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Numerical simulation and experimental studies of mandrel effect on flow-compaction behavior of CFRP hat-shaped structure during curing process

100%

Li S. , Zhan L. , Chang T.

Archives of Civil and Mechanical Engineering

2018

tom Vol. 18, no. 4

1386--1400

CFRP hat-shaped structure is a typical stiffened structure used in aerospace field. In this work, aimed to provide a theoretical basis for manufacturing CFRP hat-shaped structure, the multi physical field coupling model considering influence of mandrel was established. Effect of mandrel on resin flow and fiber compaction during curing process was studied by simulation and experiment. Results showed that temperature and curing degree affected by mandrel can be negligible in hat-shaped structure, and the distribution of temperature and curing degree was relatively homogeneous. However, the behavior of resin flow and fiber compaction during curing process was not uniform. There was a larger gradient among resin flow, pressure, fiber volume fraction and laminate thickness. Presetting a suitable hole in mandrel can effectively improve the uniformity of resin flow and fiber compaction. By simulation analysis and optimization, the acceptable aperture of 11.5–12.5 mm was obtained. Finally, the model and simulation developed in this study was validated by experiment. The reliability coefficient of 93.4–99.6% was obtained, which indicated a good agreement between simulation and experiment.

Optimizing operating conditions for advanced treatment of landfill leachate using the coagulation-fenton oxidation method

88%

Bu G. , Xian P. , Zhan L. , Feng X. , Tang H.

Polish Journal of Environmental Studies

2016

tom 25

nr 5

High COD concentrations in effluent, high membrane loading, and frequent congestion on the membrane are three common shortcomings of treating landfill leachate using the biodegradation technique. Accordingly, advanced treatment of the bio-chemical effluent of landfill leachate by Fenton oxidation combined with coagulation technique were performed in this study. The experiment was designed with the response surface method (RSM) considering three factors, i.e., the dosages of polymeric ferric sulfate (PFS), n(H2O2)/ n(Fe2+), and H2O2. Experimental results show that the fitting curve has high significance and sensitivity, and the prediction error of the COD removal rate is smaller than ±5%. The results also show that H2O2 has the greatest influence on COD removal rate, while PFS has the smallest. The optimal operating conditions for landfill leachate with a COD concentration of 2,000 mg/l are: the dosages of PFS (the concentration is 0.05g/ml), and H2O2 (30%) and n(H2O2)/n(Fe2+) are 67 ml, 17 ml, and 6 respectively. The optimized COD removal rate can reach as high as 92.11%.