Experimental and Numerical Research on Deformation Behavior of Thin-Walledand Large Expansion Ratio Guide Vane Liner in Hydroforming Process

Some tube hydroforming process tests and further research work were conducted to manufacture hollow guide vane liners (made of super alloy GH3030).The relative thickness (t₀/OD) of the tubular blank is approximately 0.01,and the maximum expansion ratio (Dmax/OD) of the needed part is more than 40％, and the length to diameter ratio of the expansion regionis more than 3.0. It is very hard to manufacture this kind of ultra-thin-wall, curved axis and large expansion ratio tubular part without fracture and wrinkles. The success of the process is highly dependent on useful wrinkles with appropriate internal pressure and axial feeding. A simplified finite element model and a theoretical model are used for detecting the deformation behavior and forming laws. Further study results demonstrate that the useful wrinkles do not appear at the same time and middle-wrinkles need bigger axial force than tube-end-wrinkles and feeding-wrinkles. The wrinkles can transfer bigger axial force after its wave peak has come into contact with the die inner surface. The thickness thinning rate of the element at the peak is bigger than that at the trough.With the increase of the axial and hoop stress ratio, the critical buckling stress also increases. Microstructure examination results show that the grain size in the maximum thinning zone has been stretched and refined after the large deformation and annealing treatment. The process is feasible and the finished part is qualified.     

聚马来酸酐抗皱整理工艺研究

研究了聚马来酸酐应用于棉织物的抗皱整理工艺.采用单因素实验考察了聚马来酸酐浓度、次亚磷酸钠浓度、焙烘温度以及焙烘时间对折皱回复角的影响,以L9(34)正交试验对其进行了优化.确定了最佳整理工艺条件:聚马来酸酐用量120 g·L-1、次亚磷酸钠用量30 g·L-1、焙烘温度170℃、焙烘时间7 min.     

Fabrication of Frog-Skin-Inspired Slippery Antibiofouling Coatings Through Degradable Block Copolymer Wrinkling

Marine biofouling is a severe problem with a wide-reaching impact on ship maintenance, the economy, and ecosystem safety, among others. Inspired by complex multifunctional frogskins, wrinkled slippery coatings are created that exhibit remarkable antifouling, anti-icing, and self-cleaning properties through a combination of degradable di-block copolymer self-assembly [i.e., polystyrene-b-polylactide (PS-b-PLA)] and hydrolysis-driven dynamic release-induced surface wrinkling. Microwrinkled patterns can generate curved surfaces that are resistant to biofouling. Gyroid-forming PS-b-PLA can be used to produce nanoporous templates with cocontinuous nanochannels, which generate strong capillary forces for trapping and storing infiltrated lubricants. In this study, block-copolymer-derived hierarchically wrinkled slippery liquid-infused nanoporous surfaces (i.e., micro wrinkles with nanochannels infused with slippery fluids) are successfully fabricated after silicone oil infiltration. The antibiofouling performance of these surfaces is examined against different foulers under various conditions. The produced coatings exhibited flexible, stable, transparent, and easily tunable antibiofouling characteristics. In particular, the formation of an eco-friendly silicon-based lubricant layer without the use of fluorinated compounds and costly material precursors is an advantage in industrial practice that can be adopted in various applications, such as fuel transport, self-cleaning windows, anticorrosion protection, nontoxic coatings for medical devices, and optical instruments.     

内外部悬索联合张拉膜结构的设计与分析

为了更好地张拉平面薄膜结构,研究其张拉悬索体系,从理论上证明了要使空间平面薄膜结构处于无褶皱状态,其最优的边界应为圆形.提出一种新型的内外部悬索联合张拉方法,给出了此张拉方法下各部分悬索张力的计算方法,并考查了边界跨数对结构的轴压的影响,发现奇数跨时支撑结构所受的轴压相对较小.通过与传统张拉方法的比较,这种新型膜面张拉方法,在固定膜面尺寸、不固定膜面跨数和不固定膜面尺寸、固定边界单跨跨度这2种情况下,所需拉索的截面面积和质量均相对较小,因此,内外部联合张拉方法不仅更易于折叠打包,而且可在一定程度上减小结构的质量.通过计算发现在支撑结构发生变形时,联合张拉方法可以减缓膜面褶皱的出现.     

薄膜二次屈曲行为的数值仿真分析

建立了薄膜二次屈曲分析的数值方法.采用施加面外扰动力的方式在薄膜中引入任意的初始缺陷,分析了薄膜的二次屈曲现象.分析表明,在薄膜的后屈曲过程中,由于初始缺陷的存在,褶皱构形不稳定,出现二次屈曲现象,产生了新的褶皱.后屈曲平衡路径呈现多阶段的特点.在不同的初始缺陷和加载过程的情况下,薄膜的后屈曲过程会出现连续的二次屈曲现象.二次屈曲过程中薄膜可能是稳定的也可能是不稳定的,与初始缺陷及加载过程有关.     

聚酯桔形漆在光学仪器上的应用

叙述在仪器、仪表的表面施涂聚酯桔形（皱纹）漆的工艺流程和操作条件。     

An Analysis of Draw-Wall Wrinkling in a Stamping Die Design

Wrinkling that occurs in the stamping of tapered square cups and stepped rectangular cups is investigated. A common characteristic of these two types of wrinkling is that the wrinkles are found at the draw wall that is relatively unsup-ported. In the stamping of a tapered square cup, the effect of process parameters, such as the die gap and blank-holder force, on the occurrence of wrinkling is examined using finite-element simulations. The simulation results show that the larger the die gap, the more severe is the wrinkling, and such wrinkling cannot be suppressed by increasing the blank-holder force. In the analysis of wrinkling that occurred in the stamping of a stepped rectangular cup, an actual production part that has a similar type of geometry was examined. The wrinkles found at the draw wall are attributed to the unbalanced stretching of the sheet metal between the punch head and the step edge. An optimum die design for the purpose of eliminating the wrinkles is determined using finite-element analysis. The good agreement between the simulation results and those observed in the wrinkle-free production part validates the accuracy of the finite-element analysis, and demonstrates the advantage of using finite-element analysis for stamping die design.     

杆系柔性成形模具及其板成形加工关键技术

提出了一种可重构、低成本、高效率的板件成形加工模具———杆系柔性成形模,该装置可以快速重构各种形状的板件成形加工模具。详细地分析了杆系柔性成形模的结构及其重构方案,采用可更换的“变形冲压头”与离散杆配合,较好地构成模具成形面,保证板件有较好的成形精度;提出了一种新颖的板成形方法———模内压板与成形复合工艺,通过这种工艺方法与杆系柔性成形模相结合,可以抑制板件在成形过程中的受压屈曲与起皱,并可以减小成形板件的回弹量。该模具对复杂曲面板件的成形加工具有明显的优越性。     

3D Modelling,Simulation and Prediction of Facial Wrinkles

The FA （facial ageing） process has been of a great interest to many researchers and some finns like airports and police departments, this is due to the fact that the face appearance changes as people age resulting in difficulties identifying certain individuals. In this paper, 2D wrinkle maps will be used in the design of a 3D system for the purpose of facial wrinkles simulation and prediction. Our findings will challenge many commercial soffwares in the innovation of the techniques in setting solid grounds to generate real-time 3D wrinkles that can be used later for various reasons. The 2D binary wrinkles will be mapped on the corresponding 3D face models using the generated outlined images. NURBS curves will then be projected on those wrinkles to form a 3D wrinkle map. The coloured wrinkle map, as well as some parameters, will be combined together in an algorithm to predict the appearance of the individual wrinkles in every age group that are divided into decades, starting from the age of 20. The novelty of the adopted procedure in comparison to the previous works is the new elements that have been integrated and collaborated to boost accuracy and generate a more realistic outcome.     

Orientation‐Dependent Strain Relaxation and Chemical Functionalization of Graphene on a Cu(111) Foil

Epitaxial graphene grown on single crystal Cu(111) foils by chemical vapor deposition is found to be free of wrinkles and under biaxial compressive strain. The compressive strain in the epitaxial regions (0.25–0.40%) is higher than regions where the graphene is not epitaxial with the underlying surface (0.20–0.25%). This orientation‐dependent strain relaxation is through the loss of local adhesion and the generation of graphene wrinkles. Density functional theory calculations suggest a large frictional force between the epitaxial graphene and the Cu(111) substrate, and this is therefore an energy barrier to the formation of wrinkles in the graphene. Enhanced chemical reactivity is found in epitaxial graphene on Cu(111) foils as compared to graphene on polycrystalline Cu foils for certain chemical reactions. A higher compressive strain possibly favors lowering the formation energy and/or the energy gap between the initial and transition states, either of which can lead to an increase in chemical reactivity.