Investigation of functional core-rim composite part production by inserted powder injection moulding

In this study, the use of Cu and Ni interlayers have been investigated for functional core-rim composite part production with WC-Co 9?wt-% feedstock/steel. For this purpose, different experiments have been performed and joining condition, shear strength and microstructure of the intermediate region have been examined. It has been found that AISI 4340 insert/WC-Co have been joined and 85.8?MPa shear strength achieved, but high speed steel insert has not joined. Moreover, it has been determined that better results are obtained with Ni interlayer. Under the same conditions, when the 40?µm Ni interlayer has been used between AISI 4340 core and WC-Co rim, shear strength has been increased approximately twice and has been 162.7?MPa.     

排风扇前盖注射模设计

分析了排风扇前盖塑件的工艺特点,介绍了排风扇前盖注射成型模结构及模具的工作过程。     

不同水针口径下的水辅助注射成型数值模拟

使用流体力学软件，对使用溢流法的三维120 °~150 °弯曲圆管件进行了水辅助注射成型可视化研究。分别改变水针口径尺寸、注水延迟时间、注水压力与熔体温度，分析其对制件内部水穿透行为的影响。结果表明，水针口直径为7 mm时，能显著增加制件的内部穿透长度并得到残余壁厚更薄的制件；受水针结构影响，注水延迟时间为1 s、注水压力为8 MPa、熔体温度为250 ℃时，水穿透长度最优能增长400 %，壁厚减少20 %；在注水延迟时间为1 s、注水压力为10 MPa、熔体温度为230 ℃时，穿透长度最大达到298 mm；注水延迟时间为1 s、注水压力为8 MPa、熔体温度为250 ℃时，比熔体温度为210 ℃和230 ℃的实验组受水针影响严重；缩短注水延迟时间、增加注水压力、升高熔体温度都能有效增大制件的中空率，成型出更薄的管件，但是水针对水辅助注射成型的影响不容忽视，其微小变化能极大地改变成型制件的内部型腔，有效提高水穿透行为的效率。     

游戏机手柄热流道立式注塑4层叠层注塑模设计

设计了一种4层叠层模用于实现游戏机手柄的高效率注塑生产，解决了塑件成型时在保证塑件成型精度的基础上，单次注塑量产数量4倍倍增难题。4层叠层模的结构由4层结构相同的单层模具通过一定的空间组序排列组装后，应用立式注塑机来进行注射成型。单层模结构设计采用两板式2次开模热流道浇注两板模形式，第一次开模用于热流道嘴与塑件的冷流道部分分离，第二次开模用于塑件从型腔镶件中脱模脱出。为解决单层模做4层叠层组合后，顶出板无动力顶出的问题，在单层模的模架模板侧边对称设置了拉杆，将单层模在开模动力转化为单层模中顶出板的顶出拉力，巧妙地解决了单层模做4层叠层安装后各单层模的顶出元件顶出板无推动力的问题。模具结构布局及机构的驱动设置设计合理，有较好的工程设计参考意义。     

Simplified anode architecture for PEMFC systems based on alternative fuel feeding: Experimental characterization and optimization for automotive applications

The need to reduce PEMFC systems cost as well as to increase their durability is crucial for their integration in various applications and especially for transport applications. A new simplified architecture of the anode circuit called Alternating Fuel Feeding (AFF) offers to reduce the development costs. Requiring a new stack concept, it combines the simplicity of Dead-End Anode (DEA) with the operation advantages of the hydrogen recirculation. The three architectures (DEA, recirculation and AFF) are compared in terms of performance on a 5-kW test bench in automotive conditions, through a sensitivity analysis. A gain of 17% on the system efficiency is observed when switching from DEA to AFF. Moreover, similar performances are obtained both for AFF and for recirculation after an accurate optimization of the AFF tuning parameters. Based on DoE data, a gain of 25% on the weight of the anodic line has been identified compared to pulsed ejector architecture and 43% with the classic recirculation architecture with blower only (Miraï).     

剂油比对煤焦油沥青质加氢过程的影响

以中低温煤焦油沥青质为原料,采用NiMoW/γ-Al_2O_3商业催化剂,在反应温度380℃、反应压力8 MPa和反应时间1.5 h条件下,分别在不同剂油质量比(1∶25、1∶20、1∶15、1∶10)条件下进行加氢实验,通过采用元素分析、FT-IR、XRD、~1H-NMR和XPS等分析表征手段,考察不同剂油质量比对中低温煤焦油沥青质加氢转化过程的影响。结果表明,随着剂油质量比的增加,沥青质转化率提高,加氢产物分布也发生大幅变化,沥青质和芳香分轻质化转化为饱和分。但随着剂油质量比的进一步提高,同时也发生了更多的裂化反应和缩合反应,剂油质量比在合适范围能够很好地起到加氢轻质化且抑制结焦的效果。     

Strain hardening behaviors and mechanisms of polyurethane under various strain rate loading

The uniaxial tension experiments are performed on thermoplastic polyurethane to investigate its mechanical behaviors and related potential mechanisms, and the loading strain rate is designing to be wide ranging from 0.0001 to 1 s⁻¹. It is found that the polyurethane presents an obvious rate-dependence, and the stress strain curves share distinct strain hardening characteristics under the investigated strain rates. Furthermore, the strain hardening ratios are sharing nearly same trends and appear to be influenced by both strain rate and the induced adiabatic heating. Besides, the ratio is also strain-dependent on previous loading history. Then, a two-dimension unit cell model is built to investigate potential equivalent mechanisms, of which the hard phase as inclusion is equivalent with crystallization zone, crosslinking sites, and so forth. The simulation results facilitate to explain the distinct strain hardening ratios, even for the matrix from the extrapolated curves under super-low strain rate loading. Finally, the analogic mechanisms of equivalent hard inclusions are proposed, which can reasonably explain the strain rate- and strain-dependence characteristics of polyurethane mechanical behaviors.     

气液螺旋环状流压降特性研究

考虑旋流衰减的影响，对气液螺旋环状流的压降特性进行研究并推导出了螺旋环状流压降预测模型。定义压降旋-直比系数为气液两相螺旋环状流和气液两相直流的压降之比，以此来表征旋流衰减对压降的影响。基于量纲分析的方法对压降旋-直比系数进行分析，推导出其表达式，压降旋-直比系数依赖于Lockhart-Martinelli 参数和气相Froude数变化。最终，得出了气液两相螺旋环状流的压降预测模型。在50 mm内径的水平管内对螺旋环状流的压降特性进行了实验研究，其中气相表观流速变化范围为10~16 m/s，体积含液率（LVF）变化范围为0.6%~4.8%。通过与实验数据进行对比，压降预测模型的相对误差在±15%以内，为工程应用提供了参考。     

全电动注塑机研究进展及在汽配电子行业中的应用

介绍了全电动注塑机的特色，综述了国内外全电动注塑机在精密注塑、智能注塑、高效注塑和绿色注塑方面的研究进展，并对全电动注塑机在汽配电子行业中的应用作了简单介绍。对双电机同步控制技术的逐渐成熟为全电动注塑机实现大型化提供了助力，全电动注塑机高效、精密、智能、节能、环保的优势在汽配电子行业显示了很好的应用前景。     

B超扫描仪支架五联动滑块机构模具设计

结合B超扫描仪支架塑件的形状特点，通过合理地选择塑件的分型面，简化了塑件的整体结构设计及脱模机构设计。针对塑件上脱模需要的复杂性，设计了一种五滑块联动机构先实施内壁5个倒扣及内壁凹形部位内壁的脱模；而后通过2个斜导柱滑块机构来实施外壁的脱模及侧端的侧孔抽芯脱模，塑件最后由推管顶出来实施最终的完全脱模。配合于脱模机构的动作需要，模架选用三板式模架，模架第一次打开设置用于驱动五滑块联动机构的抽芯动作，第二次打开设置用于驱动外壁及侧端的斜导柱驱动侧滑块机构的抽芯动作。五滑块联动机构设计中，通过一个中央T形槽驱动块，驱动中间过渡滑块，从而通过燕尾槽联结来带动5个成型滑块做内收式抽芯运动，巧妙地解决了塑件上局部区域内设置多个抽芯机构设计空间不够的问题，保证了塑件的自动化注塑生产的可靠实现。