泡沫塑料夹层梁弯曲试验和理论分析

本文对泡沫塑料夹层梁的试验结果进行了理论分析。挠度和剪应力的理论计算值与实测值很符合,面板应力的理论计算值比实测值大,经修正后的理论计算值与实测值吻合,可供夹层结构产品设计时使用。本文也指出泡沫塑料夹层梁弯曲的非线性特点,产品设计时应计及此特性。     

3 200 t/d生产线氨逃逸理论值与实测值的对比分析

对某3?200 t/d水泥生产线的氮氧化物和氨逃逸情况进行了实际测试，并计算了C1出口和窑尾烟囱的理论氨逃逸值。结果表明，氨逃逸理论计算值与实测值存在较大差异，理论计算值高于实测值，氨的氧化率和粉尘浓度、水分等是实测值与理论值存在差异的主要原因，氨水用量和分解炉出口NOx浓度是影响氨逃逸理论计算结果的主要因素。     

轿车子午线轮胎临界速度的估算

在确定轿车子午线轮胎相关力学参数及运用复合材料叠层理论计算胎冠抗弯刚度的基础上,用弹性基环形梁模型和薄膜理论估算轿车子午线轮胎的临界速度,并分析两种理论估算子午线轮胎临界速度的特点,讨论轮胎径向阻尼对临界速度计算的影响。结果表明,临界速度估算值与实测值吻合,径向阻尼对临界速度计算的影响可忽略。     

二维两轴编织铺层复合材料压缩弹性性能的一种计算方法

通过在体式显微镜下,观测编织铺层复合材料纱线走向,考虑纱线在交织处屈曲起伏,纤维轴向模量会有部分损失,提出纤维轴向模量损失系数ξ。通过测量编织复合材料中的基本参数,结合复合材料细观结构、弹性力学、迭层理论和多层等效弹性力学模型,利用推导出一套比较简单而实用的二维两轴编织铺层复合材料平均压缩模量的计算方法。实验结果表明:理论计算值与实测值吻合度较高,为编织复合材料的工业应用提供了一种简单而实用的弹性性能计算方法。     

悬浮聚合反应器U值理论算法探讨

本文基于传热原理和工厂实践经验.提出一个计算悬浮聚合反应器总传热系数U值的方法。结果表明.提出的理论估算法所得之U值与实测值相当接近。文章还探讨了强化传热的可行途径。     

预应力高强混凝土矩形支护桩的受弯性能

针对预应力混凝土预制桩在基坑支护中的应用,开发新型的预应力高强混凝土矩形支护桩。通过9根矩形支护桩的受弯性能试验,研究了矩形支护桩的受弯破坏特征、裂缝开展情况和受弯承载力。结果表明:在外荷载作用下,矩形支护桩变形体现了很好的弹性和延性;矩形支护桩截面的应变分布符合平截面假定;矩形支护桩的抗裂弯矩实测值与计算值之比平均为1.33;实测极限弯矩与理论计算值基本接近。基于试验结果,提出对矩形支护桩抗裂弯矩和极限弯矩计算方法的修正建议,计算结果与试验结果吻合较好。对比发现,在相近的成本条件下,矩形支护桩比空心方桩受弯承载力增加10%～20%。     

CdGeAs2晶体的结构、弹性和电子性能的模拟计算和分析

利用基于密度泛函理论的平面波赝势法对CdGeAs2晶体的结构,弹性和电子性能进行了研究.CdCeAs2晶体具有6个独立的弹性常数,利用计算的弹性性能可以判断晶体具有机械稳定性、延性和弹性各向异性等力学特点.通过总的和部分态密度分析了不同能带的贡献成分.计算的结构参数及弹性常数与实验值基本吻合.CdGeAs2晶体具有直接...     

混凝土碳化深度预测模型分析

碳化深度预测模型计算值与实测碳化深度值的对比分析表明,基于水灰比W/C的经验模型、基于水灰比W/C和水泥用量C的经验模型、单纯基于抗压强度的Smolczyk模型的碳化深度预测值与实测值误差较大,应根据实际情况选择使用。牛荻涛模型和张海燕模型作为以抗压强度为主要参数的经验模型,较为可靠。张誉模型基于扩散理论及碳化机理建立,具有充分的理论依据和较高的预测精度。     

混煤可磨性指数(HGI)可加性研究

对比了单煤及两两混煤可磨性指数(HGI)的实测值与计算值,说明同一配比、不同混煤的实测值与计算值不完全相等,存在一定误差。分析了存在偏差的主要原因为:实验本身的系统误差和单煤之间可磨性指数(HGI)不具有线性可加性。最后通过t检验验证可磨性指数(HGI)实测值与计算值之间的差异是否显著。结果表明:同一配比、不同混煤时,大量难磨煤与少量易磨煤组成的混煤可磨性指数(HGI)实测值与计算值具有显著性差异;其它配比条件下,不同混煤实测值与计算值之间差异性不明显。同一混煤、不同配比时,混煤可磨性指数(HGI)实测值与计算值之间误差不全在正常范围内,混煤可磨性指数(HGI)与配比不全具有线性相关性。单煤可磨性指数(HGI)不具有线性可加性。     

幻灯投影法检测透明塑料板材光学畸变

本文简述了幻灯投影法的原则和测试方法,在测定有机玻璃时,实测值和理论计算值很接近。     

Optimizing the mismatch in curvature between a flexible adherend and a rigid substrate

An analytical approach used to determine stress within an adhesive layer due to curvature mismatch between flexible adherends is implemented in an optimization analysis. The basis of this analysis is the classical beam on elastic foundation approach, where the adherend is described as a flexible beam and the foundation represents the adhesive layer. In this analysis, the optimal shape of a rigid substrate, described by the curvature of the substrate, is found based on various optimal conditions. These conditions include (1) minimizing the tensile stress in the adhesive layer (referred to as the peel stress), (2) maximizing the compressive stress at the free end and (3) minimizing the stress in the adherend. To minimize the peel stress, there should be a smooth transition between regions of differing curvatures. To minimize the stress in the adherend, the initial curvature mismatch between the adherend and the substrate should be reduced. The optimization scheme is described and results for two non-dimensionalized examples, associated with relatively stiff and relatively compliant systems, are presented.     

稠油乳状液屈服特性及环道启动压力预测

针对海上平台稠油管线停输置换、再启动难题,以旅大稠油为研究对象,利用Rheolab QC流变仪测量系统剖析稠油及其乳状液启动过程与初始阶段力学响应特性,讨论含水率、启动温度、静置时间与恒定剪切速率对启动屈服应力的影响作用,自主研制并加工搭建了室内小型再启动环道实验装置,测量与验证再启动压力理论预测值可靠性。实验结果表明：稠油乳状液启动过程可划分为屈服、衰减和平衡3个阶段,启动屈服应力均在反相点附近达到最大值,随着启动温度升高而降低,随恒定剪切速率增大而增大;适当增大启动流量可缩短管线启动时间,但同时也增大了启动压力;基于启动屈服应力的启动压力预测值是环道实验装置测量值的2～3倍,而基于平衡剪切应力的启动压力预测值与实测值吻合较好,平均相对误差为4.5%。     

本征型与添加型导静电防腐涂料的性能对比和应用

介绍了钢质油罐内壁导静电防腐涂料的性能要求。通过本征型导静电涂料与添加型导静电涂料的性能对比，以及两者的实际应用情况对比，得出本征型导静电涂料更适用于钢质油罐内壁的结论。     

大型油罐入口管油品防静电安全流速的确定

油流沿管线前进过程中,与管内壁发生摩擦将产生静电。流速过大,由摩擦产生的流动电流增大,进罐时带入油罐内的静电量将增大,为进站油罐安全储存带来隐患。且管线各油品大都处于紊流状态下进行输送,油品流速大小决定着静电形成量。为确保进站油罐的安全储存,依据理论及经验公式计算分析大型油罐入口管道的直径对安全输送流速的影响,并对两种公式所得计算结果进行比较,确定算例中油品在不同管径下输送时的进罐安全流速,为今后实现油品的安全输送及储存提供理论依据。     

Photoelastic Stress Analysis of Bonded Lap Shear Joints Having Thermoplastic Adherends

The effects of substrate stiffness and modulus on joint strength and stress distribution were investigated for a series of nylon substrates bonded with an epoxy adhesive. Substrate stiffness and modulus were controlled by the level of glass filler in the resin. Single lap shear samples having both identical (“self-bonded”) and dissimilar (“cross-bonded”) substrates were investigated. For the self-bonded samples, lap shear strength was found to increase with increasing substrate modulus and stiffness. The strengths of the cross-bonded samples were intermediate to the strengths of the corresponding self-bonded samples. Photoelastic techniques were used to observe stress patterns in the lap joints during testing. One type of stress pattern was observed for all self-bonded samples regardless of substrate stiffness. Two patterns, one for the stiff substrate and one for the more flexible substrate, were observed for cross-bonded samples. The photoelastic analysis agreed qualitatively with predictions of stress distributions based on linear elastic and linear elastic/perfectly plastic theoretical models.     

一种煤基油窄馏分折射率计算方法研究

为了考察寿德清-向正为关系式计算煤焦油及焦油加氢产物窄馏分样品折射率的准确性,在通过分析大量样品和实验数据的基础上,对比了计算值与测定值之间的差异。结果表明:计算中低温煤焦油窄馏分样品的折射率时,样品的计算结果与测定结果相差较大,寿德清-向正为关系式不可直接用于计算煤焦油窄馏分折射率;用寿德清-向正为关系式计算两种焦油加氢产物窄馏分样品的分子量时,样品的计算结果与测定结果较接近,对焦油加氢产物B样品来说,两种方法的平均误差为0.27%,均方差为0.34%;对焦油加氢产物C样品来说,两种方法的平均误差为0.21%,均方差为0.32%。寿德清-向正为关系式可直接用于计算焦油加氢产物折射率。     

Predictions and verifications of early-age stress development in hydrating blended cement concrete

A procedure for calculating the early-age stress development in concrete incorporating the aging viscoelastic effects is presented in this paper. The important features of the present procedure are the use of tensile creep and inclusion of heat of hydration. The latter is used as an aging parameter and incorporates the effect of temperature on age-dependent material parameters. To validate stress predictions, experiments to measure early-age stress development in concrete mixes made of blended cements were conducted. The predictions were found to be accurate and could be improved when the effect of temperature was included. Effects of using mineral additives (fly ash, slag, and silica fume) appeared to be beneficial in reducing the risk of cracking at early ages. The effect of temperature gradient was also studied when the stress calculation was applied to pavement or foundation slabs resting on a very stiff subgrade.     

5×10^4 m^3外浮顶罐改造成内浮顶罐实例

将服役近20年、基础倾斜、罐体形状严重超标的2台直径为60m的5×10^4m^3外浮顶原油罐改造成合格的内浮顶成品油罐,给大型油罐的旧罐技术改造工程提供了一套成功经验。     

Photoelastic Stress Analysis of Bonded Lap Shear Joints Having Thermoplastic Adherends

The effects of substrate stiffness and modulus on joint strength and stress distribution were investigated for a series of nylon substrates bonded with an epoxy adhesive. Substrate stiffness and modulus were controlled by the level of glass filler in the resin. Single lap shear samples having both identical (“self-bonded”) and dissimilar (“cross-bonded”) substrates were investigated. For the self-bonded samples, lap shear strength was found to increase with increasing substrate modulus and stiffness. The strengths of the cross-bonded samples were intermediate to the strengths of the corresponding self-bonded samples. Photoelastic techniques were used to observe stress patterns in the lap joints during testing. One type of stress pattern was observed for all self-bonded samples regardless of substrate stiffness. Two patterns, one for the stiff substrate and one for the more flexible substrate, were observed for cross-bonded samples. The photoelastic analysis agreed qualitatively with predictions of stress distributions based on linear elastic and linear elastic/perfectly plastic theoretical models.     

原油储罐高防腐体系的分析及研究

根据对本地区原油储罐腐蚀性环境的研究,归纳出储罐内部和外部腐蚀因素。介绍了储罐防腐蚀设计中涂层保护和阴极保护并用所存在的问题,提出利用长链多官能团硅烷偶联剂表面处理技术结合重防腐涂料(无溶剂纳米环氧树脂涂料、负离子吸收型导电涂料等)的解决方案。拟定建立原油储罐全面防腐蚀体系,为沿海储罐防腐蚀工作提供可行性依据和理论参考。