Bamboo Structure Research Articles

Effects of V addition on microstructure and pseudoelastic response in Fe–Mn–Al–Ni alloys

Avoiding quench cracks and controlling the formation process of NiAl precipitates are essential to regulate the microstructure and pseudoelastic properties of Fe–Mn–Al–Ni shape memory alloys (SMAs). In this study, we investigated the effect of 1.5 at.%V addition on the quench sensitivity of Fe–Mn–Al–Ni SMAs and the precipitation behavior of NiAl precipitates in air-cooled Fe–Mn–Al–Ni–V SMAs. It is found that the V addition significantly inhibits the precipitation process of non-transforming γ-phase. Polycrystalline sample of bamboo structure was prepared by abnormal grain growth and tested by incremental strain cycling tensile test at room temperature. The polycrystalline Fe–Mn–Al–Ni–V SMAs obtain fully reversible thermoelastic martensitic transformation without quenching, which also prevents the formation of quenching cracks. Single crystal samples were further prepared by directional recrystallization. High number-density and relatively large-size coherent β-NiAl precipitates were obtained to strengthen the matrix in the single crystal without aging, resulting in large stress hysteresis and irrecoverable strain. After aging Fe–Mn–Al–Ni–V single crystal for 3 h at 200 °C, both the stress hysteresis and irrecoverable strain decreased, thereby achieving good pseudoelasticity in Fe–Mn–Al–Ni–V SMAs.

Prediction and experimental validation approach to improve performance of novel hybrid bio-inspired 3D printed lattice structures using artificial neural networks

Novel Cellular lattice structures with lightweight designs are gaining more interest in the automobile and aerospace sectors. Additive manufacturing technologies have focused on designing and manufacturing cellular structures in recent years, increasing the versatility of these structures because of the significant benefits like high strength-to-weight ratio. In this research, a novel hybrid type of cellular lattice structure is designed, bio-inspired from the circular patterns seen in the bamboo tree structure and the overlapping patterns found on the dermal layers of fish-like species. The unit lattice cell with varied overlapping areas with a unit cell wall thickness of 0.4 to 0.6 mm. Fusion 360 software models the lattice structures with a constant volume of 40 × 40 × 40 mm. Utilizing the stereolithography (SLA) process and a vat polymerization type three-dimensional printing equipment is used to fabricate the 3D printed specimens. A quasi-static compression test was carried out on all 3D printed specimens, and the energy absorption capacity of each structure was calculated. Machine learning technique like the Artificial neural network (ANN) with Levenberg–Marquardt Algorithm (ANN-LM) was applied to the present research to predict the energy absorption of the lattice structure with parameters such as overlapping area, wall thickness, and size of the unit cell. The k-fold cross-validation technique was applied in the training phase to get the best training results. Overall, the results obtained using the ANN tool are validated and can be a favourable tool for lattice energy prediction with available data.

High-performance, low-cost, chemical-free, and reusable bamboo drinking straw: An all-natural substitute for plastic straws

The environmental problems caused by disposable plastic straws have been widely concerned around the world. Developing degradable straws made of eco-friendly materials is an effective solution. Nevertheless, the popular alternatives, for example, polylactic acid (PLA) straw and paper straw are far from satisfactory because of the restrictive degradation conditions, low mechanical performance, poor water stability, and the use of chemicals. As an abundant and sustainable natural resource, bamboo has been widely used in many fields. This study developed a mechanized and industrialized process with high efficiency and automation, including the preparation of bamboo sticks, hydrothermal treatment, and drilling holes in sticks to produce bamboo drinking straws. The production avoided chemicals and bamboo drinking straws retained the natural structure and degradability of bamboo. The performance evaluation shows that bamboo straws had superior mechanical properties (highest compressive strength of 71.65 MPa, bending strength of 123.90 MPa, and ring stiffness of 0.61 MPa), good wetting stability (high appearance quality and wet strength), reusability, high recovery value, and low manufacturing cost (around 17.5–35% of commercial degradable drinking straw costs). Bamboo drinking straws enrich the types of degradable straws and contribute to reducing plastic pollution.

Mechanical performance of engineered bamboo subjected to accelerated aging with single and multiple durability exposures

Durability is a critical concern for engineered bamboo structures. The results of an experimental study of the mechanical performance of engineered glue laminated bamboo, bamboo scrimber and Douglas fir specimens subjected to accelerated aging under single and multiple durability exposures are presented. In total, nineteen specimen groups comprising almost 1200 samples were prepared and tested under conditions of ultraviolet radiation, alternating wet-dry cycles, alternating hot–cold cycles, and a combination of all three exposures. Specimen density, dimensional stability and discoloration were reported. Mechanical properties assessed were longitudinal compressive strength and modulus, and bending strength and modulus. Durability exposure related damage of the laminated bamboo and Douglas fir was greater than that of the bamboo scrimber under single and multiple durability exposures; the bamboo scrimber exhibited a better durability resistance. Analysis of variation of the results of the single and multiple exposures indicated that exposure to ultraviolet radiation had the greatest contribution to the durability performance of the three materials.

A Bamboo-Inspired Exoskeleton (BiEXO) Based on Carbon Fiber for Shoulder and Elbow Joints

This paper presents a novel cable-driven exoskeleton (BiEXO) for the upper limb including shoulder and elbow joints. BiEXO is made of carbon fiber that is inspired by the Bamboo structure. The key components of BiEXO are carbon fiber tubes that mimic bamboo tubes. A combined driver is developed for BiEXO with two cable-driven mechanisms (CDMs) and a power transmission belt (PTB). The CDMs are used for shoulder and elbow flexion/extension movement utilizing cables to mimic the skeletal muscles function, while the PTB system drives a shoulder link to mimic the scapula joint for shoulder abduction/adduction movement. Simulation studies and evaluation experiments were performed to demonstrate the efficacy of the overall system. To determine the strength-to-weight of the bamboo-inspired links and guarantee high buckling strength in the face of loads imposed from the user side to the structure, finite element analysis (FEA) was performed. The results show that the carbon fiber link inspired by bamboo has more strength in comparison to the common long carbon fiber tube. The kinematic configuration was modeled by the modified Denavit-Hartenberg (D-H) notation. The mean absolute error (MAE) was 5.9 mm, and the root-mean-square error (RMSE) was 6 mm. In addition, verification experiments by tracking the trajectory in Cartesian space and the wear trials on a subject were carried out on the BiEXO prototype. The satisfactory results indicate BiEXO to be a promising system for rehabilitation or assistance in the future.

Scientific mechanism of bamboo acoustic vibration performance from structure-chemical perspective

The special melodious timbre of bamboo musical instruments is closely related to the multi-level, multi-scale, delicate structure of bamboo. In this study, the influence of different excitation surfaces, bamboo height, and bamboo age on acoustic vibration performance was investigated. The mechanism of the influence of the bamboo tissue structure on its acoustic properties was further investigated. The results show that the acoustic conversion efficiency (ACE) of the bamboo-green side is 1307.42 m4/kg·s, which is higher than that of the bamboo-yellow side (1218.60 m4/kg·s). The E'/G' ratio from the bamboo-green side is 8.21, lower than that of the bamboo-yellow side (8.45). The comprehensive acoustic performance near the root (0–1.6 m) of the plant is optimal and has the maximum ACE value; ACE value decreases gradually from root to tip. The comprehensive acoustic properties of 8-year-old bamboo are the best compared to other ages. The ACE values of 2-year-old, 5-year-old, and 8-year-old bamboo are 997.37 m4/kg·s, 1284.19 m4/kg·s, and 1355.82 m4/kg·s with E'/G' of 8.34, 8.64, and 9.49, respectively. A highly oriented vascular fiber is conductive to the vibrational efficiency of bamboo, while loose and porous parenchyma cells play a resonant and tonal role. Highly oriented microfibrils and a large number of pores with diameter > 50 nm create a sound transmission channel and resonance cavity, which is the structural basis of the clear timbre of bamboo. However, a damping dissipation effect is produced affecting the vibration capacity and vibration energy transfer of the cellulose microfibril when abundant pores < 50 nm in size are located in lignin and between hemicellulose and cellulose skeletons. The content of the matrix composed of hemicellulose and lignin in the cell wall creates a chemical material basis that affects the acoustic performance of bamboo. The structural characteristics of bamboo, including directional gradient structure, fiber-parenchyma two-phase composite structure, and muli-scale pore structure, as well as key chemical “rebar-cement-sand” components of the rigid cellulose macromolecular chain, viscoelastic hemicellulose, and lignin have synergistic effects on bamboo acoustic vibration performance.

Effects of microwave drying on the cell wall structures of round bamboo

Effects of microwave irradiation on bamboo cell wall structures were studied. Microwave treatment resulted in samples exhibiting smoother surfaces, deformed parenchyma cells, and increased porosity. Microwave treatment altered microfibril orientation through the formation of hydrogen bonds. The peak at 3440 cm-1, assigned to O-H stretching, decreased. Meanwhile, intermolecular and intramolecular bonds were formed, increasing the uniformity of microfibrils. Condensation reactions in surface hydroxyl groups and the formation of intramolecular hydroxyl groups in the amorphous region under microwave irradiation also improved the fiber arrangement uniformity. After treatment, the HCH and HOC bonds were reduced and the ester bonds were broken down. The methoxy and aromatic ring hydroxyl groups were oxidized, as indicated by the increase in the absorption peak at 148 ppm. The hydroxyl groups in the amorphous region near the fiber surface decreased, as did hemicellulose content, but there was an increase in secondary crystalline fibers.

Revealing the performance of phenoxyethanol-acid pretreatment on the intercellular structure of bamboo and its enzymatic hydrolysis

To understand the effect of sulfuric acid-based phenoxyethanol pretreatment on the enzymatic digestibility of bamboo, the changes of lignin/xylan content and their intercellular structures in pretreated bamboo were investigated by different spectrum technologies. The maximum removals of lignin and xylan achieved by pretreatment with phenoxyethanol-acid (1%, w/v) ratio of 4:1 at 120 °C resulted in pretreated bamboo with an enzymatic digestibility of 79.25%. Micro-computed tomography revealed that the macrostructure of bamboo cell wall was destroyed, exposing the macrofibers. Based on the fluorescence intensity of lignin and antibody-labeled xylan, measured by fluorescence microscopy, most of the lignin was removed from the intercellular complex layer in thin-walled cells, and the destruction of main chain of hemicellulose was more severe than that of branched chains during the pretreatment process. In addition, the number of sub-structures, functional groups, and molecular weights of dissolved lignin in the pretreatment hydrolysate was closely related to the phenoxyethanol-acid ratio employed during pretreatment. Compared with the control group, the structures of dissolved lignin changed more significantly as the percentage of phenoxyethanol in the system increased. When the proportion of phenoxyethanol in the system increased, the number of substructures (β-O-4, β-5, and β-β) and functional groups showed a decreasing trend.

Study on the Effect of Flattening Modification on Bamboo Cutting Board and Corresponding Carbon Footprint Evaluation

Bamboo, as a renewable biomass material, has received wide public attention. However, due to the thin-walled and hollow structure of bamboo, the mainstream processing method is complex and requires splitting the bamboo into narrow strips and then gluing them together for further manufacturing products. In addition, the surface glue residue makes the safety of indoor applications a concern, especially for cutting boards that come into contact with food. In response to the above problems, this paper introduces a bamboo flattening technology, which can flatten and unfold the pre-treated bamboo into a large-size flattened bamboo board (FBB). The results show that, compared to untreated bamboo, the dimensional stability of the FBB was improved and the flexural strength and elastic modulus of the FBB were increased by about 8.0%. The flattened bamboo cutting board was manufactured with the FBB as the surface layer and had a moisture content and hardness value of 9.2% and 5080 N, respectively, and the accumulated dip peel length of any glue layer was less than 25 mm. The flattened bamboo cutting board is proved to be a carbon-neutral product with a carbon footprint value of −42.92 kg CO2/t. This work provides a theoretical basis for the fabrication of large-size unspliced bamboo boards and provides new ideas for the scenario-specific application of FBBs. Using a FBB to make cutting boards can avoid contact between food and adhesives, making them more hygienic. The findings of this research can be used to make bamboo cutting boards more hygienic, environmentally friendly and possess excellent physical and mechanical properties.

Construction relationship between a functionally graded structure of bamboo and its strength and toughness: Underlying mechanisms

The special functional gradient structure of bamboo determines its excellent properties of strength and toughness, which make it an excellent candidate for biomimicking purposes in advanced material design. However, the construction relationship and underlying mechanism of the functionally graded structure in the direction of the bamboo wall and its excellent strength and toughness have not been elucidated. Accordingly, this study first conducts a quantitative analysis of the relationship between the directional gradient structure of the bamboo wall layer and its chemical composition and physical and mechanical properties. To this end, in situ scanning electron microscopy (in situ SEM) was used to investigate the mechanical behavior and failure mode of the bamboo wall layer under the effect of external loads, and to investigate the structure–activity relationship between the gradient structure of the bamboo wall layer and its strength and toughness, as well as the potential mechanism of action. From the perspective of structural mechanics, the mechanical model of the bamboo wall direction under the applied load was analyzed, and the mechanism by which the bamboo wall gradient structure improves the strength and toughness of bamboo was further elucidated. The results showed that the uniform gradient distribution of the vascular bundles and their interfaces in the direction of the bamboo wall determines the gradient distribution of its chemical components and physical and mechanical properties. Together, the uneven deformation of parenchyma cells and fibers, multi-path propagation of cracks, fiber bridging, pull-out and fracture constitute the mechanism by which the bamboo gradient structure contributes to its strength and toughness. This study provides a theoretical basis and innovative ideas for the design of biomimetic advanced materials based on the bamboo wall gradient structure by revealing the potential close relationship between the excellent mechanical properties of bamboo of high strength and toughness and its functional gradient structure.

The Off-Axis Embedment Performance of Bamboo Panels Used for Glubam Structures

The off-axis embedment behaviors of unidirectional and multidirectional laminated engineered bamboo panels used for glued-laminated bamboo (glubam) structures under dowel-type bolts with three different diameters, 12, 14, and 16 mm, were experimentally studied in this research. The half-hole loading method given by current standards was adopted to perform the embedment tests. Seven different off-axis loading directions from 0° to 90° related to the main bamboo fiber direction at an interval of 15° in the panel plane were considered. The different failure patterns, stress-displacement curves, and the corresponding full-field surface strain measured through the digital image correlation (DIC) method are reported. The loading angles significantly influenced the embedment performance of unidirectional bamboo panel specimens, and the strength values decreased with the increasing off-axis loading angles. A difference of 35% in the strength values between 0° and 90° loading specimens was observed. However, quasi-isotropic embedment properties were noticed for the multidirectional laminated engineered bamboo panels. The capacity functions were provided to predict the mean off-axis embedment strength and characteristic strength values by inputting the characteristic density values into the functions. Compared with the characteristic strength values estimated through the statistical method, with a 95% probability of exceedance and 75% significant level, the conventional capacity-function method underestimated the off-axis embedment strength values, and thus may leading to an overconservative design. The statistical characteristic embedment strength values are suggested to be used to calibrate the safety factor of capacity equations given by wood standards. Results from this research can be used to predict the ultimate strength of glubam joints under complex loading conditions and obtain reliable design values for engineering applications.

Pull-out strength of the glued-in joint in laminated bamboo structure

The glued-in joint has proven its reliability, practicality, and flexibility in timber and concrete structures since first proposed. To study the pull-out strength of the glued-in joint in laminated bamboo structure, 27 specimens in pull-pull configuration were conducted. The influence of parameters, i.e., edge distance of the rebar, glue thickness, rebar diameter, anchorage length, were all tested by monotonic pull-out tests parallel to the grain. Three failure modes were characterized by the experimental results, referring to the splitting of laminated bamboo block, pull-out, and failure of rebar after yielding. Concluded from the experimental results, it is found that the first failure mode could be avoided by restricting the edge distance of the rebar in a reasonable range. The initial stiffness and load-carrying capacity of the latter two failure modes were recognized to be estimated in terms of the rebar diameter and anchorage length. Based on the existed theory, the feasibility of the traditional method was discussed and a simplified formula was developed based on the experimental results and theoretical derivation, which showed that the deviation is less than 6%. Finally, recommendations were made for the design of glued-in joint in the laminated bamboo structure.

Carbonized Fast-Growing Bamboo as a Photothermal Device for Efficient Solar Vapor Generation

Solar steam generation is an effective method for solving the freshwater shortage problem. In this study, porous carbonized bamboo (CB) was prepared through high-temperature (700 °C) carbonization under an argon atmosphere for efficient solar steam evaporation. The vertical porous structure of natural bamboo was retained after carbonization for water transportation. Moreover, carbonized bamboo could effectively enhance the degree of graphitization, which is conducive to the absorption of sunlight. According to the results of analysis test, it was obvious that the carbonized bamboo (CB-700) possessed excellent solar energy evaporation potential. The evaporation rate was up to 2.034 kg m–2 h–1 under 1 sun illumination and its solar absorption was averagely 90% in the range of 500–2500 nm. Moreover, the thermal conductivity coefficients of CB-700 and bamboo were 0.1964 and 0.2374 W m–1 K–1, respectively. Owing to this excellent local heat concentration, the surface temperature of CB-700 could achieve 73 °C under 7 sun illumination. Additionally, the material demonstrated an excellent desalting effect on seawater with satisfactory mechanical stability. Thus, the readily available carbonized bamboo can be potentially applied for solar steam generation.

Enhancing Mechanical Properties of 3D Printing Metallic Lattice Structure Inspired by Bambusa Emeiensis.

Metallic additive manufacturing process parameters, such as inclination angle and minimum radius, impose constraints on the printable lattice cell configurations in complex components. As a result, their mechanical properties are usually lower than their design values. Meanwhile, due to unavoidable process constraints (e.g., additional support structure), engineering structures filled with various lattice cells usually fail to be printed or cannot achieve the designed mechanical performances. Optimizing the cell configuration and printing process are effective ways to solve these problems, but this is becoming more and more difficult and costly with the increasing demand for properties. Therefore, it is very important to redesign the existing printable lattice structures to improve their mechanical properties. In this paper, inspired by the macro- and meso-structures of bamboo, a bionic lattice structure was partitioned, and the cell rod had a radius gradient, similar to the macro-scale bamboo joint and meso-scale bamboo tube, respectively. Experimental and simulated results showed that this design can significantly enhance the mechanical properties without adding mass and changing the printable cell configuration. Finally, the compression and shear properties of the Bambusa-lattice structure were analyzed. Compared with the original scheme, the bamboo lattice structure design can improve the strength by 1.51 times (β=1.5). This proposed strategy offers an effective pathway to manipulate the mechanical properties of lattice structures simultaneously, which is useful for practical applications.

Bionic design of thin-walled tubes inspired by the vascular structure of bamboo

In order to improve the crashworthiness and energy absorption of thin-walled tubes, this work proposes a novel design inspired by the vascular fiber sheath flap (VF) and central through-hole characteristics of bamboo vascular bundles. The energy absorption of the bionic structure is verified by experiments and theoretical analysis. Numerical simulations are used to analyze the effect of bionic unit structure and connection settings on various crashworthiness indexes. The results show that the bionic tube achieves the optimal energy-absorbing structure when the VF unit is a semicircle and the ratio of the circle core’s radius to the straight panel’s length is 3:7. Further, the effect of connection between the bionic unit and the outer tube on crashworthiness is also explored, and the optimal αβ-connection is obtained. Finally, both parallel fractal(PF) and rotational fractal(RF) approaches are introduced to improve the crashworthiness of thin-walled tubes based on the optimal structures obtained. And the crashworthiness of PF tube is better than that of the RF tube under the same level.

Sesame Oil Addition to Bamboo Reinforced Composite Matrix

Wooden ships use jati wood. Over time jati wood has become scarce. So that jati wood is relatively expensive. therefore bamboo is researched starting from the skin, bamboo meat, and bamboo internodes contained in the plant. In the structure of bamboo there are internodes. The bamboo segment is the weakness of the bamboo structure. The effect of bamboo segments in composite construction was investigated. Sesame oil replaces mineral oil and chemicals, because sesame oil is biodegradable, non-toxic, environmentally friendly, and renewable. To determine the effect of bamboo segments, tensile and bending tests will be conducted on the bamboo composite. The results of this research are expected to find alternative materials, namely bamboo fibre-based composites or so-called bamboo reinforcement plastics (BRP) as materials for making people's ships. This study found that the more layers of bamboo and bamboo segments are very influential in influencing the tensile and bending strength of a laminated material. The tensile testing value of layer 3 with segments reached 127.556 Mpa and without segments 933.333 as well as bending testing layer 3 with segments reached 113.889 Mpa and without segments 111.111 Mpa. From this value, the value has not met the standard of the Indonesian Classification Bureau (BKI).

Morph-genetic bamboo-reinforced hydrogel complex for bio-mimetic actuator

Stimuli-responsive hydrogels are most promising for the fabrication of autonomous bio-mimetic soft actuators. However, their weak actuation forces and isotropic volume change hinder their practical utilization as versatile actuators, owing to their fragility. Herein, we used the morph-genetic method to fabricate anisotropic bamboo/poly(N-isopropylacrylamide) hydrogel (ABH) complex for use as soft actuator. First of all, the bamboo fiber structure provides an anisotropic framework for the ABH actuator to achieve precise deformational programmability. Secondly, benefiting from the ultra-high directional strength (110 MPa) of bamboo, ABH actuator exhibits sufficiently robust mechanical property, which generates a powerful actuating force. Lastly, owing to the regulation of bamboo sheet and PNIPAM hydrogel, the ABH actuator not only achieves ultra-fast response speed (825°/s of the bending speed), but also has excellent synergetic performance. We demonstrate several bio-mimetic actuating devices based on ABH actuator, inspired by the intricate motions of natural organisms, to highlight how the specific materials properties and their synergy can be systematically exploited for the rational design of soft actuators. Henceforth, it is anticipated that the development of hydrogel actuators could continue to benefit from the use of various naturally-anisotropic materials, such as shape-memory polymers or liquid crystals, for the preparation of further advanced hydrogel actuators by the morph-genetic method.

Experimental investigations on the load-bearing properties of dowel connection joints of bamboo scrimber

The joints in bamboo structures are critical, and dowel connections are the most convenient form of joint. Research on dowel-bearing behaviour is important to develop the theory of joints for bamboo structures. One hundred fifteen half-hole dowel-compression specimens were tested in this study to explore the effects of specimen length, dowel diameter and fibre direction on the dowel-bearing behaviour of bamboo scrimber. Results showed that length had little effect on the stiffness and dowel-bearing strength of bamboo scrimber. When the dowel diameter increased from 8 to 20 mm, the stiffnesses of parallel to grain and perpendicular to grain specimens both increased by more than 43%, while the dowel-bearing strength of parallel to grain specimens decreased linearly from 177.11 MPa to 126.74 MPa, and the variation law of the perpendicular to grain specimens conformed to the trend of the quadratic function. When the angle between the direction of the bamboo fibre and the horizontal direction changed from 90° to 0°, the stiffness decreased from 63.55 kN/mm to 32.62 kN/mm, and the dowel-bearing strength decreased from 167.22 MPa to 138.43 MPa and exhibited different downwards trends with 45° as a boundary. Based on the calculation concept in Code for the design of timber structures in China, the calculation formula of dowel-bearing strength of bamboo scrimber was proposed by considering the influence of dowel diameter and fibre direction. The predicted results are in good agreement with the test results, which have good applicability to bamboo scrimber and can effectively provide a design method for dowel connection joints of bamboo structures.

Bioinspired anti-freezing 3D-printable conductive hydrogel microfibers for highly-sensitive and wide-range detection of ultralow and high strains

Soft strain sensors that can transduce stretch stimuli into electrical readouts are promising as sustainable wearable electronics. However, most strain sensors cannot achieve highly-sensitive and wide-range detection of ultralow and high strains. Inspired by bamboo structures, anti-freezing microfibers made of conductive poly(vinyl alcohol) hydrogel with poly(3,4-ethylenedioxythiphene)-poly(styrenesulfonate) are developed via continuous microfluidic spinning. The microfibers provide unique bamboo-like structures with enhanced local stress to improve both their length change and resistance change upon stretching for efficient signal conversion. The microfibers allow highly-sensitive (detection limit: 0.05% strain) and wide-range (0%–400% strain) detection of ultralow and high strains, as well as features of good stretchability (485% strain) and anti-freezing property (freezing temperature: −41.1 °C), fast response (200 ms), and good repeatability. The experimental results, together with theoretical foundation analysis and finite element analysis, prove their enhanced length and resistance changes upon stretching for efficient signal conversion. By integrating microfluidic spinning with 3D-printing technique, the textiles of the microfibers can be flexibly constructed. The microfibers and their 3D-printed textiles enable high-performance monitoring of human motions including finger bending and throat vibrating during phonation. This work provides an efficient and general strategy for developing advanced conductive hydrogel microfibers as high-performance wearable strain sensors.

An experimental and numerical investigation on the performance of novel hybrid bio-inspired 3D printed lattice structures for stiffness and energy absorption applications

The modern additive manufacturing process enables the fabrication of innovative structural designs of lattice structures with enhanced mechanical properties. Characterizing the designability of lattice geometries and the corresponding mechanical performance, particularly the compressive strength is vital to commercializing lattice structures for lightweight components. In this paper, a Novel hybrid type of lattice structure was developed inspired by the overlapping pattern of scales on dermal layers of the species like fish and circular patterns observed from the bamboo tree structure. This research designed the lattice cell with 20%,30%,40%, and 50% overlapping areas based on the proposed circular area. The unit cell wall thickness varies between 0.4 mm and 0.6 mm. The designed structures with a constant volume of 40x40x40 mm, varied circular diameters, overlapping areas, and unit wall thickness are modeled in Fusion 360 software. 3D-printed lattice structures were fabricated using the vat polymerization type three-dimensional printing machine using the principle of stereolithography (SLA) technique. Then, the 3D-printed specimens are tested for quasi-static compressive response in a universal testing machine (UTM) by following ASTM standards. The test results are evaluated and compared with the simulation results. Finally, the best lattice structure is selected for energy absorption application in the aerospace and defense sectors.