Distribution Of Fibers Research Articles

A novel algorithm for generating random fiber distributions for fiber reinforced composites based on lattice partition

AbstractThis paper propose a random fiber distribution generation algorithm based on lattice partition, which addresses the issue of limited increase in fiber volume fraction caused by the random movement of fibers in previous methods. By partitioning the representative volume element (RVE) window into lattices and moving fibers directionally, the proposed algorithm significantly increases the number of fibers within the RVE window. The generated fiber distribution achieves a fiber volume fraction of up to 80%, with an average execution time of 243.4 s. The influence of algorithm parameters on the randomness of fiber distribution is examined through statistical analysis of the generated distributions. Finite element models with various parameters are established to predict the elastic properties of the composites. The average relative error between the predicted values and the experimental results is 8.6%, demonstrating the effectiveness of the proposed algorithm. This algorithm offers a simple and effective approach for generating fiber distributions in the numerical study of the micromechanics of composites.Highlights A new lattice‐partition method is proposed to generate fiber distributions. The fiber volume fraction of generated fiber distribution is up to 80%. The randomness of fiber distribution is analyzed through statistical analysis. The algorithm predicts elastic properties with an average relative error of 8.6%.

Parametric analysis of 3D printing parameters on stiffness and hysteresis characteristics of pediatric prosthetic foot coupon samples

Background: This research paper presents a comprehensive parametric study that investigates the influence of various 3D printing parameters on the mechanical properties of a pediatric prosthetic keel using coupon samples. Objective: To analyze how 3D printing parameters impact upon on 2 crucial mechanical properties: stiffness and hysteresis. Methods: Key 3D printing parameters including the amount of continuous carbon fiber layers, fiber distribution, and matrix fill pattern, are systematically varied, and mechanically tested through compression to analyze the results. Results: The results demonstrate the substantial impact that printing parameters have on the mechanical characteristics of 3D-printed pediatric prosthetic feet. Notably, the selection of these parameters for the prosthetic keel plays a pivotal role in shaping the overall performance and functionality of the prosthetic foot, emphasizing the need for precise parameter optimization in pediatric prosthetic design, if 3D printing is the manufacturing process. Conclusions: The findings of this study contribute to a better understanding of the manufacturing process for pediatric prosthetic feet via 3D printing and offer valuable insights for optimizing their design. By identifying the ideal combination of 3D printing parameters that yield the desired stiffness and minimize hysteresis, we aim to enhance the performance and comfort of pediatric prosthetic devices, ultimately improving the quality of life for young users.

A unified method to generate representative volume elements with tailored random fibre arrangements to estimate the shear and transverse behaviours of unidirectional continuous fibres composite plies

Axial compressible strength is a key design parameter of CFRP laminate structures, especially for Aerospace where maximum flexure on wings is driven by the global margin of safety on compressive loads. One of its main limiting contributors is the non-linear shear behaviour of the unidirectional ply. This shear response can be predicted by using generated (quasi-)random microstructures set within representative volume elements (RVE). Different microstructures with or without clusters of fibres (resulting from manufacturing processes) are necessary to quantify the mechanical variability. The variability of the microstructures is characterised by the variation of the arrangement, the volume fraction and the misalignment of the fibres. This leads to significant variations in the mechanical performance, in particular for the shear behaviour. In this study, we propose a unified algorithm that makes it possible to generate all the different positions of fibres in microstructures with very high fibre volume fractions. The microstructural parameters responsible for variations in mechanical behaviour are identified to establish a correlation between fibre distribution and the mechanical response. Finally, a composite cross-section is analysed to estimate the local non-linear shear behaviour as well as the compressive strength as an example to illustrate the benefit of complex microstructures modelling.

Myokine BDNF highly expressed in Type I fibers inhibits the differentiation of myotubes into Type II fibers.

Myofibers are broadly classified as slow-twitch (Type I) and fast-twitch (Type II) fibers. These two types of myofibers coexist within the same skeletal muscle tissue, determining the contractile and metabolic properties of skeletal muscle tissue by fiber type distribution. By examining each fiber type separately, we confirmed that brain-derived neurotrophic factor (BDNF) gene is highly expressed in Type I fibers. When exposed to BDNF, primary myotubes exhibited reduced expression of Myosin Heavy Chain (MyHC) II, a marker protein characteristic of Type II fibers. BDNF overexpression in regenerating muscle tissue led to a decrease in the distribution of Type IIA fibers. We suggest that BDNF highly expressed in Type I fibers downregulates MyHC II expression in myotubes, eventually inhibiting Type IIA fiber generation.

Investigating the Impact of Physical and Mechanical Characteristics of Palf/Glass Fiber Reinforced In Epoxy Resin

Recent times, the nature fibers deepen its roots in the field of composite materials. Owing to its ecofriendly characteristics, the natural fibers had its upper hand to the synthetic fiber. But, usage of natural fiber alone doesn’t bring desirable characteristics to the fabricated material. Therefore, the amalgamation of synthetic and natural fiber as the reinforcement in the polymer composite brings desirable property to the newly fabricating material. In this paper, we utilized the Pineapple Leaf Fiber (PALF) and glass fiber as the reinforcement in the epoxy resin and fabricated the new material. The paper mainly concentrates to study the physical and mechanical characteristics of the material. The uniform distribution of PALF and glass fiber over the polymer matrix was confirmed with the help of images of Scanning Electron Microscope (SEM). The PALF and glass fiber of composition of 20 % and 15% of weight ratio shows significant resistance to brittleness and have high tensile strength. Consecutively, the PALF and glass fiber of composition of 25% and 10% of weight ratio yields higher bending strength and shows implacable resistance to compression and impact load.

The Shear Performance of an Aircraft off Pin Made of Quartz Fiber Reinforced Phenolics: The Effect of the Fiber Distribution Property

Emergency breakaway pins (EBPs) have been widely used in aircraft, especially in the suspension connection between the engine device and the airfoil. Currently, the existing EBPs, which are made of metal materials, barely satisfy the lightweight requirement of the airplane industry. Thus, the construction of a novel EBP with quartz fiber reinforced phenolics is proposed in this study, and the shear response is examined experimentally using a double-sided shear test. The effect of the fiber distribution characteristic on the shear strength is then assessed quantitatively. The failure patterns, including the damage morphology of the two types of samples were then reconstructed using scanning electron microscopy (SEM). Experimental results showed that the breakaway composite pin fabricated by the laminated composite had a superior shear response than its counterpart with randomly distributed fibers for its uniaxially distributed fiber yarns provided a longer put-out damage trace that contributed to a higher shear-loading bearing capacity for the entire composite EBP. In specific, the average values of the shear strength and the shear stiffness for the former samples were higher by 61% and 22%, respectively, than that for the latter samples. Additionally, the composite EBP also has an excellent combination of lightweight advantage and stronger shear-bearing capacity over competing pins, providing novel insight for more secure designs for civil and military aviation.

Bonding strength of short carbon fiber reinforced PA6 composites ultrasonic welding joints

AbstractShort carbon fiber composites have high specific modulus, high specific strength and excellent formability, which are suitable for short‐term and environmentally friendly ultrasonic welding. In this study, ultrasonic welding experiments were conducted on short carbon fiber reinforced PA6 composites using a servo‐driven non‐metallic ultrasonic welder. The weld specimens were analyzed for spot weld morphologies, interfacial bonding strength, failure modes and compressive shear fracture to establish the correlation between weld energy and weld quality. The results indicate that when the welding energy is 450 J, the short carbon fibers are interlaced at the interface, which has a pinning effect, thereby enhancing the joint strength reaching 2990 N, and the welding efficiency reaches 46%. Besides, the compressive shear section is divided into regions. The proportion of heat and area in different compressive shear regions are quantitatively analyzed, and the calculation model of joint strength is proposed. Meanwhile, the correlation between welding energy and its correlation, as well as three different shear failure modes, is obtained. This work is helpful for the optimization of carbon fiber reinforced thermoplastic (CFRTP) ultrasonic welding process parameters and the evaluation of joint strength.Highlights A special fixture for ultrasonic welding was designed to optimize the welding energy process of ultrasonic welding CFRTP, and the properties of ultrasonic welded joints were analyzed. When the welding energy is 450 J, a high shear strength welded joint of 2990 N was successfully prepared. The shear fracture of the welded joint was successfully obtained by designing a special clamp for compression shearing. The welding area was qualitatively divided according to the temperature measurement results of the interface center. In addition, the heat and area ratio of different zones in the compression‐shearing area under different welding energy were quantitatively analyzed, and the calculation model of joint strength was proposed. At the same time, the welding energy and its correlation, as well as three different shear failure modes were obtained. The short fiber distribution characterization and pores effect on the joint's strength were analyzed. The appearance of porosity defects has a significant weakening effect on the welded joint.

A two‐scale numerical analysis of intra‐yarn hybrid natural/synthetic woven composites

AbstractThis paper investigates how combining natural and synthetic fibers within yarns, altering the degree of hybridisation, and varying weave architectures affect the homogenized elastic properties and stress distributions in 2D woven composite laminae using a two‐scale homogenization scheme. The novelty lies in integrating a micro‐scale representative volume element model with a meso‐scale repeating unit cell model to capture intra‐yarn natural/synthetic fiber hybridisation. The study focuses on 2/2 twill and 5‐harness satin woven laminae with flax/E‐glass, hemp/E‐glass and basalt/E‐glass hybrid yarns, all with a total fiber volume fraction of 0.6. Fiber distributions are created through a random sequential expansion algorithm for hybrid RVEs, while periodic meso‐structures are used to define weave architectures for RUCs. Results show that yarn‐level fiber hybridisation significantly influences matrix stress distributions, with variations of up to 22%. In contrast, weave architecture has a minimal effect, with variations in homogenized properties below 2%. Varying fiber types, degrees of hybridisation and weave architectures allow for the tailoring of yarn and lamina properties and altering the stress distributions at micro‐ and meso‐scales and potentially influencing damage mechanisms. The modeling approach for analyzing the mechanical behavior of intra‐yarn hybrid natural/synthetic woven laminae could potentially be used to tailor their tolerance to damage.Highlights Two‐scale homogenization integrates RVE and RUC for 2D woven hybrid composites. Analyzed flax/E‐glass, hemp/E‐glass, basalt/E‐glass in twill and satin weaves. Intra‐yarn hybridisation significantly affects properties and stress fields. Hybridizing fibers offers tailored properties and may improve damage tolerance.

Effect of multi‐angle lamination on mechanical properties and damages behavior of carbon fiber reinforced resin matrix composites

AbstractCarbon fiber reinforced resin matrix composites, when subjected to multi‐angle delamination during vacuum hot pressing, suffered from defects such as uneven fiber distribution, resin‐rich zones, and voids. These defects caused varied damage and failure behaviors in the composites, seriously affecting their mechanical properties. In this paper, the defect distribution, tensile and flexural properties, and damage behaviors of multi‐angle lay‐up specimens prepared in an autoclave were studied. The results indicated that irregularly shaped voids in laminates with a 0° angle difference primarily led to local stress concentration. Elliptical and elongated voids in laminates with a 90° angle difference were mainly susceptible to delamination. The [0/90]8 layer exhibited the best overall mechanical properties. The proportion of 0° laminates had a direct impact on the mechanical properties, with 0° contact laminates on the bending‐compression side capable of withstanding higher bending loads. The [+45/−45]8 plyer demonstrated pseudo‐delayed behavior, enabling the laminate to show better toughness under load. Variations in damage due to the proportions and positions of the laminates influenced the mechanical properties and damages behavior of multi‐angle laminates.Highlights Angular differences were observed to affect void and resin distribution. The best overall mechanical properties were attributed to [0/90]8 laminates. Pseudo‐delay behavior was exhibited by [+45/−45]8 laminates. Proportion of 0° layers impacted mechanical properties. Greater bending loads were withstood by the 0° contact layer.

Overview and recent applications of the miniaturized HiPoLas ignition system

The requirements of the space industry for reusable, low cost or clustered engines have triggered high interest in a laser ignition system capable of multi-point ignition. The miniaturized SAL HiPoLas laser ignition system developed for single-point direct-plasma ignition has recently been enhanced towards a fiber coupling, multiplexing, and distribution system. A brief history of the HiPoLas development with an overview of the latest, highly miniaturized generation V ignition system is shown. Applications of the miniaturized ignition system, summarizing more than 10 years of development in the field of rocket engine laser ignition, as well as the first results of a recently developed prototype of a fiber distribution system, based on diffractive optical elements, are presented.

Fibre Distribution and Dosage Performance on the Impact Resistance of Oil Palm Shells Concrete with Hybrid Polypropylene Fibre-Mesh

Fibre Distribution and Dosage Performance on the Impact Resistance of Oil Palm Shells Concrete with Hybrid Polypropylene Fibre-Mesh

Non-destructive AC impedance spectroscopy (ACIS) analysis to characterize the evolution of impact damage in UHPC

Ultra-high performance concrete (UHPC) widely serves as protection material owing to superior impact resistance. Rapid and effective assessment of impact damage level is crucial for ensuring structural safety. The non-destructive AC impedance responds sensitively to impact-induced microstructural changes, providing important information for understanding the damage development mechanism. Therefore, this paper intends to investigate the feasibility of AC impedance spectroscopy (ACIS) for UHPC impact damage detection. UHPC specimens with different types and volume fractions of steel fibers were prepared, subjected to multiple repetitive low-velocity hammer impacts to induce cumulative damage, and the impedance responses were simultaneously tested in the frequency range of 10 Hz-5 MHz. Additionally, the effects of steel fiber distribution characteristics and pull-out mechanism on the conductive path and impact resistance were explained through microstructural analysis and 3D reconstructed model. The results show that ACIS exhibits a strong correlation with impact damage, where the increment of the imaginary part can be used as an effective and sensitive indicator to achieve whole-process damage assessment. Compared to straight steel fibers, hooked-end and corrugated fibers greatly enhance the impact resistance of UHPC but cause a nonlinear response in impedance due to extracted deformations and orifice complexities. These findings demonstrate the potential application of ACIS for detecting impact damage in UHPC and warrant further investigation.

Optimizing aligned steel fiber distribution in UHPC: Unraveling the electromagnetic influence of steel reinforcements

The performance of ultra-high performance concrete (UHPC) can be improved by the magnetic orientation of steel fibers. The reinforcement frame has strong interference with the magnetic field, and this interference may even make the production of oriented steel fibers fail. However, the study of the electromagnetic interference caused by fixed steel reinforcements has not been undertaken. In this paper, the steel fiber distributions under the interference of steel bars were tested, and the impact of different steel reinforcement diameters, lengths, and magnetic flux densities on the magnetic field was studied. The results reveal that stirrups minimally impact the magnetic field, whereas longitudinal reinforcement exerts a substantial influence. Therefore, it is feasible to manufacture an aligned steel fiber UHPC reinforced structure with a steel framework, and only the influence of longitudinal reinforcements needs to be considered. An analytical model based on electromagnetic theory was employed to elucidate the influence of longitudinal reinforcement and analyze the distribution of magnetic lines. Numerical analysis shows that the influenced range of the magnetic lines exhibited a logarithmic relationship with the flux density and a linear relationship with the length and diameter of the reinforcement. Therefore, when accompanied by a judiciously selected magnetic flux density, longer and thinner steel reinforcements are found to be conducive to achieving a comprehensive orientation of steel fibers.

Development of a novel DNA-shaped steel fiber and its performance on fresh and hardened concrete

Adding small discrete random fibers in concrete has enhanced concrete behavior in various ways. Diverse types of fibers are available in terms of materials, shapes, and applications. Different shapes of steel fibers are available like hooked ends, crimped, stranded, helix, spherical, etc. Having the grade of concrete and the fiber dosage added as constant, the structural behavior and performance will vary for different types of fibers. It shows that the shape of fiber has a great role in enhancing the properties of concrete. The challenges in existing two-dimensional steel fibers in concrete like the mechanism and contribution of fiber in arresting cracks developed in all directions and balling effect can be overcome by a new type of three-dimensional steel fiber. A novel three-dimensional DNA-shaped steel fiber is designed and fabricated. This paper presents the fresh concrete and hardened concrete properties of DNA-shaped fiber-reinforced concrete (DNAFRC) and compares it with hooked-end fiber-reinforced concrete (HEFRC) by incorporating a volume fraction varying from 0.5 to 2% of grade M30 concrete and aspect ratio of 60 for both fibers. The fresh properties of concrete were evaluated by measuring the slump for workability and wash-out test for the fiber distribution. The hardened concrete properties were assessed by compressive, split tensile, flexural, impact, shear, and pull-out strength which demonstrated considerable increase by 5% at 1.5% volume fraction, 32%, 136%, 21%, and 35% at 2% volume fraction respectively for DNAFRC than the HEFRC. Scanning Electronic Microscope (SEM) images were studied on failed samples to evaluate the bonding of DNA fiber with concrete.

Influence of fiber shapes on the compressive behaviors of ultra-high performance concrete containing coarse aggregate

The addition of coarse aggregate in ultra-high performance concrete (UHPC-CA) has the potential to reduce autogenous shrinkage and improve mechanical properties. However, it also affects the fiber distribution and crack propagation, thereby compressive relationship of UHPC. This study investigated the effects of different fiber shapes on the compressive behaviors of UHPC-CA. Three fiber shapes (straight fiber, hooked fiber, and hybrid fiber) and six coarse aggregate content (0 - 1200 kg/m3) are the main variables. The test results have indicated that the addition of coarse aggregate in UHPC rendered wider main cracks. Hybrid fiber was preferred over the hooked-end and straight fibers to optimize ductility in UHPC-CA. An increase in compressive strength of up to 17.7% and elastic modulus of UHPC of up to 23.7% after moderate addition of coarse aggregate contents, The fiber shape affected peak strain and ultimate strain values for UHPC-CA. Their peak and ultimate strains were improved by 12.8% - 15.3% and 38.2%-127.4% with the inclusion of 2% hooked and hybrid fibers. Based on the experimental data and relevant equations, a proper rational equation from the existing literature is used to generate the complete compressive stress-strain curves of UHPC-CA with different fiber shapes. In summary, this study establishes that hybrid fiber shapes significantly enhance the compressive properties of UHPC-CA. The high elastic modulus and ductility of the UHPC-CA with hybrid fiber are particularly promising for blast and impact applications.

Anatomical Structure and Bending Properties of Calamus zollingeri

The relationship between the structure and mechanical properties of materials has been a hot topic. However, there is a lack of research on the relationship between the structure of rattan and its mechanical properties. This study investigated the anatomical structure and bending properties of Calamus zollingeri, a commercially important rattan species. Samples were collected from different radial positions of the stem and analyzed for their microstructural features and mechanical properties. The distribution and morphology of vascular bundles (VBs), parenchyma cells (PCs), vessels, and fibers were examined using light microscopy. Bending tests were conducted to determine the modulus of rupture (MOR) and modulus of elasticity (MOE). Stepwise linear regression analysis was employed to explore the relationship between structural features and mechanical properties. The results showed that the diameters, lengths and distribution densities of the vessel elements were 280.32 μm, 2163.56 μm, and 3.68 pcs/mm2, respectively; the double wall thickness, lumen diameter, diameter, length, length–width ratio were 7.55 μm, 4.30 μm, 11.85 μm, 1569.39 μm, and 134.08, respectively; the tissue ratios of the vessel elements, fibers, sieve elements, and PCs were 22.76%, 20.5%, 4.83%, and 51.87%, respectively. The MOR of C. zollingeri was 55.77 MPa, while the MOE was 2669.11 MPa. The MOR of C. zollingeri was mainly affected by a double wall thickness of fiber and the tissue ratio of PCs, while the MOE was mainly affected by a double arm thickness of fiber and the tissue ratio of the vessel elements. This research provides valuable insights into the structure–property relationships of rattan, which can inform its optimal utilization in various applications.

Reconstruction of intra- and extra-neurite conductivity tensors via conductivity at Larmor frequency and DWI data patterns

The developed magnetic resonance electrical properties tomography (MREPT) techniques visualize the internal conductivity distribution at Larmor frequency by measuring the B1 transceive phase data. In biological tissues, electrical conductivity is influenced by ion concentrations and mobility. To visualize the anisotropic conductivity tensor of biological tissues, we use the Einstein–Smoluchowski equation, which links the diffusion coefficient to particle mobility. By assuming a correlation between ion mobility and water diffusivity, we aim to decompose the internal isotropic conductivity at Larmor frequency into anisotropic conductivity tensors within the intra- and extra-neurite compartments. The multi-compartment spherical mean technique (MC-SMT), utilizing both high and low b-value diffusion-weighted imaging (DWI) data, characterizes the diffusion of water molecules within and across the intra- and extra-neurite compartments by analyzing the microstructural intricacies and the foundational architectural arrangement of the brain’s tissues. By analyzing the relationships between the measured DWI data, the microscopic diffusion signal, and the fiber orientation distribution function, we predict the DWI data for the intra- and extra-neurite compartments using spherical harmonic decomposition. Using the predicted DWI data for the intra- and extra-neurite compartments, we develop a conductivity tensor imaging method that operates specifically within the separated compartments. Human brain experiments, involving four healthy volunteers and a brain tumor patient, were performed to assess and confirm the reliability of the proposed method.

Fully automated measurement of the spatial distribution of both fibre length and orientation from micro-CT images of short fibre reinforced polymers

The morphology of Short Fibre Reinforced Polymers (SFRPs) plays a fundamental role in determining their stiffness, strength and fracture behaviour. Measurements tools for the analysis of their microstructure are therefore of paramount importance. To this end, a fully automated algorithm able to segment single fibres from X-ray micro-computed tomography images was developed. This method was tailored to reconstruct the microstructure of large volumes of material; in particular, to acquire fibre length, position and orientation, even dealing with low-resolution images. The algorithm was tested on different specimens of short glass fibre-reinforced polyamide and it was validated comparing the fibre orientation with the one obtained with commercial software analysis and the fibre length with the experimentally determined one. Therefore, the proposed algorithm allows to easily identify microstructural trends without requiring the usual complex evaluating procedures.

Interlaminar fracture toughness of flax, carbon, and hybrid flax carbon‐woven fiber‐reinforced composites

AbstractThe effect of the asymmetric distribution of woven flax fiber on the interlaminar fracture toughness of carbon fiber‐reinforced polymer (CFRP) is investigated experimentally via a double cantilever beam test, and the results are backed by analytical and numerical analysis. Four hybrid configurations are fabricated with different stacking sequences of (CFRP) and flax fiber‐reinforced polymer (FFRP) plies. The results of hybrid specimens are compared with those of all CFRP and all FFRP specimens. The hybrid composite with one carbon/flax fiber layer at the interface requires the highest critical energy release rate, GC, to initiate cracks. A resin layer on top of the flax plies and a carbon fiber imprint in that layer are observed, thus signifying an increase in GC for the hybrid composites with dissimilar interface layers. Varying the number of carbon/flax fiber layers at the interface adversely affects GC. Mode II contribution to the GC was verified analytically for asymmetric hybrid configurations. The agreement between experimental, numerical, and analytical results is excellent. The hybridization of flax with carbon enhances the fracture toughness of CFRP while providing an opportunity to achieve lightweight, high‐performance, and eco‐friendly structures.Highlights Flax fiber is used to increase the fracture toughness (GC) of CFRP Asymmetric carbon/flax fiber hybrid composites are designed for this purpose One interface carbon/flax hybrid exhibits a 70% increase in GC Blocking the plies together results in reduced GC and mode‐II fracture as well Numerical and analytical analysis agrees well with experimental results

Neutrophil extracellular traps, deoxyribonuclease and fibrosis in thoracic aortic aneurysm

Abstract Introduction Thoracic aortic aneurysm (TAA) is a rare but severe cardiovascular disease. The condition often goes undiagnosed, increasing the risk of acute aortic events. It is characterized by medial degeneration, caused by neutrophils infiltrating aortic tissue. Neutrophils can form proinflammatory and prothrombotic neutrophil extracellular traps (NETs), promoting disease progression. Purpose Recently, NETs and abdominal aortic aneurysm (AAA) were linked, while their effects on TAA development and progression remain unclear. We aimed to characterize NETs and NET-specific markers in tissue and plasma samples of TAA patients. Methods We included 171 patients with either ascending TAA (n=153) or Type A dissection (n=18). Healthy subjects were recruited as controls (n=135). Sample fiber composition was analyzed using trichrome; NET burden was quantified using immunofluorescence. Plasma NET surrogate markers including double-stranded (ds)DNA, myeloperoxidase (MPO), DNase activity and matrixmetalloproteinases (MMP) were measured using a fluorescence-based assay and ELISA, respectively. mRNA expression was assessed using qPCR. Results Median patient age was 65 years, and most were male (68.4%). Cardiovascular risk factors were common, including hypertension (77.8%), hyperlipidemia (57.9%), coronary artery disease (26.3%), and diabetes (18.7%). TAA patients were older with high BMI and impaired kidney function. Trichrome staining revealed abundant fibrotic material (median 47.99%), while collagen and elastic fiber distributions were 27.67% and 20.17%, respectively. TAA patients had increased amounts of aortic fibrotic material (47.99% vs 38.94%, p=0.001). Using immunofluorescence, we found higher NET expression in diseased tissue (0.87 [0.3, 1.85] vs 0.15 [0.03, 0.22]%, p=0.0017). This increase was primarily driven by the dissection patients (1.76 [0.89, 2.83]%, p=0.0037). Plasma MPO levels were increased in TAA compared to controls (36.93 [23.46, 57.55] vs 26.8 [19.7, 36.2]ng/mL, p<0.001), while DNase activity was decreased in patients (4.16 [2.66, 6.24] vs 6.06 [4.25, 8.11]mU/mL, p<0.001). Moreover, circulating plasma levels of MMP2 were elevated in TAA (250.36 [190.24, 351.32] vs 218.85 [171.32, 263.87]ng/mL, p=0.004). qPCR analysis of mRNA expressions in TAA cryospecimens revealed upregulations of TNFα (p=0.033) and CD45 (p=0.003), when compared to aortic disease-free controls. Conclusion Aortic fibrosis at the aneurysm site may be caused by inflammatory mechanisms involving TNFα and leucocytes (CD45+). High local NET-burden is indicative of activated neutrophils in the aortic media. TAA patients have suppressed DNase activity and higher MPO levels in venous blood, leading to dsDNA accumulation and increased neutrophil turnover. Elevated MMP2 suggests its involvement in TAA formation. Our findings could enable further research targeting NETs and inflammation in TAA, possibly finding novel therapies capable of mitigating aneurysm development.