Composite Cylinders Research Articles

Constructing an efficient segregated thermally conductive network for a PBX substitute using graphene aerogels

High-energy explosives prompt stringent control over their experimental environment, which limits the feasibility of conducting experiments. This study explores the use of melamine (Me), a safe material with a structure and physical properties similar to 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), as a substitute for TATB in composite formulations aimed at improving the thermal conductivity of polymer-bonded explosives (PBXs). In waterborne polyurethane emulsion (WPU), graphene oxide (GO) was reduced and self-assembled into graphene aerogels (GA) on the surface of Me, resulting in the formation of Me@GA/PU (MGP) particles with a core-shell structure. The GA surface coating enhanced the interfacial bonding between the thermally conductive fillers (GA) and Me, improving the dispersion of the fillers within the composite. After freeze-drying and hot pressing, cylinders of MGP with a segregated thermally conductive network were obtained. The segregated network, formed by GA at low filler loading, provided an effective pathway for heat transfer and improved the thermal stability of the composites. The thermal conductivity of the MGP composite, prepared with 0.5 wt.% GO content, increased by 80% compared to the pure sample. The temperature gradient and thermal stress distribution in the composite cylinders during complex thermal cycling were evaluated using finite element analysis.

Design optimization of sandwich composite cylinder using modified differential evolution algorithm

This study presents a modified differential evolution algorithm for optimizing sandwich composite cylinders under hydrostatic pressure. The algorithm enforces balanced laminates using a while loop to enforce balanced laminates in both the initial population and trial vectors, reducing computational demands and accelerating convergence. Unlike previous studies, it demonstrates another novelty by including the number of plies and core thickness as design variables, alongside ply angles and layup sequences, enabling practical, customizable optimization. The approach increases failure load by 35.4% while reducing mass and demonstrates robustness by tolerating stochastic layup errors, resulting in resilient designs with enhanced performance.

The Influence of Adhesive Systems on Microshear Bond Strength in Bur or Laser-Prepared Enamel

Background: The aim of this study was to assess the microshear bond strength(μSBS) of various adhesive systems on enamel surfaces prepared using either an Er, Cr:YSGG laser or a conventional diamond bur. Methods: Twenty-eight caries-free human molars were longitudinally sectioned, resulting in 56 samples. Buccal or lingual surfaces were embedded in acrylic blocks. Enamel surfaces were prepared using either an Er, Cr: YSGG laser (Biolase Technologies, USA) or a traditional diamond bur (Diatech, Switzerland), referencing the midline of each tooth. Laser treatment was applied to the left side, while the right half underwent bur treatment. The samples were randomly separated into four groups(n=14): [G1] Optibond FL (Kerr, USA), a three-step etch-and-rinse adhesive; [G2] Clearfil SE Bond(Kuraray,Japan), a two-step self-etch adhesive; [G3]Prime&Bond Universal(Dentsply,USA),universal-adhesive/etch-and-rinse-mode; and [G4]Prime&Bond Universal(Dentsply,USA),universal-adhesive/self-etch-mode. Composite cylinders with a diameter of 0.8 mm (Harmonize, Kerr, USA) were affixed to the center of both the laser-prepared and bur-prepared regions of all specimens. The adhesive interface of one randomly chosen representative from each group was analyzed using a Scanning Electron Microscope(SEM). The remaining samples were subjected to μSBS testing. Data were analyzed statistically using Two-Way ANOVA(p0.05). Regardless of the preparation modalities, the adhesive systems did not exhibit any statistically significant differences(p>0.05). Furthermore, the correlation between various adhesive systems and preparation techniques did not result in statistically significant variations in μSBS values(p>0.05). Conclusion: The measured μSBS values of the adhesive systems examined on enamel surfaces prepared using either an Er, Cr:YSGG laser or a diamond bur showed similarity. Keywords: Laser preparation, Microshear bond strength, Scanning electron microscopy, Universal adhesive.

Theoretical modeling of the interfacial shear and contact stresses of 2D braided composite cylinders

AbstractThis research aims to develop an analytical model to predict the interfacial shear stress distribution and contact stress of 2D braided composite cylinders. For this purpose, a tubular structure including a helix braid on a cylindrical mandrel is considered. The interfacial shear stress and axial tensile stress in the composite structure was estimated by applying shear lag assumptions. The contact normal stress and adhesion energy were estimated by applying the assumptions of Johnson‐Kendall‐Robert (JKR) and the Hertzian contact stress theory. The results show that the geometry of the braid and different braid yarn paths have a significant influence on the interfacial shear stress, normal stress in the contact zone, and adhesion energy of composite cylinders. As a novel approach, the proposed model considers the effect of surface roughness in the composite. The results of a parametric study indicated that the composite cylinders with larger braiding angles have lower debonding initiation force. The results also showed that the yarn diameter affected the pullout force in composite cylinders by a large extent.Highlights Normal contact stress and adhesion energy of composite cylinders are affected by the braid yarn path. The 30° composite presented the largest adhesion energy and normal contact stress. Normal tensile stress and interfacial shear stress are influenced by the reinforcement path in the composite. Normal tensile stress and interfacial shear stress in composite cylinders decreased with increased braid angle.

Experimental study on fatigue performance of TC4 titanium alloy liner carbon fiber composite cylinders in seawater environment

Abstract The corrosive nature of seawater poses significant challenges to the design of gas cylinders in marine environments. Currently, TC4 titanium-alloy cylinders are predominantly used because of their resistance; however, they are costly and challenging to manufacture. To address this issue, this study proposes employing TC4 titanium alloy liner carbon fiber composite cylinders, which can reduce the manufacturing cost and processing difficulty while ensuring excellent protection against seawater corrosion and fatigue resistance. The fatigue life of the cylinders was predicted and analyzed using the finite element method, and a prototype was manufactured for verification. The results show that the composite layer can effectively share the stress load for the liner under the working pressure cycle, which increases the fatigue life of the titanium alloy liner carbon fiber composite cylinders and provides strong support for their application in marine engineering.

Optimization of the Filament Winding Process for Glass Fiber-Reinforced PPS and PP Composites Using Box–Behnken Design

Filament winding is a widely used out-of-autoclave manufacturing technique for producing continuous fiber-reinforced thermoplastic composites. This study focuses on optimizing key filament winding process parameters, including heater temperature, roller pressure, and winding speed, to produce thermoplastic composites. Using Box–Behnken response surface methodology (RSM), the study investigates the effects of these parameters on the compressive load of glass fiber-reinforced polypropylene (GF/PP) and polyphenylene sulfide (GF/PPS) composite cylinders. Mathematical models were developed to quantify the impact of each parameter and optimal processing conditions were identified across a wide temperature range, enhancing both manufacturing efficiency and the overall quality of the composites. This study demonstrates the potential of thermoplastic filament winding as a cost-effective and time-efficient alternative to conventional methods, addressing the growing demand for lightweight, high-performance, out-of-autoclave composites in industries such as aerospace, automotive, and energy. The optimized process significantly improved the performance and reliability of filament winding for various thermoplastic applications, offering potential benefits for industrial, aerospace, and other advanced sectors. The results indicate that GF/PPS composites achieved a compressive load of 3356.99 N, whereas GF/PP composites reached 2946.04 N under optimized conditions. It was also revealed that operating at elevated temperatures and reduced pressure levels enhances the quality of GF/PPS composites, while for GF/PP composites, maintaining lower temperature and pressure values is crucial for maximizing strength.

Design Optimization for Hydrostatic Pressure in Hybrid Composite Cylinders

AbstractThis study explores an optimization system to achieve the highest collapse pressure on glass-carbon hybrid composite cylinders under hydrostatic loading conditions. This work evaluates and validates previously established composite buckling solutions for cylindrical composite structures under hydrostatic pressure with experimental results of hybrid composite shells. It utilizes the validated analytical solution to optimize the buckling pressure by varying layup configuration, optimum layup angle, material content, and thickness of each lamina. The optimization is performed on asymmetric and symmetric layup cases to evaluate the influence of the hybrid layup construction on the buckling performance of the structure. Results show that the thicker glass fiber plies are preferred for inner layers and the stiffer carbon fiber plies for the outermost layers to achieve maximum buckling collapse pressure for all the optimization cases, as this configuration provides superior flexural rigidity. For hybrid composite structures with asymmetric configurations, the collapse pressure can be higher when most layers are made of glass fiber if the glass layers are at least twice as thick as the carbon layers. Similarly, axial-load-resistant layers (0°) should be located around the geometric center of the laminate with the hoop-load-resistant layers (90°) on or near the outermost layers and shear-resistant layers (45°) between these layers for both symmetric and asymmetric hybrid structures. Moreover, long tubes with small diameters (L/D > 10) favor hoop bending stiffnesses (90°) for all layers in the laminate due to less influence of boundary conditions at endcap locations.

INVESTIGATION OF IMPACT PERFORMANCE OF CYLINDER CORRUGATED SANDWICH STRUCTURES WITH DIFFERENT GEOMETRIC CONFIGURATIONS

The aim of this study is to numerically investigate and compare the impact performance of CFRP composite cylinder sandwich structures with five different geometric configurations. The impact performances and damage types of composite cylinder structures for different core configurations were determined. The impact analyses were performed in LS DYNA finite element program using MAT-54 material model with Progressive damage analysis based on the combination of Hashin damage criterion, Cohesive zone model and Bilinear traction-separation law. Among the five different specimens in the study, the highest peak force (PF) value of 1.88 kN was obtained at impact point P2 of the Trapeozidal sandwich structure. The lowest value was obtained at P1 impact point in Triangular sandwich structure with 0.62 kN. The highest and lowest energy absorption efficiency occurred in the Triangular structure, 78% and 38% respectively. The PF value at P2 point is higher than P1. The effect of core support on PF is very important. Since point P1 is not supported by the core, it is determined that the deformation is larger than P2.

Experimental and numerical analysis of damage progression in composite cylinders with cutouts under combined loading using structural health monitoring techniques

Experimental and numerical analysis of damage progression in composite cylinders with cutouts under combined loading using structural health monitoring techniques

Exploration of processability limitations of fiber placement and thickness stacking optimization of thermoplastic composite hydrogen storage cylinders for hydrogen-powered aircraft

Exploration of processability limitations of fiber placement and thickness stacking optimization of thermoplastic composite hydrogen storage cylinders for hydrogen-powered aircraft

Delamination defects in composite hydrogen storage cylinders: CT scanning and shearography measurement

Carbon fiber-reinforced composite hydrogen storage cylinder is a key component used in hydrogen fuel cell electric vehicles. However, some micro defects such as voids and delamination are inevitable during the manufacturing process. An efficient detection method for manufacturing defects is still lacking at present. In this work, industrial computerized tomography (CT) scanning was carried out and a large number of micro delamination with scattered sizes and random locations were found in the filament winding layer. Shearography technique based on digital speckle pattern interferometry (DSPI) was used to measure the surface deformation of the cylinders. It was found that the "butterfly-shaped” interference fringes representing the anomalous responses from defects can be significantly observed at the pressure difference of 0.62%–0.69% working pressure. Also, the crack was found originated from the delamination defect with the most significant “butterfly-shaped” fringes, which leads to a large area of interlaminar destruction during the hydraulic bursting test.

Comparative analysis of modal, static, and buckling behaviors in thin-walled composite cylinders: A detailed study

This investigation delves into the dynamics of buckling, modal, and static analyses within delaminated composite cylinders, integral to sectors such as aerospace, automotive, naval, and civil engineering. The escalating dependence on composite materials, attributed to their exceptional strength-to-weight ratio and adaptability in design, necessitates a deep dive into their failure modes, with a focus on delamination. Employing a systematic analytical framework, this study delineates the intricate impact of delamination on the structural integrity of composite cylinders, underscoring the synergy between buckling behavior, modal characteristics, and static performance. The methodology includes simulating a series of identical tubes, each with varying degrees of delamination, to perform a comparative analysis across three distinct tests. The procedural stages include specifying the parameters for cylinder construction and delamination, applying numerical modeling techniques for static, modal, and buckling analyses, and conducting a comprehensive correlation analysis of the outcomes. The results indicate that while fiber angles have a negligible impact on modal and buckling results, a 0°orientation significantly increases the likelihood of structural collapse in static analysis. Additionally, the correlation study among the analyses underscores the independence of results, necessitating thorough verifications in cylindrical structure development or maintenance validations. Notably, the position along the axis, the angle, and the aspect ratio of delamination are critical parameters influencing static outcomes. This research not only broadens our understanding of composite material behavior but also emphasizes the need for advanced analytical models to predict and mitigate failures, thus enhancing material design and the reliability of engineering systems.

Proteomic Analysis of Fibroblasts Exposed to Resin Composite Release.

To investigate the potential effects of products released by a resin composite on the proteome of human gingival fibroblasts. Fifteen resin composite cylinders of a Bis-GMA-based resin composite (Tetric EvoCeram, Ivoclar) were made and placed in a culture medium for 24h. Then, 30mL of this medium was placed for 72h in contact with human gingival fibroblasts and a second control group consisted of cells placed in culture medium only. Afterward, cells were collected, washed, and their proteins extracted. Three two-dimensional electrophoresis were performed per condition. Image analysis of the gels was carried out to highlight the differential protein spots. These spots were then analyzed by an ESI/qTOF mass spectrometer. Finally, specific databases provided protein identification, their interactions, and the pathways where they are implicated. Delta2D software allowed the detection of 21 spots of different proteins. The MASCOT identified 28 proteins. Five proteins from four spots were upregulated, 23 proteins from 17 spots were downregulated. The UniProt database showed that all these proteins were involved in cellular architecture, structural modifications and quality control of proteins, cellular homeostasis, and metabolic pathways. The STRING database revealed the interactions between the regulated proteins. The GO enrichment analysis showed that 19 pathways were affected. The products released from the resin composite tested led to changes in the fibroblast proteome. Under the conditions of this study, resin composite released products can cause early adverse effects on cells, but without complete inhibition of their cellular functions.

Gradient composites Al2O3-Ni obtained via the CSC technique in a magnetic field - microstructure and mechanical properties

This article presents the formation of composite microstructures by combining two established concepts: centrifugal slip casting and the utilization of a magnetic field to control the distribution of magnetic particles. The integration of these methodologies offers the potential to create zones within the composite with distinct hardness values. The study introduces a novel method for fabricating ceramic-metal composites, with a key focus on determining the feasibility of manipulating the location of the metallic phase using a magnetic field. Through this innovative approach, the research aims to produce composite hollow cylinders with a gradient distribution of metallic particles. The relative density of the composites was 97 %. The hardness values for the samples range from 970 HV to 2700 HV, displaying variability based on the metallic phase content within the material. The compressive strength for Al2O3-Ni samples was equal to 128.92 MPa. The Al2O3 grains in zone III after the sintering process have an average size of 1.27 ± 0.68 µm. The Al2O3-Ni composites indicate a smaller heat capacity of the material compared to pure Al2O3 samples.

Impact of repair protocols on the bond strength to composite resin.

This study evaluated the impact of different repair protocols on a composite resin substrate using distinct bonding agents submitted or not to artificial aging. Unopened sets of a single-step universal adhesive system (UA) and silane-coupling agents, a single-step pre-hydrolyzed (PH) or a two-step immediately hydrolyzed (IH), were used. Half of the sets were subjected to artificial aging being stored at 48°C for 30days, while the other half remained unaged. The composite resin substrates were prepared and aged in distilled water, sandblasted (Al2O3), and cleaned. Then the different repair protocols were applied according to the groups. UA was used without a previous silane layer, while PH and IH were applied followed by a single-step etch-and-rinse adhesive system. Adhesive systems were light-activated, and four composite resin cylinders were formed over the substrate. After 24h, the specimens were subjected to microshear bond strength (μSBS) test and failure mode analysis. The μSBS data were subjected to two-way ANOVA followed by Tukey HSD; Kruskal-Wallis analysis was used for failure mode distribution (α = 0.05). After aging the products, UA showed higher bond strength, while PH had significantly lower results, and IH showed no significant differences (p = 0.157). No significant differences were found for bond strength among the repair protocols when using non-aged products (p > 0.05). The protocols using UA and IH showed no significant differences between aged and non-aged bottles, whereas PH exhibited lower bond strength whencomparing aged and non-aged products. More cohesive failures were observed in the resin substrate for the IH groupwithout aging.

Assessment of Surface Roughness, Color, and Bonding Efficacy: Self-Adhesive vs. Conventional Flowable Resin.

This in vitro study aimed to analyze the surface roughness (Ra) and color stability (ΔEab, ΔE00) following simulated mechanical brushing and to evaluate the microtensile (μTBS) of self-adhering resin flowable (SARF) to dentin. The selected materials were Constic, Yflow AS, and Tetric N flow (TNF/control). Thirty composite resin cylinders were fabricated for surface property evaluation. Ra and color were assessed both before and after simulated brushing. The thresholds of 50:50% perceptibility and acceptability of color differences in the evaluated resins were assessed. For μTBS analysis, fifteen molars were selected, sectioned to expose flat dentin surfaces, and restored according to the manufacturers' instructions for microtensile testing. There were statistically significant differences in Ra among the groups, with Constic exhibiting the highest Ra value (0.702 µm; p < 0.05), whereas Yflow AS presented the lowest Ra value (0.184 µm). No statistically significant difference in color was observed among the groups (p > 0.05). The 50:50% perceptibility and acceptability thresholds were set at 1.2 and 2.7 for ΔEab and 0.8 and 1.8 for ΔE 00. All the results fell within the acceptable limits. The mean μTBS values of Constic, Yflow AS, and TNF were 10.649 MPa, 8.170 MPa, and 33.669 MPa, respectively. This study revealed increased Ra and comparable color stability among all the tested composite resins after abrasion. However, the SARF exhibited lower μTBS compared to conventional using an adhesive system.

Repair Bond Strength of Composite Resin to Dental Ceramic Using Various Surface Treatments: An In Vitro Study.

This research aims to evaluate and compare the effect of various surface treatments and adhesive types on the bond strength between composite resin and two types of ceramic materials. A total of 98 disk-shaped of 10 mm diameter and 4 mm thickness were fabricated for each of the zirconia (H. C. Starck) and lithium disilicate (IPS E-Max computer-aided design), which were implanted individually in the acrylic resin mold leaving one surface exposed. The disks in each group were sub-divided according to the surface treatments into seven groups (n = 14): [hydrofluoric acid (HF, 9.5%), air abrasion, bur, laser, HF + bur, HF + air abrasion, HF + laser]. Each sub-group was further divided into two groups (n = 7) according to the type of adhesive used for the repairing procedure [G-Premio Bond universal adhesive group and intraoral repair kit (BISCO) group]. Each adhesive was applied depending on manufacturer instructions and, then, the composite cylinder (4 mm in diameter and 4 mm in height) was built on the pre-determined treated ceramic surface area by the addition of rubber mold. Then the samples were stored in distal water for 24 h. After that, all groups were submitted to a shear bond test using an Instron testing machine (TSTM 02500; Elista Ltd., Istanbul, Turkey) at 0.5 mm/min a crosshead speed. The data were analyzed by three-way analysis of variance and Tukey post hoc test at (P ≤ 0.05). The HF + air abrasion groups registered the higher bond strength but with no statistically significant difference from groups of HF + bur. While the laser groups showed the lowest mean bond strength. Generally, E-Max registered significantly higher bond strength in comparison to zirconia. Finally, the BISCO repair system registered a significantly higher bond strength value in comparison to G-Premio. Combined surface treatment of HF + air abrasion with an intraoral repair kit can provide a promising method for repairing cracked ceramic restorations. However, repairing lithium disilicate is more predictable and successful than zirconia.

Optimization of composite cylinder subjected to hydrostatic pressure using customized evolutionary algorithm

The structure for optimization is a composite cylinder subjected to hydrostatic pressure. The customization is in the method of incorporating the balanced laminate constraint using a while loop which not only improves buckling resistance but also drastically reduces the computation time. The formulation of the objective function is carried out in a novel way. The third customization is in considering geometric variables along with layup in optimization to arrive at the most optimal configuration. The results suggest a significant increase in buckling load ranging from 61.3% to 92.2% and a reduction by about 76.3% in time required for optimization.

Semi-destructive methods for evaluating the micro-scale residual stresses of carbon fiber reinforced polymers

Micro-scale residual stress in carbon fiber reinforced polymers have a significant impact on their mechanical performance. The residual stresses in the carbon fibers were released by micro-slotting and micro-ring-core methods using focused ion beam (FIB). The released deformation fields were captured by cross-gratings and mapped by geometric phase analysis (GPA) and digital image correlation (DIC) methods. The in-plane residual stresses in the carbon fibers were experimentally determined to be −40.5 MPa using elastic constitutive relations, which is consistent with the composites cylinder model. The axial compressive residual stresses in the fibers were found to be greater than −100 MPa. Moreover, the maximum value of residual stress in the polymer matrix was observed at the interface, potentially serving as a crack initiation site.

Erosive Influence of Amazonian Tucupi on Microshear Bond Strength to Enamel and Dentin.

The scientific literature has studies that assess the influence of erosive challenges with citric acidic drinks and substances on the adhesive bond strength to enamel and dentin, but does not contain information about the influence of regional components of an acidic diet on this process. Thus, this study evaluated the erosive influence of Amazonian tucupi on enamel and dentin microshear bond strength. One hundred and sixty-eight healthy bovine incisors teeth were used, divided into 12 groups (n = 14). For erosive cycling, distilled water (negative control), cola-based soft drink (positive control), or tucupi were used, followed by adhesive strategies of (1) etch-and-rinse (conventional) (Adper™ Single Bond 2) and (2) self-etching (Clearfil SE Bond). All specimens were subjected to erosive cycling for 5 days and, after 24 h, composite resin cylinders were built up for the microshear bond strength test. The data showed normal distribution and were analyzed by two-way ANOVA, followed by the Tukey post and test (P ≤ 0.05). There were no significant differences in enamel (P > 0.05). In dentin, only the groups exposed to cola-based soft drink showed significant differences (P < 0.01). The failure mode showed that Type II (mixed) was predominant (95%). The erosive challenge with tucupi did not influence the bond strength to enamel and dentin, regardless of the adhesive strategy used.