铀基聚变-裂变混合堆次临界能源包层有限元力学分析

次临界能源包层是聚变-裂变混合堆的重要部件,对其进行力学特性分析研究是确保整个反应堆正常运行的关键。本文利用有限元分析软件对次临界能源包层的第一壁结构、支撑固定结构的相关零部件开展了初步的力学分析,得到了各零部件相关结构的最大应力值、应力分布云图和变形分布云图,其中支撑结构的最大应力位于加强筋板与圆柱定位销的连接处,应力值为310.2 MPa;第一壁的最大应力位于“U”形流道拐角处,应力值为240.7 MPa;按相应的评价准则进行结构的强度和刚度校核,计算结果表明次临界能源包层各零部件能够满足计算工况下的强度和刚度要求。     

钨合金的层裂强度研究

 用压缩空气炮做冲击加载装置研究一种钨合金的层裂特性,加载应力峰值为5~10 GPa,加载应力时间宽度为0.2~0.6 μs。实验用钨合金由粉末热压烧结制成,是一种均匀混合材料。它的成份重量百分比为W（90%）、Ni（6.8%）、Fe（2.7%）和Cr（0.5%）。由锰铜压阻计测量样品靶后界面应力历史表明,此种钨合金的层裂强度与拉伸应力率的平方根呈单调递增关系,与加载应力峰值无关。回收样品的金相分析结果表明,此钨合金的拉伸断裂主要发生在铁镍混合物部位,钨晶粒的穿晶断裂只占很小部分。断口上的“杯状”凹坑表明,它主要属延性断裂机制。     

中国氦冷固态增殖剂试验包层模块第一壁的改进设计与分析

根据中国氦冷固态增殖剂试验包层模块(CH HCCB TBM)设计方案,对TBM 第一壁进行改进设计,在ITER 相应运行工况条件下,进行了热工水力及应力计算与分析。分析结果表明,改进后的第一壁要求、最大应力值和在最高温度、冷却剂压降及应力分布方面,表现均优于原设计方案第一壁。     

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对中国氦冷固态增殖剂实验包层模块(CH HCSB TBM)第一壁的重力分析结果表明,由重力导致的应力和位移形变很小,可以忽略其影响;而第一壁的热结构分析表明,第一壁铍保护板的应力偏大,从结构设计角度出发建议采用钨铜合金代替铍作为第一壁的保护材料。     

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在ITER试验包层模块HC-SB TBM结构设计和热工计算分析的基础上,对包层模块中的重要部件第一壁做了优化分析。利用有限元分析软件ANSYS的可编程命令流模式,对HC-SB TBM第一壁前壁进行了温度和应力的数值模拟,在满足结构材料的许用温度和应力的前提下,给出了第一壁前壁的最佳设计方案。     

ITER屏蔽包层最新设计的热工水力和热应力分析

介绍了屏蔽包层最新的设计方案,对比了2004年DDD设计方案与新方案在第一壁和屏蔽块结构上的差别,并对第8号包层模块的屏蔽块进行了热工水力和热应力的分析。结果表明,第8号包层模块屏蔽块的最高温度不超过200ºC,最大Von-Mise应力在200MPa以内,基本满足ITER设计要求,但冷却剂压降稍微偏大,达到0.44MPa。另外,在屏蔽块前端暴露在等离子体表面热负荷的部位,根据热应力分析计算结果,对其承载热负荷能力进行评估,改进了设计方案。     

偏Hugoniot状态下93钨状态方程

利用动高压实验装置二级气体炮和5层阻抗梯度飞片,在2.12和5.02km/s的碰撞速度下测量了93钨样品的自由面速度,同时基于冲击波理论对实验测量的自由面速度进行了解读。高温高压下93钨的偏Hugoniot状态方程分析表明,在较低的碰撞速度下多次压缩后93钨的压强和温度要高于单次Hugoniot压缩的压强和温度,而在较高的碰撞速度下截然相反,其主要原因是93钨在多次加载过程中Hugoniot参数和相对压缩性发生了变化。     

金刚石层厚度对复合片(PDC)残余应力的影响

 通过X射线应力测试和有限元分析相结合的方法,研究了金刚石层厚度对聚晶金刚石复合片（PDC）残余应力的影响,并根据实验测试结果推导出了PDC表面中心与边缘的应力随金刚石层厚度变化的关系式。随着金刚石层厚度由0.5 mm增加到2.0 mm,PDC表面中心的压应力从1 800 MPa下降至700 MPa左右,而边缘部分的应力逐渐由压应力转为拉应力。金刚石层加厚虽然对边缘部分的最大拉应力影响不大,但使PDC边缘拉应力区宽度由0.76 mm增加到了2.85 mm。金刚石层厚度的增加还使得PDC边缘界面附近y方向的最大拉应力和位于界面边缘处的最大剪应力显著加大,这是金刚石层较厚的PDC界面容易产生裂纹的主要原因。     

拉伸法测Vicryl缝合线的力学性能

在FD-YC-II型杨氏模量测定仪的基础上,用JCD3型读数显微镜代替JC10型读数显微镜.在室温下利用拉伸法测1-0型Vicryl缝合线加载卸载时的轴向伸长量,得到了Vicryl缝合线的应力-应变曲线、拉伸强度为518.824 MPa、断裂伸长率为14.087%、屈服应力为76.8 MPa、屈服应变为1.57%,杨氏模量为81.505 MPa.最后测定了Vicryl缝合线的应力-应变滞后回线.     

内爆加载下热塑性管壳的应力波演化与层裂效应研究

 在引入材料损伤软化、温度软化效应的基础上，对一维柱对称内聚爆加载管壳中应力波的传播、材料的变形和层裂问题开展了研究。成功地通过自编写有限元代码，完成了系列数值模拟计算，得到了管壁中与物理事实一致的应力波传播图像和材料的变形、损伤、层裂的发展规律，成功模拟了内聚爆加载管壳的多次层裂现象。     

Underwater explosive compaction-sintering of tungsten–copper coating on a copper surface

This study investigated underwater explosive compaction-sintering for coating a high-density tungsten–copper composite on a copper surface. First, 50% W–50% Cu tungsten–copper composite powder was prepared by mechanical alloying. The composite powder was pre-compacted and sintered by hydrogen. Underwater explosive compaction was carried out. Finally, a high-density tungsten–copper coating was obtained by diffusion sintering of the specimen after explosive compaction. A simulation of the underwater explosive compaction process showed that the peak value of the pressure in the coating was between 3.0 and 4.8?GPa. The hardness values of the tungsten–copper layer and the copper substrate were in the range of 87–133 and 49?HV, respectively. The bonding strength between the coating and the substrate was approximately 100–105?MPa.     

冷动力喷涂法制备钨和钨合金涂层 及其涂层的计算模拟

采用冷动力喷涂法以纯钨和钨-镍-铁合金为原料在铜合金基体上制备了钨涂层和钨-镍-铁涂层. 研究了冷喷涂过程中钨粉粒径、喷涂距离等因素对涂层性能的影响. 用扫描电子显微镜分析了涂层的表面、断面微观结构, 并用原子力显微镜测量了涂层的粗糙度. 此外, 计算了冷喷涂过程中粉末颗粒的实际速度, 并采用有限元分析软件ANSYS/LS-DYNA模拟了冷喷涂过程中颗粒撞击基体时的变形情况.     

适用于聚变装置偏滤器部件的高热负荷测试平台真空腔体系统设计

对托卡马克聚变装置偏滤器的高热负荷测试平台真空腔体系统进行了结构设计,其中包括真空室、真空抽气系统、部件调节机构、小型水冷系统和电子枪操作平台,利用Ansys对真空室主体结构的合理性和可靠性进行了验证.模拟结果表明:真空室外壁温度不超过50℃,真空室及其支撑上的最大应力分别为134.49MPa和48.76MPa,满足许...     

Residual stresses in continuous-tungsten-fibre-reinforced Kanthal-matrix composites

Residual stresses were measured in four Kanthal matrix-continuous-tungsten-fibre composites (with different tungsten fibre volume fractions V f = 10, 20, 30 and 70 vol.%) using neutron diffraction. Parallel to the fibres the stress in the Kanthal ranged from 40 MPa ( V f = 10 vol.%) to 1100 MPa ( V f = 70 vol.%) compared with m1877 MPa ( V f = 10 vol.%) to m400 MPa ( V f = 70 vol.%) for the tungsten. Perpendicular to the fibres the stress ranged from m52 MPa ( V f = 10 vol.%) to 620 MPa ( V f = 70 vol.%) in the Kanthal compared with m778 MPa ( V f = 10vol.%) to m195 MPa ( V f = 70 vol.%) in the tungsten. Assuming that the measured residual stresses were solely thermal in origin, predictions were made using concentric cylinder and finite-element models. In the absence of hardening data the assumed material behaviour was elastic-perfectly plastic and the predictions underestimated the measured stresses for all volume fractions. Nevertheless the model results were consistent with the experimental measurements. The transverse stress in the fibres is discussed in the context of the interface normal stress, which is significant to the global mechanical response.     

层压工艺对埋入光纤传输性能影响分析

针对层压工艺下,埋入挠性光电基板的光纤,其应力、位移的变化,会影响光路的耦合效率,改变光纤有效折射率,导致传输性能发生变化的问题,采用有限元分析软件,对光纤埋入不同槽型的挠性光电基板进行了力学、传热和电磁场耦合分析.分析结果表明:光纤埋入梯形槽挠性基板的应力最大,达到68.336 7MPa.埋入梯形槽的光纤位移量最大,其值为1.430 4μm.随着槽宽增加,光纤最大等效应力从52.667MPa增加至71.907 MPa;随着槽间距增加,光纤最大应力从51.589 MPa增加至53.567MPa;随着槽深增加,光纤最大应力从52.667MPa减小至47.793 8 MPa,然后增加到67.349 6MPa.随着温度和压力的增加,单模光纤在X方向的有效折射率从1.446 249 977增加至1.446 259 084;Y方向的有效折射率从1.446 326 398增加至1.446 393 041.光纤有效折射率差会随着温度的增加而增大,随着压力的增加而减小.光纤有效折射率增加,限制光的能力增加,能够有效地减小光纤弯曲损耗.本文分析结果对挠性光电基板光纤埋入结构设计和层压工艺具有一定的参考价值和指导意义.     

L–H power threshold studies with tungsten/carbon divertor on the EAST tokamak

The power threshold for low (L) to high (H) confinement mode transition achieved by radio-frequency heating and molybdenum first wall with lithium coating has been experimentally investigated on the EAST tokamak for two sets of divertor geometries and materials: tungsten/carbon divertor and full carbon divertor. For both sets of divertors, the power threshold was found to decrease with gradual accumulation of the lithium wall coating, suggesting the important role played by the low Z impurities and/or the edge neutral density on the L–H power threshold. When operating in the upper single null configuration, with the ion grad-B drift direction away from the primary X-point, a lower normalized power threshold is observed in EAST with the tungsten/carbon divertor, compared to the carbon divertor after intensive lithium wall coating. A newly installed cryopump increasing the pumping efficiency also plays an important part in the observed lower threshold. In addition, the H-mode in the Quasi-Snowflake divertor configuration has been obtained on EAST, exhibiting higher L–H power threshold compared to the lower single null configuration with similar I_P/B_T pairs.     

船载光电转台设计及特定环境下可行性分析

结合船载光电转台的技术要求,通过pro/E软件设计舰载光电转台的机械结构。根据转台的表面材料,运用ABAQUS软件对其在海洋的等价静力风载、极端温度场和海浪振动3种特殊环境下进行表面变形分析,校验结构的应力和应变,确保满足船载光电转台的设计精度要求;得到在等价静力风载作用下,光电转台的最大应力点大小为255 MPa,小于钢的屈服强度355 MPa;在温差作用下最大应力点分别为174.8 MPa、247.1 MPa,均小于铝合金的屈服强度274 MPa;在海浪振动作用下,1~5阶振型的最大形变位置均不在转轴附近。     

Temperature and concentration effects in electron-stimulated desorption of sodium atoms from sodium layers adsorbed on tungsten coated with a gold film

The yield and energy distributions of sodium atoms upon electron-stimulated desorption from sodium layers adsorbed on tungsten coated with a gold film are investigated for the first time as functions of the thickness of the gold film, the concentration of deposited sodium, and the surface temperature. It is found that the energy distributions exhibit two peaks, namely, a narrow peak with a maximum at about 0.15 eV, whose intensity continuously increases with increasing temperature, and a broad peak with a maximum at about 0.35 eV, whose intensity either decreases or remains constant with increasing temperature. It is shown that both peaks arise as a result of the same excitation, which gives rise to different channels of electron-stimulated desorption of sodium atoms. Possible mechanisms of electron-stimulated desorption and the kinetics of destruction of the surface coating are discussed.     

ITER偏滤器朗缪尔探针的设计与研制进展

对ITER 偏滤器朗缪尔探针进行了物理需求分析和结构设计,确定了探针离偏滤器靶板瓦表面的高度范围。通过结构设计和模拟仿真,得到了探针在稳态热负载条件下的温度场分布和应力状况,探针的最高温度低于相应的偏滤器靶板瓦最高温度,探针各个部件的应力低于材料的屈服强度。同时对探针进行了加工工艺和连接工艺的探索研发,初步确定探针体和钨屏蔽结构选用锻造钨材料,而且使用锻造钨试制了探针体和钨屏蔽结构。探针体与钨屏蔽结构之间使用氧化铝陶瓷绝缘,并使用特殊的工艺连接探针体、陶瓷和钨屏蔽结构。