Glass Fiber Research Articles

Influences of hybrid fiber on functional and drilling characteristics study of polymer hybrid Nanocomposite

The severe environmental pollution related to the manufacturing, recycling and disposal of metal-based and synthetic fiber-based composites has a major impact on human and animal life. A wide range of studies are conducted on alternative materials in order to reduce greenhouse gas emissions. Various industries are focusing on using natural fibers from banana, jute, coir, hemp, pineapple, areca, kenaf, Sterculia foetida and Delonix regia that are the key sources of different components for developing nanocomposites. Drilling is a vital factor in the assembly process of composites. The amorphous structure of the natural fibers causes the formation of cracks at the entry and exit sides of the drilled hole. So, in the present work a nanocomposite was synthesized and optimized the machining parameters, which affect the surface finish of the hole at the entry, exit and inner surface of the drilled hole. The effect of the hybridization of glass fiber with the pineapple leaf fiber and areca fiber was studied in terms of tensile properties, delamination around the hole and surface roughness. The microstructure of the holes was studied by Scanning Electron Microscopy.

Evaluation of glass fiber-reinforced polymer bars for application in sections of reinforced concrete

In order to evaluate the effectiveness and acceptability of glass fiber reinforced polymer (GFRP) bars as a substitute for conventional steel reinforcement, this study looks into their use in reinforced concrete sections. To assess the mechanical qualities of GFRP bars, the research includes mix design, casting, and extensive testing, such as flexural and tensile tests. Furthermore, a comprehensive study of GFRP-integrated reinforced concrete building sections is carried out, looking at factors like primary stresses, bending stresses, shear stresses, and deflection. Additionally, using ANSYS software, a comparative study of beam-column junctions using GFRP and RCC sections is conducted to evaluate structural performance under various loading circumstances. The results demonstrate how GFRP bars can improve building projects' structural integrity, toughness, and sustainability

Graphene nanoplatelet additive impact on compression and bending strength of S-2 glass face-sheet honeycomb sandwich panels: An experimental study

In this study, the three-point bending, edge-wise, and flat-wise strengths of Nomex® sandwich structures with un-doped S-2 glass fiber face-sheet (Neat/S-2/glass) and those with Graphene nanoplatelet-doped S-2 glass fiber face-sheet (GNPs/S-2/glass) were examined parametrically. In the macroscopic images obtained post-experimentation, the damage to the structures’ face layer, core, and interface with GNP (graphene nanoplatelet) additives was visualized. Morphological images depicting the damaged structures were obtained by applying image processing techniques to the macroscopic images. Finally, the fracture mechanisms of fiber/fiber and fiber/matrix interfaces within the shell layers were examined in SEM images. As a result of the study, the addition of GNPs increased the strength of the interfaces between the fiber layers and the fiber core within the face layers of S-2 glass face-sheet Nomex® sandwich structures, leading to a 40% enhancement in bending strength, a 14% improvement in core compressive strength, and a 2.85% increase in edge-wise compressive strength. Moreover, the delamination damage between the face layer and the core, which undermines the structural integrity of the sandwich structure, was not observed in GNPs/S-2/glass sandwich structures. Thus, the damage propagation throughout the sandwich structure contributed to enhancing its load-carrying capacity. The collapse extent of the sandwich structures, determined through image processing, measured 8676 mm in Neat/S-2/glass sandwiches, whereas it amounted to 10,410 mm in GNPs/S-2/glass sandwiches. The inclusion of GNPs additive augmented the collapse strength of the sandwich structure by 19.9%. Utilizing GNPs as a filler in the matrix material has been recognized as a practical approach to enhancing the mechanical strength of sandwich structures.

Fatigue and Ultimate Strength Evaluation of GFRP-Reinforced, Laterally-Restrained, Full-Depth Precast Deck Panels with Developed UHPFRC-Filled Transverse Closure Strips

A depth precast deck panel (FDDP) is one element of the prefabricated bridge element and systems (PBES) that allows for quick un-shored assembly of the bridge deck on-site as part of the accelerated bridge construction (ABC) technology. This paper investigates the structural response of full-depth precast deck panels (FDDPs) constructed with new construction materials and connection details. FDDP is cast with normal strength concrete (NSC) and reinforced with high modulus (HM) glass fiber reinforced polymer (GFRP) ribbed bars. The panel-to-girder V-shape connections use the shear pockets to accommodate the clustering of the shear connectors. A novel transverse connection between panels has been developed, featuring three distinct female-to-female joint configurations, each with 175-mm projected GFRP bars extending from the FDDP into the closure strip, complemented by a female vertical shear key and filled with cementitious materials. The ultra-high performance fiber reinforced concrete (UHPFRC) was selectively used to joint-fill the 200-mm transverse joint between adjacent precast panels and the shear pockets connecting the panels to the supporting girders to ensure full shear interaction. Two actual-size FDDP specimens for each type of the three developed joints were erected to perform fatigue tests under the footprint of the Canadian Highway Bridge Design Code (CHBDC) truck wheel loading. The FDDP had a 200-mm thickness, 2500-mm width, and 2400-mm length in traffic direction; the rest was over braced steel twin girders. Two types of fatigue test were performed: incremental variable amplitude fatigue (VAF) loading and constant amplitude fatigue (CAF) loading, followed by monotonically loading the slab ultimate-to-collapse. It was observed that fatigue test results showed that the ultimate capacity of the slab under VAF loading or after 4 million cycles of CAF exceeded the factored design wheel load specified in the CHBDC. Also, the punching shear failure mode was dominant in all the tested FDDP specimens.

O-PHTHALALDEHYDE CROSS-LINKED CHITOSAN MEMBRANE AS A QUASI-SOLID-STATE ELECTROLYTE FOR SUPERCAPACITORS

This study reports a stepwise formation method of a chitosan membrane cross-linked with o-phthalaldehyde and its use as a polymer matrix in a quasi-solid-state-electrolytebased supercapacitor. The proposed method of cross-linking in chitosan solution and evaporation of the solvent yielded a homogeneous and durable chitosan-o-phthalaldehyde membrane, which, after dipping in an aqueous 2 M lithium sulfate solution, formed a quasi-solid-state-electrolyte (CS/OPAQSSE). The prepared CS/OPA-QSSE was then used in an electric double layer capacitor (EDLC) cell to study its electrochemical properties. The electrochemical performance of the EDLC cell was determined by using the electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charging/discharging techniques. The results showed that the EDLC cell with the CS/OPA-QSSE is a fully functional and efficient device. The specific capacitance values calculated for the CS/OPA-QSSE EDLC (up to 115 F g–1) always surpassed the reference cell based on a commercial glass fibre separator Therefore, the proposed chitosan modification can be considered as a future alternative to produce other polysaccharide-based materials for electrochemical use.

Thermomechanical and Viscoelastic Characterization of Continuous GF/PETG Tape for Extreme Environment Applications

The thermomechanical and viscoelastic properties of a glass fiber polyethylene terephthalate glycol (GF/PETG) continuous unidirectional (UD) tape were investigated using differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and dynamic mechanical analysis (DMA). This study identified five operational conditions based on the Army Regulation 70-38 Standard. The DSC results revealed a glass transition temperature of 78.0 ± 0.3 °C, guiding the selection of temperatures for TMA and DMA tests. TMA provided the coefficient of thermal expansion in three principal directions, consistent with known values for PETG and GF materials. DMA tests, including strain sweep, temperature ramp, frequency sweep, creep, and stress relaxation, defined the material’s linear viscoelastic region and temperature-dependent properties. The frequency sweep indicated an increased modulus with rising frequency, identifying several natural frequency modes. Creep and stress relaxation tests showed time-dependent behavior, with strain increasing under higher loads and stress decreasing over time for all tested input values. Viscoelastic models fitted to the data yielded R2 values of 0.99, demonstrating good agreement. The study successfully measured thermomechanical and viscoelastic properties across various conditions, providing insights into how temperature influences the material’s mechanical response under extreme conditions.

INVESTIGATION OF THE SHEAR STRENGTH OF REINFORCED SILTY SAND

Introduction: This paper presents an experimental investigation that aims to study the influence of silt content, glass fiber content, and their combined effect on the shear behavior of silty sand. For this purpose, a series of tests using direct shear apparatus (as methods) were carried out on sand mixed with various silt and fiber contents. Samples were prepared with a relative density of 50 %, and each mixture was tested at three different normal stresses. The experimental results indicated an increase in shear strength at 10 % silt content, followed by a decrease in shear strength with increasing silt content from 10 % to 30 %. It was also found that 0.5 % is the optimal content that can be added to sand-silt mixtures to enhance their shear strength and friction angle, although the mixtures become more contractive.

Design and fabrication of an accelerometer structure using glass fiber reinforced epoxy resin for seismic P-wave early warning

Earthquake early warning represents a vital and effective strategy for mitigating earthquake-related losses. Among the existing sensors for earthquake early warning, MEMS accelerometers involve complex manufacturing process, leading to high research and development costs and long cycles. Traditional mechanical sensors are bulky, costly, hence not suitable for large-scale, high-density monitoring network. In this study, a low-cost accelerometer using glass fiber reinforced epoxy resin is proposed for longitudinal seismic waves (P-waves) early warning. Both theorical and finite element analysis are carried out to define and optimize the initial structure of the accelerometer. A pre-deformation structure is implemented into the spring suspension system to offset the influence of the sensor’s gravity, so that a self-balanced state in the direction of gravity is achieved. The simulation results show that the accelerator can achieve an eigenfrequency of 12.67 Hz, a Q-value of 49.2, and mechanical thermal noise of 1.72×10-9g/Hz. Based on the simulation results, the accelerometer’s structure is processed using a computer numerical control (CNC) milling machine, and tested by collecting the voltage signals when the accelerometer’s structure undergoes an impact in the direction of the gravity. The measured eigenfrequency is around 10 Hz, and the signal attenuation rate closely aligns with the simulation results. The accelerometer structure has dimensions within 6 cm and a relatively simplified manufacturing process, making it a cost-effective solution for the development of large-scale, high-density earthquake early warning systems.

Study of Composite Light Weight Leaf Spring

The fundamental Objective of this project is to represent plan and exploratory examination of composite leaf spring made of glass fiber reinforced polymer. The intention is to look at the load carrying capacity, weight and stiffness effective of composite leaf spring with that of steel leaf spring. The design imperatives are stresses and deflections. The measurements of a current ordinary steel leaf spring of a light business vehicle are taken. Static investigation of leaf spring is likew ise performed utilizing analysis software and compared with experimental results. Limited component investigation with full load on 3D model of composite multi leaf spring is done utilizing analysis software and the analytical results are compared with experimentalresult

AN ANALYSIS ON THE USE OF MODIFIED EXPANDED PERLITE AND PUMICE IN INORGANIC BONDED FIBROUS COMPOSITE BOARDS

It is often stated that there is an energy efficiency difference between optimum energy use and actual energy use in the world. In the construction industry, various building materials are produced and used to optimize energy efficiency in buildings. Among these building materials, inorganic bonded fibrous composite boards, whose energy efficiency criteria have begun to be improved, are widely used both in Türkiye and in the world. This article presents an experimental analysis of the utilization of modified expanded perlite and pumice as key constituents in the development of inorganic bonded fibrous composite boards. The study investigates the influence of these modified porous materials on the physical, mechanical, and thermal properties of the composite boards. For this purpose; composite mortars were produced using micronized quartz sand, a hybrid fiber consisting of cellulose and glass fiber, modified expanded perlite (MEP) with stearic acid (1, 2, 3, 4, 5, 6, 7, 8, 9 wt.%) and modified pumice (MPU) with stearic acid (1, 2, 3, 4, 5, 6, 7, 8, 9 wt.%). In order to make a comparison, a control mortar that did not contain modified expanded perlite and modified pumice was produced. Through a series of experiments, it is concluded that the density values of all other mixture designs with MEP and MPU aggregate additives under equivalent conditions are lower than the control sample. The water absorption values of the samples always remained below the control sample, and with the increase in the MPU ratio and decrease in the MEP ratio, the water absorption values of the samples also decreased. The average modulus of rupture (MOR) value of control sample in the analysis made after 14 days of curing under ambient conditions is 3.73 MPa. The highest MOR value of the test samples is 3.51 MPa, which is the mixture using the highest MPU. The thermal conductivity value of the control mixture is 0.352 W/mK. The thermal conductivity value of test mixtures with MEP and MPU aggregates varies between 0.175 W/mK and 0.287 W/mK.

Optimizing dielectric constant of noncommercial biobased fibres - Acacia Nilotica, Acacia Leucophloea and Prosopis juliflora - For composite applications with selected fillers

In recent decades, most electrical/electronic products possess non – biodegradable components. The expanding consumption of these goods and their eventual disposal pose a serious environmental threat. To cope up with this issue, biodegradable electrical/electronic components using biobased fibres can be an alternative option. The novel exploration of this research work is the usage of underutilized biobased fibres, such as Acacia Nilotica, Acacia Leucophloea and Prosopis Juliflora, as sustainable alternatives to traditional synthetic fibres in natural fibre-reinforced epoxy composites. The novelty lies in the combination of these natural fibres with ceramic fillers like Silicon Carbide, Boron Nitride and Aluminium Oxide, aiming to enhance the composite properties. The objective of the study is to optimize the type of fibre, fibre content (2 wt%, 4 wt% and 6 wt%) and types of fillers (1 wt%) combinations using the Box-Behnken Design to improve the dielectric properties of these composites. Analysis of Variance (ANOVA) is used to evaluate the relevance of each parameter on dielectric constant of the biobased fibre reinforced epoxy composite. The significant outcome is identified that Prosopis Juliflora (6 wt%) combined with Boron Nitride (1 wt%) yields an optimal dielectric constant of 1.11, highlighting the potential of these biobased fibres to serve as effective substitutes for conventional glass and carbon fibres for electrical insulating materials used in switchboards and socket pins to prevent electrical conduction and ensure safety. This research not only contributes to the field of sustainable materials but also addresses critical environmental concerns associated with electric/electronic waste.

Influence of Processing Parameters in Injection Molding on the Properties of Short Carbon and Glass Fiber Reinforced Polypropylene Composites

Short-fiber reinforcement is a potent approach to improving the material properties of injection-molded parts. The main consideration in such reinforced materials is to preserve the fiber length, as this is the major influence on the properties of a given composite. The aim of this work was to investigate the different influencing parameters in injection molding processing on the properties of short carbon and glass fiber-reinforced polypropylene. We investigated parameters like melt temperature and back pressure, but also machine size and pre-heating regarding their influence on the tensile properties. We found that adjustments of melt temperature and back pressure only yield small improvements in the fiber length and the tensile properties, also depending on machine size, but a pre-heating step of the granules can significantly improve the properties.

Dynamic fracture characterization of glass fiber composites reinforced with through-thickness nylon fibers

ABSTRACT A detailed experimental study is performed to investigate the mode-I dynamic fracture initiation toughness of through-thickness Nylon fibers reinforced glass/epoxy composites using a wet electrostatic flocking method. Composites of a double cantilever beam specimen configuration of two different deniers 1.5D and 3D of 0.75 mm long Nylon fibers with two different fiber densities 150 and 300 fiber/mm2 and composites without Nylon fibers (control) are fabricated. The dynamic fracture initiation toughness is investigated by using a modified split Hopkinson pressure bar setup with a novel fixture in conjunction with a high-speed video camera. In addition, rate sensitivity on dynamic fracture initiation toughness is also investigated for control and composites of 1.5D with fiber density of 300 fibers/mm2 as a function of three different rates of dynamic fracture toughness ( G ˙ = 1500, 2010, and 2,150 kJ/m2/s). Results show that for the composite of 3D–0.75 mm Nylon fiber, G IC values reach 0.78 kJ/m2 (110% increase) and 1.3 kJ/m2 (250% increase) at flock densities of 150 and 300 fibers/mm2 compared to the control sample with the lowest G IC value at 0.37 kJ/m2. The same pattern is observed for a 1.5D–0.75 mm configuration at the flock fiber density of 150 fiber/mm2 where G IC value demonstrates a 75% increase compared to control conditions. The dynamic fracture initiation toughness of flocked composites demonstrates significant rate sensitivity.

Comparison of Experimental and Numerical Investigation of Mono-Composite and Metal Leaf Spring

The automotive industry is increasingly focused on reducing vehicle weight, leading to the widespread adoption of composite materials with high strength-to-weight ratios in both aviation and automotive sectors. These materials are gradually replacing traditional options like steel. Leaf springs, one of the oldest and most common suspension components, continue to be widely used in vehicles. This study aims to replace conventional multi-leaf steel springs with mono-composite leaf springs while preserving the same load-carrying capacity and stiffness. Composite materials, such as glass fiber and epoxy resin, provide advantages including higher elastic strain energy storage, superior strength-to-weight ratios, and enhanced corrosion resistance compared to steel. Consequently, the weight of leaf springs can be reduced without sacrificing performance. The steel and mono-composite leaf springs were modeled using Catia software, and their performance was evaluated using ANSYS 15.0 software.

Flat silk cocoons: A candidate material for fabricating lightweight and impact-resistant composites

The utilization of silk cocoons in the production of lightweight and tough composites has been gaining increasing attention. However, the limited applications of normal silk cocoons (NSC) are attributed to their small size and irregular shape. To overcome this deficiency, flat silk cocoons (FSC) with a similar structure and controllable size were prepared. Next, we systematically characterized and compared the microstructures, morphologies, compositions, thermal properties, and mechanical properties of FSC with NSC. Subsequently, FSC was successfully utilized to fabricate a novel silk fibroin fiber reinforced sericin matrix composite (HPFSC) using a hot pressing method, followed by the analysis of its microstructure evolution, mechanical properties, failure modes, and theoretical modeling. This composite has outstanding mechanical properties including hardness, modulus, and strength. HPFSC has a relatively low density of ~1.3 g/cm3, whose absorbed impact energy can reach a maximum value of 11.1 J/mm, exceeding that of most engineering materials, such as aluminum alloy, ceramics, glass, and carbon fiber composites. The exceptional performance of HPFSC can be attributed to the reduced porosity, enhanced bonding between silk fibroin fibers facilitated by sericin, and their structural transformation. This study offers valuable guidance for the fabrication of lightweight and impact-resistant composites using flat silk cocoons.

Tension stiffening and cracking behaviors in glass fiber reinforced polymer bar enhanced precast recycled aggregate concrete specimen

Glass fiber reinforced polymer (GFRP) bar-enhanced precast recycled aggregate concrete (PRAC) elements combine PRAC’s environmental benefits with GFRP’s corrosion resistance, making them ideal for coastal urban infrastructure. However, in-depth research on the tensile stiffness and cracking behaviors of this composite is lacking. The significant mechanical differences between GFRP bars (low modulus, high strength) and PRAC, as compared to traditional materials, raise safety concerns for widespread use. This study investigates the short-term load capacity, deformation and cracking characteristics of GFRP bar-reinforced PRAC tensile specimens through tests and analyses. The tests examine how variables like water-to-binder ratio, coarse aggregate type, recycled aggregate (RA) content and mixing methods affect the specimens' mechanical responses. Theoretical analyses, using existing equations and a partial interaction model, clarify stress-strain relationships and crack propagation under applied loads, revealing: (a) As RA content increases, PRAC shows a moderate decrease in workability and mechanical performance. The strength variability in PRAC generally falls between that of natural aggregate concrete (NAC) and conventional recycled aggregate concrete (CRAC) using RAs from construction and demolition waste, being closer to NAC. Additionally, the strength conversion relation seen in NAC applies similarly to PRAC. (b) During tension at both ends of the specimen, PRAC's resistance decreases by 24.3 % compared to NAC but is still 20.3 % higher than CRAC. (c) The number of cracks in the PRAC specimen decreases with higher RA content and basalt fibers, while the ratio of stabilized load to cracking load increases. (d) The CEB-FIP standard offers more accurate predictions of the specimen’s composite stress-strain relation, while the Chinese code excels in predicting crack width. The partial interaction model effectively predicts the specimen’s load, deformation and crack characteristics by accounting for the behaviors and bonding of both PRAC and GFRP bars.

Investigation on mechanical property and failure mechanism of the carbon/glass hybrid laminate bolted joints using acoustic emission

In this study, tensile tests and acoustic emission (AE) monitoring were performed on single lap specimens of carbon/glass hybrid laminates with different carbon fiber layer angles. The results indicated that the carbon fiber layer angle not only affects the bearing strength and bearing stiffness of hybrid laminates, but also influences the macroscopic extension direction of damage. The study also found that carbon fiber and glass fiber damage exhibit different centroid frequencies. Building on these findings, the analysis identified the primary fiber type involved in fiber damage to different hybrid fiber laminates. Additionally, it was noted that the friction generated between the bolt and the laminate under load triggers AE signals with a high centroid frequency.

Exploring mechanical properties of eco-friendly hybrid epoxy composites reinforced with sisal, hemp, and glass fibers

It is now widely accepted that various subsets of hybrid fiber composites reinforced with combined natural and synthetic fibers can significantly expand the applicability of composite-based materials in design and technology practice. The already existing unnatural circumstances on the planet put natural fibers far ahead of traditions in the field of materials thanks to their biodegradability characteristics, availability and over-term endurance and corrosion resistance. At the same time, composites are rapidly taking their place in many industries and sectors of the economy as metals in as much as it is economically and energetically justified. This study evaluates the mechanical properties of hybrid composites reinforced with glass, hemp, and sisal fibers. Using a hand lay-up method with epoxy resin, composite laminates were fabricated and tested for tensile, flexural, impact strengths and hardness test in accordance with ASTM standards. The experimental results revealed that glass-sisal fiber composites achieved the highest tensile strength of 69.1 MPa, while glass-hemp-sisal fiber composites exhibited superior flexural strength of 15.22 MPa and impact strength of 137.45 kJ/m2 while best hardness value was 24.73 HV for glass-sisal fibre composite. These findings underscore the potential of glass-sisal-hemp fiber-reinforced epoxy composites as viable alternatives to traditional synthetic fiber-reinforced materials in automotive industry where there are no structural loadings i.e. automobile interiors; offering enhanced mechanical performance and sustainability.

Mechanical properties of epoxy composites filled with multi-walled carbon nanotube, Nanoaluminum particles and glass fibers at elevated temperatures

The present work investigates the mechanical properties of a composite material composed of multi-walled carbon nanotubes (MWCNTs), nano-aluminum powder (NAP), and glass fibers (GF) for five different compositions. The study further investigated how MWCNTs contribute to maintaining the mechanical properties of nanocomposites when exposed to elevated temperatures, up to 180 °C. The evaluation of impact strength revealed that the nanocomposite, composed of 2 % MWCNTs, 15 % NAP, and 10 % GF, demonstrated the greatest impact strength. At room temperature, the composite containing 2 % MWCNTs, 5 % NAP, and 20 % GF exhibited the highest ultimate tensile strength (UTS). Conversely, at elevated temperatures reaching up to 180 °C, the highest UTS was observed in the composition with 2 % MWCNTs, 10 % NAP, and 15 % GF. The hardness of the nanocomposite was influenced by its composition; at room temperature, the maximum hardness was observed in the mixture containing 2 % MWCNTs, 20 % NAP, and 5 % GF. In contrast, at elevated temperatures, the composition with 2 % MWCNTs, 5 % NAP, and 20 % GF exhibited the highest hardness. Overall, the study found that incorporating GF and NAP improved the mechanical properties of the composite. These results indicate that the composite's performance could be further optimized for specific applications through the addition of filler materials.

Experimental research on the glass fiber-reinforced effect and mechanisms of sand powder 3D-printed rock-like materials

Conducting laboratory tests on natural rocks has significant value for the scientific and practical advancement of various types of rock engineering. The investigation of a rock-like materials that is similar in characteristics and structure to natural rock is key to the further advancement of laboratory rock experiments. The rapid development of sand powder 3D printing technology in recent years has provided a solution for fabricating rock-like materials. However, the low strength and elastic modulus of sand powder 3D-printed materials limit their application in simulating natural rocks. Therefore, this paper proposes a method to enhance the mechanical properties of sand powder 3D-printed materials utilizing glass fiber reinforcement by incorporating glass fiber into sand powder 3D-printed rock-like specimens. The mechanical properties and microstructural variations of the specimens with varying glass fiber contents are investigated utilizing mechanical testing, acoustic emission, scanning electron microscopy, etc. The results indicate that (1) it is feasible to utilize glass fiber to enhance the mechanical properties of sand powder 3D-printed materials; (2) The mechanical properties of sand powder 3D printing materials are significantly enhanced by the addition of glass fiber; and (3) the mechanisms controlling the reinforcement effect of glass fiber addition on sand powder 3D-printed specimens are determined by analyzing the microstructural characteristics of the specimens. This study improves the applicability of sand powder 3D-printed materials in simulating natural rock, thereby promoting the further application of 3D printing in the field of rock mechanics.