In this study, injection molding process of ultrahigh molecular weight polyethylene (UHMWPE) reinforced with nano-hydroxyapatite (nHA) was simulated and optimized through minimizing the shrinkage and warpage of the hip liners as an essential part of a hip prosthesis. Fractional factorial design (FFD) was applied to the design of the experiment, modeling, and optimizing the shrinkage and warpage of UHMWPE/nHA composite liners. The Analysis of variance (ANOVA) was applied to find the importance of operative parameters and their effects. In this experiment, seven input parameters were surveyed, including mold temperature (A), melt temperature (B), injection time (C), packing time (D), packing pressure (E), coolant temperature (F), and type of liner (G). Two models were capable of predicting warpage and volumetric shrinkage (%) in different conditions with R² of 0.9949 and 0.9989, respectively. According to the models, the optimized values of warpage and volumetric shrinkage are 0.287222 mm and 13.6613%, respectively. Meanwhile, a finite element analysis (FE analysis) was also carried out to examine the stress distribution in liners under the force values of demanding and daily activities. The Von-Mises stress distribution showed that both of the liners can be applied to all activities with no failure. However, UHMWPE/nHA liner is more resistant to the highest loads than UHMWPE liner due to the effect of nHA in the nanocomposite. Finally, according to the results of injection molding simulations, optimization, structural analysis as well as the tensile strength and wear resistance, UHMWPE/nHA liner is recommended for the production of a hip prosthesis.

在这项研究中，通过最小化作为髋关节假体必不可少的部分的内衬的收缩和翘曲，模拟和优化了纳米羟基磷灰石（nHA）增强的超高分子量聚乙烯（UHMWPE）的注塑工艺。将分数阶因子设计（FFD）应用于实验设计，建模和优化UHMWPE / nHA复合衬里的收缩和翘曲。应用方差分析（ANOVA）来发现手术参数及其效果的重要性。在该实验中，调查了七个输入参数，包括模具温度（A），熔体温度（B），注射时间（C），保压时间（D），保压压力（E），冷却液温度（F）和冷却液类型。衬板（G）。²分别为0.9949和0.9989。根据这些模型，翘曲和体积收缩率的最佳值分别为0.287222 mm和13.6613％。同时，还进行了有限元分析（FE分析）以检查衬板在需求和日常活动的力值下的应力分布。Von-Mises应力分布表明，两个衬套均可无故障地应用于所有活动。但是，由于nHA在纳米复合材料中的作用，UHMWPE / nHA衬里比UHMWPE衬里更能抵抗最高载荷。最后，根据注塑成型仿真，优化，结构分析以及拉伸强度和耐磨性的结果，建议将UHMWPE / nHA衬里用于髋关节假体的生产。