长管拖车气瓶用4130X钢的应变疲劳特性及寿命预测

研究了长管拖车钢制无缝气瓶用材料4130X在4种不同应变幅控制下的低周应变-疲劳特性,分别对其循环应力-应变关系、应力-应变迟滞回线及疲劳寿命预测等进行研究,着重分析4130X钢的疲劳循环软化行为,提出了考虑循环软化作用的疲劳寿命预测修正模型。     

ASTM标准在实验室间检测汽油结果再现性的评价

目前石油产品标准方法在测试质控工作中,已广泛进行实验室间的协作,实验室B通过与实验室A检测结果的比对,对采用ASTM标准检测汽油的结果进行再现性分析,评价两个实验室的结果吻合性,同时,对出现实验室结果不吻合的情况进行了原因分析并提出解决措施.     

用边界效应理论考虑断裂韧性和拉伸强度对破坏的影响

采用边界效应理论,研究了断裂韧性和拉伸强度对材料与结构破坏的影响。边界效应模型中通过引入等效裂缝,可同时反映试件前边界与后边界对断裂特性的影响;基于等效裂缝与特征裂缝的比值,即可判断试件处于强度准则、韧度准则或准脆性断裂等何种破坏模式。边界效应模型不仅适用于线弹性断裂条件,而且适用于弹塑性断裂分析,解决了ASTM规范及RILEM规范的局限。鉴于ASTM规范确定材料断裂韧度对试件初始缝长与试件尺寸等的严格限制,本文基于边界效应理论,建立了由RILEM规范中小尺寸试件确定材料断裂韧度与拉伸强度的方法,相关试验成果证明了所提方法的合理性与适用性。     

某台国产压水堆压力容器锻件材料断裂韧性韧脆转变的参考温度

摘要：采用紧凑拉伸c（T）试样测试了某台国产反应堆压力容器用508-Ⅲ锻件的主曲线参考温度死。为了方便今后在热室中进行辐照材料的断裂韧性试验,专门修改了c（T）试样的前端面设计。有限元分析和采用修改、未经修改的C（T）试样的试验结果均表明,对试样的修改不会影响断裂韧性试验。发现C（T）试样测得的瓦值与前期采用三点弯曲SE（B）试样确定的％值仅相差约1℃。为此详细探讨了ASTME1921标准第1．3和5．7条款有关试样形式对％的影响,试验结果印证了这些条款的阐述,所测得的r,n试验值接近材料的％平均值。     

高性能混凝土的强度与渗透性的关系

一般认为，混凝土的强度越高，其渗透性越低，以及耐久性越好。通过掺与不掺矿渣或粉煤灰高性能混凝土的试验结果表明，纯水泥混凝土的强度与渗透性之间有很好的相关性，其相关系数为０．９７６７；矿渣混凝土及粉煤灰混凝土的强度与渗透性之间相关性较差，相关系数分别为０．８０８１和０．８４１９；所有混凝土的强度与渗透性之间，相关性更差，相关系数为０．６５６６。可见，除非用于纯水泥混凝土之间的相对比较，高性能混凝土的强度通常不能反映其渗透性     

NEL法与ASTM C1202法氯离子渗透性对比试验研究

在原理分析可行的基础上,以同一试件分别采用ASTM C1202法和NEL法对高强混凝土和普通混凝土进行了氯离子渗透性对比试验研究,这样可以消除不同试件对比所产生的离散误差.原理分析和试验结果证实了:先进行电通量测试对于随后进行的NEL法测试影响小,可以忽略.从而确定了在同一试件对比试验中,应当首先进行电通量测试然后再进行NEL法渗透试验.用同一试件消除离散误差的措施,为两种渗透指标之间建立科学的关系打下基础.初步试验结果表明:低水胶比高性能混凝土两种渗透指标(即氯离子扩散系数和电通量)的离散性比较小,容易确定两种指标之间的定量关系;而高水胶比普通混凝土的两个指标之间的离散性很大,很难为二者确定同样的定量关系.     

基于常规物性参数的石脑油组成预估方法

研究了在石脑油详细组成未知的情况下 ,通过常规物性参数预估其详细组成的方法。经过对大量石脑油样本的分析 ,确定其主要由分属于正构烷烃、异构烷烃、环烷烃和芳烃 4个族的 31种烃类物质组成。利用工业上可以方便获得的ASTMD86数据、PONA值、密度和氢含量等数据 ,计算出这 31种物质在石脑油中的质量分数。针对燕山石化公司的石脑油试样进行估算 ,结果表明 ,估算结果与实验分析结果吻合良好     

Measurements of thermal insulation performance: The challenge of the next decade

The past two decades have stimulated significant growth both in thermal insulation materials and product development and in their use for new and different applications. These activities have had a resultant impact both on existing methods of measurement of relevant thermal properties and on the development of new or modified measurement techniques. Various examples of present measurement technologies applicable to the new materials and applications are discussed in relation to the current state of the art. These include (1) measurements on very high-thermal resistance per unit thickness insulation systems for appliances and buildings, (2) improvements in current standard methods of test, particularly in speed of operation and relevance to application, and (3)in situ and field measurements. The discussion includes examples of current limitations. These relate particularly to accuracy, especially at elevated temperatures, product variability, a need for relevant transient techniques, and very urgent requirements for reference materials and transfer standards. As a result, recommendations are proposed in the hope that they will stimulate necessary research and development work in the next decade.Paper presented at the Second U.S.-Japan Joint Seminar on Thermophysical Properties, June 23, 1988, Gaithersburg, Maryland, U.S.A.     

Development of inferential measurements using neural networks

In many industrial processes, the most desirable variables to control are measured infrequently off-line in a quality control laboratory. In these situations, use of advanced control or optimization techniques requires use of inferred measurements generated from correlations. For well-understood processes, the structure of the correlation as well as the choice of inputs may be known a priori. However, many industrial processes are too complex and the appropriate form of the correlation and choice of input measurements are not obvious. Here, process knowledge, operating experience, and statistical methods play an important role in development of correlations. This paper describes a systematic approach to the development of nonlinear correlations for inferential measurements using neural networks. A three-step procedure is proposed. The first step consists of data collection and preprocessing. Next, the process variables are subjected to simple statistical analyses to identify a subset of measurements to be used in the inferential scheme. The third step involves generation of the inferential scheme. We demonstrate the methodology by inferring the ASTM 95% endpoint of a petroleum product using data from a domestic US refinery.     

JG600-Ⅰ高压加热器管板堆焊焊接工艺试验

文中介绍了为解决JG600-Ⅰ高压加热器管板(20MnMoNb锻件)和管子(美国ASTM规范A556《无缝冷拔碳钢给水加热器钢管》中B2级)异种材料焊接问题,而采用在管板上堆焊一层低碳钢,从而实现接近同种材料焊接的方法.并制定了堆焊工艺,进行了工艺试验.