棉织物的柠檬酸与有机硅复合整理

为了提高棉织物的疏水性能和抗皱性能,采用柠檬酸与侧链乙烯基聚硅氧烷(相对分子质量5000)改性聚丙烯酸酯(PASi)作为复合整理剂对棉织物进行整理.研究了复配种类、用量、焙烘温度和时间对织物抗皱性能、疏水性能、白度、透湿性能的影响.结果 表明:柠檬酸与PASi复配使用,用量均为10 g/L,160℃焙烘3 min时,整...     

基于Dynaform的汽车发动机盖内板成形分析

对汽车发动机盖内板的成形过程进行了研究,基于数值模拟的方法对其成形过程进行了有限元仿真分析,得到零件的成形极限图和厚度变化图,并以此来判断成形效果。针对成形过程中出现的拉深不足和起皱等缺陷,通过反复调整工艺参数和拉深筋尺寸及分布,得出了较好的零件成形状态,零件的最大减薄率为22.8%,最大增厚率为5.9%。根据该工艺方案进行了实际冲压试验,通过比较仿真分析与试验结果不同测点位置的厚度,其偏差小于3%,从而验证了两者的一致性。研究结果表明,数值模拟分析用于板料成形分析是可行的,能够提高设计生产效率。     

内高压成形机理与关键技术

在中国国家杰出青年科学基金资助项目“镁合金热态液力成形技术”、中国国家自然科学基金资助项目“轻体件高内压液力成形机理的研究”、“管材热态内压成形新方法及其机理研究”和“激光拼焊管内高压成形机理”、以及中国教育部高等学校博士学科点专项科研基金资助项目“镁合金热态内高压成形机理研究”共同资助下,开展内高压成形机理及关键技术研究,在内高压成形塑性变形规律、起皱和破裂等失稳行为、提高成形极限和降低成形压力方法,以及液力胀接、热态内压成形和拼焊管内高压成形等方面取得重要进展,并在汽车和航天等领域实现内高压成形技术产业化应用,报告上述研究的理论和工程体系。 根据塑性变形特点,将内高压成形分为变径管内高压成形(IHPF of TPVD)、弯曲轴线管内高压成形(IHPF of TPCA)和多通管内高压成形(IHPF of TPB/BT)等3类,提出IHPF of TPVD由充填、成形、整形等步骤组成,IHPF of TPCA由弯曲、预成形、内高压成形等步骤组成,IHPF of TPB/BT由胀形、补料、整形等步骤组成。以此为出发点,通过实验和理论分析,研究IHPF塑性变形规律与失稳行为。     

混合多羧酸、复配催化剂对真丝织物抗皱整理的探讨

探讨了柠檬酸(CA)和1,2,3,4-丁烷四羧酸(BTCA)混合用于真丝织物无甲醛抗皱整理的效果,分析了在相同的整理工艺条件下,用不同配比的CA和BTCA整理真丝织物的折皱回复角、断裂强力、增重率和硬挺度的变化,得出w(CA)为4%、w(BTCA)为4%较合适.同时探讨了在相同的整理工艺条件下,用含磷和不含磷的混合催化剂整理的效果,结果证明混合的无磷催化剂柠檬酸钠和酒石酸钠,可代替含磷的混合催化剂.     

聚马来酸防皱整理剂的合成与应用

通过L9(34)正交试验,选择具有合适分子量的聚马来酸(PMA)无醛防皱整理剂和最优防皱整理工艺.并对棉织物进行防皱整理,获得良好的防皱整理效果,WRA值可达到243.5°,断裂强度保留率在70%以上.同时优选出合成PMA的最佳条件.     

聚合-交联整理棉织物的断裂强力损失

采用马来酸(MA)和衣康酸(IA)或单独采用MA以在位聚合交联法对棉织物进行免烫整理,并对整理品的断裂强力与折皱回复角、酯键量之间的相关性进行了分析,提出用强力损失因子BSLF这一指标来判断免烫整理品的强力损失程度。结果表明,经不同焙烘条件处理的棉织物其酯键量与折皱回复角、断裂强力保留率之间存在着良好的线性关系;织物的断裂强力与折皱回复角之间也具有良好的线性关系,并推导出该拟合直线斜率与BSLF间的数学关系式。与拟合直线的斜率相比,BSLF计算方便,为比较不同整理体系的强力损失程度提供了一种方法。     

RESEARCH ON HYDROFORMING TUBULAR PART WITH LARGE PERIMETER DIFFERENCE

The tube hydroforming process for manufacturing the tubular part with large perimeter difference was studied by means of experiments and FE simulation. It is an asymmetrical one and the expansion ratio is 70 percent. The part is successfully hydroformed by applying the useful wrinkles to accumulate suffcient metal in the area with large expansion ratio. The thickness distribution is analyzed, and the maximum thinning ratio of the part is 21.6 percent. It is shown from the experiment and simulation results that the tubular part with large perimeter difference, long expansion area and asymmetrical shape can be obtained in one step, applying the useful wrinkles. Typical failure modes were analyzed.     

内皱发生的临界计算及校核条件

通过对球形和锥形零件在拉深过程中各部分的应力分析 ,得到了拉深过程中悬空区切向压应力最大值的计算公式 ,以此作为引发内皱的条件 ,在保证工件不被拉裂的前提下 ,建立了临界计算公式。     

鞍面力-位移分控多点成形起皱的数值模拟研究

在多点成形中,起皱是影响板材成形质量的重要因素。针对鞍面在力-位移分控多点成形方式下的起皱,以ABAQUS为模拟分析平台,模拟了鞍面的成形过程,并分析了其起皱缺陷。研究结果表明:在鞍面力-位移分控多点成形过程中,当板厚较小(1和1.5 mm)时,板材中心区域发生了较为严重的起皱,且优先变形的方向发生的起皱现象更明显;随着板厚和曲率半径的增大,起皱趋势减小。针对起皱现象探明了起皱的原因,提出了鞍面起皱的抑制方法,并进行了模拟计算和成形试验,结果表明,增大成形力和错位都可以抑制起皱,错位并结合增大成形力可以显著改善板材成形质量。     

The origin of wrinkles on transferred graphene

When two-dimensional graphene is exfoliated from three-dimensional highly oriented pyrolytic graphite (HOPG), ripples or corrugations always exist due to the intrinsic thermal fluctuations. Surface-grown graphenes also exhibit wrinkles, which are larger in dimension and are thought to be caused by the difference in thermal expansion coefficients between graphene and the underlying substrate in the cooling process after high temperature growth. For further characterization and applications, it is necessary to transfer the surface-grown graphenes onto dielectric substrates, and other wrinkles are generated during this process. Here, we focus on the wrinkles of transferred graphene and demonstrate that the surface morphology of the growth substrate is the origin of the new wrinkles which arise in the surface-to-surface transfer process; we call these morphology-induced wrinkles. Based on a careful statistical analysis of thousands of atomic force microscopy (AFM) topographic data, we have concluded that these wrinkles on transferred few-layer graphene (typically 1–3 layers) are determined by both the growth substrate morphology and the transfer process. Depending on the transfer medium and conditions, most of the wrinkles can be either erased or preserved. Our work suggests a new route for graphene engineering involving structuring the growth substrate and tailoring the transfer process.