汽车薄壁保险杠蒙皮材料特性分析与服役性能研究

目的 优化薄壁保险杠蒙皮材料的力学性能,评价薄壁保险杠蒙皮的服役性能。方法 以纳米碳酸钙(nano-CaCO3)、蒙脱土(MMT)和氢化苯乙烯-丁二烯嵌段共聚物(SEBS)为添加剂对PP进行协同改性。采用双螺杆挤压机制备PP/SEBS/nano-CaCO3和PP/SEBS/MMT共混材料,研究刚性粒子与SEBS对薄壁注塑用聚丙烯(PP)的强韧协同效应。研究无机填料/弹性体协同改性作用对薄壁注塑用聚丙烯结晶行为、力学性能与微观结构的影响规律。建立薄壁注塑用聚丙烯保险杠蒙皮有限元仿真模型,通过多个工况有限元仿真和实验来评价薄壁保险杠蒙皮的服役性能。结果 共混材料的结晶度相比PP/SEBS提高了1.2%~7.3%,结晶温度未产生显著变化;nano-CaCO3质量分数为4%的PP/SEBS/nano-CaCO3综合性能最好。仿真结果表明,薄壁保险杠蒙皮具有较好的服役性能,并且通过实验验证了该评价方法的有效性。结论 薄壁保险杠蒙皮材料可以通过共混改性达到理想的刚韧平衡效果,基于材料性能-成形质量-服役性能的方法为高效设计薄壁汽车保险杠蒙皮提供了新途径。     

汽车仪表板整体优化设计要点探讨

仪表板是一种集安全性、功能性、舒适性及装饰性等功能为一体的重要部件,从仪表面板的优化设计、仪表布置的优化设计、仪表面罩的优化设计、组合仪表罩布置的优化设计、操纵按钮布置的优化设计等方面,详细探讨了汽车仪表板整体优化设计要点。     

光氧老化对聚碳酸酯结构和性能的影响

研究了光氧老化后聚碳酸酯(PC)的结构和性能变化。力学性能测试结果表明,老化后,PC的冲击强度下降,拉伸强度、弯曲强度上升;扫描电镜断口形貌分析和差示扫描量热分析显示,光氧老化后PC材料的韧性有一定损失;傅立叶变换红外光谱分析显示PC老化后有酚类、酮类产物生成;PC的光氧老化可能是由于弗利斯重排反应产生自由基诱发PC分子链光氧降解反应所致。     

HIPS/nano-TiO2复合材料的吸光及光老化性能研究

研究了高抗冲聚苯乙烯／纳米TiO2（HIPS／nano—TiO2）复合材料的吸光及光老化性能,以紫外-可见光（UV—Vis）吸收光谱表征吸光性能,以傅里叶红外（FT—IR）及熔体流动速率（FMI）表征老化样品的结构．结果表明,与钛白粉相比,锐钛矿nano—TiO2对紫外光的吸收加强,但对可见光的反射率咯低．复合材料对250-400nm区域的紫外光有较强吸收,且随纳米质量含量的提高而增强．钛白粉也可提高复合材料的紫外吸收性能,且能大幅度提高对可见光的反射能力．锐钛矿nano—TiO2在老化样品中发挥了刚性粒子增韧作用．光老化后复合材料的力学性能明显优于HIPS老化样品,冲击强度可提高30％以上．光老化集中于HIPS的聚1,4-丁二烯（PB）相,老化以断链方式为主．     

耐候性聚丙烯汽车保险杠的研究

利用正交试验研究了多种PP常用光稳定剂UV944、UV770、UV327和抗氧剂B215互配使用情况,考察其对改性后保险杠料B的Izod缺口冲击强度、拉伸性能和弯曲性能的协同作用及其最佳互配使用量.由正交实验分析可得,当UV944、UV770、UV327和13215用量分别为0.5%、0.5%、0.2%和0.3%时,可得到既可涂敷又耐候且符合生产要求的PP保险杠专用料.采用紫外光人工加速老化实验(波长为300nm紫外线,70℃下,不淋水),168h后,不添加稳定剂的保险杠料B的Izod缺口冲击强度、拉伸屈服强度和弯曲强度分别为0.9kJ/m2、17MPa和10MPa,经一系列配方改性后的保险杠料B则分别为9～10kJ/m2、35～40MPa和50～60MPa.     

Ce掺杂对TbFeCo材料磁光性能影响的研究

采用射频磁控溅射方法制备了TbFeCo非晶磁光薄膜，并在TbFeCo中引入轻稀土元素Ce，测试了薄膜的磁光性能。研究了薄膜成分对其磁光性能的影响。结果表明；在TbFeCo薄膜中掺入少量Ce时，薄膜的磁光克尔角及矫顽力都有所提高，矩形度也增加了。但随Ce掺入量的增加，薄膜的磁光性能发生恶化，较好的掺杂在10.31?左右。     

铜导电胶老化性能的研究

将铜导电胶进行热老化、自然老化、耐水等试验，以研究其老化性能，并探求改善铜胶抗老化性能的途径。结果表明：铜胶的抗老化性能好，其主要影响因素是树脂与铜粉用量之比。     

铜导电胶老化性能的研究

将铜导电胶进行热老化、自然老化、耐水等试验，以研究其老化性能，并探求改善铜胶抗老化性能的途径。结果表明：铜胶的抗老化性能好，其主要影响因素是树脂与铜粉用量之比。     

包装箱用高性能工程塑料老化性能研究

采用热老化试验和傅立叶红外光谱仪(FTIR)对包装箱材料用高性能工程塑料的贮存老化性能进行评估，研究了其老化过程的变化规律，并通过回归处理外推预测了常温下的贮存寿命。     

Development of bumper shield using low density materials

In order to avoid critical accidents due to space debris, this paper proposes an extra bumper shield called an inflatable bumper. It consists of aluminum (Al2024-T3), high strength fiber Vectran and inflatable polyurethane. Because of this inflatability, it is compactly stored during its transportation. And after the installation outside of the space structures, this bumper is then inflated by the effect of expandable polyurethane. This method saves the amount of the transportation and the involved cost. In this paper the experiments, using several polyurethane's with different areal density, have been conducted, compared and evaluated from the viewpoints of the penetrated areal density, the total thickness penetrated, and mass distribution of the fragments captured inside the shield. As the results of the experiments, it is found that the protection ability of the proposed structure depends on the areal density of polyurethane layers and the optimum areal density is 0.525kg/m². And by using polyurethane between Vectran layers, this expandable structure captures the fragments of the secondary debris, which might cause a secondary impact on the space structure.     

Application of Taguchi''s method on the optimal process design of an injection molded PC/PBT automobile bumper

The manufacturing process of an injection molded polycarbonate/ poly(butylene terephthalate) automobile bumper was optimized, using Taguchi's method, to eliminate silver streaks on the surface of the product. First, a set of process factors was selected and a preliminary experiment was conducted with an L₁₂ orthogonal array to screen the significant factors, check the validity of the data fitting model, and predict an improved process condition to overcome the filling difficulties. Second, using the selected control factors, a principal experiment was conducted with an L₁₈ orthogonal array to predict an optimal process condition that solve the quality problem. Finally, the predicted process condition was tested on an 2500-ton injection molding machine to confirm the prediction. The results reveal that the main factors that directly relate to the generation of silver streaks are the mold temperature, the fill time, the fill/ postfill switch over control, and the injection rate.     

空压机仪表电气控制盘的改进处理

分析了制约空分设备原料空压机连续稳定运行的原因,对其现场仪表电气控制盘进行了改进处理,技改后效果良好,空分设备再也没有因空压机仪表电气控制盘温度偏高而停车。     

基于Yoshida-Uemori材料模型的汽车结构件冲压回弹分析

Yoshida-Uemori随动硬化材料模型能够准确描述应变路径发生变化时材料性能的改变,从而较好地反映复杂加载情况下材料的各向异性.本文基于JSTAMP件分别采用Yoshida-Uemori随动硬化材料模型和各向同性硬化材料模型对汽车高强钢结构件的冲压成形进行了仿真分析与回弹预测,研究了不同材料硬化模型对回弹预测精度...     

A virtual instrument for the measurement of the characteristics ofmagnetic materials

A completely digital method for the fast and accurate measurement of the magnetic behavior (such as the magnetization curve, the hysteresis loop, and the total loss) of magnetic materials under cyclic magnetization is presented. The mathematical basis of this method is discussed and used to develop a virtual instrument dedicated to the determination of the magnetic behavior. The experimental results for ferrosilicon plats and amorphous materials are reported, and the accuracy and sensitivity of the technique are discussed     

A new instrument for measuring the elastic modulus of sheet materials

Summary By the use of a photoelectric pickup and an electronic counting circuit, the instrument which has been described allows one to measure infrasonic damped oscillations with great accuracy. Further, the measurements have been automated.In order to attain a high accuracy of measurement of the modulus of elasticity, it is necessary that the amplitudes of oscillation of the specimen be as small as possible with respect to its length. This allows one to determine the modulus of elasticity and its temperature coefficient for flexible sheet materials.     

汽车覆盖件自由曲面特征识别算法研究

特征技术应用于汽车覆盖件冲压工艺CAPP系统被认为是提高汽车覆盖件制造水平,并逐步实现CIMS的关键.应用特征识别技术,从CAD系统中识别出CAPP系统所需要的信息,将为工艺设计提供丰富的信息.通过汽车覆盖件自由曲面特征识别技术研究,提出了一种新的基于规则的特征识别算法,实现了从自由曲面模型识别出两种最基本的特征,孔类和翻边类特征.以UGII软件为平台,开发了汽车覆盖件零件模型自动特征识别功能,基本上解决了基于特征的覆盖件冲压工艺CAPP系统信息输入问题.     

汽车覆盖件冲压工艺CAPP系统特征建模技术

特征技术应用于汽车覆盖件冲压工艺CAPP系统被认为是提高汽车覆盖件制造水平,并逐步实现CIMS的关键.为此,本文对汽车覆盖件进行了特征分类,建立了面向CAPP系统的覆盖件特征表达模式.以UGII软件为开发平台,提出自动识别孔类特征算法,采用交互式特征识别方式识别其他特征,建立了覆盖件特征模型,解决基于特征的覆盖件冲压工艺CAPP系统信息输入问题.     

汽车前围板内隔音垫声学性能的试验方法

基于小型混响室法测量某汽车前围板内隔音垫的吸声系数,探究被测试件、声源及传声器布置形式对测量结果的影响规律,结果表明:三者均对低频结果有较大影响,对中高频结果的影响很小。要准确获得吸声系数,应采取尽可能多的配置并对所有结果取平均;该隔音垫的平均吸声系数约为0.45。进一步基于混响室-消声室声强法测量其插入损失,识别其隔声薄弱部位,结果表明:该隔音垫的平均插入损失约为12 d B,转向机构、空调鼓风机及转向机防尘罩安装位置为隔声薄弱部位。研究结果为该隔音垫声学性能的分析改进提供了依据,也为声学材料性能研究试验的实施提供了参考。