和物夹层材料对减振复合钢板拉伸剪切性能的影响

高聚物夹层厚度为０．１５ｍｍ的减振复合钢板拉伸剪切特性与高聚物本身的拉伸变形规律一致,其破坏形态为高聚物内聚破坏;炕聚物夹层厚度为０．１０ｍｍ的复合钢板具有较高的拉伸剪切强度,其破坏形态为钢板与高聚物夹层间的类似界面破坏。聚氨酯和氯丁橡胶改性酚醛树脂含有极性基团,用它们分别作夹层制成的复合钢板具有较高的拉伸剪切强度;增加钢板表面粗糙度,有利于提高钢板和高聚物间的结合力。     

酚醛树脂/氯丁橡胶作夹层的复合钢板的性能

研究了酚醛树脂／氯丁橡胶作夹层的复合钢板的性能，该复合钢板在20－150℃范围内具有良好的减振性能；在较低温度和较高形变速率下，复合钢板具有较高的拉伸剪切强度，在80℃附近，拉伸剪切强度最低，在80－150℃范围内，拉伸剪切强度随温度升高而增加；增加钢板表面粗糙度有利于改善复合钢板的成型性。     

胶厚对钛合金-复合材料接头胶接性能的影响

采用钛合金与芳纶纤维复合材料制备了不同胶层厚度的单搭接接头。利用DIC与万能试验机对接头进行了拉伸-剪切性能测试,研究了不同胶层厚度异质材料的接头胶接性能、应变场与破坏模式的变化规律,分析了在拉伸载荷下,不同胶层厚度接头的失效特点。结果表明,当胶层厚度由0. 2 mm增加至1. 2 mm时,接头极限载荷由6. 13k N降低至5. 89 k N,损伤后剩余强度降低,薄胶层接头出现渐进失效;复合材料端头高剥离与拉伸应变区域面积增加,厚胶层与被胶接件一同变形,导致接头提前失效;钛合金-胶层界面破坏模式增多,芳纶纤维复合材料层间破坏模式减少;接头在发生复合材料层间破坏后,仍能够保持较高的剩余强度,当钛合金-胶层界面遭到破坏后,易整体失效。     

缝合复合材料的制备与力学性能分析

采用新型的锥管针刺技术,将铺层平纹碳布在厚度方向上进行缝合,通过控制针距和行距,得到缝合密度不同的缝合预制体,再采用RTM工艺将预制体与环氧树脂进行复合,得到三维缝合复合材料。通过拉伸、弯曲和层间剪切试验,探究缝合密度对缝合复合材料力学性能的影响。结果表明,与未缝合碳纤维/环氧树脂复合材料相比,加入缝合线后,复合材料的拉伸性能降低,拉伸强度降低了3. 1%～12. 4%;缝合复合材料弯曲强度,随缝合密度的增加呈现先下降后上升再下降的趋势,其中密度为5 mm×5 mm的缝合复合材料弯曲强度提高了2. 2%;缝合复合材料层间剪切性能较未缝合复合材料均出现了不同程度提高,当缝合密度为5 mm×5 mm时,提高率达到最大值,为41. 6%。对试样的断口形貌进行讨论,结果表明,缝合线是影响材料破坏模式的重要因素。     

低介电聚酰亚胺复合片材的结构设计与性能研究

基于夹层结构设计,在聚酰亚胺（PI）薄膜夹层间引入多孔聚酰亚胺泡沫（PIF）,成功制备具有低介电常数的PI复合片材,并研究PIF厚度对复合片材介电性能、力学性能和导热性能的影响。结果表明：介电常数随着PIF厚度的增加而增加,厚度为1 mm的复合片材的介电性能最佳,100 Hz下介电常数低至1.55。随着PIF厚度的增加,复合片材的拉伸强度降低,导热系数先降低后趋于平缓。FFF-15-5样品的导热系数最低为0.046 W/（m·K）,复合片材显示良好的隔热性能。该PI复合片材为低介电材料的设计提供新思路。     

夹芯式复合结构抗高速破片侵彻性能试验

为抵御反舰导弹产生的高速破片,设计制作了以高强玻璃纤维板为面板、聚氯乙烯(PVC)泡沫材料和高强聚乙烯纤维板为芯层的复合结构,并开展弹道试验研究其抗侵彻性能,为对比分析开展了945钢抗高速破片侵彻试验。结果表明,前置高强玻璃纤维板产生纤维剪切、拉伸断裂、基体碎裂和纤维脱粘破坏,前置PVC泡沫产生压实坍塌、胞壁剪切断裂和压碎破坏,高强聚乙烯纤维板主要产生纤维剪切、拉伸断裂并出现背凸大变形,后置PVC泡沫板产生压实破坏,后置高强玻纤板并未明显破坏裂纹;立方体弹侵彻945钢板时产生严重墩粗变形,钢板产生剪切冲塞破坏;复合结构单位面密度吸能较945钢板提高34%。     

G／Epoxy复合材料胶接强度研究

使用G／Epoxy作为底材研究了垫板、结构胶黏剂厚度和底材表面处理对拉伸剪切强度的影响。使用光学显微镜观察了断口形貌。结果表明加垫板能减小试验过程中由于加载偏心引起剥离应力,测试结果较大;结构胶黏剂的厚度和底材表面处理对拉伸剪切强度影响十分明显,随着厚度的增大而减小,经打磨表面裸露出纤维的试样拉伸剪切强度很低。结构胶黏剂厚度较小时以内聚破坏为主,随着厚度的增加破坏模式转变为粘接破坏。     

高聚物夹层材料对层压减振复合钢板减振性能的影响

高聚物夹层材料对层压减振复合钢板的减振性能影响很大,用聚氨酯和酚醛树脂-氯丁橡胶共混物分别作夹层制得的复合钢板具有良好的减振性能。层压减振复合钢板的结构损耗因子的试验值高于计算值,但二者随温度的变化规律具有很好的一致性。     

胶层厚度对有机硅密封胶拉伸剪切强度的影响

研究了胶层厚度对有机硅密封胶拉伸剪切强度的影响,结果表明:随着胶层厚度减小拉伸剪切强度增大,拉伸剪切位移减小,粘结破坏面积增大。     

聚脲弹性体复合夹层结构的防爆性能

应用LS–DYNA有限元软件,对聚脲弹性体复合夹层结构在0.5 kg炸药(TNT)爆炸载荷作用下的动态响应过程进行数值模拟。研究了复合夹层结构厚度和质量固定条件下聚脲弹性体夹层厚度对复合夹层结构抗爆性能的影响。分析了不同聚脲弹性体夹层厚度对复合夹层结构变形的影响,并分析了聚脲弹性体夹层的吸波和吸能特性。结果表明,在爆炸载荷作用下,当复合夹层结构总厚度固定时,随着聚脲弹性体夹层厚度的减小,复合夹层结构的抗爆性能先增大后减小,当钢板与聚脲弹性体夹层厚度比为1.4∶1.2∶1.4时,变形的整体性最好,其抗爆的潜力最大,其冲击波衰减率最大为85.6%,能量吸收效果也最好,其综合抗爆能力较好;在质量固定条件下,随着聚脲弹性体夹层厚度的增加,其抗爆能力先增大后减小,当钢板与聚脲弹性体夹层厚度比为0.903∶3.5∶0.903时,其变形和能量吸收效果最好,冲击波衰减率最大为81.87%,其综合抗爆能力较好。     

Prediction of vibration damping properties of polymer-laminated steel sheet using time–temperature superposition principle

The vibration damping properties of the polymer-laminated steel sheet have been investigated theoretically and experimentally. The laminate consisted of a polymer layer, which was sandwiched between two steel sheets. Two polymers a polyvinyl butyral and a copolymer of ethylene and acrylic acid, were used. The theoretical analysis was based on a model proposed by Ungar. A frequency analyzer was used to measure the loss factor of the laminate. The model required rheological data, such as storage modulus G′ and loss tangent of the polymer at high frequency, which could not be obtained from commercially available dynamic rheometers. The time–temperature superposition principle was applied to the laminated polymer to construct the master curves of G′ and loss tangent vs. frequency. These master curves provided rheological data at high frequency, which were superposed from data measured at low temperature. The results showed that a discrepancy existed between the loss factors predicted with superposed and without superposed data and the reasons for this discrepancy were discussed. The measured loss factors of the laminates at high frequency followed the predictions using superposed data, but not for those measured at low frequency. Factors accounting for this deviation were analyzed. The results also indicated that, in general, the transition temperature of the polymer-laminated steel sheet was 15°C–30°C higher than the corresponding glass transition temperature of the laminated polymer.     

尿素合成塔衬里贴衬板材的选择与应用

根据现场施工的具体情况,考虑材料的强度、耐蚀性及工艺操作特点,在尿素合成塔衬里实施贴衬时,选用国产4.2mm厚的25-22-2冷轧钢板,从而解决尿素合成塔衬里腐蚀减薄的问题。     

Study of Polymer Blends as a Vibration Damper

Metallic materials have too small internal friction to damp vibration making noise, whereas plastics show remarkably large damping capacity in some characteristic temperature ranges where a considerable part of the vibrational energy is consumed as a result of molecular friction.

If the two kinds of materials are combined, one can expect that the vibration of the composite materials will be damped to a greater extent than that of the metal itself.

In this study dynamic mechanical properties of a variety of polymer blends were measured and those which have a broad E' peak around 0°C were chosen from among them.

Sandwich structures of Al/polymer/Al type were then constructed and the dynamic mechanical properties of the composite systems were measured by means of a vibration reed technique. It was found that the sandwich structures with these polymer blends had larger damping capacity than that with poly (vinyl acetate) or Al itself.     

玻/碳纤维混杂复合材料层合板的振动特性研究

为了获取玻/碳纤维混杂复合材料层合板的振动特性,以玻/碳纤维混杂复合材料层合板为研究对象,基于有限元分析软件ANSYS Workbench分析了夹芯混杂、层间混杂两种混杂方式下的复合材料层合板的振动特性,得到了层合板的混杂类型、铺设厚度、长宽比、铺设角度对玻/碳纤维混杂复合材料层合板固有频率的影响规律.结果表明:夹芯混...     

Developments of high performance vibration absorber from poly(vinyl chloride)/chlorinated polyethylene/epoxidized natural rubber blend

A high performance vibration absorber requires a high loss factor behavior over a wide temperature and frequency range. An investigation was carried out to prepare such materials based on poly(vinyl chloride), chlorinated polyethylene, and epoxidized natural rubber ternary blends. The loss factor and damping behavior of several compositions were measured using a viscoelastic spectrometer and a polymer‐laminated steel cantilever‐beam damping device. Suitable compositions were found to give good mechanical properties and high loss factor over a wide temperature and frequency range. It was also observed that flake‐type fillers improve the damping behavior. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 855–863, 1999     

Study of Polymer Blends as a Vibration Damper

Metallic materials have too small internal friction to damp vibration making noise, whereas plastics show remarkably large damping capacity in some characteristic temperature ranges where a considerable part of the vibrational energy is consumed as a result of molecular friction.

If the two kinds of materials are combined, one can expect that the vibration of the composite materials will be damped to a greater extent than that of the metal itself.

In this study dynamic mechanical properties of a variety of polymer blends were measured and those which have a broad E″ peak around 0°C were chosen from among them.

Sandwich structures of Al/polymer/Al type were then constructed and the dynamic mechanical properties of the composite systems were measured by means of a vibration reed technique. It was found that the sandwich structures with these polymer blends had larger damping capacity than that with poly (vinyl acetate) or Al itself.     

Dynamic mechanical studies of a highly filled composite structure: A lightweight coated paper

A composite sandwich structure, consisting of a paper sheet as a middle layer and two porous coating layers of a highly filled acrylate–styrene–butadiene copolymer, has been studied by means of a dynamic mechanical test in torsion. Stiffness and mechanical damping, tan δ, were recorded over the temperature region where the latex polymer exhibits a glass transition. The mechanical damping decreases with increasing filler content in the coating. Variations in the thickness of the coating layers did not influence the mechanical damping. The glass transition temperature of the latex polymer increases with increasing volume fraction of filler at high filler contents as an effect of filler–matrix interaction. The outer layers partly penetrate into the middle layer, as indicated by thickness measurements on the coated paper. A theoretical comparison of the peak heights of the mechanical damping using lamination theory shows a discrepancy in the experimental results. If penetration of the outer layer is allowed for, i.e., if using a thicker outer layer of the composite in the calculations, a favorable correlation between the theoretical and the experimental results is obtained. © 1993 John Wiley & Sons, Inc.     

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     

Study of a 'T'-type peel test on a metal/polymer/metal sheet sandwich

This paper describes the specific 'T'-type peel mode in the case of a metal/polymer/metal sheet sandwich and gives experimental results on the influence of plastic deformation in the metallic substrates on the peel energy. We propose an experimental method of carefully determining the peel energy of a metal-polymer interface in a sandwich structure. Based on the mechanical properties of the stainless steel substrates and the maximum curvature of the metallic sheet measured experimentally during the peel test, several expressions for the clastoplastic deformation energy of the metal substrates are given. It is noteworthy that the curvature of the metal substrate layers depends not only on the mechanical properties of the material, but also on the work necessary to overcome the interfacial or cohesive forces. It is shown that even for thin metallic substrates (0.1 mm thick stainless steel), the work absorbed by the deformation represents roughly 50% of the total measured energy. During peeling the same specimen at different rates, the propagation peel force is higher or lower than the initiation force depending on the previous curvature of the metal sheets.