Research on six-pile caps mainly focused on reinforced concrete six-pile caps and steel fiber reinforced ordinary strength concrete six-pile caps. In order to study the force mechanism of steel fiber reinforced high strength concrete (SFRHSC) six-pile caps, eight SFRHSC six-pile caps with the plane dimensions of 960 mm × 600 mm were subjected to static load test. The experimental variables include the volume fraction of steel fiber (0 %, 0.5 %, 1.0 %, 1.5 %), concrete strength grade (C40, C60), effective thickness of pile caps (160 mm, 210 mm, 260 mm) and reinforcement layout (uniform grid, bunched). The tests were carried out to measure and analyze the crack development and failure mode, the load-deflection curve, the concrete strain and steel strain of specimens. On this basis, finite element analysis was conducted by ABAQUS and compared with the experiments. The results show that the failure mode of SFRHSC six-pile caps is the punching failure, and the load-transferring mechanism of six-pile caps conforms to strut-and-tie model. With the increase of the effective thickness of pile caps, the bearing capacity of specimens can significantly increase, and the fiber volume fraction of about 1 % has the best effect on enhancing the bearing capacity of SFRHSC pile caps. Finally, the calculation method for the punching shear capacity of SFRHSC six-pile caps based on strut-and-tie model was proposed.
To procure environmentally – friendly and sustainable super-absorbent polymers (SAP), a concurrent irradiation approach utilizing 60Co γ-rays is employed to graft acrylic acid (AA) and acrylamide (AM) onto mung bean straw cellulose (MBS-cellulose). Using different solvents to dissolve the straw yielded a more soluble form. The structural characteristics and thermal stability of MBS-cellulose and the graft copolymer are also comprehensively analyzed. The influence of the MBS pre-treatment method, irradiation dose, irradiation rate, cross-linking agent dosage, monomer ratio, and MBS-cellulose proportion on the water absorption capacity and salt resistance of the graft copolymer is investigated. The research indicates that under specific synthesis conditions, the optimal reaction conditions for graft copolymerization were determined via single-factor experiments. The monomer ratio, specifically m (AA):m (Am), was set at 1.4. The material ratio, defined as m (AA + AM):m (MBS-cellulose), was 11. The neutralization degree of the monomer approximated 90 %. The irradiation dose was 6 kGy, the dose rate was 1.4 kGy/h, and the cross-linker dosage was 2.4 %. The resultant MBS-cellulose grafted copolymer exhibited a water absorption capacity of 2,340 g/g and a brine absorption capacity of 211 g/g.
This study evaluated the effects of thermal activation and replacement ratio of waste brick powder (WBP) on the physicochemical characteristics and engineering performance of mortar to recycle waste bricks generated from construction waste as a cement replacement material. Thermogravimetric analysis and X-ray diffraction were performed to analyze the thermal and mineralogical properties of WBP. The flow, compressive and flexural strengths, and water absorption were measured for mortar with WBP thermally activated at 600 °C and 800 °C with replacement ratios of 6 %, 13 %, and 20 %. The results showed that WBP exhibited thermally stable behavior up to 900 °C, with limited mineralogical phase changes observed after heat treatment. For mechanical properties of WBP-based mortar, thermal activation did not have a consistent effect on improving compressive or flexural strength, suggesting that additional thermal activation is inefficient for waste bricks that have already been calcined at high temperatures. In contrast, under low replacement ratio, regardless of thermal activation, WBP-based mortars satisfied most of the compressive strength requirements specified by current industrial standards, confirming the practical applicability of WBP as a cementitious material.
Marble processing facilities produce significant quantities of marble waste, and the disposal of this waste presents economic and environmental challenges. Recent years have seen research focused on composite materials, especially those applicable as building materials, to tackle this issue. This study developed polyurethane (PUR) composite samples incorporating varying proportions of waste marble dust (WMD) for acoustic insulation applications. Composite samples were generated with volume filler ratios between 10 % and 30 % and evaluated against a pure PUR reference. The acoustic properties, including sound absorption and Sound Transmission Loss (STL), were evaluated across low and high-frequency ranges utilising impedance tube methods in compliance with ISO and ASTM standards. Experimental data indicates a direct correlation between increased WMD loading and a marked enhancement in the acoustic damping characteristics of the matrix. The composite with 30 % WMD demonstrated superior performance, especially in the high-frequency range. This research concludes that WMD-reinforced PUR composites provide a cost-efficient and sustainable solution for noise insulation in the construction industry.
The reduction in factor of safety (FOS) of any slope is due to a reduction in total stress. To increase the strength of the soil slope, commonly adopted techniques lead to environmental impact. To overcome this situation, an inert material like Polyurethane (PU) can be mixed in the soil medium to increase the stability of the slope. The present study aims to use PU to stabilise the topsoil of the slope, which effectively increases the FOS. Direct shear tests were performed to understand changes in the shear strength parameters with the addition of various percentages of PU. FOS of slope is understood using Plaxis-2D. Results of the Direct shear tests showed the improvement of cohesion from 15 kPa of virgin soil to around 138 kPa and angle of shearing resistance from 17 degrees to around 58 degrees with the addition of 10 % PU to the soil, with just 7 h of curing. Plaxis-2D analysis indicates the increase in FOS by 22 % with stabilisation of topsoil up to 0.3 m. The study recommends the use of PU to stabilise embankments, as it provides a rapid increase in strength and quick enhancement of slope stability.
A novel antimicrobial packaging film containing konjac glucomannan, corn starch, and garviecin LG34 was prepared and its mechanical, physical, and antibacterial properties were investigated. Fourier transform infrared (FT-IR) spectra indicated that an interaction was produced between the functional groups in konjac glucomannan or corn starch and groups in garviecin LG34. The X-ray diffraction (XRD) patterns showed that the incorporation of garviecin LG34 made the network more orderly and decreased crystallinity. SEM analysis showed that garviecin LG34 significantly improved the surface state and made the surface flatter and smoother. The crystallinity decreased due to disruption of ordered starch domains caused by intermolecular interactions, and FTIR suggested possible intermolecular interactions, likely hydrogen bonding. Incorporation of garviecin LG34 significantly improved the thermal stability of composite film, and the T 10 % and the residual weight at 600 degrees C respectively increased by 38.23 % and 205.13 % when 6 % garviecin LG34 was added. The increase in heat stability suggested garviecin LG34, which could be inserted into the film structure, may serve as a mass tranfer barrier or thermal insulator in the composite film. When the addition amount of garviecin LG34 was increased from 0 % to 6 %, the breaking elongation, swelling degree and water solubility decreased by 16.65 %, 26.22 % and 28.71 %, and the tensile strength increased by 49.42 %. The konjac glucomannan/corn starch composite film containing garviecin LG34 not only inhibited gram-positive foodborne pathogenic Staphylococcus aureus but also Gram-negative Salmonella typhimurium. The konjac glucomannan, corn starch, and garviecin LG34 composite film can served as a novel broad spectrum antimicrobial packaging material cantainning natural antimicrobial peptide and safty for application in the food industry.
This study integrates numerical simulation and experimental analysis to investigate the mesomechanical response of 93W Cu alloy under quasistatic compression, focusing on stress and strain distributions. The results reveal a highly heterogeneous distribution of stress and strain at the mesoscale, driven by the significant mechanical property mismatch between the tungsten and copper phases. Stress is predominantly concentrated in the high-modulus, high-strength tungsten skeleton, which serves as the primary load-bearing network, while macroscopic plastic strain is largely accommodated by the ductile copper binder phase through plastic flow. The deformation mechanism features sliding and rotation of tungsten particles along copper interfaces, with negligible plastic strain within the tungsten itself. This work elucidates the synergistic deformation mechanism, “hardphase load bearing and softphase flow”, in W Cu alloys, providing a theoretical foundation for optimizing macroscopic mechanical properties through mesostructural tailoring.
Preparing iron-based composites with zirconia toughened alumina particles (ZTAp) and mixed carbide niobium particles (NbCp) by powder metallurgy has been established as an important way to extend the service life of the cutting teeth. However, the severe shedding of ZTAp under harsh working conditions significantly reduces the performance of the composite material. In this paper, the surface of ZTAp was plated with cobalt to improve interface bonding with the iron matrix. Subsequently, the composite material was subjected to impact abrasive wear tests. The primary factor affecting the electroless plating process is the pH value of the plating solution, followed by the concentration of NaH2PO2 & centerdot;H2O, and the concentration of C4H4Na2O6 & centerdot;2H(2)O. The composite material containing 15 % mass fraction of irregularly shaped ZTAp particles (2 mm) exhibited enhanced hardness and excellent overall performance. The wear progression of the composite material was characterized by three stages: matrix wear, the particle wear resistance, and particle shedding. The cobalt layer deposited on the surface of ZTAp mainly reinforced the bonding with the iron matrix, improved wear resistance during the particle wear resistance phase, and prolonged the protective influence of ZTAp on the matrix. Overall, these findings provide a valuable basis for optimizing the wear performance of composite.
In marine environments, the concrete deterioration due to chloride ion attack is influenced by a number of factors. A chloride diffusion model considering multiple factors was proposed and validated through experiments. Meanwhile, a comprehensive model was established based on the Monte-Carlo method to predict the service life of concrete subjected to chloride corrosion. This model takes into account factors including time of exposure, chloride ion binding capacity, temperature and relative humidity. The results indicated that: the durability lifespan decreases with increasing time decay coefficient, ambient temperature, and relative humidity. As the temperature rises from 20 to 30 degrees C, the service life reduces by 31.6 %; when relative humidity increases from 70 to 90 %, the service life decreases by 50.6 %; and when the time decay coefficient rises from 0.2 to 0.4, lifespan diminishes by 54.2 %. Conversely, the increase in chloride binding capacity exerts a favorable effect on durability life. In addition, sensitivity analyses were conducted and the factors influencing the durability life of concrete structures, ranked from highest to lowest impact, is as follows: protective layer thickness, diffusion coefficient, surface chloride concentration and critical chloride concentration. The results of the study can provide a reference for predicting the durability life of concrete structures.
With the expanding use of woven composites in critical load-bearing applications under harsh environmental conditions, it is essential to evaluate how hygrothermal exposure affects their performance. This study aims to systematically analyze the hygrothermal effects on the dynamic characteristics of carbon fiber reinforced polymer (CFRP) composites with different weaving types: plain, satin, and twill. Accelerated hygrothermal tests were conducted by immersing specimens in water at 70 degrees C for 48 days until moisture saturation. The experimental methodology integrated microstructural analysis via scanning electron microscopy (SEM), static mechanical testing, and experimental modal analysis (EMA). Additionally, a coupled hygrothermal finite element model incorporating the Tsai hygrothermal aging model was developed to predict the hygrothermal changes. SEM observations revealed substantial microstructural deterioration, including matrix pulverization, surface cracking, and increased porosity, with porosity growth rates quantified at 315 % for plain, 72.7 % for twill, and 213 % for satin weaves. The static mechanical properties of CFRPs were significantly degraded, with compressive properties being the most sensitive - twill weaves exhibited the most pronounced reduction in compressive modulus with a 40.12 % decrease, tensile and interlaminar shear strength (ILSS) properties showed relatively moderate degradation across all weaving types. Experimentally, the first five natural frequencies declined across all weaving types, with the most pronounced reduction in the fundamental frequency 1.07 % for plain, 2.08 % for twill, and 1.73 % for satin weaves. Dynamic stiffness degradation was measured at 15.7 % for plain, 10.93 % for twill, and 7.83 % for satin weaves. In contrast, damping ratios consistently increased for all specimens. The finite element simulation showed good agreement with experimental modal frequencies for low-order modes with an average error of less than 10 %, though discrepancies in higher-order modes indicated limitations in capturing microstructure-dependent hygrothermal variations. Owing to its longer float length, the satin weave exhibited the least degradation in compressive strength and dynamic stiffness, along with enhanced damping capacity resulting from high-density mechanical interlocking of matrix microparticles. Therefore, the satin weave is recommended for engineering applications in hygrothermal environments to better maintain structural dynamic stability.
Prestressed concrete cylinder pipe (PCCP) is composed of concrete, steel cylinder, mortar and prestressed steel wire, which has been widely used in water conveyance and diversion projects. PCCP employs high-strength concrete, which undergoes a series of temperature responses due to hydration and external temperature variations, consequently affecting its bearing capacity. This study takes a DN3200 embedded prestressed concrete cylinder pipe (PCCPE) as the research object, and a hydration degree calculation model that considers both temperature and concrete age is proposed. The influence of the construction season is taken into account, and a full lifecycle simulation - from production and storage to buried operation - is conducted to investigate the bearing characteristics under temperature effects. The results show that: (1) through the overload failure analysis of PCCP under ideal conditions (without considering temperature effects), it is found that the safest way to determine the bearing capacity of PCCP is by analyzing the stress variation at the inner side of the concrete core invert at the mid-section of the pipeline. (2) After considering the effects of construction-season ambient temperatures, it is found that the higher the construction temperature, the lower the prestress in the concrete core and the greater the stress difference between the inner and outer sides, which has a more adverse impact on the pipeline's bearing capacity. (3) Under the influence of construction temperatures in different seasons, the bearing capacity of the PCCP concrete core is significantly lower than that under ideal conditions. This study can provide a valuable reference for engineering design and construction.
This work introduces a novel geometrical and analytical modeling framework for predicting the stiffness properties of knitted composites, a class of materials known for their complex architectures and versatile mechanical behavior. The proposed approach integrates multi-scale modeling techniques with finite element homogenization to derive an accurate stiffness matrix that accounts for yarn geometry, stitch configuration, and material properties. A user-friendly “click-and-drop” interface was developed to streamline the design and construction of knitted composite geometries, incorporating automated validation checks to ensure structural accuracy. Analytical formulations were combined with discretization techniques to evaluate layer-by-layer contributions and compute macroscopic stiffness with high precision. The model was validated against experimental benchmarks from Huang, Gommers, and Ramakrishna for plain knitted, weft-knitted, and glass-fiber-reinforced composites, yielding prediction errors consistently below 5 % for longitudinal, transverse, and shear moduli. These results confirm the robustness of the proposed framework and its ability to replicate real-world mechanical behavior. The methodology offers a significant improvement over traditional modeling approaches by providing greater accuracy, adaptability to various composite configurations, and reduced computational complexity. This research contributes a generalized, scalable, and practical tool for engineers and researchers, enabling efficient analysis and optimization of knitted composites for applications in aerospace, automotive, biomedical, and wearable technologies. Future developments may extend the model to account for nonlinear, viscoelastic, and failure behaviors, further enhancing its utility for advanced material design.
To investigate the dynamic mechanical behavior and fragmentation characteristics of layered rock under the combined effects of chemical corrosion and impact loading, split Hopkinson pressure bar (SHPB) tests were performed on layered sandstone specimens with bedding angles of 0 degrees, 30 degrees, 45 degrees, 60 degrees, and 90 degrees. The tests were conducted under solutions with various pH levels and under multiple impact pressure conditions. Stress-strain responses, strength and deformation parameters, and failure modes were analyzed to evaluate the anisotropy in mechanical behavior. Fragment size distribution was systematically examined using fractal theory to quantify the degree of fragmentation. The results show that the dynamic compressive strength exhibits U-shaped anisotropy, which is significantly intensified by chemical corrosion. Strength degradation was most pronounced under acidic conditions (pH = 4), followed by alkaline (pH = 10) and neutral (pH = 7) environments, with the greatest reduction observed at bedding angles of 45 degrees and 60 degrees. Both dynamic strength and peak strain increase with rising impact pressure, whereas the influence of chemical corrosion gradually diminishes. The fractal dimension also increases with impact pressure, but at a declining rate. Acidic conditions led to the highest fractal dimension, reflecting more intense fragmentation. These findings provide valuable insights for disaster prevention and the optimization of fragmentation efficiency in engineering practices involving chemically corroded layered rock masses.
This study focusing on a carbon fibre-reinforced polyamide 6 (CFPA6) crash box system designed, manufactured, and crash-tested within an aluminium environment as part of a novel automotive front-end structure (FES). A key challenge in this work was the multi-material joining required for assembling the carbon fibre reinforced polymer (CFRP) crash box with its aluminium surroundings. Only a limited number of viable joining techniques - such as mechanical fastening (e.g. bolting, riveting) and adhesive bonding - were found to be suitable. Investigations were conducted to evaluate the impact of these joining methods on crash behaviour and overall crash performance. The crash box system was tested under axial crushing conditions to further explore the use of an inversion mechanism, aimed at enhancing energy absorption and crash performance. The adoption of a thermoplastic matrix (PA6) significantly reduced dust and particle emissions during impact, thereby improving environmental and occupational safety. Furthermore, the material's recyclability and the long service life of the composite structure enable potential reuse in future vehicle generations at the End-of-Life (EoL) stage - a reuse strategy that is also described in this work.
Thermoplastic polymers have emerged as compelling alternatives to conventional thermosets in response to increasing environmental concerns, primarily due to their superior recyclability and enhanced sustainability characteristics. Among them, Elium (R) resin is particularly promising because it can be polymerized at room temperature using conventional liquid molding processes, such as resin transfer molding or vacuum infusion, and provides mechanical performance comparable to that of thermoset systems. In this study, the rheological behavior of Elium (R) resin and Elium (R)/graphene oxide (GO)/solvent mixtures was systematically examined to assess the effects of varying solvent content and GO loading. First, the baseline viscosity of neat Elium (R) resin was evaluated to establish the processing requirements for liquid molding. Subsequently, the effect of GO addition on viscosity, along with the viscosity-reducing capability of acetone as a solvent, was quantitatively analyzed to identify the primary factors governing the viscosity behavior. The results indicate that the addition of GO consistently increased the viscosity, whereas the incorporation of acetone effectively reduced it. Moreover, the sensitivity of viscosity to GO loading decreased as the solvent ratio increased, indicating that the viscosity-reducing efficiency did not scale linearly with the solvent content. These findings offer valuable insights into the optimization of resin formulations to enhance processability and nanoparticle dispersion in Elium (R)-based nanocomposites.
This study investigates the formation mechanisms of metal foil textures on composites surface, focusing on the distinct stripes and patterns observed in areas with layer thickness variations, overlaps, stringer bonding, and curved surface. The primary influencing factors identified include resin flow, fiber compaction, stringer spring-back, and non-normal forces during the curing cycle. Under the combined effects of these factors, metal foils migrate toward the tooling surface, causing the resin film to thin and aggregate among fiber bundles, which results in visible stripes and textures. Through experimental analysis and metallographic observations, this study provides insights into fiber bed movement in composite materials and constitutes the first empirical validation under actual manufacturing conditions of the applicability and correctness of classical theories.
In this study, 0.5 wt % GNPs reinforced Al-Zn-Mg-Cu matrix composites were prepared by vacuum hot pressing sintering and hot extrusion using Al-Zn-Mg-Cu alloy powder as matrix and graphene as reinforcing phase. The effects of different hot extrusion temperatures on the properties of the composites and the strengthening mechanism of Al-Zn-Mg-Cu matrix with graphene were studied. The results show that when the hot extrusion temperature is 420 degrees C, the extruded products have higher properties, and the tensile strength is 359 +/- 2 MPa. This is because the increase of temperature will accelerate the diffusion rate of metal atoms, especially in the hot extrusion process, thus improving the extrusion quality of the products. It can be seen from the microscopic characterization that the black material after extrusion is distributed in a dispersed chain along the extrusion direction. With the increase of extrusion temperature, the graphene agglomeration improvement effect is better, and the orientation trend is more obvious. When the extrusion temperature is 420 degrees C, the dispersion traces are the most, the distribution is the most uniform and fine. The uniform distribution of graphene and the second phase (Mg2Si and MgZn2) in the composites will be beneficial to the improvement of the mechanical properties of the composites. There are a large number of dimples and tearing edges in the tensile fracture of the composite extruded at 420 degrees C, and the dimples are more and smaller and equiaxed. The interfacial bonding between graphene and Al-Zn-Mg-Cu alloy matrix is better, and the graphene sheets are thinner and more evenly distributed, which is beneficial to the improvement of mechanical properties. At the extrusion temperature of 420 degrees C, the reinforcement of graphene aluminum matrix composites is evenly distributed and deformed, which is conducive to the formation of higher mechanical properties of the composites.
Unmanned aerial vehicle (UAV) technology has revolutionized numerous sectors, including precision agriculture, infrastructure inspection and defense. Consequently, there is a critical need to develop a unique composite structures that offer high durability, low density, and enhanced mechanical properties for UAV airframes. This study addresses this demand by investigating the enhancement of glass and carbon fiber reinforced polymer (GFRP/CFRP) composites through the integration of multi-walled carbon nanotubes (MWCNTs at 0.5 and 1 wt%). The mechanical properties including tensile, flexural, and interlaminar shear strength (ILSS) were experimentally characterized and microstructural analysis was performed using scanning electron microscopy (SEM). The results indicated that carbon fiber composites (CFRP) with 1.0 wt% MWCNTs achieved a strength of 289 MPa, representing a 9.5 % improvement in tensile strength over the 0.5 wt% CFRP. However, the CFRP with 0.5 wt% MWCNTs demonstrated better performance in both flexural and ILSS strength, exhibiting 8.8 % and 13.6 % higher than the 1.0 wt% CFRP sample, respectively the same pattern was observed for glass fiber composites (GFRP), where the 0.5 wt% MWCNTs showed higher flexural and ILSS characteristics compared to the 1.0 wt% GFRP sample. SEM analysis confirmed that the superior performance of the 0.5 wt% samples was due to better fiber-matrix adhesion and uniform dispersion. It was concluded that a 0.5 wt% MWCNTs is optimal for both CFRP and GFRP, providing the best balance of mechanical properties for weight sensitive UAV applications, while higher concentrations lead to property degradation due to agglomeration.
Ceramifiable coatings, renowned for their exceptional resistance to high temperatures, oxidation, and corrosion, are widely used in fields such as power transmission and aerospace. In this study, a ceramifiable coating with a thickness of 0.3 mm was prepared via the scrape-coating method using silicone resin as the matrix and a 0.5 mm mica plate (MP) as the substrate, with aluminum hydroxide (ATH), aluminum phosphate (AP), mica powder, wollastonite, and glass powder as fillers. The synergistic effects of ATH and AP on the refractory properties and ceramization behavior of the coating were investigated. Results show that when the mass ratio of ATH to AP is 1:2, the coated mica plate exhibits a flexural strength of 36.9 MPa after 10 min of flame ablation (1,150-1,200 degrees C), significantly higher than that of an uncoated 0.8 mm mica plate (13.5 MPa). The crystalline phase composition and microstructure of the coating after flame ablation were characterized by XRD and SEM. Analysis indicates that ATH decomposes at high temperatures to form aluminum oxide, which acts as a ceramic filler participating in the formation of the ceramic framework. Meanwhile, aluminum phosphate enhances the bonding between ceramic fillers and promotes the ceramization reaction.
The use of marble waste as a secondary raw material in production helps to reduce environmental damage. In this study, samples of ceramic wall tiles (WT) (10 % calcite replacement) and samples of polypropylene (PP) composites washing machine drums (43 % calcite replacement) were prepared using marble waste powders (WMP). Measurements of water absorption (%), fracture strength (kg/cm2), firing strength (kg/cm2) and color properties (L, a, b) were performed on the WT samples. In addition, the physical and mechanical properties such as compression, tensile and flexural behavior were investigated on the specimens of polypropylene composites with calcite (PP-C) and polypropylene composites with WMP (PP-WM) composites. The use of WMP in the production of WTs reduces the water absorption capacity due to its hydrophobicity. However, no significant changes were observed in the fracture strength values for WMP-WT samples and STD-WT samples. When waste marble powder was used in PP drum composites, an increase in MFi of approximately 23 % was observed, although the mechanical properties of the composites decreased slightly. Regarding the use of WMP as a secondary raw material, the predicted results were in agreement with the experimental observations.
