Sublimation of composite ice and its influence on performance of ice shells

2021 ◽  
Vol 36 (1) ◽  
pp. 67-77
Author(s):  
Yue Wu ◽  
Junkai Huang ◽  
Jiafeng Chen
Keyword(s):  
Numerical Simulation ◽  
Shell Structure ◽  
Composite Shell ◽  
Engineering Practice ◽  
Sublimation Rate ◽  
Long Span ◽  
Static Performance ◽  
New Type ◽  
Ice Sublimation ◽  
Composite Shell Structure

The long-span ice composite shell structure is a new type of ice and snow structure developed in recent years. The engineering practice of ice composite shell shows that sublimation is one of the important reasons for its damage and even collapse. In this paper, we firstly supplemented the existing H-K equation and obtained the revised ice sublimation equation through indoor evaporative plate experiment considering the influence of admixtures and wind speed. Afterwards, combining the simulations of solar radiation and CFD, the numerical simulation of sublimation distribution on the surface of were realized by programming in Grasshopper platform. During sublimation, the thickness of the ice composite shell decreases by 0.38 mm every 10 days and the sublimation rate on the sunny side was 1.7 times that on the shady side. Finally, the static performance and stability of the sublimated ice composite spherical shell were analyzed. After 70 days of sublimation, the thickness of the ice composite shell structure becomes thinner and uneven, which leads its sensitivity to external load increases.

scholarly journals Preparation and characterization of polydopamine/melamine microencapsulated red phosphorus and its flame retardance in epoxy resin

RSC Advances ◽  
2021 ◽  
Vol 11 (33) ◽  
pp. 20391-20402
Author(s):  
Chen Cheng ◽  
Yanling Lu ◽  
Weining Ma ◽  
Shaojie Li ◽  
Jun Yan ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Epoxy Resin ◽  
Shell Structure ◽  
Composite Shell ◽  
Intumescent Flame Retardant ◽  
Smoke Suppression ◽  
Flame Retardance ◽  
Red Phosphorus ◽  
Composite Shell Structure

Red phosphorus was coated by a polydopamine/melamine composite shell structure, which constituted an intumescent flame retardant with superior flame retardance and smoke suppression performance for epoxy resin.

scholarly journals Vibration and Damping Analysis of Composite Fiber Reinforced Wind Blade with Viscoelastic Damping Control

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Tai-Hong Cheng ◽  
Ming Ren ◽  
Zhen-Zhe Li ◽  
Yun-De Shen
Keyword(s):  
Frequency Response ◽  
Natural Frequency ◽  
Shell Structure ◽  
Loss Factor ◽  
Composite Shell ◽  
Composite Fiber ◽  
Viscoelastic Damping ◽  
Response Functions ◽  
Damping Control ◽  
Composite Shell Structure

Composite materials are increasingly used in wind blade because of their superior mechanical properties such as high strength-to-weight and stiffness-to-weight ratio. This paper presents vibration and damping analysis of fiberreinforced composite wind turbine blade with viscoelastic damping treatment. The finite element method based on full layerwise displacement theory was employed to analyze the damping, natural frequency, and modal loss factor of composite shell structure. The lamination angle was considered in mathematical modeling. The curved geometry, transverse shear, and normal strains were exactly considered in present layerwise shell model, which can depict the zig-zag in-plane and out-of-plane displacements. The frequency response functions of curved composite shell structure and wind blade were calculated. The results show that the damping ratio of viscoelastic layer is found to be very sensitive to determination of magnitude of composite structures. The frequency response functions with variety of thickness of damping layer were investigated. Moreover, the natural frequency, modal loss factor, and mode shapes of composite fiber reinforced wind blade with viscoelastic damping control were calculated.

scholarly journals Lightweight cylindrical composite shell structures to support optical instruments in extremely large telescopes: A case study

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110361
Author(s):  
Lingyu Zheng ◽  
Daxu Zhang ◽  
Long Wang ◽  
Aman Shrestha ◽  
Zhensen Song ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Shell Structure ◽  
Composite Shell ◽  
Wide Field ◽  
Maximum Displacement ◽  
Optical Instruments ◽  
Before And After ◽  
Cylindrical Composite Shell ◽  
Large Telescopes ◽  
Composite Shell Structure

Aiming at the issues of heavy weight and insufficient structural performance of optical instrument supporting structures in extremely large telescopes, the Wide-Field Optical Spectrograph (WFOS) of the Thirty Meter Telescope (TMT) was taken as a case to study. In order to develop lightweight structures which satisfies the design requirements for mass and stiffness, a design scheme of cylindrical composite shells supporting structure was proposed and their finite element models were developed. A size optimisation and a ply sequence optimisation of the composite structure were carried out. The structures before and after optimisation were evaluated from the aspects of mass, displacement, failure index and fundamental frequency. After the optimised design, the mass of the optimised WFOS cylindrical composite shell structure is reduced to approximately 50%, but its maximum displacement (0.513 mm) and fundamental frequency (8.275 Hz) are nearly unchanged. The study indicates that a cylindrical composite shell structure is an efficient structural form for large optical instruments.

Based on Numerical Simulation of the Water Conservancy Hub Two-Way Flow under the Condition of Lock Approach Guide Wall Type Optimization Research

2015 ◽  
Vol 744-746 ◽  
pp. 1056-1061
Author(s):  
Xiao Li Yang ◽  
Kai Wu ◽  
Wen Chao Fang ◽  
Long Hua Wu ◽  
Meng Di Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Shape Optimization ◽  
Engineering Practice ◽  
Optimization Study ◽  
Engineering Measures ◽  
Guide Wall ◽  
New Type ◽  
Water Conservancy ◽  
Ship Navigation ◽  
Set Up

Navigation task of water conservancy when the over-current buildings are in runtime often affect the flow regime lock approach, endangers the ship navigation safety. In engineering we often set up guide wall protection approaches between approaches and flow buildings. By means of numerical simulation, the guide wall shape optimization study, and combining with the engineering practice, this paper proposes a microbend flood guide wall of new type. The results show that this new type of guide wall can in a variety of flow circumstances change such flow structure, reduce the horizontal speed of the approaches, is a simple and effective engineering measures.

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