共查询到19条相似文献,搜索用时 937 毫秒
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反应注射成型充模参数的选择 总被引:3,自引:1,他引:2
本文在分析聚氨酯反应注射成型反应动力学基本方程的基础上,对影响选择充模过程的主要因素进行了分析,并得出聚氨酯反应注射成型流动阶段充模区域图。 相似文献
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RIM充模过程中流动行为研究 总被引:1,自引:0,他引:1
本文采用无化学反应的低粘度流体进行RIM充模过程的冷态模拟研究。考察了充模过程中的基本流动行为。对稳定铺展流、失稳流、射流和绕流等各种充模现象进行了描述、分析,并提出了各种流动行为的判别准则。 相似文献
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注射成型充模流动模拟的边界元方法 总被引:1,自引:0,他引:1
有限差分法和有限元法用于注射成型充模过程数值模拟时,迭代过程和区域积分不可避免。本文通过对充模过程非线性压力控制方程的合理变换,将边界元方法引入充模过程的数值模拟,从而有效地避免复杂的迭代过程和区域积分。 相似文献
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提出了一种研究和分析注塑充模过程中Fountain(喷泉)区流动的方法,得到充模过程的流线图、速度分布和压力分布的图形,从而使得充模过程数值化,对确定工艺条件和提高产品的产量和质量都有实际意义。 相似文献
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本文建立了描述气体辅助注射成型充模流动过程的数学模型,并采用有限元/有限差分混合算法进行数值求解,在对移动边界的处理上采用控制体积法对充模过程中的两类移动边界:熔体前沿、熔体-气体边界进行跟踪,从而实现气体辅助注射成型充模过程的数值模拟。通过对一平板带厚筋结构进行数值分析验证了本文给出的理论算法及软件的可靠性。 相似文献
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注射成型中充模阶段熔体喷泉流动的研究 总被引:1,自引:0,他引:1
建立了聚合物熔体充模流动的数学模型,并结合实验结果对充模流动中喷泉效应进行了分析,得到了一些结论。为整个充模过程的控制机理提供了理论依据,对控制注射工艺、模具设计有指导意义。 相似文献
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探讨注射成型过程中振动力场对圆盘模腔充模过程的影响,建立起数学模型,推导出相应的功率表达式,分析了振动频率和振幅对圆盘模腔充模功率的影响,而且通过实验验证了振动力场的引入使得圆盘模腔充模功率降低。 相似文献
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In the resin transfer molding (RTM) process, preplaced fiber mat is set up in a mold and thermoset resin is injected into the mold. An important issue in RTM processing is minimizing the cycle time without sacrificing part quality or increasing the cost. In this study, a numerical simulation and optimization process for the filling stage was conducted in order to determine the optimum gate locations. The control volume finite element method (CVFEM), modeled as a 2‐dimensional flow, was used in this numerical analysis along with the coordinate transformation method to analyze a complex 3‐dimensional structure. Experiments were performed to monitor the flow front to validate the simulation results. The results of the numerical simulation corresponded with that of the experimental quite well for every single, simultaneous, and sequential injection procedure. The optimization analysis of the sequential injection procedure was performed to minimize fill time. The complex geometry of an automobile bumper core was chosen. A genetic algorithm was used to determine the optimum gate locations in the 3‐step sequential injection case. Taguchi's experimental design method was also used for determining the pressure contribution of each gate. These results could provide the information on the optimum gate locations and injection pressure in each injection step and predict the filling time and flow front. 相似文献
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注塑模充填过程动态模拟 总被引:7,自引:0,他引:7
本文基于注塑模型腔内充填机理和流体力学基本方程,视聚合物熔体在型腔中的流动为平行板中的流动,在浇注系统中的流动为等效圆柱管内的流动,在此假定的基础上进行合理简化,建立了三维薄壁型腔的基于非弹性、非牛顿流体在非等温下的Hele-Shaw流动的数学模型及浇注系统的数学模型,并采用混合有限元/有限差分数值方法耦合求解压力方程和能量方程,采用控制体积法自动跟踪熔体前峰面,从而实现充填过程的动态模拟。模拟结 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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This work presents the results of numerical simulation and experimental visualization of the mold filling process in resin injection molding with preplaced fiber mats. The mold filling experiments were conducted with various mat stacks consisting of continuous random glass fiber mats and bidirectional stitched glass fiber mats. The use of two different mat types in the mat stack created porosity and permeability variations. The effect of these permeability variations was studied by taking flow pressure measurements and observing the progress of the flow front of a non-reactive fluid filling a clear acrylic mold that contained the reinforcement mat stack. Numerical simulation corresponding to each experiment was also carried out. The numerical results were compared to the experimental measurements. 相似文献
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Gas‐assisted injection molding can effectively produce parts free of sink marks in thick sections and free of warpage in long plates. This article concerns the numerical simulation of melt flow and gas penetration during the filling stage in gas‐assisted injection molding. By taking the influence of gas penetration on the melt flow as boundary conditions of the melt‐filling region, a hybrid finite‐element/finite‐difference method similar to conventional‐injection molding simulation was used in the gas‐assisted injection molding‐filling simulation. For gas penetration within the gas channel, an analytical formulation of the gas‐penetration thickness ratio was deduced based on the matching asymptotic expansion method. Finally, an experiment was employed to verify this proposed simulation scheme and gas‐penetration model, by comparing the results of the experiment with the simulation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2377–2384, 2003 相似文献
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为了提高三元乙丙橡胶(EPDM)包覆层注射成型工艺的研发效率,通过数值模拟和实验验证相结合的方式研究了EPDM的流动规律并优选出合适的工艺参数。采用Carreau模型拟合EPDM的流变特性方程,使用Moldflow软件模拟EPDM包覆层的注射成型过程;模拟过程选择了合适的浇口位置,预测了气穴、熔接线位置以及前沿温度的变化,结果与实验一致,气穴易于在弧形顶部形成,同时选择侧面对称的双注射口更有助于成型;分析了温度、压力以及流动速率对填充过程的影响,得到初步的预测成型参数。基于此,进一步通过实验验证得到了合格产品的工艺参数。使用拉伸实验研究所选范围的压力和注射速率对包覆层制品质量的影响,结果表明,合适的工艺参数为:注压温度170℃,镀铬模具温度170℃,注压最大压力30MPa,注压量为148cm3,注压速率为12mm/s。 相似文献