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Three-dimensional finite element analysis of process-induced residual stress in resin transfer moldi
A three-dimensional finite element analysis of process-induced residual stress in resin transfer mold-ing (RTM) process is presented. The finite element method ( FEM ) was employed to solve the coupled equa-tions involved in the transient heat transfer and the cure kinetics of the resin, and the distributions of internal temperature and cure degree of the composite at any instant time were obtained. The self-consistent field micro-mechanics model was used to predict the cure-dependent mechanical properties of the composites. Thermal ex-pansion and cure shrinkage were included in the analysis. The thermo-elastie mechanical governing equationswere solved using the incremental stress-strain relationship based FEM and the residual stress development was predicted. The present results were validated by the comparisons with the pertinent literature. The numerical example of a half cylinder was presented. The results show that it is necessary to carry out the three-dimensional analysis due to the complex distributions of temperatures, cure degrees and process-induced stress for thick parts, which can be predicted at any point within composite structures in the present analysis....
2020-11-11 22:33:38浏览：63
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Numerical Simulation and Analysis of Migration Law of Gas Mixture Using Carbon Dioxide as Cushion Ga
One of the major technical challenges in using carbon dioxide ( CO2 ) as part of the cushion gas of the underground gas storage reservoir ( UGSR) is the mixture of CO2 and natural gas. To decrease the mixing extent and manage the migration of the mixed zone, an understanding of the mechanism of CO2 and natural gas mixing and the diffusion of the mixed gas in aquifer is necessary. In this paper, a numerical model based on the three dimensional gas-water two-phase flow theory and gas diffusion theory is developed to understand this mechanism. This model is validated by the actual operational data in Dazhangtuo UGSR in Tianjin City, China. Using the validated model, the mixed characteristic of CO2 and natural gas and the migration mechanism of the mixed zone in an underground porous reservoir is further studied. Particularly, the impacts of the following factors on the migration mechanism are studied:the ratio of CO2 injection, the reservoir porosity and the initial operating pressure. Based on the results, the optimal CO2 injection ratio and an optimal control strategy to manage the migration of the mixed zone are obtained. These results provide technical guides for using CO2 as cushion gas for UGSR in real projects....
2020-09-13 23:35:02浏览：53
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神府煤水煤浆管道输送试验研究
为获得神府煤水煤浆最佳管道输送参数，进行了水煤浆流变性试验，确定了水煤浆临界剪切速率。通过水煤浆剪切速率和剪切应力的关系确定神府煤水煤浆流变性模型，拟合出适于神府煤水煤浆流变性的数学方程。在不同管道直径和水煤浆浓度下，研究了水煤浆平均速率对管道压力损失的影响，得到了最佳水煤浆管道输送参数。结果表明：神府煤水煤浆临界剪切速率为40?74 s-1，水煤浆拟合后的流变方程符合宾汉塑性体模型，适宜泵送和管道输送。低浓度、低黏度的水煤浆更适合管道输送。在水煤浆平均流速相同的条件下，管道直径越小，管道压力损失越大。管道直径为200~300 mm时，神府煤水煤浆在管道输送中的压力损失在工业应用合理范围内，适宜管道输送。...
2020-06-12 14:34:26浏览：1407
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神府煤水煤浆管道输送试验研究
为获得神府煤水煤浆最佳管道输送参数，进行了水煤浆流变性试验，确定了水煤浆临界剪切速率。通过水煤浆剪切速率和剪切应力的关系确定神府煤水煤浆流变性模型，拟合出适于神府煤水煤浆流变性的数学方程。在不同管道直径和水煤浆浓度下，研究了水煤浆平均速率对管道压力损失的影响，得到了最佳水煤浆管道输送参数。结果表明：神府煤水煤浆临界剪切速率为40?74 s-1，水煤浆拟合后的流变方程符合宾汉塑性体模型，适宜泵送和管道输送。低浓度、低黏度的水煤浆更适合管道输送。在水煤浆平均流速相同的条件下，管道直径越小，管道压力损失越大。管道直径为200~300 mm时，神府煤水煤浆在管道输送中的压力损失在工业应用合理范围内，适宜管道输送。...
2020-03-23 18:44:21浏览：1416
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