共查询到18条相似文献,搜索用时 109 毫秒
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综述凤凰山铜矿充填采矿法从上向水平分层充填法,两步回采一次充填到无间柱连续开采快速充填等工艺的发展过程,在此基础上,提出进一步改变采场结构,将过去已经掌握了的采场工艺优点,集中到新的采场生产工艺上。 相似文献
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高性能复合材料树脂传递膜技术(RTM)研究 总被引:6,自引:2,他引:6
树脂传递模塑法(RTM)是一种低成本、效益好的复合材料成型工艺。研究了RTM用树脂体系、预成型技术、成型模具、成型工艺以及RTM在航空航天领域的应用。 相似文献
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RTM工艺可实现扩张段构件近净尺寸成型,纤维体积含量可达53. 1%~59. 9%。本文对法向增强预制体/酚醛扩张段RTM制备技术涉及的树脂基体、法向增强预制体、注射设备与模具进行了讨论。采用RTM工艺制备以酚醛树脂为基体,以2. 5 D编织预制体或针刺预制体为增强材料的扩张段材料并分析其性能,研究结果表明,扩张段构件的层间剪切强度高达59. 2 MPa以上,抗烧蚀冲刷性能显著提高。 相似文献
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高精度雷达罩RTM工艺与模具设计 总被引:1,自引:0,他引:1
介绍了RTM(树脂传递模塑)工艺的特点,并对RTM法制造高精度飞机雷达罩的充模流动、工艺控制要点和模具设计方法等作了简要的论述。 相似文献
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树脂传递模塑(RTM)成型工艺及应用 总被引:3,自引:0,他引:3
本文概述了树脂传递模塑(RTM)的成型工艺过程及其应用前景。由此可了解 RTM 技术的全貌。通过对 RTM 与其它几种主要的复合材料加工工艺的比较,如SRIM(结构反应注射成型),SMC(片材成型)等,可以清楚地认识到 RTM 作为新一代复合材料加工工艺在航空、航天、航海、汽车和建筑等各个领域的发展潜力。 相似文献
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RTM充模过程的数值模拟 总被引:6,自引:0,他引:6
本文首先建立了RTM充模过程的二维数学模型。然后选用控制体积有限元法(FEM/CV)确定了模拟RTM充模过程的数值计算方法,最后进行了对恒流量充模过程的模拟计算,并通过将计算结果与W.B.Young的试验结果比较验证了数学模型和数值方法的正确性。 相似文献
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Wen-Bin Young 《Polymer Composites》1994,15(2):118-127
The manufacture of polymer composites through the process of resin transfer molding (RTM) involves the impregnation of the reactive polymer resing into a mold with preplaced fibrous reinforcements. Determination of RTM processing conditions requires the understanding of various parameters, such as material properties, mold geometry, and mold filling conditions. Modeling of the entire RTM process provides a tool for analyzing the relationship of the important parameters. This study developed a nonisothermal 3-D computer simulation model for the mold filling process of RTM based on the control volume finite element method. The model will be able to simulate mold filing in molds with complicated 3-D geometry. Results of some numerical studies in RTM show the applications of the proposed model. 相似文献
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正弦波形梁构件的RTM工艺模拟研究 总被引:1,自引:0,他引:1
本文采用PAM-RTM软件对航空用正弦波形梁典型构件进行了模拟分析,对构件进行了几何建模及有限元划分,选择构件不同位置采用线注胶或点注胶的注射方式对构件进行了常压力注射下RTM工艺模拟研究,由此确定了最佳注射方式以及注胶口、出胶口位置,根据干斑缺陷可能出现的位置优化了出胶口的设置,得到了无缺陷的构件制品并对预成型体铺放过程中可能出现的边缘效应对树脂流动及干斑缺陷的影响进行了研究。研究表明:合理设置出胶口是一种较好的消除干斑缺陷的方法,计算机RTM模拟为复合材料模具设计及构件制造提供了重要依据。 相似文献
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Aouatif Saad Adil Echchelh Mohamed Hattabi Mohammed El Ganaoui 《Polymer Composites》2011,32(6):857-868
The numerical simulation of mass and heat transfer model for the curing stage of the resin transfer molding (RTM) process is known as a useful method to analyze the process before the mold is actually built. Despite the intense interest in the modeling and simulation of this process, the relevant work is currently limited to development of flow models during filling stage. Optimization of non‐isothermal mold filling simulation time without losing the efficiency remains an important challenge in RTM process. These were some reasons that motivate our work; namely the interested on the amelioration of the performance of RTM simulation code in term of execution time and memory space occupation. Our approach is accomplished in two steps; first by the modification of the control volume/ finite element method (CV/FEM) and second by the implementation in the modified code of an adapted conjugate gradient algorithm to the compressed sparse row storage scheme. The validity of our approach is evaluated with analytical results and excellent agreement was found. The results show that our optimization strategy leads to maximum reduction in time and space memory. This allows one to deal with problems with great and complex dimensions mostly encountered in RTM application field, without interesting in the constraint of space or time. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers 相似文献
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The art of resin transfer molding (RTM) process optimization requires a clear understanding of how the process performance is affected by variations in some important process parameters. In this paper, maximum pressure and mold filling time of the RTM process are considered as characteristics of the process performance to evaluate the process design. The five process parameters taken into consideration are flow rate, fiber volume fraction, number of gates, gate location, and number of vents. An integrated methodology was proposed to investigate the effects of process prameters on maximum pressure and mold filling time and to find the optimum processing conditions. The method combines numerical simulation and design of experiments (DOE) approach and is applied to process design for a cylindrical composite part. Using RTM simulation, a series of numerical experiments were conducted to predict maximum pressure and mold filling time of the RTM process. A half‐fractional factorial design was conducted to identify the significant factors in the RTM process. Furthermore, the empirical models and sensitivity coefficients for maximum pressure and mold filling time were developed. Comparatively close agreements were found among the empirical approximations, numerical simulations, and actual experiments. These results were further utilized to find the optimal processing conditions for the example part. 相似文献
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A review of current approaches in modeling and simulation of the resin transfer molding (RTM) process is presented. The processing technology of RTM is discussed and some available experimental techniques to monitor the process cycle are presented. A master model is proposed for the entire process cycle consisting of mold filling and curing stages. This master model contains the fundamental and constitutive sub‐models for both stages. The key elements of the master model discussed in this study are: flow, heat and mass balance equations for fundamental sub‐models, permeability, cure kinetics, resin viscosity and void formation for constitutive sub‐models. At the end, numerical methods widely used to simulate the filling process are presented and published simulation results of mold filling and process cycle are reviewed. 相似文献
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Yanyu Ding Yuxi Jia Junying Yang Haidong He Sheng Sun Tongfei Shi 《Polymer Composites》2011,32(4):648-656
At the reactive mould‐filling stage in resin transfer moulding (RTM) processes, the correlation analysis of epoxy/amine resin cure, structure and chemorheological behavior plays a key role in the optimum control of RTM processes. A new methodology used to simulate the reactive resin flow in RTM processes with edge effect is presented in this article. The recursive approach and the branching theory are used to describe the evolution of molecular structure and resin viscosity, respectively. And then the resin flow process is simulated by means of a semi‐implicit iterative calculation method and the finite volume method. The results reveal the proposed resin cure‐structure‐viscosity model provides excellent agreement with the experimental viscosity data during the RTM filling process. It is also observed that the curing reaction causes the inhomogeneous distribution of resin conversion and resin molecular weight in the mould cavity, which will result in the spatially structural and performance inhomogeneities in the finished products. With the injection temperature or the edge width increasing, the discrepancy of resin conversion and resin molecular weight in the mould cavity is more evident. This study is helpful for understanding the complicated relationship among the processing variables, resin structures, and properties. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers 相似文献
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In this work, a computer model has been developed to investigate the effect of reinforcement thickness variation and edge effect on infiltration and mold filling in resin transfer molding (RTM) process. The developed code is able to predict the flow front location of the resin, the pressure, and the temperature distribution at each time step in a mold with complex geometries. It can also optimize the positioning of injection ports and vents. The filling stage is simulated in a full two‐dimensional space by using control volume/finite element method CV/FEM and based upon an appropriate filling algorithm. Results show that the injection time as well as flow front progression depends on the edge effect, the variation of reinforcement thickness, and the position of injection ports; this highlights that the inclusion of these effects in RTM simulation is of definite need for the better prediction and optimization of the process parameters. The validity of our developed model is evaluated in comparison with analytical solutions for simple geometries, and excellent agreements are observed. POLYM. COMPOS., 2012. © 2011 Society of Plastics Engineers 相似文献