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61.
62.
同步辐射单色器冷却压弯机构 总被引:4,自引:2,他引:2
研究了带有柔性铰链组合体的冷却压弯机构,以用于减少晶体的热变形.给出了晶体热变形的种类及其机理,以及冷却压弯机构的受力分析及机构结构.运用有限元方法对这种机构进行了分析.结果表明:此种机构大大降低了第一晶体的热变形,在承受5N/mm2峰值功率密度条件下,面型误差仅为0.04μrad 3μrad,远远小于同步辐射光束线设计要求.结果还表明:此种机构尤其适用于高热载情况,是解决第三代同步辐射光源关键技术. 相似文献
63.
Vanessa Harumi Kiyan Flávia Pires Rodrigues Ricardo Elgul Samad Denise Maria Zezell Marco Antonio Bottino Nelson Batista De Lima Cintia Helena Coury Saraceni 《Ceramics International》2021,47(4):4455-4465
Femtosecond pulses from a Ti:Sapphire laser were used to irradiate specimens of yttria-stabilised (35% mol) tetragonal zirconia (Y-TZP) with the purpose of studying the effects of the irradiations on their surface properties and morphology after ageing. Zirconia disks were divided into eight groups (n = 32) according to their surface treatment and subsequent ageing: Control: no treatment; sandblasting: Al2O3 sandblasting 50 μm; and ultrashort laser pulses irradiation with 25 μJ pulses, considering two different scanning steps based on the width between two grooves. These groups were duplicated and submitted to ageing. The surfaces were analysed using scanning electron microscopy (SEM), and X-ray diffraction. A finite element analysis, a biaxial flexure test, as well as fractographic and Weibull analyses, were performed. The strengths of the disks were statistically different for the treatment factor, and the principal stresses seemed to be concentrated at the centre of the specimens, as predicted by the computer simulations. Ageing decreased the strengths for all groups and increased the Weibull modulus for the laser group with the 40 μm-width between two grooves. The sandblasting group presented the highest monoclinic phase peak. Although the most significant strength was found within the sandblasting group, the phase transformation was favourable to the laser groups. The Weibull modulus was higher for the laser group with the 60 μm-width between two grooves, confirming the highest homogeneity of its failure distribution. Regardless of the surface treatment, strength was decreased with ageing in all groups. The femtosecond Ti:Sa ultra-short pulse laser irradiation can be suggested as an alternative to the gold standard sandblasting in long-term Y-TZP zirconia rehabilitations, such as crowns and veneers. 相似文献
64.
A. Delbariani‐Nejad M. Malakouti A. Farrokhabadi 《Fatigue & Fracture of Engineering Materials & Structures》2019,42(12):2644-2662
In the present study, the experimental and finite element (FE) analyses are first carried out to investigate the deboning behavior of metal‐composite adhesive joints under modes of I and mode II loading. To conduct an FE on the debonding propagation, cohesive zone method (CZM), as well as maximum nominal stress and energy criteria, is applied. In the reliability analysis, to achieve the probability of debonding growth (PODG), limit state functions are formulated based on the energy release rate. To that end, the first‐order reliability method (FORM), the second‐order reliability method (SORM), and the Monte Carlo simulation (MCS) are used to calculate the PODG. The effect of initial debonding length on the PODG in all mentioned modes is investigated. Results obtained from reliability analysis reveal that the random variables including the initial debonding length, width, and thickness are the most sensitive variables to ascertain the PODG. 相似文献
65.
柔性铰链转动刚度计算公式的推导 总被引:16,自引:3,他引:16
柔性铰链作为无摩擦的支点有着成千上万的应用,以力学的基本公式和微积分为基础,给出了一般柔性铰链转动刚度计算公式的推导过程。在此基础上,得出了常用的直圆柔性铰链的设计计算公式,计算公式是精确的推导结果,且在表达上较迄今沿用的Paros给出的柔性铰链精确设计计算公式来得简洁,有利于柔性铰链及其机构的计算和分析。当直圆柔性铰链的切割半径与最小厚度相当时,Paros给出的简化公式存在一定的误差,这里的计算公式尤其适用于该类直圆柔性铰链。 相似文献
66.
对Ⅰ型铰链夹紧机构的两种结构形式的性能进行了比较,分析总结了结构中各主要参数对夹紧性能的影响规律和关系,给出了确定结构形式和主要参数的一些经验和方法,可为设计者提供必要的设计依据。 相似文献
67.
三种形状柔性铰链转动刚度的计算与分析 总被引:7,自引:0,他引:7
本文针对3种形状的柔性铰链进行力学分析,推导出它们各自绕z轴的转动刚度计算公式;通过计算、比较和分析得出柔性铰链中外形、几何尺寸等设计参数对转动刚度的影响程度。根据分析结果确定3种形状柔性铰链各自的微制造工艺及适用场合,为MEMS中柔性铰链的设计与应用提供一定的依据。 相似文献
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69.
The design and fabrication processes of a novel scanner withminimized coupling motions for a high-speed atomic force microscope (AFM) were addressed.An appropriate design modification was proposed through the analyses of the dynamic characteristics of existing linear motion stages using a dynamic analysis program,Recurdyn.Because the scanning speed of each direction may differ,the linear motion stage for a high-speed scanner was designed to have different resonance frequencies for the modes,with one dominan... 相似文献
70.