硬质聚氨酯泡沫塑料抗爆炸冲击作用的研究

硬质聚氨酯泡沫塑料具有刚度小、材质松散、易于吸收爆炸能量的特点。本文根据硬质聚氨酯泡沫塑料的这些性能和特点,结合军事工程的要求,介绍了硬质聚氨酯泡沫塑料在在抗爆、隔爆方面的应用情况。通过一个简化的防护工事的抗爆性能分析,说明硬质聚氨酯泡沫塑料具有良好的抗爆、隔爆性能,非常适合于防护工程的应用。     

硬质聚氨酯泡沫塑料在伪装工程中的应用研究

介绍了硬质聚氨酯泡沫塑料在伪装工程中的研究及应用现状,并依据硬质聚氨酯(RPUR)泡沫塑料的性能和特点,结合伪装工程的使用性能及要求,指出硬质聚氨酯泡沫塑料因具有良好的性能和伪装效果而非常适合在军事伪装工程中应用.     

玻璃纤维增强聚酯类聚氨酯硬质泡沫塑料

一、前言聚氨酯泡沫塑料是由多元羟基化合物和多异氰酸酯,在其它添加剂的参与下,经混合、反应和起泡的一种泡沫塑料。它能常温固化,就地浇注。密度可在0.03～0.3g/cm~3之间任意调节。可制成软质、硬质、阻燃、耐高温等不同品种的泡沫塑料。可作为优良的绝热、隔音、包装、起浮、填充、增强等材料。玻璃纤维增强聚氨酯硬质泡沫塑料,国外已开始用作建筑材料、玻璃钢夹层结构材料、内燃机底座、船体外壳和高速机车所要     

硬质聚氨酯泡沫塑料难燃化技术的研究

作者对硬质聚氨酸泡沫塑料的难燃化技术进行了研究，并开发出难燃型硬质聚氨酯泡沫塑料。该技术在保持了一般硬质聚氨酯泡沫塑料基本性能不变或降低很少的同时，又赋予了材料难燃性、低发烟性及耐火隔热的性能。     

稀土金属氧化物与聚磷酸铵阻燃剂在硬质聚氨酯泡沫塑料中协同作用的研究

本文从聚合物材料的燃烧特点出发，分析和讨论了聚合物材料的阻燃特性。实验采用添加无机阻燃剂聚磷酸铵及稀土金属氧化物，提高了硬质聚氨酯泡沫塑料的阻燃性能，并研究了添加型无机阻燃剂与硬质聚氨酯泡沫塑料氧指数的关系，得出了一些规律性结果，这些结果对进一步研究耐燃的硬质聚氨酯泡沫塑料配方有一定的指导意义。     

硬质聚氨酯泡沫塑料本构方程在包装设计中的应用

从硬质聚氨酯泡沫塑料的本构方程出发,分析了硬质聚氨酯泡沫塑料在包装工程中的设计方法,并给出了具体的计算公式及求解方法,可见泡沫塑料的本构方程对其在包装设计中具有十分重要的应用价值。     

碛质聚氨酯泡沫塑料本构方程在包装设计中的应用

从硬质聚氨酯泡沫塑料的本构方程出发,分析了硬质聚氨酯泡沫塑料在包装工程中的设计方法,并给出了具体的计算公式及求解方法,可见泡沫塑料的本构方程对其在包装设计中具有十分重要的应用价值。     

玻璃纤维对硬质聚氨酯泡沫塑料增强机理的探讨

研究了硬质聚氨酯泡沫塑料的微观结构形态，通过实验探讨了玻璃纤维对聚氨酯泡沫塑料的增强作用，并分析了增强泡沫塑料的压缩破坏机理。     

硬质聚氨酯现场发泡及在冷藏柜应用的若干问题

一、绪论聚氨酯是聚氨基甲酸酯的简称。一般聚氨酯由二元或多元异氰酸酯与多元醇化合物(聚醚多元醇或聚酯多元醇)发生聚合反应而得。若采用不同种类的异氰酸酯和多元醇,则可以生产出软质、半硬质和硬质聚氨酯泡沫塑料。区别软质、半硬质、硬质聚氨酯泡沫塑料的主要参数为抗压强度的大小。     

硬质聚氨酯泡沫塑料的显微结构

聚氨酯泡沫塑料是把含有羟基的聚醚树脂或聚酯树脂与异氰酸酯反应生成聚氨酯y 体,并由异氰酸酯与水反应生成二氧化碳发泡,或由低沸点氟碳化合物(如三氯氟甲烷)作为发泡剂发泡,制造过程中为了加速发泡和有利于气泡的形成还加入适量的催化剂和稳定剂等,然后通过聚合凝固而成泡沫塑料。聚氨酯泡沫塑料按性质不同,可分为硬质、半硬质和软质三种。硬质聚氨酯泡沫塑料具     

Structure and Mechanical Properties of AFS Sandwiches Studied by in‐situ Compression Tests in X‐ray Microtomography

Al foam core / Al alloy skins sandwiches have potential for application in light weight structures. Recently, the foaming processes have improved and large, thick and 3D‐shape panels can be produced using the precursor technology. The microstructure of an AFS sandwich is analysed in this paper at a microscale and a mesoscale using X‐ray tomography and conventional SEM analysis. The main deformation mechanism of the core under compression is also studied thanks to in situ test. It is shown that the foam first present plastic buckling and then walls rupture. This is well correlated to the microstructure of the constitutive material of the core.     

Forming limit diagram prediction of AA5052/polyethylene/AA5052 sandwich sheets

Metal–plastic sandwich sheet has received increasing attention in aeronautical, automotive, marine and civil engineering industries due to its lower density, higher specific flexural stiffness, better dent resistance, better sound and vibration damping characteristics. In the present study, an AA5052/polyethylene/AA5052 sandwich sheet is developed and its formabilities are investigated. A numerical simulation method based on the Gurson–Tvergaard–Needleman (GTN) damage model is used for simulating the forming process of sandwich sheet, in which the interface conditions between skin sheet and core materials are considered by using the cohesive zone model (CZM). The rigid punch dome tests and the Nakazima forming tests are carried out to build the forming limit diagrams (FLDs) of sandwich sheet. A strain history method is applied to determine the limited strain. Comparisons between predictions and experimental results validate the used numerical simulation method. Finally, the influences of polyethylene’s thickness on the formabilities of sandwich sheet are analyzed. Research results show that: AA5052/polyethylene/AA5052 sandwich sheet has a better formability than monolithic AA5052 sheet and the formability of AA5052/polyethylene/AA5052 sandwich sheet increases with increasing the thickness of polyethylene core layer.     

镁的添加对制备泡沫铝夹芯板泡孔稳定性的影响

通过粉末-铝板复合轧制方法制备出一种界面为冶金结合的泡沫铝夹芯板.分别采用对发泡剂的处理和添加Mg元素的方法来提高芯材泡沫的稳定性.研究发现只有同时对发泡剂处理以及添加Mg元素才能够提高泡沫的稳定性.研究了此种方法中重要的泡沫稳定机制,Mg元素的添加改善了铝硅合金粉末原料生产过程中产生的氧化物颗粒在孔壁上的润湿性,使氧化物颗粒嵌入孔壁中,阻碍了孔壁上金属排液现象的产生,有效的起到稳定泡孔的作用.     

Modelling of the non-linear material behaviour of cellular sandwich foam core

The aim of this study is to develop a simple and reliable engineering method of modelling the non-linear behaviour of rigid cellular sandwich cores. It is assumed that shear dominates the stress state in a core and, hence, the approach is only valid when this condition is satisfied. On the basis of shear domination, the usual anisotropy associated with cellular solids can be neglected in favour of a simpler isotropic consideration. This allows the use of well-developed finite element codes for isotropic materials which account for plastic behaviour. It is shown how experimentally obtained shear properties can be converted analytically to a format suitable as input for such finite element programs, and a sandwich beam subjected to four-point bending is modelled numerically with material input according to the suggested method. The results are compared with those from an experiment in which substantial core yielding took place, and the behaviour is found to be predicted quite accurately. A numerical analysis of the ASTM C-273 shear test is used to show the validity of this test method, and thereby the data on which the suggested method of modelling must rely, well into the plastic response.     

泡沫塑料的单轴压缩力学性能(上)

泡沫塑料具有优良的缓冲减震性能、良好的温湿度稳定性以及机械性能,仍是目前应用最普遍的缓冲材料之一,是大中型产品包装或高安全防护包装的首选.以EPS、EPP与EPE 3种具有较大性能差异的低密度发泡塑料作为主要研究对象,分析讨论了其在静态单轴压缩条件下的应力-应变关系及材料静压力学性能的影响因素.     

改性偶氮二甲酰胺/水复合发泡在硬质聚氨酯发泡中的应用研究

目的 通过偶氮二甲酰胺(AC)热分解反应释放出发泡用气体,用改性偶氮二甲酰胺/水复合发泡制备无卤素硬质聚氨酯泡沫(RPUF)。探讨改性偶氮二甲酰胺在聚氨酯发泡中的可行性。方法 通过改变体系中改性偶氮二甲酰胺的用量,探讨改性偶氮二甲酰胺对聚醚发泡体系黏度、聚氨酯泡沫力学性能和导热系数的影响。结果 发泡剂的加入能显著降低聚醚体系的黏度,提高发泡物料的流动性,随着改性AC用量的增加,体系黏度逐渐增加,当改性AC的添加量为0.3 g时,体系黏度最低为2 080 mPa.s。当改性AC用量为0.75 g时,聚氨酯泡沫的表观密度为78.65 kg/m³,压缩强度为539.35 kPa,改性AC的加入使得聚氨酯泡沫的导热系数增高,导热系数为0.023 51 W/mK。结论 改性AC的加入能显著提高硬质聚氨酯泡沫的压缩强度,相比纯水发泡,二者复合发泡性能更优异,可以作为无卤素发泡剂应用于聚氨酯发泡。     

发泡木塑复合材料发泡及成型工艺研究

介绍了发泡木塑复合材料的基本原料及发泡方法,同时对发泡木塑复合材料的主要成型工艺及其影响因素进行了说明,在此基础上指出了发泡木塑复合材料的研究趋势。     

The contact behavior between a foam core sandwich plate and a rigid indentor

The purpose of this paper is to determine the indentation produced by a rigid indentor falling on a sandwich plate with a height–density closed cellular foam core. Two different indentor shapes are considered: a rigid sphere and a cylindrical rigid punch. By assuming that the time of complete indentation of the indentors is much larger than the time required by the elastic waves to propagate from the point of first contact to the boundary of the plate, a static analysis is performed. A distribution of surface pressures reproducing the contact law of the rigid indentor on an elastic half-space is introduced and the sandwich plate theory proposed by Dundrová, Kovarı́k and Slapák (1970) is adopted; the explicit solutions with pre-assigned surface pressures are obtained and the contact force–indentation relations, before the sandwich plate is damaged, are found. The contact laws are obtained for both a simply supported and a clamped circular sandwich plate and the relevant influence of boundary conditions on the elastic response of the sandwich plate is shown.     

泡沫铝夹芯板的制备技术

泡沫金属是一类具有低密度以及新奇的物理、力学、电学、声学等特殊性能的新型材料.而泡沫铝的潜在用途之一是作为泡沫铝夹芯板的芯材使用.详细介绍了制备泡沫铝夹芯板的不同方法,如胶粘法、超声焊接法、激光协助发泡法、扩散焊接法、面板与预制材料轧制-包覆法和粉末复合轧制法等.通过比较,在国内粉末复合轧制法工艺简单,是最有希望适合高温作业和大批量生产的方法.     

煤基炭泡沫孔结构调控

以肥煤镜质组富集物为前驱体, 采用高压渗氮法制备煤基炭泡沫, 研究了发泡温度、发泡压力和发泡时间对炭泡沫孔结构的影响。利用SEM观察炭泡沫的孔胞形貌, 同时利用Nano Measurer分析软件统计SEM照片孔胞直径分布和孔喉直径分布以及平均孔径。结果表明: 微孔塑料成核理论可以定性解释炭泡沫的孔结构变化趋势。发泡温度的升高导致成核密度增加, 同时导致气体在胶质体的溶解度降低, 不利于孔胞长大。发泡压力的增大导致炭泡沫的孔胞密度增加, 临界成核半径降低, 同时加剧了热聚合反应, 导致胶质体的粘度增大, 不利于孔胞长大。发泡时间的延长会使热聚合更加充分, 影响胶质体粘度, 进而影响孔结构。