that the specific strength and the specific energy absorption values of FCC lattice samples have higher than those of diamond samples at strain rates of 750 and 1100 s−1. While the overall strains and deformation modes were well predicted by numerical analyzes, a deeper insight into local stress concentrations under dynamic loads was achieved. Consequently, the obtained J–C model parameters offer valuable insight into characterizing the dynamic behavior of AlSi10Mg lattice structures produced by SLM.

A Parameter Reduction-Based Decision-Making Method with Interval-Valued Neutrosophic Soft Sets for the Selection of Bionic Thin-Wall Structures.

Bio-inspired thin-wall structures with excellent mechanical properties, high-energy absorption capabilities, and a desirable lightweight level have been extensively applied to the passive safety protection of transportation and aerospace. Collaboration matching and the selection of optional structures with different bionic principles considering the multiple attribute evaluation index and engineering preference information have become an urgent problem. This paper proposes a parameter reduction-based indifference threshold-based attribute ratio analysis method under an interval-valued neutrosophic soft set (IVNS-SOFT) to obtain the weight vector of an evaluation indicator system for the selection of bionic thin-wall structures, which can avoid the problem of an inadequate subjective evaluation and reduce redundant parameters. An IVNS-SOFT-based multi-attributive border approximation area comparison (MABAC) method is proposed to obtain an optimal alternative, which can quantify uncertainty explicitly and handle the uncertain and inconsistent information prevalent in the expert system. Subsequently, an application of five bio-inspired thin-wall structures is applied to demonstrate that this proposed method is valid and practical. Comparative analysis, sensitivity analysis, and discussion are conducted in this research. The results show that this study provides an effective tool for the selection of bionic thin-wall structures.

Novel hierarchical bioinspired cellular structures with enhanced energy absorption under uniaxial compression

Biological thin-walled cellular structures, such as hierarchical structures of bone, exhibit unique internal structures that offer lightweight characteristics and high energy absorption capabilities. The compact bone shell can protect against local damage during high-impact events, while the porous cancellous bone is essential in absorbing energy. This research proposed five novel bioinspired cellular structures inspired by the well-arranged structure of femur bones. These structures comprise four distinct cell types: hexagonal honeycomb, re-entrant, hybrid, and hierarchical hybrid cells. A comprehensive numerical model, validated with experimental data, was employed to assess the performance of these structures under uniaxial compression. Some key characteristics were revealed, including peak elastic load, plateau load, energy absorption capacity, Poisson's ratio, and the effect of hierarchical cell size. The results demonstrated that the novel bioinspired structures surpassed the energy absorption performance of traditional designs, such as hexagonal design, re-entrant, and trabecular-bone-inspired structures. This enhanced performance was due to the progressive buckling and collapse mechanisms, showing promising implications for future engineering applications, particularly where energy absorption is of paramount importance.

Experimental study on crashworthiness and lightweight of cutting-type energy-absorbing structure of magnesium alloy for trains

Cutting-type structures, because of their desirable mechanical characteristics, high energy absorption capabilities and excellent guiding performance, has been extensively employed in high-speed trains. Its lightweight design and optimization problems are also the hotspot of research directions in present. This paper designed a new-type structure, i.e., magnesium alloy cutting-type energy-absorbing structure (CTEAS), taking into account its excellent properties of high lightweight level and ease of processing demonstrated through AZ31B magnesium alloy tensile mechanical test. Subsequently, experimental study on magnesium alloy CTEAS are conducted by trolley impact tests of train considering different cutting depths and different velocity levels. The results confirmed the outstanding advantages, including high lightweight level and higher absorbed energy properties, and lower demands of knives, compared with the structures with Q345 steel. In addition, the mechanism of knives cracking and melting phenomenon found in the experiment is explored by finite element analytical method. The results show that the temperature difference between the high-temperature surface and the interior during the cutting Q345 steel process is maybe the key influencing factor leading to knives damage. This research provides an effective tool for the design and analysis of excellent performance energy absorbing structure of high-speed trains.

Characteristic analysis of bionic-induced structures with negative stiffness inspired by the growth and deformation differences of branches

Negative stiffness (NS) structures with curved beams easily experience beam fracture in small-scale designs, limiting their repeatability and energy absorption. The induced energy absorption structure (IEAS), which achieves negative stiffness by altering load transfer paths, is designed inspired by the growth and deformation of tree branches. By means of the variation method of geometric parameters, a unique asymmetric buckling deformation mode is realized in IEAS. The NS and energy absorption characteristics in IEAS are analyzed based on load distribution and major principal strain theory. Compression results demonstrate that the asymmetric buckling mode exhibits higher energy absorption and specific energy absorption compared to symmetric linear buckling, effectively improving structural toughness. Through gradient analysis of geometric parameters and comprehensive analysis of induced structure layouts, the asymmetric buckling mode is successfully implemented in multi-layer IEAS. The multi-layer IESA exhibits excellent ability of energy absorption and toughness, making it have potential applications in areas that require small-sized designs with high energy absorption capabilities.

Non-dimensional analysis on blast wave propagation in foam concrete: Minimum thickness to avoid stress enhancement

Foam concrete is a prospective material in defense engineering to protect structures due to its high energy absorption capability resulted from the long plateau stage. However, stress enhancement rather than stress mitigation may happen when foam concrete is used as sacrificial claddings placed in the path of an incoming blast load. To investigate this interesting phenomenon, a one-dimensional difference model for blast wave propagation in foam concrete is firstly proposed and numerically solved by improving the second-order Godunov method. The difference model and numerical algorithm are validated against experimental results including both the stress mitigation and the stress enhancement. The difference model is then used to numerically analyze the blast wave propagation and deformation of material in which the effects of blast loads, stress–strain relation and length of foam concrete are considered. In particular, the concept of minimum thickness of foam concrete to avoid stress enhancement is proposed. Finally, non-dimensional analysis on the minimum thickness is conducted and an empirical formula is proposed by curve-fitting the numerical data, which can provide a reference for the application of foam concrete in defense engineering.

Enhancing impact resistance of hybrid structures designed with triply periodic minimal surfaces

The triply periodic minimal surface (TPMS) represents an engineered structure characterized by its mathematically controllable geometric topology and exceptional mechanical properties. This structure offers notable features such as high porosity, specific strength, stiffness, and energy absorption capabilities. Drawing inspiration from the structure of the human tibia, we developed hybrid structures that combine side-by-side, circular, and elliptical connections, utilizing two TPMS types: IWP and Gyroid. Our comprehensive study delves into the impact resistance of these hybrid structures when subjected to high strain rate loading. To conduct our research, we employed selective laser melting (SLM) to fabricate TPMS samples based on AlSi10Mg, and we validated our finite element model through quasi-static compression experiments. By conducting numerical simulations, we analyzed the mechanical properties and deformation patterns of these structures under strain rates of 250s−1 and 1250s−1, comparing them to commonly used porous structures such as Honeycomb, FCC, and BCC. Through quantitative analysis utilizing various evaluation indexes, we effectively demonstrated how the design of hybrid structures enhances energy absorption. Furthermore, we discussed the impact of strain rate on the mechanical properties of these structures, and the Gibson-Ashby model accurately predicted the mechanical properties of partial structures. These findings hold significant implications for guiding the design of lightweight porous structures, improving energy absorption, and enhancing impact resistance.

Topological design factor optimization in the development of periodic‐type honeycomb lattice structure on the carbon fiber reinforced polyethylene terephthalate glycol composite

AbstractIn most of the automobile and aerospace materials, cellular structures are extensively used due to their lightweight and high energy absorption capabilities. Naturally available animal bones and plant stems are light in weight due to their natural cellular structures. This may inspire various researchers for integrating the various lattice structures such as beam, planar, triply periodic minimal surfaces, and voronoi structures on the various structural materials. The development of lattice structures using 3D printing technology has opened up major attention towards fabricating lightweight components without any complications. In this study, the detailed crashworthiness responses such as compressive strength was optimized in terms of varying the topology‐related factors on the carbon fiber reinforced polyethylene terephthalate glycol (CF/PETG) composite. The experimentation was conducted concerning variable topology factors such as shell thickness, unit cell type, wall thickness (WT), unit cell orientation (UCO), skewing angle, and unit cell size. The model was examined and optimized by means of the Taguchi optimization technique. The crashworthiness response was analyzed using the compression test and moreover, this experimental response is used for the optimization processes. From the observation, the topology factors which contributed more for the higher compressive strength will be UCO of 65.47% and WT of 15.20%. Results of the regression study show that the R square value with concern to the compressive strength will be 92.74%. The optimized design parametric condition for CF/PETG composite established a higher compressive strength of 41.179 MPa, From the overall results, it is clear that the variation in the topology factors has developed a huge and favorable impact on the mechanical characteristics of the lattice‐structured CF/PETG polymer composite.Highlights Hexagonal Lattice structure incorporation on the carbon fiber reinforced PETG composite. Design optimization on the compressive properties. Taguchi optimization is performed on design‐based lattice structures. Unit cell orientation has higher percentage contribution on compressive strength.

Investigation of the performance of the structure and energy absorption in sandwich panels of PLA/TPU manufactured by the FFF technique

Sandwich structures are often used in the automotive, marine, aerospace, and many other industrial sectors due to their desirable performance properties, energy absorption, and ability to reduce the weight of parts. Multilayer composite materials also provide various design possibilities, making it simple for producers to fabricate intricate parts. One of the most popular additive manufacturing technologies for producing complicated objects is fused filament fabrication (FFF). In this study, sandwich samples with a dual-core of polylactic acid (PLA) and thermoplastic polyurethane (TPU) were fabricated by FFF technique in three different configurations, including cylindrical, honeycomb, and tetrahedral truss cells. Their properties were determined and investigated through tensile, three-point bending, Izod impact, microhardness tests, and scanning electron microscopy. The results were compared with samples manufactured with monolithic PLA. The results demonstrated that sandwich structures with TPU cores had a high-energy absorption capability. In comparison to monolithic PLA samples, these materials’ ultimate elongation and impact strength were dramatically enhanced. However, TPU cores had lower flexural and tensile strengths than samples with PLA cores. The structure's shape significantly influences both its strength and energy absorption characteristics. Firstly, tetrahedral truss core samples revealed that the samples’ elongation climbed considerably and exceeded three times with the deposition of TPU as the inner core compared to monolithic PLA. Last but not least, in flexural testing, sandwich panels with honeycomb manufactured of PLA/TPU showed the ultimate strain unit to be about 0.08, twice as much as samples made of monolithic PLA. The lowest impact resistance and the amount of energy absorbed before collapsing were demonstrated by monolithic PLA with a honeycomb inner core. Regarding energy absorption, dual sandwich panels with PLA/TPU, including cylindrical and tetrahedral truss cores, showed the best results.

Low-velocity impact responses of composite structures incorporating shear thickening fluid tubes under various temperatures

This study proposes a novel approach to enhance the impact resistance of carbon fiber reinforced polymer (CFRP) composite plates by incorporating an additional layer consisting of shear thickening fluid (STF)-filled tubes, resulting in a hybrid composite referred to as STF hybrid composite (STFC). The proposed STFC plates were subjected to low-velocity impact tests under varying impact energies and temperatures to consider realistic operating conditions for practical applications. It was found that the insertion of STF-filled tubes into the composite structure led to lower contact forces during impact and reduced residual velocities of the impact striker at temperatures ranging from 25 to 100 °C, thereby improving the impact resistance of the structure. Specifically, the STFC plates exhibited enhanced energy absorption capabilities, with energy absorption increasing by up to 38.10% at 25 °C under the impact energy of 2 J, potentially mitigating secondary damages within the composite structure. These results suggest that the proposed STFC hybrid composite is a promising solution for applications requiring high energy absorption capabilities.

Design and development of fused deposition modeling (FDM) 3D-Printed Orthotic Insole by using gyroid structure

The orthotic insole is a device that is placed between the bottom of the foot and the sole of the shoe. It bears the body weight and directly influences the biomechanics of the foot and the body. These insoles are used to minimize the stress by reducing plantar pressure between support points hence minimizing the pressure. Such customized insoles have usually been produced by either handmade or subtractive methods. Fused deposition modeling (FDM) has opened innovative ways for the manufacture of orthotic insoles. In recent studies, no specific computer-aided design (CAD) tools are available to design and manufacture the insole, which is the primary focus. This work aims to evaluate established CAD techniques for designing and fabricating insoles utilizing different manufacturing processes. The evaluation is based on a prior analysis of the possibilities for functionalizing insole materials and structures. In this study, multiple software tools are utilized for designing custom insoles, considering pressure points and a three-dimensional (3D) foot scan of an individual. The research highlights how the implementation of software enables a significant level of customization by integrating pressure mapping data into the insole design process. A novel CAD approach for designing an orthotic insole has been provided in this work. Soft poly-lactic acid (PLA) is used to fabricate an insole using FDM technology. The gyroid and solid samples were evaluated following ASTM standards. When compared to the solid construction, the gyroid structure has a high specific energy absorption capability, which is used to create the orthotic insole. The results of the experiment suggest that the selection of the structure for customized insole design is significantly affected by the infill density parameter.

Crashworthiness performance and optimization of multi-cell aluminum tubes under axial loading

Multi-cell thin-walled tubes have been proven to be an efficient energy absorber with well-controlled deformation stability and high energy absorption capability. Nevertheless, research on multi-cell tube energy absorbing structures mainly focused on the fields of small size and light energy absorption. The high cost and low crushing force significantly restrict their applications in practical engineering, especially for large-size equipment, such as train crashworthiness protection. To address this limitation, this paper presents a novel multi-cell tube energy absorption structure made of aluminum alloy for ultra-large energy absorption field with features of low cost (extrusion and welding processing), large size (450 mm × 280 mm × 280 mm), light weight (∼9 kg), high energy absorption capacity (>200 kJ) and large crushing force (>600 kN). The proposed multi-cell structure is composed of four extruded square tubes connected by welding. To demonstrate the feasibility of the proposed structure, the sample is fabricated and dynamic impact test is performed. Experimental results show that the tube buckles progressively and forms plastic folding lobes with a total absorbed energy of 235.6 kJ and a mean impact force of 668.7 kN, which are about 500% higher than that of previous reported multi-cell structures. Finite element simulation and theoretical model are developed and well-capture the experimental deformation process. The relative errors of theoretical and simulation mean crushing force, Effective crushing distance coefficient, energy absorption and maximum crushing distance in comparison experimental results are all within 10%. Based on the validated finite element model, the effect of geometrical parameters of the proposed structure on its crashworthiness performance is analyzed. Finally, we construct the response surface models of the multi-cell tube and optimize the absorbed energy under a mass constraint by Multi-objective Non-dominated Sorting Genetic Algorithm (NSGA-II). The Pareto front of structure energy absorption and mass is obtained. In particular, under the constraint of total mass M = 9 kg, the optimal solution with maxing energy absorption is t = 4.999 mm, α = 0.342 mm, and w = 281.5 mm. The proposed structure can be applied to ultra-large energy absorption fields such as train crashworthiness protection.

Effects of Dopants and Processing Parameters on the Properties of ZnO-V2O5-Based Varistors Prepared by Powder Metallurgy: A Review.

This article reviews the progress in developing ZnO-V2O5-based metal oxide varistors (MOVs) using powder metallurgy (PM) techniques. The aim is to create new, advanced ceramic materials for MOVs with comparable or superior functional properties to ZnO-Bi2O3 varistors using fewer dopants. The survey emphasizes the importance of a homogeneous microstructure and desirable varistor properties, such as high nonlinearity (α), low leakage current density (JL), high energy absorption capability, reduced power loss, and stability for reliable MOVs. This study investigates the effect of V2O5 and MO additives on the microstructure, electrical and dielectric properties, and aging behavior of ZnO-based varistors. The findings show that MOVs with 0.25-2 mol.% V2O5 and MO additives sintered in air over 800 °C contain a primary phase of ZnO with a hexagonal wurtzite structure and several secondary phases that impact the MOV performance. The MO additives, such as Bi2O3, In2O3, Sb2O3, transition element oxides, and rare earth oxides, act as ZnO grain growth inhibitors and enhance the density, microstructure homogeneity, and nonlinearity. Refinement of the microstructure of MOVs and consolidation under appropriate PM conditions improve their electrical properties (JL ≤ 0.2 mA/cm2, α of 22-153) and stability. The review recommends further developing and investigating large-sized MOVs from the ZnO-V2O5 systems using these techniques.

3D PRINTING OF A CRANIAL IMPLANT WITH ENERGY-ABSORBING POLYMER VIA ARBURG PLASTIC FREEFORMING TECHNOLOGY

Additive Manufacturing (AM) brings ground-breaking opportunities to provide customized healthcare solutions with reasonable time and cost. These benefits become more evident if reducing the distance between the printing process and surgery. In this direction, the Arburg Plastic Freeforming (APF) process offers unprecedented opportunities. The absence of hazardous feedstock materials such as powders allows for the utilization of this technology within hospitals. Also, unlike traditional AM processes, APF makes it possible to process medically approved standard granulates without compromising their certification. In this study, APF has been used to manufacture, for the first time, a patient-specific cranial implant (PSCI) using a biocompatible polymer with a high energy absorption capability, namely, PolyCarbonate Urethane (PCU). The main technological issue was represented by the lack of a solvable support material compatible with PCU. This obstacle was overcome by a custom support structure made of the same material, which can be removed at the end of the process with limited damage to the PSCI. The orientation of the part within the building chamber was chosen to optimize the accuracy of critical features and the surface quality of the regions facing the brain. The 3D-printed cranial implant showed high toughness during mechanical impact tests.