玻纤增强塑料V型剪切性能测试的研究

本文介绍了玻璃纤维增强塑料V型剪切性能的测试,采用电阻应变片、动态电阻应变仪及试验夹具在试验机上完成剪切模量和剪切强度的测试。     

美国ASTM物理测试标准目录(十)

ASTM D3386—94《电绝缘材料的线性热膨胀系数试验方法》ASTM D3420—95《塑料薄膜的摆锤式冲击试验方法》ASTM D3433—93《粘结接头中胶粘剂的断裂强度试验方法》ASTM D3479/D3479M—96《有序纤维树脂基质混合物的拉伸和拉伸疲劳试验方法》ASTM D3482—90《胶粘剂对铜的电解腐蚀试验方法》ASTM D3528—96《双搭接剪切粘结接头的拉伸试验方法》     

ASTM金属材料拉伸试验方法介绍

介绍了ASTM E8(E8M)标准中的金属材料屈服强度、屈服点伸长率、均匀伸长率、抗拉强度、伸长率和断面收缩率的测量方法，并与我国相应的标准试验方法进行了比较。     

阻尼橡胶材料阻尼性能悬臂梁共振法测试方法

根据标准ASTM E756-05(2010)，对阻尼橡胶材料阻尼性能悬臂梁共振法的测试方法进行了研究，分析接触式响应传感器引入的附加质量及激励传感器和响应传感器的安装位置对测试结果的影响，并得到有意义的结论。试验结果表明：质量为0.6 g的接触式响应传感器引入的附加质量对材料的弹性剪切模量和剪切损耗因子的影响较小，测试结果满足标准ASTM E756-05(2010)对测试精度的规定；选择合适的激励器安装位置有利于提高传递函数曲线幅值；响应传感器的安装位置对传递函数曲线影响较大，测试时应根据所要获得的模态信息选择合适的测点。     

纤维增强塑料力学性能试验方法标准审定会

一九八二年四月二十六至二十九日在济南召开的审定会,审定了纤维增强塑料的拉伸、纵横剪、弯曲及层间剪切四项试验方法标准。这四项标准由纤维增强塑料标准化分会归口,由航空工业部与建材部联合提出。主要起草单位有航空材料研究所、北京航空学院、哈尔滨玻璃钢研究所、上海玻璃钢研究所及北京玻璃     

ASTM消费品安全标准化活动及对我国消费品安全标准化的借鉴

美国试验与材料协会（ASTM International）是发达国家技术领先标准制定组织的代表，一直活跃在消费品安全标准化领域。特别是在2007年度对中国玩具业产生严重冲击的玩具召回事件中，ASTM标准产生了至关重要的作用。2008年3月，两项ASTM标准经参议院投票成为美国联邦政府玩具检验的强制规定，足以说明ASTM标准在消费品安全领域的权威性。     

硬度试验ASTM标准与国内标准的对比分析及应用

从试验方法、硬度计的检定/校准、硬度块的检定/校准等方面,对硬度试验的ASTM标准与国内标准(包括国家标准和国家计量检定规程)进行了对比分析,找出两者之间存在的主要差异,并对硬度试验ASTM标准的特点进行了总结,为国内标准的制定及应用提供借鉴;另外还介绍了硬度试验ASTM标准在国际转包生产业务中的应用,为更好地理解和应用外贸标准提供参考。     

浇铸式铜-钢复合板在制冷装置中的应用

介绍一种适用于制冷装置压力容器的浇铸式铜-钢复合板。通过对比分析爆炸焊接复合板和堆焊复合板基层与复层结合机制及相关标准的试验、检测要求,提出应对浇铸式铜-钢复合板进行剪切强度试验、超声波检测、化学分析等检验项目,以确保压力容器安全。     

金属材料高温拉伸试验标准对比研究

为制定适合我国民用航空业的金属高温拉伸试验标准,并与国际先进的标准体系接轨,全方位对比分析美国宇航材料标准(ASTM)和中国国家标准(GB)金属高温拉伸试验标准的主要的差异。对比分析结果表明:1)在试验设备方面,ASTM较GB引伸计准确度高50%,600℃以上加热装置准确度高25%。ASTM增加试验机轴向性检测程序和易腐蚀材料的保护装置,并要求安装引伸计指示应变率装置,提高试验的准确性。GB明确测温设备的检测周期,提高检测可靠性。2)在试样制备方面,ASTM相较于GB明确规定试样的产品批次、最终状态和取样位置。3)在试验程序方面,ASTM增加试样清洗环节,试样的最低保温时间比GB多一倍。GB在测200 MPa以下屈服和抗拉强度时修约结果更准确,ASTM在测200 MPa以上屈服和抗拉强度时修约结果更准确。4)在试验报告方面,ASTM较GB从试样、温度控制、特殊情况、试验结果等方面进行全面而详细的要求,整份报告能够提供很好的数据信息支撑。综上,金属高温拉伸试验GB标准有别于ASTM,提高设备准确度,加强条件控制准确度,考虑试验环境与特殊状况,才能制定出满足中国民航业的高标准国际化金属高温拉伸试验标准。     

火灾高温后混凝土内GFRP筋剪切性能退化试验与理论

为研究火灾高温后混凝土内玻璃纤维增强树脂复合材料(GFRP)筋材的剪切性能，选取了100℃、150℃、200℃、300℃、350℃、400℃、500℃、650℃及800℃共9个温度工况，对混凝土内GFRP筋进行了高温作用及水平剪切试验；结合本试验及已有相关试验结果，对高温后混凝土内GFRP筋水平剪切强度预测方法进行了探讨。试验及分析结果表明：300℃高温以内，混凝土内GFRP筋表面温度存在滞后现象，其高温劣化程度明显低于裸筋，剪切强度退化也较缓慢；随着温度超过300℃及混凝土表面裂缝不断发展，内部GFRP筋受高温侵蚀逐步加大，剪切强度出现急剧下降，并出现与裸筋相似的退化规律；在300℃(接近树脂热分解温度)高温下，GFRP筋剪切强度随恒温时间的增加而线性下降，恒温1～3 h时其剪切强度保留率从76.4%降为46.5%。结合双曲正切函数模型，建立了高温后混凝土内GFRP筋水平剪切强度预测模型，其预测值与试验值吻合较好。最后，以剪切强度保留系数0.7为基准，给出了不同保护层厚度下GFRP筋的耐火时间预测值，供工程应用参考。     

Accelerated weathering effects on the mechanical and surface properties of CFRP composites

This study provides data regarding the characteristics of three carbon fiber reinforced polymer (FRP) systems with three types of resins exposed to accelerated natural weathering conditions according to ASTM G-154-00a for 1000 h. The FRP system consists of three-layered CFRP sheets bonded together with an adhesive. Degussa, Sika and Fosroc were the providers of the three FRP systems. Three-point bend testing according to ASTM D790 showed that ultra-violet (UV) light exposure decreased the flexural modulus of the three-layered FRP samples by 10%, 36% and 2% for Deagussa, Fosroc and Sika samples, respectively. While the reduction for the resin samples was 11.8%, 8.3% and 14.3% for Deagussa, Fosroc and Sika samples, respectively. SEM analysis showed cracking and deterioration in the resin and FRP systems as a result of the exposure to natural weathering.     

ASTM布氏硬度试验标准简介

介绍了ASTM金属材料布氏硬度试验方法并与相应的国家标准进行了比较。     

Experimental Evaluation of Thermal Effects on the Tensile Mechanical Properties of Pultruded GFRP Rods

This work represents a preliminary study of a more articulate research project whose aim is to show the possible applications of pultruded products in civil engineering and, in particular, the substitution of FRP rods in classic concrete structures. We present an experimental procedure to first degrade FRP rods with aligned continuous glass fibres through exposure to elevated temperature and then evaluate the changes in their tensile mechanical parameters. The procedure to expose the rods to heat is defined starting from the specifications contained in ASTM D794-68, while the evaluation of the tensile mechanical parameters was set up in a previous work for analogous undamaged FRP rods. From the observation of the experimental data obtained in this work, it is possible to show the strong effects of heat on the ultimate strength and on the Young's modulus of the material that constitutes the rods. In particular, the ultimate strength shows a constant degradation when the temperature increases. By contrast, the Young's modulus is subject to different changes at different temperature exposures.     

冲击试验机的检定标准及其欧标间接检定方法介绍

对JJG 145—2007,ASTM E23—2002和EN 10045-2—1992三种常用冲击试验机检定标准进行了介绍,并按照欧标EN 10045-2—1992对国内某制造厂生产的摆锤冲击试验机进行了间接检定,对间接检定的过程及应注意的事项进行了详细的介绍,并给出了检定结论。结果表明:在中、低能量档,所检定摆锤冲击试验机的重复性误差和误差均符合EN 10045-2—1992要求,但在高能量档,其重复性误差高于标准要求;所检定摆锤冲击试验机的有效使用范围为0～110 J。     

Physico-mechanical properties and decay resistance of Cupressus spp. cement-bonded particleboards

Control and hot water treated particles of cypress (Cupressus spp.) were used to manufacture cement-bonded particleboards (CBPB). Three replications were carried out for each treatment, totaling six single layered boards. Physical and mechanical properties of the boards were evaluated according to ASTM D 1037-96a [Annual Book of ASTM Standards, vols. 04–09. Philadelphia: American Society for Testing and Materials––ASTM, ASTM D 1037-96a, 1998] standard. The wood of cypress showed suitability as raw material for the manufacture of CBPB. All the properties of cypress CBPB were higher than the Bison HZ type building boards used as reference. The light color and easy wood processing of cypress wood are favorable parameters for panels manufacturing. The results corroborate those reported for CBPB using pine, rubberwood, acacia, babassu, and eucalyptus particles. The CBPB were also submitted to fungi decay resistance test according to ASTM D 2017-81 [Annual Book of ASTM Standards, vols. 04–09. Philadelphia: American Society for Testing and Materials––ASTM, 1994-e1. ASTM D 2017-81, p. 324–8] standard and exposed to the attack of Gloeophyllum trabeum (Persoon ex Fries) Murr. and Trametes versicolor (Linnaeus ex Fries) Pilát. Twelve specimens were tested for each treatment and the average weight loss was determined after 12 weeks of exposure. Laboratory tests showed that there was no measurable wood degradation (weight loss). Fungi mycelium did not even cover completely the surface of the specimens. CBPB when exposed to both brown- and white-rot fungi, rather than weight loss, showed weight gains ranging from 2% to 4%. Therefore, CBPB is technically suitable for exterior use where both moisture and favorable conditions for fungi development are present.     

FRP tube encased rubberized concrete cylinders

In this study, FRP tube encased waste tire rubber modified concrete cylinders were investigated. Four batches of confined and unconfined concrete cylinders with a diameter of 101.6 mm and a height of 304.8 mm were prepared. Each batch contained three confined cylinders and three unconfined cylinders. The total number of effective cylinders prepared was 24. Batches 1–3 were made of rubberized concrete. In Batch 1, 15% by volume of coarse aggregate was replaced by waste tire fibers or stripes; in Batches 2 and 3, 15% by volume of sand and 30% by volume of sand were replaced by crumb rubbers, respectively. Batch 4 was a control batch with conventional plain concrete. Uniaxial compression tests were conducted on all the cylinders per ASTM C39. Strain gages were installed on the encased rubberized concrete cylinders to obtain local strain distributions. The compressive strength and strain at the peak load were compared with the predictions by available design-oriented confinement models. It is found that the FRP tube encased rubberized concrete cylinders have higher confinement effectiveness, ductility, and elastic regions than FRP tube encased conventional concrete cylinders. Waste tire fiber modified concrete performs better than crumb rubber modified concrete with a lower cost. Instead of volume contraction, FRP encased rubberized concrete cylinders experience volumetric expansion. The current design-oriented confinement models cannot consistently predict the compressive strength and strain of the encased cylinders. An 1-D coupon test cannot uniquely determine the hoop tensile strength of the FRP tubes which are subjected to a 2-D stress condition.     

国内外金属材料热机械疲劳试验方法标准比较

对GJB 6213-2008,ASTM E2368-2010和ISO CD 12111-2002三个金属材料热机械疲劳试验方法标准分别从试验设备要求、试样要求、试验程序控制和试验结果评定等方面进行了对比分析,归纳总结了以上标准的异同点,建议今后在制定或修订热机械疲劳试验方法国家标准时增加对试样温度梯度、感应线圈温度场分布、应变速率变化和热应变补偿精度检验等参数要求。     

On the characterisation of carbon black from tire pyrolysis

Abstract

A commercially available pyrolytic carbon black (CBp) produced from the pyrolysis of used tires was analysed by TGA-DTA showing that the effective carbon black content about 70% by weight, while about 14% are ashes and about 16% rubber pyrolysis residues adsorbed on the surface. GC-MS analysis of the latter fraction has permitted to identify at least 34 different molecules, some of them under the form of alkylated benzenes and alkylated naphthalenes and higher PAHs. Two simple procedures are shown to be effective in the quantitative determination of zinc and sulphur content of CBp. The surface area of CBp should be evaluated with both the ASTM D6559-19 and the ASTM D4607 test methods. CBp was also analysed with SEM-EDX and with FT-IR and Raman Spectroscopy. The latter spectroscopical technique was employed both on pristine and thermally annealed CBp, demonstrating that also CBp is a partially graphitizable carbon black similar to the N774 ASTM grade.     

热导性电绝缘界面材料热传输特性参数的测量

介绍了热导性电绝缘界面材料的热传输特性标准试验方法ASTM D 5470-2006,讨论了提高测量精度的措施。标准试验方法的提出,使得不同厂商生产的热导性电绝缘界面材料的比较成为可能;此外,也便于热设计工作者更好地选用热导性电绝缘界面材料。     

A simple test method,NAL-II,to evaluate the strength and elastic modulus of polymer matrix composite laminates

This study proposes and assesses a simple test method (NAL-II) to evaluate compressive properties of carbon fiber-reinforced polymer matrix composite laminates (CFRP). Compressive tests based on ASTM D6641 and NAL-II methods were conducted for direct comparison using three kinds of quasi-isotropic composite laminates (T800H/3633, T800S/3900-2B, and IM600/133). Stress–strain curves including the compressive modulus obtained using the NAL-II method showed good agreement with those obtained using the ASTM D6641. The NAL-II method gave slightly higher (approximately 10%) compressive strengths than the ASTM D6641 method, probably because of suppression of bending (buckling) before failure. The experimentally obtained results suggest that the NAL-II method can be useful for international standard testing of the non-hole compressive strength of CFRP laminates.