棱柱形径向剖分式超高压模具应力分析与实验研究

为了获得更高的承压能力和更大的样品腔容积,在传统年轮式超高压模具的基础上,提出了一种新型棱柱形腔体剖分式超高压模具。其特点在于内部的硬质合金压缸是离散组合式的,且腔体内部的面为平面,可有效减小周向拉应力。压缸剖分块在预紧力的作用下相互挤压,提供了大质量支撑和侧向支撑效果。对剖分成6块的棱柱形腔体剖分式压缸的剖分角度进行了研究,仿真结果表明,剖分角度越大,压缸受力越小。棱柱形腔体剖分式压缸在径向、周向和轴向均承受压应力,其应力条件接近于静水压力状态,可有效提高装置的使用寿命。对压缸的应力分布情况进行进一步分析,发现棱柱形径向剖分式压缸在各方面的表现均最优。经实验验证,相较于年轮式压缸,剖分式压缸具有更高的极限承压能力,并且棱柱形径向剖分式压缸的承压能力大于切向剖分式压缸。     

新型多层交错剖分超高压模具的数值模拟及其试验验证

介绍了一种新型的双斜边扇形块式多层交错剖分超高压模具,这种超高压模具是由箍紧环、多层交错剖分的预紧环和双斜边扇形组合压缸3部分构成。分析了双斜边扇形块式多层交错剖分超高压模具的受力情况,并与年轮式超高压模具做对比。结果表明:在相同腔体压力的情况下,双斜边扇形块压缸的等效应力和最大切应力分别降低46.8%和50.9%;双斜边扇形块压缸破坏时的油压为年轮式整体压缸油压的1.78倍;新型多层交错剖分超高压模具可实现大腔体超高压模具的制造,且具有装配方便、维修简单的特点。     

新型切向分块式两面顶超高压模具

以提高年轮式超高压模具的压力承载能力为目标,设计一种新型切向剖分式模具结构。切向剖分式结构通过剖分面上的相互摩擦和挤压,不仅能够消除压缸内壁的周向拉应力,而且在内壁上产生较大的周向压应力。这种受压状态对硬质合金材料非常有利,可以显著提高压缸的极限承载能力。数值模拟结果显示,在相同的载荷条件下,分块式压缸受到的等效应力显著小于年轮式压缸。分块式压缸内壁的3个主应力均为压应力,且差值较小,接近于等静压状态,因此能够承受更高的样品腔压力。对比实验结果同样证明切向剖分式超高压模具结构具有更高的极限承载能力。     

具有碳纤维材料环的超高压模具

介绍了一种使用钢环和碳纤维复合材料环共同预紧方式的两面顶超高压模具,该结构在全钢环两面顶模具的基础上,使用一层碳纤维复合材料环代替最外层钢环,得到了一种具有碳纤维复合材料环的超高压模具。这种设计避免了大直径钢环难以制造加工的问题,形成一种以钢环与复合材料环共同对压缸预紧的新型预紧方式。数值分析表明:该模具结构设计具有可行性,可以在一定程度上减小压缸的周向应力、最大剪切应力和等效应力。此外,对碳纤维复合材料环进行了失效判别。     

基于分布式光纤Bragg光栅传感技术的光缆卷盘静态压力研究

基于对光缆卷盘缆层静态压力分布的理论分析, 建立了光缆缠绕体系中的受力理论模型. 研究表明, 随着缠绕层数的增加, 卷盘各层光缆所受压强先快速增大而后变化平缓. 采用分布式光纤Bragg光栅(FBG)对光缆绕线装置上缆层的静态压力进行了实时传感, 理论上给出了FBG的中心波长偏移量与体系压强的定量关系, 实验上发现各层FBG的中心波长随着光缆卷盘缠绕层数的增加先较快速变化而后趋于平缓, 理论模拟和实验测量结果符合得很好. 该技术解决了光缆绕线过程中无法对缆层所受压力进行实时监测的难题.     

极紫外多层膜残余应力初步研究

 针对极紫外多层膜在激光等离子体诊断、极紫外光刻等方面的应用,进行了Mo/Si多层膜残余应力的实验研究,讨论了多层膜残余应力的成因。实验结果表明：Mo单层膜表现为张应力, Si单层膜表现为压应力;通过传统方法制备的13.0 nm处高反射率的40对Mo/Si多层膜会产生-500 MPa左右的压应力,其压应力主要是由膜层之间的贯穿扩散引起的;通过改变膜层比率可以在一定程度上补偿因贯穿扩散产生的压应力,但是以牺牲多层膜反射率为代价。     

含有断裂缺陷的复合材料壳体的力学行为

利用湿法缠绕制备了玻璃纤维增强环氧树脂基复合材料壳体,通过拉伸、双悬臂梁和三点端部开口弯曲试验对该复合材料层合板进行基本力学性能评估,得到强度和刚度参数并用于有限元模拟中。同时,在Abaqus中建立了含有不同深度断裂缺陷复合材料壳体的三维渐进损伤有限元模型,预测内压作用下壳体的力学响应。试验和模拟结果表明:复合材料主向拉伸强度为(222.7±18)MPa,弹性模量为39.39 GPa,Ⅰ型和Ⅱ型断裂韧性层间强度分别为(4.67±0.24)和(4.98±0.26)kJ/m~2。随着内压增大,Mises应力也不断增大;当断裂缺陷在最深层(接近内压的第一层,深度为18 mm)时,Mises应力最大;当内压为0.3 MPa时,Mises应力高达28.8 MPa,且周向应变小于纵向应变。     

高压电导研究

高压下物质结构和性质会发生很大的改变，电导对于认识压力的作用效应和寻找新的导电材料具有重要意义．高压电导研究所采用的设备主要有金刚石压腔、超高压大腔体装置(大压机)以及高压电导池三种．金刚石压腔可达550GPa压力；超高压大腔体装置压力一般在30GPa以下，可以提供较大体积的样品；高压电导池主要进行流体的电导研究，压力在400MPa以下，有静止和流动两种类型，流动式高压电导池是近年来才发展起来的，其准确方便．文章对目前高压电导的研究进行简单的介绍和分析．     

超高压碳化钨顶砧新结构的设计与研究

基于高压顶砧设计原理——大质量支撑原理,借助有限元仿真技术,开展了一体式超高压碳化钨顶砧新结构的设计与研究工作。研究结果表明,采用圆角技术以及凹形支撑区技术,设计出的新结构顶砧能够降低传统碳化钨顶砧拐角处的应力集中效应,同时为碳化钨顶砧提供足够的侧向支撑作用,从而大幅提高顶砧的性能;一体式超高压碳化钨顶砧的传压效率较传统顶砧升高58.5%、破裂几率较传统顶砧降低33%、获得的极限腔体压力较传统顶砧升高44.2%,达到9.56GPa。为大腔体、超高压环境下物质新结构与性质研究、新型功能材料的设计与合成研究提供了一种易于操作的可行性方案。     

相位对比读出三维光数据存储的实验研究

使用波长800 nm、脉冲宽度150f s的近红外激光脉冲紧聚焦到PMMA（聚甲基丙烯酸甲酯）和熔融石英中实现了三维逐位式光数据存储,分别记录下了5、10、 15和20层数据位点.利用相位对比光学显微原理对各层数据并行读出,实验分析了各层数据位点的读出对比度的变化.结果表明:各层数据位点的折射率对比度由内至外依次增加,记录层数越多,其内部层的对比度下降越明显.由于飞秒激光脉冲与透明介质相互作用中,熔融石英内部产生的残余应力比PMMA内大,因此数据位点参数相同的情况下,利用PMMA材料记录的层数更多.     

Finite element analysis and experiment on high pressure apparatus with split cylinder

Ultra-high pressure belt-type die was designed with a large sample volume prism cavity and a split cylinder which was divided into eight segments to eliminate circumferential stress. The cylinder of this type die has no cambered surface on inner wall, and the inner hole is a hexagonal prism-type cavity. The divided bodies squeeze with each other, providing the massive support and lateral support effect of the cylinder. Simulation results indicate that the split cylinder with the prism cavity possesses much smaller stress and more uniform stress distribution. The split cylinder with the prism cavity has been shown to bear larger compressive stresses in radial, circumferential and axial directions due to its structure, and tungsten carbide is most effective in pure compression so this type cylinder could bear higher pressure. Experimental results prove that the high pressure apparatus with a prism-type cavity could bear higher pressure. The apparatus with a prism cavity could bear 52.2% more pressure than the belt-type die.     

钢丝网混凝土电磁波反射和透射性能数值模拟

通过数值模拟的方法研究了素混凝土、钢丝网和钢丝网混凝土板对电磁波的屏蔽和吸收性能。首先将模拟得到的素混凝土反射率和透射率曲线和试验得到的曲线进行对比。对两种不同规格的钢丝网进行了数值模拟,并与试验和理论解进行了比较,对不同直径、网径、层数的钢丝网进行了数值模拟。最后研究了钢丝网及钢丝网位置对混凝土反射和透射性能的影响。数值模拟采用三维电磁仿真软件HFSS15.0。相同网径条件下,钢丝网直径越大,反射率越大,透射率越小。钢丝网直径相同的条件下,网径越大,反射率越小,透射率越大。在混凝土中间加入钢丝网对反射率平均值大小影响很小,主要影响反射率曲线的谐振性。     

Modeling and testing of static pressure within an optical fiber cable spool using distributed fiber Bragg gratings

Based on the force analysis, we establish a theoretical model to study the static pressure distribution of the fiber cable spool for the fiber optic guided missile (FOG-M). Simulations indicate that for each fiber layer in the fiber cable spool, the applied static pressure on it asymptotically converges as the number of fiber layers increases. Using the distributed fiber Bragg grating (FBG) sensing technique, the static pressure of fiber cable layers in the spool on the cable winding device was measured. Experiments show that the Bragg wavelength of FBG in every layer varies very quickly at the beginning and then becomes gently as the subsequent fiber cable was twisted onto the spool layer by layer. Theoretical simulations agree qualitatively with experimental results. This technology provides us a real-time method to monitor the pressure within the fiber cable layer during the cable winding process.     

A novel split-belt apparatus: the stress distribution and performance of its tangent split die

A novel high pressure device with a tangent split cylinder was investigated on the basis of the belt-type apparatus. The cylinder is split into several blocks and the dividing line is tangent to the inner hole. This structure of the cylinder can eliminate the tangential tensile stress due to the friction and squeeze each other on the contact surface between the divided bodies. In this paper, different split numbers of the cylinders were choosen to study the stress distribution and the pressure-bearing capacity, and compare them with the traditional belt-type die (BTD). Simulation results show that the more the number of divided bodies, the smaller the stress and the higher the pressure-bearing capacity. The experiments also indicate that the tangent split die can bear higher pressure than the BTD. The tangent split tungsten carbide cylinder has the advantages of easy manufacture, strong bearing capacity and replaceable performance.     

65T脉冲强磁体设计与实验研究

研制并实验测试一台65T脉冲强磁场磁体。磁体线圈采用14层纯铜导线与Zylon纤维交替缠绕而成,内绕组采用分布式加固技术,实现应力分布的优化,外层由不锈钢套筒与碳纤维加固。内外绕组分别采用两种不同横截面导线平衡能量分布,实现内外绕组温度分布相对均匀,避免局部过热。磁体孔径为12mm,高为120mm,通过1MJ/3.2mF/25kV高储能密度电容器供电,在20.6kV电压时,获得了磁感应强度为65T、持续时间为20ms的脉冲磁场。     

Study on fracture of tungsten wire induced by acoustic cavitation at different hydrostatic pressures and driving electric powers

The near-solid wall multi-bubble cavitation is an extremely complex phenomenon, and cavitation has strong erosiveness. The melting point (about 3410 °C) of tungsten is highest among all pure metals, and its hardness is also very high (its yield strength is greater than 1 GPa). What would happen to pure tungsten wire under extreme conditions caused by collapsing cavitation bubbles at high hydrostatic pressure? In this paper, we have studied the fracture process of pure tungsten wire with diameter of 0.2 mm mounted at the focus of a standing acoustic wave produced by a spherical cavity transducer with two open ends placed in a near spherical pressure container, and also studied the macro and micro morphological characteristics of the fracture and the surface damage at different fracture stages of tungsten wire under various hydrostatic pressures and driving electric powers. The results have shown that the fracture time of tungsten wire is inversely proportional to avitation intensity with hydrostatic pressure and driving electric power, the higher the acoustic pressure caused by higher electric power, the shorter the fracture time. The possible fracture mechanisms of tungsten wire in this situation we found mainly contributed to asymmetrically bubbles collapse near the surface of tungsten wire, leading to tearing the surface apart; consequently cracks along the radial and axial directions of a tungsten wire extend simultaneously, classified as trans-granular fracture and inter-granular fracture, respectively. With the increase of cavitation intensity, the cracks tend to extend more radially and the axial crack propagation path becomes shorter, that is, mainly for trans-granular fracture; with the decrease of cavitation intensity, intergranular fracture becomes more obvious. When the hydrostatic pressure was 10 MPa and the driving electric power was 2 kW, the fibers became softener due to the fracture of the tungsten wire. The fracture caused by acoustic cavitation was different from conventional mechanical fracture, such as tensile, shear, fatigue fracture, on macro and micro morphology.     

大功率780nm半导体激光器的设计与制备

设计并制备了一款780 nm半导体激光器,并进行了外腔反馈锁模研究。利用金属有机化学气相沉积技术制备了激光器外延层,采用GaAsP/GaInP作为量子阱/波导层有源区,限制层采用低折射率AlGaInP材料。采用超高真空解理钝化技术,在激光器腔面蒸镀无定形ZnSe钝化层。未钝化器件在输出功率2.5 W时发生腔面灾变损伤（COD）,钝化后器件未发生COD现象,电流在10 A时输出功率10.1 W,电光转换效率54%。体布拉格光栅（VBG）外腔锁定前后,器件的光谱半峰全宽分别为2.6 nm和0.06 nm,VBG变温调控波长范围约230 pm。     

一种基于开口空心球的声学超材料

提出了一种基于局域共振的开口空心球(spilt hollow spheres,SHS)模型,数值计算和声学透射实验结果表明基于该模型的声学超材料可以实现负的弹性模量.为了说明SHS的局域共振性质,研究了微结构SHS几何尺寸(例如开口孔径d和空心球直径D)变化时材料的透射性质,结果表明SHS的几何尺寸的改变对声学超材料的透射吸收峰频率有显著影响.另外,还研究了SHS不同排列方式对透射行为的影响,发现单层样品中SHS单元数目以及晶格常数的变化不会引起谐振频率的变化,但是随着SHS单元数目或者样品 关键词： 开口空心球(SHS) 声学超材料 吸收峰 等效弹性模量