Sound Absorption Performance Research Articles

Deep subwavelength sound absorption by a buckling plate resonator

Conventional sound-absorbing materials face great difficulties in achieving deep subwavelength broadband sound absorption due to the causal constraint on the minimum thickness. A buckling plate resonator is proposed to alleviate the causal constraint on the thickness of sound-absorbing materials. The resonator consists of a back cavity sealed by an elastic circular thin plate. When the plate is subjected to a uniform in-plane compressive force up to its critical load, it buckles and behaves as a negative stiffness spring. The positive stiffness of the back cavity is counteracted by the negative stiffness of the buckling plate, resulting in resonance absorption at the deep subwavelength scale. The sound absorption performance of the buckling plate resonator under different in-plane loads was measured in an impedance tube. Quasi-perfect sound absorption was observed in a buckling plate resonator with a thickness less than 1% of the wavelength corresponding to the resonance frequency. This work provides a solution for the design of ultra-thin broadband sound absorbers.

Acoustics response of granular porous material: experiment and modeling

Granular porous materials such as activated carbon have drawn increasing attention due to their good sound absorption performance at low frequency. However, some unique acoustical behaviors have been observed during sound absorption measurements of granular porous materials in impedance tubes: e.g., circumferential edge-constraint effects, level-dependent absorption behavior, and time-dependent absorption behavior. In order to explain these observations, a 1-dimensional poro-elastic model was first applied to describe the sound propagation in granules stacked in a cylindrical sample holder, as in a standing wave tube. Then this model was extended to a 2-dimensional finite difference (2DFD) model with depth-dependent stiffness of the granule stack considered by combining Janssen's model and Hertzian contact theory. The 2DFD model was validated with the measurements of the granular porous materials, and it was found that the 2DFD model is a powerful tool to analyze the acoustic response of granular porous material, thus providing a means of characterizing the granular materials. In the present work, the above-mentioned experimental observations and the 2DFD model are introduced, and the experiment results are analyzed with the 2DFD model. Finally some future work on granular porous materials is introduced.

Experimental and numerical investigation of soundproof panels using acoustic metamaterials with porous material

Acoustic panels are often used in buildings and automobiles. For sound absorption in panels, high sound absorption performance in a wide frequency band can be achieved by combining porous sound absorption, resonant sound absorption, vibration sound absorption, and acoustic metamaterials. This study proposes a highly sound-absorbing panel structure by using an acoustic metamaterial that generates local resonance to a double-walled structure filled with porous material. In the soundproof panel of this study, local resonance is generated by a structure in which slits are made in a porous material. By the through-holes of the slits, local resonance occurs, but sound leakage and thermal viscosity in the slits may affect the sound absorption effect. Therefore, in this study, sound transmission loss for various cases with differing factors such as the use of porous materials, the presence of spiral slits, and layer configurations are compared through the acoustic analysis and experiments. The results substantiate that the proposed panel structure has high soundproofing performance in wide frequency ranges, each driven by distinct physical principles.

The effect of temperature difference on the acoustic performance of Helmholtz resonator

Passive control devices such as liners and Helmholtz resonators (HRs) are commonly employed in practical applications to mitigate thermoacoustic instabilities. To safeguard the HR from being corroded by the invasion of hot flow from the combustor, a cooling flow with significantly lower temperature than that in the combustor is injected from the rear of the HR cavity. However, this results in a dynamic mixing of cold bias and hot grazing flows in the combustor, which may generate an entropy wave downstream of the HR, thereby affecting its sound absorption performance. Unfortunately, these effects are often neglected when modelling such systems. In this context, an acoustic model is derived for a one-dimensional combustor duct with distinct temperature compared to that of the attached HR. The model offers physical insights into the underlying mechanisms of the impact of HR on the acoustic fields. It considers not only the mean temperature difference between the cooling bias flow and the main flow in the combustor, but also the mean temperature difference between the up- and downstream sides of the combustor across the HR. The effect of both temperature differences on the HR’s performance will be discussed.

Study on the effect of thickness on sound absorption performance of foam aluminum

Abstract This paper investigates the effects of different thicknesses on the sound absorption performance of foam aluminum with different pore sizes through a combination of experiments and theoretical research. The results show that the average sound absorption coefficient of small-pore foam aluminum increases with increasing material thickness. As the thickness increases, there is a trend of the peak sound absorption performance shifting towards lower frequencies. In the mid-frequency range, although the sound absorption coefficient increases with the thickness of foam aluminum, the growth rate decreases. The average sound absorption coefficient of large-pore foam aluminum significantly increases with the material thickness and is reflected across various frequency ranges. With the increase in thickness, the sound absorption efficiency also improves, but the rate of improvement gradually slows down after reaching a certain thickness. Samples with the same thickness exhibit different performances in sound absorption coefficient, especially in frequencies above 2000Hz, where these differences are more pronounced. In the high-frequency range, the sound absorption coefficient of 100mm-thick large-pore foam aluminum material approaches 1, approximately 0.95.

Design of metamaterial for broadband sound absorption through double resonances

Abstract Broadband acoustic absorber via a structure with sub-wavelength thickness is of great and continuing interest in research and engineering communities. To broaden the absorption band of acoustic absorbers, common methods often involve using septum to create a double-layer structure or replacing cavity walls with flexible materials. However, such approaches require strict restrictions of thickness and structure design for the absorbers. This work presents a metamaterial design method that uses an external frame to construct double resonant metamaterials, effectively improving broadband sound absorption performance. Specifically, this method can be decoupled from the design of original cavity-type absorber structure and external frame. The absorption performance is significantly improved by adding an external frame to wrap around a cavity-type acoustic absorber structure with air. Furthermore, utilizing the coaction of cascade coupling and external frame, the average absorption ratio of the metamaterial in high frequency domain (above 2000 Hz) can be improved by 6 times. Since this structural design broadens the absorption band without changing structural parameters of the original absorber, it has potentials to be applied in various engineering fields.

Acoustic resonant metasurfaces with roughened necks for effective low-frequency sound absorption

The rise in environmental low-frequency noise from human-induced activities due to global urbanization has had a noticeable effect on the health and life quality of urban residents. Despite the implementation of conventional noise mitigation methods, they are only effective within a narrowband frequency range and their efficiency deteriorates when dealing with low-frequency noise. To address the existing problem in noise attenuation, an acoustic resonant metasurface that incorporates sliced Helmholtz-resonator-like substructures with embedded roughened necks is designed to achieve low-frequency sound absorption within a subwavelength scale. The theoretical model of this metasurface is first established, and then parametric studies are conducted to analyze the impact of various geometrical parameters on the sound absorption effect of the proposed metasurface. Subsequently, the sound absorption performance of the proposed design is investigated through numerical and experimental studies using two samples at both single and broadband frequencies. Excellent absorption performances by the samples at a low-frequency spectrum have been achieved. To understand the underlying absorptive mechanism of the proposed metasurface models, theoretical investigations are conducted for acoustic impedance and complex frequency, while numerical studies are also carried out to examine the distribution of acoustic pressure, acoustic velocity and thermoviscous power dissipation density. The research findings presented in this study may facilitate the development of an effective acoustic barrier for low-frequency noise (≤ 200 Hz).

Sound absorption performance of honeycomb metamaterials Inspired by Mortise-and-Tenon structures

To address the limitations of traditional honeycomb sandwich structures in attenuating mid to low-frequency sounds, particularly in configurations with minimal thickness and weight, this study introduces an innovative honeycomb acoustic metamaterial incorporating the traditional Chinese mortise-and-tenon joint. We systematically investigate the acoustic absorption characteristics of the modified honeycomb structure through theoretical analysis, empirical validation, and numerical simulations. Our experimental setup maintained consistent geometric parameters across all trials and demonstrated that the resonance frequency of the modified honeycomb structure decreased by 10 % relative to its conventional counterpart. We conducted detailed analyses on the influence of micropore positioning, tenon geometric dimensions, and micropore diameters on the acoustic performance. Notably, elongating the tenon from 2 mm to 6 mm resulted in a 15 % reduction in resonance frequency, whereas increasing the micropore-to-tenon distance from 0 mm to 4 mm led to a 30 % increase. The integration of the mortise-and-tenon joint significantly enhances the mid to low-frequency sound absorption performance of the honeycomb panels. This improvement is achieved while preserving the structural benefits of low panel thickness and shallow cavity depth, alongside simplified processing of micropores. Our findings elucidate a promising approach to augmenting the acoustic properties of lightweight structural materials, thereby extending their application potential in noise control engineering. This study not only contributes a novel perspective to the design and optimization of acoustic metamaterials but also highlights the potential for integrating traditional architectural techniques with modern material science to enhance noise control solutions.

Broadband and high-efficiency acoustic energy harvesting with loudspeaker enhanced by sonic black hole

It is well-known that acoustic energy sources can be seen as a promising alternative energy resource by using acoustic energy harvester (AEH) which can transform sound energy into usable electrical power. However, the current AEHs have been restricted by their narrow bandwidths and low energy conversion efficiencies. In this study, a broadband and high efficient AEH is presented. The proposed AEH comprises an open-end sonic black hole (SBH) structure and an electrodynamic loudspeaker. The sound pressure is amplified through the open-end SBH structure, then the loudspeaker is used as electricity generator to convert acoustic energy into electric energy. The open-end SBH is a cylindrical tube with an array of regularly-spaced rigid-walled thin rings. The inner radii of the SBH rings are quadratically decreasing and the SBH effect can be obtained. The model for energy harvesting and sound absorption performance of the proposed AEH is then presented. Finally, the open-end SBH is fabricated by 3D printing apparatus. A prototype of the AEH is designed and tested by using an impedance tube. The energy conversion efficiency and absorption coefficient from calculation and experiment show a reasonable agreement. The proposed AEH can convert 11 % of total incident sound energy from 50 Hz to 800 Hz. The maximum energy conversion efficiency can achieve 65 % at 425 Hz under optimal resistance load. Furthermore, the broadband sound absorption can also be achieved by using the proposed AEH.

Simulation Analysis of Influence Laws of Sound Barrier Acoustic Performance When Using Ceramic as Sound-absorbing Materials

Abstract The excellent sound absorption performance of Sound Barrier which using Ceramic as Sound-absorbing Materials can be attributed to their corrosion resistance, lightweight nature, small particle size, and internal microporous structure. As a result, the application of new ceramic-based sound absorption materials in sound barriers is becoming increasingly widespread. To address the challenging issue of predicting the sound absorption and isolation performance of ceramic sound barriers and understanding the influencing factors on acoustic parameters, a simulation analysis method was employed for analyzing and studying various factors affecting the acoustic performance of these barriers. The calculation results demonstrate that increasing the thickness of both the sound absorption material and air layer behind exhibits similar effects on enhancing the sound absorption and isolation performance of ceramic acoustic barriers. Specifically, increasing either parameter leads to improved sound absorption performance by significantly increasing the sound absorption coefficient at 125Hz and 250Hz while decreasing it at 500Hz. However, in high-frequency bands above 1000Hz, structural parameters have minimal overall influence. Moreover, when keeping the thickness of ceramic sound absorption plates constant, every additional 20mm increase in air layer thickness behind results in a weighted increase in sound isolation by approximately 1dB; notable improvements are observed when this air layer thickness is below 1600Hz. When the thickness of the air layer behind is kept constant, an increase in the thickness of the sound absorption material by 10mm results in a 1dB increment in weighted sound isolation. However, when maintaining a total thickness of the sound barrier at 140mm, increasing the material’s thickness leads to a reduction in air layer thickness. Consequently, there is a slight enhancement in the sound absorption coefficient at frequencies of 125Hz and 250Hz while a minor decrease occurs at frequencies of 500Hz and 1000Hz. The impact on other frequency bands and overall sound absorption performance remains inconspicuous. Moreover, variations in weighted sound insulation quantity have minimal influence on sound insulation characteristics.

Sound absorption properties and mechanism of multi‐layer micro‐perforated nanofiber membrane

AbstractAiming at achieving low‐frequency and broadband sound absorption under the premise of light and thin layers, in this paper, polyvinyl butyral (PVB) nanofiber membranes were micro‐perforated and then combined sequentially to prepare multi‐layer micro‐perforated nanofiber membrane (MPNM) for acoustic noise reduction. It was demonstrated that the multi‐layer MPNM exhibited a high absorption (constantly over 50%) in the frequency of 480–2500 Hz. In addition, the established theoretical model of the sound absorbing coefficient can accurately predict the sound absorption performance of the structure with different layers, which can provide a theoretical foundation for the design of the structure of the nanofibrous membrane acoustic absorber. Based on the proposed acoustic model, the relationships between the absorption properties and the parameters were investigated, and it was found that the effective acoustic absorption frequency range and acoustic absorption coefficient curve of the multi‐layer MPNM were closely related to the size and arrangement of hole diameter, perforation rate, fiber membrane thickness, and cavity depth. Optimization of the structural parameters utilizing algorithms can achieve superior sound absorption performance, with an average absorption coefficient of 0.81 in the frequency of 100–2500 Hz. This study provides a theoretical and experimental basis for the development of low‐frequency sound‐absorbing materials and is of great significance for optimizing the acoustic performance of nanofiber membranes and expanding their applications in various acoustic engineering applications.

Time-domain model for spherical wave reflection in a flat surface with absorber character – Application to the SOPRA measurement method

This paper presents a developed time-domain model for the reflection of spherical waves in an absorber-like surface. The model is made to enable evaluation of measurement methods for assessing the sound absorptive properties of traffic noise barriers in direct sound field, it is thus called the Direct Field Absorption (DFA) model. In this study, the DFA model is applied to the in-situ SOPRA method for quick sound reflection index measurements on road noise barriers. The DFA model results in an impulse response (IR), based on a theoretically derived impedance of a certain absorber. The DFA IR is entered to the SOPRA formula to calculate the reflection index, RIQ, of the absorber, which is subsequently compared to the measured RIQ of a wall fitted with the absorber in question. If the results are similar, it is reasonable to assume that the SOPRA measurement results are valid. But if there are any significant differences between the DFA and SOPRA sound reflection indices, possible reasons for them should be examined.The first results are encouraging, showing that the DFA model can be a valuable tool to evaluate the results of reflection measurements. Furthermore, the DFA model could be useful for estimating the sound absorptive performance at lower frequencies of a noise barrier limited to its spatial extent in width and height, i.e., when it is physically impossible to measure. Further studies are necessary though, since the conclusions of this paper are based on only one kind of absorber.

Low-frequency broadband acoustic metamaterial absorber based on nested resonator and synergistic coupled weak resonances

Utilizing absorbers with sub-wavelength thickness for low-frequency broadband noise control is a challenging problem, and rapid on-demand design of structures based on target noise frequency has received continuous attention. In this work, nested cavities are introduced into the typical neck-embedded Helmholtz resonator (NEHR) to obtain the nested neck-embedded Helmholtz resonator (NNEHR), which exhibits better cavity partitioning volume fraction and covers wider sound absorption band. Both theoretical analysis and simulations demonstrate that NNEHR possesses superior acoustic properties: generating an additional absorption peak, lowering the position of the first absorption peak by 11 %, and increasing the absorption coefficient by 4.7 %. Instantaneous velocity fields and thermal-viscous energy dissipation density illustrate that the efficient sound absorption of NNEHR originates from resonant dissipation in the neck and surrounding areas. Furthermore, by combining the theoretical model with genetic algorithms, three sets of NNEHR metasurfaces are optimized. The optimized structures achieve average absorption coefficients of 0.831, 0.913, and 0.885 in the range of 250–550 Hz, 400–1000 Hz, and 500–2000 Hz, with a thickness of only 50 mm, reflecting sub-wavelength, low-frequency broadband sound absorption characteristics. The excellent absorption stems from synergistic coupled weak resonances and higher-order absorption peaks of constituent units, and the overdamping characteristic ensures the realization of the optimal structure with minimal thickness. The contribution of weak resonant units to the total sound absorption performance can be measured by the surface admittance normalized by the total incident area, and the essence of the coupling effect is the strong interaction between units with adjacent absorbing frequencies. The proposed structure exhibits good sound absorption performance and great adjustability, while the genetic algorithm optimization based on the theoretical model demonstrates high efficiency and robustness, providing a methodology for the design and on-demand optimization of low-frequency broadband structures.

Ultralow-frequency absorption mechanism of a hybrid membrane resonator with acoustic soft boundary condition

Hybrid membrane resonator (HMR) as a typical metamaterial-based absorber with acoustic hard boundary condition (AHBC) has demonstrated excellent noise absorption abilities, but the challenge lies in achieving broadband absorption of ultralow-frequency noise in the tens of Hz to 150 Hz regime. In this research, we investigate systematically the absorption characteristics, absorption mechanisms, and casual optimality of an HMR with three openings in lower surface of the cavity, which functioned as an acoustic soft boundary condition (ASBC). Compared to the well-studied HMR with AHBC, a new absorption mechanism, which states that most energy dissipates occur in the opening region rather than in the membrane, has been found first. As a result, the HMR with ASBC can demonstrate outstanding ultralow-frequency sound absorption performance with a very small thickness, and the full width at half maximum of the HMR can be enlarged over 7 times. Furthermore, the causal inequalities of the absorbers with ideal AHBC and ASBC are derived based on the Cauchy integral and causality principle. The causal optimality of the proposed absorber is also achieved. This research provides valuable guidelines for the design of excellent ultralow-frequency sound absorbers which could contribute to solving the major issue of noise reduction.

Optimal ultra-broadband sound-absorption performance design for coiled up space structures with nonlinear robustness

In this paper, based on a high- sound-pressure microperforated plate model, a nonlinear sound-absorption model for multi-unit couplings based on coiled-up space structures is proposed. The sound absorption performance and relative impedance of two-unit coupled structures (TUCSs) were studied. The results show that the TUCS sound-absorption performance, which is good at low sound pressures, decreases significantly as the incident sound pressure increases owing to impedance mismatch. Furthermore, the influence of parameters such as aperture size, plate thickness, perforation rate, and equivalent length on the unit’s structural sound-absorption performance was studied. By employing the particle swarm optimization algorithm, we optimized the parameters of an eight-unit coupled structure (EUCS) using the proposed model. The optimization results reveal the nonlinear robust sound-absorption characteristics of the structure, which means the EUCS can maintain a stable and good sound-absorption performance when the incident sound pressure level and frequency are within 125–155 dB and 400–3000 Hz, respectively. Experimental assessments of the EUCS sound-absorption performance within the 300–1900 Hz range confirmed the accuracy of the proposed model and the efficacy of the optimized sound-absorption capabilities of the structure. Consequently, the proposed model and sound-absorption structure demonstrated potential applications in the acoustic lining design of aircraft engines.

Hybrid honeycomb structure for enhanced broadband underwater sound absorption

A hybrid honeycomb structure (HHS) with energy dissipation enhancement effect is proposed for broadband underwater sound absorption. The HHS is constructed using hexagonal honeycomb structure with embedded metal rings of different size and filled with viscoelastic rubber. A theoretical model is developed to study the sound absorption performance of the HHS by applying the transfer matrix method, and a finite element model is also developed to validate the theoretical model. The innovative introduction of metal rings concentrates rubber vibrations near the ring edges and within conical regions formed by the ring holes and the longitudinal waves in the rubber are converted into transverse waves, these vibrations increase the friction within the rubber at the rubber-metal interface, which significantly increases the friction loss at the rubber-metal interface, thus increasing the dissipation of acoustic energy. Compared to the homogeneous rubber layer and the rubber-filled honeycomb wall structure, the average increase in energy dissipation is 238 % and 181 %, respectively. The results of the energy dissipation distribution of the HHS confirm that the energy dissipation is mainly concentrated in the conical region, indicating a significant energy dissipation enhancement effect. By designing the structural parameters of the rings, the shape of the conical region can be changed, thereby achieving the regulation of energy dissipation enhancement effect. In addition, the key structural and material parameters of the hybrid honeycomb structure are optimized using the particle swarm optimization algorithm, resulting in a broadband sound absorption performance with an average sound absorption coefficient of 0.96 in the range of 1–10 kHz. This work proposes a new design concept and provides valuable guidance for the development of underwater sound absorption structures.

Potential of wood fiber/polylactic acid composite microperforated panel for sound absorption application in indoor environment

This study introduces a novel approach using wood fiber/PLA composite microperforated panel (WFCMPP) for indoor sound absorption purposes. WFCMPP, comprising rubber tree chip-derived fibers and a polylactic acid (PLA) matrix, with the dimensions of the rubber tree chip-derived fibers ranging from 0.5 to 1 mm, demonstrated promising sound absorption coefficients comparable to other natural fiber composite microperforated panels. The maximum sound absorption coefficient was recorded at 0.989 with a resonance frequency of 1416 Hz when the wood fiber composition was 30 %. The study also investigates the impact of wood fiber composition on sound absorption, revealing a linear relationship between fiber content and both porosity and sound absorption. The peak sound absorption coefficient of WFCMPP remained almost identical at different air gap thicknesses, showcasing the versatility and effectiveness of the samples. Additionally, the performance remained robust even with variations in air gap size. Scanning electron microscope analysis confirms the irregular porous structure and complexity contributing to enhanced sound absorption. WFCMPP presents a sustainable and effective alternative for acoustic applications, combining sound absorption performance with environmental considerations.

Waste ramie fiber/EVA composites with wideband sound-absorbing performance with mixing and foaming process

Increasing noise pollution and ramie fibers waste resource problems need to be solved urgently. In order to resolve the problems, the porous sound-absorbing composites with high sound-absorbing performance were prepared by using waste ramie fibers as reinforcement materials, vinyl acetate copolymer (EVA) as matrix materials, azodicarbonamide(AC) as foaming agent, ZnO as auxiliary foaming agent, and dicumyl peroxide (DCP) as cross-linking agent, which were mixed in a two-stick mixer according to a certain ratio and then hot-pressing process. The process conditions were optimized using single factor analysis. Under the optimal process conditions, the sound-absorbing composites had a maximum sound absorption coefficient (SAC) of 0.72, an average SAC of 0.37, and a noise reduction coefficient (NRC) of 0.41. The sound absorption performance grade reached level III, and the sound absorption performance was excellent in the frequency range of 600 ∼ 6300 Hz. The introduction of foaming agents made the composites with more pores, and the average SAC of foamed composites increased by 346 %(compared with the unfoamed composites). Then, the sound-absorbing mechanism was analyzed. This study presents a novel approach to the recycling and reusing of the waste ramie fibers. It also provides a theoretical and experimental basis for the development of sound-absorbing composites with wider sound absorption band, larger (sound absorption coefficient) SAC and wider application, which is of great significance for sound absorption in the building fields.

Effect of density and thickness on sound absorption performance of flexible porous material-aerogel

Abstract Aerogel is recognized for its effective sound absorption capabilities, which contribute to its widespread application in reducing vibrations and noise. Consequently, it is often employed as a sound-absorbing material in various settings, including industrial machinery and the construction sector. In this research, we conducted an experimental analysis and employed standing wave tube testing to evaluate the sound absorption coefficient of aerogel. The investigation specifically focused on the impact of density and thickness on the sound absorption performance of aerogel. Through this process, we established the optimal structural parameters for aerogel to maximize its sound absorption efficiency. The study’s findings indicate that the sound absorption coefficient of aerogel sees a swift rise as its density increases from 0.4g/cm3 to 0.7g/cm3, with a subsequent deceleration in the rate of increase beyond the 0.7g/cm3 threshold. Concerning thickness, the sound absorption coefficient also experiences a rapid increase as the aerogel’s thickness is below 20mm, after which the rate of increase diminishes for thicknesses above 20mm. By considering both sound absorption performance and economic optimization, the research identifies a density of 0.7g/cm3 and a thickness of 20mm as the optimal parameters for achieving the best sound absorption with aerogel.

Fibro-porous materials: 3D-printed hybrid porous materials for multifunctional applications

This work demonstrates the additive manufacturing of fibro-porous materials—hybrid materials with a fiber mesh integrated within the open cells of a base porous scaffold. The presented method allows seamless incorporation of fibers, with precise control of the fiber diameter and mesh density, into the scaffold without requiring any additional postprocessing steps. Here, using a gyroid pore architecture as the base scaffold, this study fabricates the fibro-porous materials using an extrusion-based additive technique and investigates their resultant sound absorption, pressure drop, mechanical stiffness, and energy absorption properties. Two-microphone normal incidence impedance tube measurements reveal significant improvements in the sound absorption performance compared to that of denser, fiberless porous material counterparts while maintaining a 33 % lighter weight. Additional tests, including pressure drop and static airflow resistivity measurements, indicate that fiber integration reduces the effective pore size and increases flow resistance, boosting sound absorption at lower frequencies. The mechanical properties are also markedly improved, with stiffness and yield stress increasing by 27 % and 37.85 %, respectively. The fibro-porous samples provide 30 % more energy absorption per unit volume due to their increased resistance to deformation. This research demonstrates that additively manufactured fibro-porous materials provide substantial multifunctional performance gains without significant weight increase. The adaptable manufacturing process is compatible with various extrudable materials and opens a new route to designing complex, customized engineering structures with application-specific functionalities.