A Digital Deformation Vacuum Gauge with an LC-Generator

The design of a sylphon bellows sensor and the basic circuits of an LC-generator and of a microprocessor unit are presented. An analytical pressure–frequency conversion function and a special method of adjusting the sensor ensure an error of less than 0.05%. The dynamic range is up to 10⁵. The instruments developed cover the ranges 10³, 10⁴, and 10⁵ Pa.     

Axial vibrations of U-shaped bellows with elastically restrained end conditions

Previous work by Li et al. in the area of axial vibrations of bellows dealt with fixed end conditions. However, it is seen on several occasions that bellow ends are welded to a small pipe spool that has a lumped mass such as a valve or an instrument. Hence, the present paper aims at finding out the effect of elastically restrained ends on the axial natural frequencies. The analysis considers finite stiffness axial restraints on the bellows, i.e. solving the set of equations with non-homogeneous boundary conditions. Two bellow specimens are considered for comparison having the same dimensions as taken by Li in his analysis. The transcendental frequency equation deduced is accurate as the first, second and third mode frequencies computed are in close agreement to the ones obtained by Li.     

复合载荷下波纹管横向非线性弯曲摄动有限元法

采用新的小参数、将摄动法和有限元法相结合,研究了复合载荷作用下波纹管横向非线性弯曲的位移和应力分布。小参数为结构环向应变的均方根。将节点位移摄动展开,并以复合载荷的等效节点载荷为参考载荷,将其公共系数1摄动展开。由此划分载荷的级别、建立各级载荷和相应位移的关系,避免了常规的迭代运算。算例为一考虑自重的U型波纹管在注满水时的横向非线性弯曲问题。计算表明,波纹管的挠度和膜应力有非常显著的非线性效应;当最大挠度与壁厚之比达到5.1后本法将失效。本法在摄动小参数的选取和复合载荷的处理上有特色,能解决较大的挠度问题。     

The Dynamical FSI Simulation for Bellows Inflating to Disperse Bomblets

According to the characteristics of fluid-structure interaction(FSI) in the process of metal bellows inflating to disperse bomblets,a 3D dynamical FSI model(W model) which describes the interaction between a viscous compressible flow and a structure undergoing large deformationis established.Then the dynamic characteristics of the metal bellows deformation, the changing law of the internal flow field and the motion law of the bombs are acquired.Where the internal pressure and bombs'' moving law are approximate to interior ballistic results, which indicates the W model established reasonably.Besides, considering gaps existing atthe bellows'' tow ends, the dynamical FSI modelcontaining gaps(Y model) is also built.The results of the W and Y models are compared and the results show that the existence of the gaps has little influence to the flow field and the stress distributionin the bellows,but obviously reduces the separation speed of the bomblets about 10%.     

热力管线中不锈钢波纹管破裂原因分析

采用金相显微镜和扫描电镜分析了热力管线中不锈钢 波纹管破裂原因.该波纹管破裂特征与一般环向开裂不同，裂纹沿轴向扩展.分析认为，破裂 属穿晶应力腐蚀.引起应力腐蚀的介质是土壤中的氯化物，而应力则来自环向工作应力和冷 加工残余应力，而环向工作应力起主导作用。     

Pre-Buried ETL with Bottom-Up Strategy Toward Flexible Perovskite Solar Cells with Efficiency Over 23%

With rapid development of photovoltaic technology, flexible perovskite solar cells (f-PSCs) have attracted much attention for their light weight, high flexibility and portability. However, the power conversion efficiency (PCE) achieved so far is not yet comparable to that of rigid devices. This is mainly due to the great challenge of depositing homogeneous and high-quality perovskite films on flexible substrate. In this study, the pre-buried 3-aminopropionic acid hydroiodide (3AAH) additives into the electron transport layer (ETL) and modified the ETL/perovskite (PVK) interface by a bottom-up strategy. 3AAH treatment induced a templated perovskite grain growth and improved the quality of the ETL. By this, the residual stresses generated in PVK during the annealing-cooling process are released and converted into micro-compressive stresses. As a result, the defect density of f-PSCs with pre-buried 3AAH is reduced and the photovoltaic performance is greatly improved, reaching an exceptional PCE of 23.36%. This strategy provides a new idea to bridge the gap between flexible and rigid devices.     

波纹管内高压成形焊接区变形特征研究

准确建立焊接管材母材、热影响区和焊缝的材料力学模型,是焊接波纹管内高压胀形工艺分析的前提条件。基于焊接区单向拉伸试验和硬度测试等条件建立焊接区混合材料准则,确定了热影响区和焊缝的材料力学模型。通过波纹管液压胀形工艺仿真与试验,研究胀形液体压力和凹模初始高度等工艺参数对波纹管变形特征的影响,并结合变形前后的组织分析发现,焊接区的枝状晶组织使成形后波纹管焊接区与母材壁厚存在差异,并且变形后马氏体相的存在促进裂纹的形核,引起后期使用中的应力腐蚀破裂。     

GIS母线波纹管设置原则探讨

在气体绝缘金属封闭开关设备（GIS）中,母线是重要的组成部分。针对母线因温度变化或地基沉降等导致尺寸变化的情况,根据计算模型,以ZF12-126型GIS为例分析了母线波纹管的设置原则,为相关的母线工程设计提供参考。     

Accuracy of a Bellows vacuum meter with an LC-generator

Errors of pressure measurement are considered. The error as a function of the pressure for a vacuum gauge rated at up to 1000 Pa is calculated as an example. It is 0.15 ≤ δp/p ≤ 0.2% over a pressure range of 14 ≤ p ≤ 1000 Pa and it increases hyperbolically up to 100% with p = 0.01 Pa. The parametric reliability of the instrument and its immunity to an accidental increase in pressure the atmospheric level is substantiated. __________ Translated from Izmeritel’naya Tekhnika, No. 9, pp. 37–41, September, 2006.     

混凝土圆柱采用新材料支模施工技术的应用

针对当前混凝土圆柱施工工艺中采用木模板时截面尺寸难以保证或者实体观感较差以及采用定型钢模一次性投入过大,施工不方便的问题,通过市场考察以及实际试验操作,提出了采用PVC-U双壁波纹管作为模板材料的施工工艺,保证了工程质量和观感效果,并取得了较好的经济效益。