Improving the Mechanical Performance of Timber Railway Sleepers with Carbon Fabric Reinforcement: An Experimental and Numerical Study

Biocomposites based on thermoplastic polymers and natural fibers have recently been used in wind turbine blades, to replace non-biodegradable materials. In addition, carbon nanofillers, including carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs), are being implemented to enhance the mechanical performance of composites. In this work, the Mori–Tanaka approach is used for homogenization of a polymer matrix reinforced by CNT and GNP nanofillers for the first homogenization, and then, for the second homogenization, the effective matrix was used with alfa and E-glass isotropic fibers. The objective is to study the influence of the volume fraction Vf and aspect ratio AR of nanofillers on the elastic properties of the composite. The inclusions are considered in a unidirectional and random orientation by using a computational method by Digimat-MF/FE and analytical approaches by Chamis, Hashin–Rosen and Halpin–Tsai. The results show that CNT- and GNP-reinforced nanocomposites have better performance than those without reinforcement. Additionally, by increasing the volume fraction and aspect ratio of nanofillers, Young’s modulus E increases and Poisson’s ratio ν decreases. In addition, the composites have enhanced mechanical characteristics in the longitudinal orientation for CNT- reinforced polymer and in the transversal orientation for GNP-reinforced polymer.

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Numerical study on the influence of high altitude environment on hydraulic mechanical performance

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/163/1/012088 ◽

2018 ◽

Vol 163 ◽

pp. 012088

Author(s):

B Xue ◽

Y P Zhao ◽

W L Liao ◽

Z H Li

Keyword(s):

High Altitude ◽

Mechanical Performance ◽

Numerical Study

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A Numerical Study of Railway Ballast Subjected to Direct Shearing Using the Discrete Element Method

Advances in Materials Science and Engineering ◽

10.1155/2020/3404208 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13

Author(s):

Hongyi Zhao ◽

Jing Chen

Keyword(s):

Discrete Element Method ◽

Mechanical Performance ◽

Numerical Study ◽

Discrete Element ◽

Contact Forces ◽

Angle Of Repose ◽

Particle Rotation ◽

Railway Ballast ◽

Depth Analysis ◽

Element Method

Railway ballast is a coarse granular material used to carry train loads and provide drainage for the rail tracks. This study presents numerical explorations of the mechanical performance of ballast aggregates subjected to direct shear tests. The discrete element method (DEM) was used to investigate the microscopic characteristics of ballast aggregates during shearing while considering contact distribution, particle rotation, and particle displacement. By testing the angle of repose of ballast aggregates, the parameters for the DEM contact model could be calibrated. Four specimens were prepared and then subjected to different normal pressures. The results show that the contact between ballast particles intensifies in terms of the amount and magnitude as the normal pressure increases. A Fourier analysis was applied to investigate the anisotropy of contact normal and the contact forces for ballast aggregates at different shearing phases. The rotational and translational movements of ballast particles were investigated, and this investigation revealed that particle rotation gradually increased as the shearing propagated. Four regions in the aggregates were identified according to the translational pattern of ballast particles. The results of this research provide an in-depth analysis of microscopic characteristics from a particulate scale.

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An experimental and numerical study of the expansion forming of a thick-walled microgroove tube

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/09544062jmes1189 ◽

2008 ◽

Vol 223 (3) ◽

pp. 689-697 ◽

Cited By ~ 3

Author(s):

D Tang ◽

Y Peng ◽

D Li

Keyword(s):

Mechanical Performance ◽

Numerical Study ◽

Surface Profile ◽

Processing Parameters ◽

Forming Process ◽

Axial Section ◽

Die Geometry ◽

Contact Points ◽

Industrial Sectors ◽

Full Contact

CO2 refrigerant-based air conditioning and refrigeration (ACR) is an increasing concern in many industrial sectors for its zero ozone depletion potential. One of the major requirements in its application is the forming technology of thick-walled tube according to the extremely high pressure working conditions of the ACR system. This article presents a study on the expansion process joining the thick-walled microgroove copper tube to aluminium fins. Experiments of the forming process have been carried out. Finite-element models are developed to investigate the deformation of overall and local structures. Evaluation of the joining quality along the longitude axis of the tube is first attempted. The agreement of the results on the contact surface profile confirms that the joint is far away from full contact in the axial section. Formation mechanism of the unexpected contact status lies in displacement of the contact points along the section of the fin collar, which is mainly related to the expanding ratio. To improve the forming quality, discussion on processing parameters and die geometry is conducted. Results show that the expanding ratio is the major factor influencing the thermal—mechanical performance of the joint and 2–6 per cent can be the comprehensively beneficial range for a thick-walled ACR tube; average contact pressure can reach 1.76 Mpa under proper set. The results are helpful for improving the energy efficiency ratio performance of the natural refrigerant-based system.

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Effect of carbon fabric type on the mechanical performance of 2D carbon/carbon composites

Polymer Composites ◽

10.1002/pc.10135 ◽

1998 ◽

Vol 19 (5) ◽

pp. 618-625 ◽

Cited By ~ 9

Author(s):

Tse-Hao Ko ◽

Wen-Shyong Kuo

Keyword(s):

Mechanical Performance ◽

Carbon Composites ◽

Carbon Fabric

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Bioepoxy based hybrid composites from nano-fillers of chicken feather and lignocellulose Ceiba Pentandra

Scientific Reports ◽

10.1038/s41598-021-04386-2 ◽

2022 ◽

Vol 12 (1) ◽

Author(s):

Sanjay Mavinkere Rangappa ◽

Jyotishkumar Parameswaranpillai ◽

Suchart Siengchin ◽

Mohammad Jawaid ◽

Togay Ozbakkaloglu

Keyword(s):

Dimensional Stability ◽

Mechanical Performance ◽

Hybrid Composites ◽

Scanning Electron Micrographs ◽

Chicken Feather ◽

Carbon Fabric ◽

Ceiba Pentandra ◽

Structural Applications ◽

Feather Fiber ◽

Chicken Feather Fiber

AbstractIn this work, fillers of waste chicken feather and abundantly available lignocellulose Ceiba Pentandra bark fibers were used as reinforcement with Biopoxy matrix to produce the sustainable composites. The aim of this work was to evaluate the mechanical, thermal, dimensional stability, and morphological performance of waste chicken feather fiber/Ceiba Pentandra bark fiber filler as potential reinforcement in carbon fabric-layered bioepoxy hybrid composites intended for engineering applications. These composites were prepared by a simple, low cost and user-friendly fabrication methods. The mechanical (tensile, flexural, impact, hardness), dimensional stability, thermal stability, and morphological properties of composites were characterized. The Ceiba Pentandra bark fiber filler-reinforced carbon fabric-layered bioepoxy hybrid composites display better mechanical performance compared to chicken feather fiber/Ceiba Pentandra bark fiber reinforced carbon fabrics layered bioepoxy hybrid composites. The Scanning electron micrographs indicated that the composites exhibited good adhesion at the interface of the reinforcement material and matrix system. The thermogravimetric studies revealed that the composites possess multiple degradation steps, however, they are stable up to 300 °C. The thermos-mechanical studies showed good dimensional stability of the composites. Both studied composites display better thermal and mechanical performance compared to neat bioepoxy or non-bioepoxy thermosets and are suitable for semi-structural applications.

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Ablation Behavior of a Carbon Fabric Reinforced Phenolic Composite Modified by Surface-Decorated ZrB2/SiC

Materials ◽

10.3390/ma13020256 ◽

2020 ◽

Vol 13 (2) ◽

pp. 256 ◽

Cited By ~ 1

Author(s):

Feng Xu ◽

Shizhen Zhu ◽

Jingdan Hu ◽

Zhuang Ma ◽

Yanbo Liu

Keyword(s):

Heat Dissipation ◽

Mechanical Performance ◽

Thermal Protection ◽

Ablation Rate ◽

Carbon Fabric ◽

Good Surface ◽

Sic Particles ◽

Ablation Resistance ◽

Service Environments ◽

Phenolic Composite

Carbon fabric reinforced phenolic composites were widely used as TPSs (thermal protection system) material in the aerospace industry. However, their limited oxidative ablation resistance restricted their further utility in more serious service conditions. In this study, the surface-decorated ZrB2/SiC and its modified carbon fabric reinforced phenolic composites have been successfully prepared. The self-modification mechanism of the surface-decorated ZrB2/SiC particles were characterized. The mechanical performance and ablation behavior of the composites were investigated. Results showed that the ZrB2/SiC particles possessed a good surface-decorated effect, which achieved good compatibility with the phenolic resin. The mechanical performance of the modified phenolic composite was effectively improved. The anti-oxidative ablation performance of the composite was improved. The mass ablation rate of the surface-decorated ZrB2–SiC-modified carbon fabric reinforced phenolic composites was 25% lower than that of the unmodified composites. The formed ZrO2 ceramic layer attached to the surface of the residual chars prevented the heat energy and oxygen from the inner material. Meanwhile, the volatilization of SiO2 and B2O3 effectively increased the heat dissipation. All these results confirmed that the ZrB2–SiC particles can effectively improve the ablation resistance of the composite, which provided a basis for the application of the composites to more serious service environments.

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