陶瓷涂层三明治板的抗热震性

采用解析法研究了第3类边界条件下双面陶瓷涂层三明治板的瞬态温度场及瞬态热应力场.对不同Biot模数的热冲击过程中,Al2O3涂层/硬质合金(WC-8%Co,质量分数)基体/Al2O3涂层三明治板的瞬态热应力进行了数值计算.分析了涂层/基体厚度比、涂层与基体热-物理性能匹配对陶瓷涂层三明治板表面热应力峰值的影响.结果表明:陶瓷涂层三明治板的基体的热导率、线膨胀系数和弹性模量应高于涂层,这样可以降低其表面热应力,获得高抗热震性陶瓷涂层三明治板.此外,涂层厚度应尽可能小,以利于改善涂层的抗热震性.     

泡沫铝发泡效率与泡体均匀性研究

研究了用TiH2作为发泡剂制备泡沫铝过程中发泡剂加入量、发泡温度、搅拌时间、搅拌速度和保温时间对泡沫铝孔隙率、发泡效率和结构均匀性的影响。研究结果表明,随着发泡剂加入量的增加,泡沫铝的孔隙率逐渐上升;随着发泡温度的升高,发泡效率和均匀度逐渐减小;随着保温时间的增加,泡沫铝样品的孔隙率上升、发泡效率降低、均匀度减小;在5个因素中,搅拌时间和搅拌速度属于次要因素。当发泡剂的加入量为1.1%～1.3%、发泡温度在620～640℃之间、搅拌时间2.5～5.0 m in、搅拌速度1 500～2 500 rpm和保温时间3.0～5.0 m in时可以制备出孔隙率75%～85%、发泡效率80%以上、均匀性80以上、平均孔径1～4 mm的泡沫铝样品。     

基于Voronoi模型的梯度孔隙率泡沫铝力学性能研究

通过孔径梯度的变化调整孔隙率梯度,得到多组整体孔隙率相同、但内部孔隙率梯度不同的胞状泡沫金属Voronoi模型。对具有均匀孔隙率的泡沫铝试件进行冲击试验和数值模拟,两种结果吻合良好,初步验证了采用Voronoi模型可以较为准确地模拟泡沫金属材料的力学行为。基于Voronoi模型对具有不同孔隙率梯度的泡沫铝的压缩过程进行数值模拟,研究孔隙率梯度、梯度方向、围压作用等因素对泡沫铝力学性能的影响。结果表明:在不同荷载情况下,梯度的存在使得泡沫铝的坪应力降低,同时在屈服平台阶段出现了明显的硬化现象;外力较大时,梯度泡沫铝有更好的承载能力和吸能能力。     

泡沫铁铬镍规整填料的性能实验研究

为了考察泡沫铁铬镍规整填料的性能,对电沉积法制备的泡沫铁铬镍规整填料进行了流体力学和传质性能实验。结果表明:泡沫铁铬镍规整填料的压降随F因子和喷淋密度的增大而增大,液泛点的Ff因子达到2 m/(s·kg~(0.5)·m~(1.5))以上,且每米填料的理论板数达到3块板以上。相比铸造法制备的泡沫铝和泡沫碳化硅规整填料,泡沫铁铬镍规整填料的压降低、持液量小、操作弹性大,其传质性能与传统规整填料M250Y和BX500相当。在实验基础上,拟合了泡沫铁铬镍规整填料的压降关联式和液泛气速关联式,为今后的工业化设计提供指导。     

生物发泡法制备多级孔结构AT-M陶瓷及其微观结构表征

本文采用生物发泡与面粉固化相结合的冰浴法制备了具有可控多级孔结构的大孔钛酸铝莫来石(AT-M)陶瓷。研究了面粉、酵母和固体含量对发泡性能和泡沫稳定性的影响。此外,还对试样的微观结构、孔隙分布进行了系统的研究。结果表明,通过调节酵母和面粉的含量,可以控制AT-M陶瓷的孔隙率和孔隙结构。获得了大孔尺寸为200～400μm,孔隙率为58.77～76.74%的多孔陶瓷。     

含酰亚胺基团环氧泡沫的制备及其性能

合成了一种端氨基酰亚胺固化剂MDIA,以其在不同温度、不同发泡剂含量下固化双酚A环氧树脂制备大孔环氧泡沫材料。研究结果表明,在固化剂中引入酰亚胺结构可以提高环氧树脂的耐热性能和力学性能。随发泡温度的提高,孔隙率增加,Tg和5%失重温度(Td5)提高,制备的环氧泡沫材料Tg可达120℃,Td5可达300℃,孔隙率为47%时,压缩强度可达16 6MPa。     

低界面张力泡沫体系DJM-2复配及性能评价研究

针对目标油藏对复配的低界面张力泡沫体系DJM-2性能以及影响因素开展研究,确定了目标油藏用低界面张力泡沫体系DJM-2的最佳体系配方,并对所筛选的体系性能进行评价。实验结果表明:在目标油藏(矿化度6284mg/L、温度70℃)条件下,低界面张力泡沫体系DJM-2油水界面张力为1.58×10~(-3)mN/m,且在渗透率极差为5的油藏条件下,该体系的驱油效果可基于水驱提高采收率16.64%,同时该体系具有良好的稳定性和乳化性。     

城轨车辆复合材料板件及组合结构隔声量分析研究

纤维增强复合材料、高分子复合材料、三明治板等基础板件及其组合结构在城轨车辆中已经被广泛应用。由于其特有的性能和功能以及组合方案的多样性,在使用过程中往往很难判断和取舍。基于试验测试数据,重点分析了目前几种典型的单层复合材料板,玻璃纤维与碳纤维复合材料板,铝蜂窝、泡沫夹芯等三明治板及多种材料组合结构的隔声量,同时综合考虑了轻量化要求,提出了城轨车辆复合材料选择的基本建议,可为城轨车辆复合材料的选择提供参考。     

多孔介质冰蓄冷板的融化过程

模拟研究了泡沫铝、泡沫铜、网状聚氨酯泡沫的孔隙参数对多孔介质冰蓄冷板的融化过程的影响,得到了第三类边界条件下多孔介质冰蓄冷板融化过程的时间、温度分布、相界面移动等的规律。结果表明,多孔介质热导率越高,温度分布越均匀,相界面越模糊,冰蓄冷板融化时间越短;融化时间随多孔介质孔隙率的减小和孔密度的减少而缩短,孔隙率的影响程度大于孔密度;与纯冰相比,本研究中泡沫铜最多可将冰蓄冷板融化时间缩短15.2%。多孔介质热导率越低,冰蓄冷板的融化时间越长;融化时间随着孔密度的增加而缩短,随孔隙率的减小而略增;与纯冰相比,本研究中网状聚氨酯泡沫最多可将冰蓄冷板释冷时间延长11.8%。最后对填充泡沫铜和网状聚氨酯泡沫冰蓄冷板的融化时间进行了试验验证,试验结果与模拟结果较为一致。     

泡沫载体的表面处理对泡沫陶瓷性能的影响

采用有机泡沫浸渍法制备细孔径氧化铝基泡沫陶瓷过滤器。研究了有机泡沫载体的表面活化处理对氧化铝基泡沫陶瓷过滤器性能的影响。结果表明:羧甲基纤维素钠(CMC)、木质素磺酸钙、聚乙烯亚胺(PEI)三种表面活性剂对泡沫陶瓷性能的影响程度由大到小依次为CMCPEI木质素。当取活化剂CMC的浓度为1.5%时,制备出的泡沫陶瓷性能最佳,其容重、抗压强度和孔隙率可分别达到0.49g.cm-3、2.40MPa、83%。     

复合材料泡沫夹层结构的缺陷评定方法研究

本文以厚壁碳纤维复合材料为面板,硬质聚氨酯泡沫为芯材制造复合材料泡沫夹层结构,模拟实际生产过程中容易出现的面板与芯材之间界面的脱粘和界面胶层过厚的现象,采用人工制造试块的方法,研究了超声波探伤对夹层复合材料缺陷的评定方法,解决了实际检测过程中的疑问,为夹层复合材料结构产品的质量检验提供依据。得出了粘接良好区胶层过厚不会被判定为脱粘的结论。     

High-velocity impact loading in honeycomb sandwich panels reinforced with polymer foam: a numerical approach study

The employment of lightweight structures is one of the most important goals in various industries. The lightweight sandwich panel is an excellent energy absorber and also a perfect way for decreasing the risk of impact. In this paper, a numerical study of high-velocity impact on honeycomb sandwich panels reinforced with polymer foam was performed. The results of numerical simulation are compared with the experimental findings. The numerical modeling of high-velocity penetration process was carried out using nonlinear explicit finite-element code, LS-DYNA. The aluminum honeycomb structure, unfilled honeycomb sandwich panel, and the sandwich panels filled with three types of polyurethane foam (foam 1: 56.94, foam 2: 108.65, and foam 3: 137.13 kg/m³) were investigated to demonstrate damage modes, ballistic limit velocity, absorbed energy, and specific energy absorption (SEA) capacity. The numerical ballistic limit velocity of sandwich panels, filled with three types of foam, was more than that of a bare honeycomb core and unfilled sandwich panel. In addition, the numerical results showed that the sandwich panel filled with the highest density foam could increase the strength of sandwich panel and the numerical specific energy absorption of this structure was 23% more than that of unfilled. Finally, the numerical results were in good agreement with experimental findings.

     

轨道车辆泡沫夹芯中顶板夹层设计与优化

轨道车辆的生产中大量采用平板铝合金或玻璃钢板件,产品质量偏重且材料容易出现下垂,满足不了车体轻量化与美观的需求.通过仿真与试验结合的方式研究酚醛泡沫、聚对苯二甲酸乙二醇酯(PET)泡沫、聚氯乙烯(PVC)泡沫夹芯中的面板厚度、芯材模量对中顶板质量及下垂挠度的影响,测试了不同复合夹芯板的平拉强度、平压强度以及弯曲强度.结...     

Comparison of foam core sandwich panel and through‐thickness polymer pin–reinforced foam core sandwich panel subject to indentation and flatwise compression loadings

Through‐thickness polymer pin–reinforced foam core sandwich (FCS) panels are new type of composite sandwich structure as the foam core of this structure was reinforced with cylindrical polymer pins, which also rigidly connect the face sheets. These sandwich panels are made of glass fiber–reinforced polyester face sheets and closed‐cell polyurethane foam core with cylindrical polymer pins produced during fabrication process. The indentation and compression behavior of these sandwich panels were compared with common traditional sandwich panel, and it has been found that by reinforcing the foam core with cylindrical polymer pins, the indentation strength, energy absorption, and compression strength of the sandwich panels were improved significantly. The effect of diameter of polymer pins on indentation and compression behavior of both sandwich panels was studied and results showed that the diameter of polymer pins had a large influence on the compression and indentation behavior of through‐thickness polymer pin–reinforced FCS panel, and the effect of adding polymer pins to FCS panel on indentation behavior is similar to the effect of increasing the thickness of face sheet. The effect of strain rate on indentation behavior of FCS panel and through‐thickness polymer pin–reinforced FCS panel were studied, and results showed that both types of composite sandwich panels are strain rate dependent structure as by increasing strain rate, the indentation properties and energy absorption properties of these structures are increased. POLYM. COMPOS., 37:612–619, 2016. © 2014 Society of Plastics Engineers     

熔融沉积成型木塑复合夹层板的弯曲性能

采用熔融沉积成型(FDM)制造方法,以木塑复合线材为原料,利用3D打印软件Ultimaker Cura的“填充结构”功能设计网格、直线、三角形等13种芯层结构(二维6种、立体7种),并将其与纸板粘接得到木塑复合夹层板。利用三点弯曲测试,研究不同夹层板的破坏失效形式与弯曲性能。结果表明:木塑夹层板的失效模式主要有弹性变形、面板起皱、芯子剪切和芯子压溃。在13种芯层结构中,立体的同心3D芯层结构夹层板弯曲性能最佳,弯曲模量和静曲强度分别为159.56 MPa和4.85 MPa,分别是网格芯层结构夹层板的5.4倍和2.3倍,具有较强的抗弯曲变形能力,适合于设计制造轻质高强度制品。     

The impact response of aluminum foam sandwich structures based on a glass fiber-reinforced polypropylene fiber-metal laminate

The fracture properties and impact response of a series of aluminum foam sandwich structures with the glass fiber–reinforced polypropylene-based fiber-metal laminate (FML) skins have been studied. Initially, the manufacturing process for producing the FML skins was optimized to obtain a strong bond between the composite plies and the aluminum layers. The degree of adhesion between the composite plies and the aluminum was characterized by conducting single cantilever beam tests. Here, it was found that the composites could be successfully bonded to the aluminum using a simple short stamping procedure. A detailed examination of the fracture surfaces indicated that crack propagation occurred within the composite ply in the fiber-metal laminates and along the composite-aluminum foam interface in the sandwich structures. The low velocity impact response of the FMLs and the sandwich structures was investigated using an instrumented drop-weight impact tower and a laser-Doppler velocimeter. The energy absorption characteristics of the sandwich structures were investigated along with the failure processes. Finally, a series of tensile tests on the damaged FMLs and thermoplastic sandwich structures showed that both systems offer promising residual load-bearing properties. Here, shear failure in the aluminum foam was observed in the sandwich structures, indicative of a strong bond between the FML skins and the aluminum core. Polym. Compos. 25:499–509, 2004. © 2004 Society of Plastics Engineers.     

格栅增强夹芯板弯曲刚度影响因素及规律研究

基于有限元仿真和实验,对格栅增强夹芯板弯曲刚度的影响因素及规律开展了研究。首先,针对格栅结构对夹芯板抗弯特性的影响进行仿真分析,认为格栅结构能够较为显著地提高夹芯板的抗弯刚度;其次,针对格栅增强夹芯板的蒙皮纤维铺层角度、格栅密度等几个重要参数对其弯曲刚度的影响进行仿真计算并对其规律进行分析;最后,通过实验验证了仿真的准确性。分析结果表明,夹芯板蒙皮纤维±45°铺设时夹芯板具有最优的抗弯刚度,且在格栅总体积即含筋量一定的情况下,一定范围内降低单层格栅的厚度以增加格栅的密度会大幅度提高夹芯板的抗弯刚度。     

Impact resistance and bonding capability of sandwich panels with fibre–metal laminate skins and aluminium foam core

Sandwich panels with aluminium foam core and fibre–metal laminate (FML) skins for enhanced impact resistance have been designed and manufactured during this research activity. The FML skins are made of a combination of aluminium sheets and E-glass fibre/epoxy-laminated plies. Drop-weight impact tests are conducted on two groups of sandwich panels with aluminium foam core bonded to the aluminium sheet in Group 1 panels, and aluminium foam core bonded to the E-glass/epoxy ply in Group 2 panels to allow an investigation of the bonding capability between the aluminium foam and the FML skins under impact and the impact resistance of the sandwich panels. The delamination and debonding ranges, the maximum deformed height in the impact area are measured and the deformed volumes of the sandwich panels after drop-weight tests are evaluated. via comparison of these parameters for the two groups of sandwich panels, it is found that the bonding between aluminium foam to the E-glass/epoxy surface provides a better resistance to impact than that between aluminium foam bonded to the aluminium sheet of the FML facing, and that overall Group 2 panels exhibit better bonding capability and impact resistance with less facing delamination and core/facing debonding than the Group 1 panels.     

双向格构腹板增强泡沫夹层复合材料梁弯曲性能试验

复合材料夹层结构具有比强度高、比刚度高、可设计性强、耐腐蚀等特点,以聚氨酯泡沫为芯材,以玻璃纤维增强复合材料为面板和格构腹板,采用真空导入成型工艺,制备双向格构腹板增强泡沫夹层复合材料梁。对无格构泡沫夹芯复合材料梁,不同腹板高度、腹板间距双向格构增强泡沫夹层复合材料梁进行三点弯曲试验,研究其破坏模式和机理。基于泡沫填充矩形蜂窝芯材的等效十字模型,预估试件的抗弯刚度和挠度,计算值与试验值吻合较好。     

铝合金内衬复合材料高压容器界面粘结的研究

复合材料高压容器由于其质量轻近年来被广泛应用在航天方面,但是复合材料气密性差,通常用金属内衬来提高其气密性.由于铝合金和复合材料变形不协调,致使铝合金内衬耐疲劳性能很差.界面良好的粘接使铝合金和复合材料形变相协调,能够很好的提高铝合金内衬复合材料高压容器的耐疲劳性能.因此,对复合材料和铝合金界面粘结的研究具有重要的意义.