Results 11 to 20 of about 252,774 (130)
Jianzhu Gangjiegou Jinzhan, 2021 为研究冲击荷载下节点刚度和冲击速度对焊接球节点动力响应的影响,对缩尺节点试件进行不同高度下的冲击试验;采用ANSYS/LS-DYNA软件中的Shell163壳单元模拟焊接球和杆件,采用Solid164实体单元模拟冲击物,建立焊接空心球节点精细化有限元模型。将试验结果和有限元分析结果进行对比,验证有限元模型的有效性。通过改变钢球冲击高度、球节点壁厚和直径,从节点的动应力、动应变、动位移、冲击力以及冲击能量5个方面,对焊接球节点开展动力响应分析。研究结果表明:动力响应随冲击能量的增加而增大 ...
吴长, 刘家乐, 王仁红
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Jianzhu Gangjiegou Jinzhan建立Levy型索穹顶结构有限元分析模型，给出有限元结果合理性的判定准则，提出冲击失效准则。进行大量冲击工况下的动力响应全过程分析，给出杆件破坏分布规律和失效模式，揭示在竖向冲击荷载作用下的失效机理。依据冲击失效机理及参数分析，提出抗冲击措施。研究结果表明：所有冲击工况均符合冲击判定准则，在所选竖向冲击荷载范围内，Levy型索穹顶结构的失效模式分为4种，即结构轻度损伤、结构局部1级失效、结构局部2级失效和结构整体破坏。随着冲击动的增加，结构的动力响应模式逐渐呈模式1→模式2→模式3→模式4发展趋势 ...
高占远, 朱佳静, 薛素铎, 阮冬
doaj +5 more sources
, 2023 无序合金是一种新型金属材料,突破了传统的合金设计理念,表现出不同于传统合金的优异力学性能、冲击释能及剪切自锐特性,在高温、高压、高应变率等环境具有良好的应用前景。分析活性无序合金的冲击释能特性对其应用于军事领域有着重要的指导作用,能为弹药战斗部的设计提供参考。本文阐述了静动态力学实验中典型无序合金的反应释能现象;总结了撞击速度与活性无序合金释能超压、释能效率之间的关系;讨论了撞击速度、材料破碎程度及靶标特征等因素对活性无序合金释能机理的影响;归纳了制备工艺及元素类型对活性无序合金释能特性的调控效果 ...
谈梦婷 +5 more
core +4 more sources
Populism, jihad, and economic resistance: Studying the political discourse of Iran's supreme leader
Digest of Middle East Studies, Volume 32, Issue 4, Page 321-339, Fall 2023., 2023 Abstract Political leaders of pariah authoritarian states communicate their political discourse unilaterally, in a closed environment without free and open media access or the space for public scrutiny or debate. They use their speeches for various aims such as to respond to external shocks, justify hardship, appeal to domestic and international ...
Sara Bazoobandi
wiley +1 more source
European Policy Analysis, Volume 8, Issue 3, Page 327-344, Summer 2022., 2022 Abstract The Swedish response to the pandemic at the national level has attracted considerable international attention, but little focus has been placed on the way municipalities dealt with the crisis. Using Hay's dimensions of politicization, namely the capacity for human agency, deliberation in the public domain, and social context, we analyze the ...
Jörgen Sparf +4 more
wiley +1 more source
Review of Policy Research, Volume 39, Issue 5, Page 541-569, September 2022., 2022 Abstract Scholarship on boom‐busts cycles in resource extraction often assumes that affected resource‐rich communities are at best reactive, at worst helpless, in the face of the large, exogenous shocks this cycle visits upon them. Researchers infrequently examine what communities themselves can do to improve their economic prospects and residents ...
Gwen Arnold +11 more
wiley +1 more source
Jianzhu Gangjiegou Jinzhan, 2022 采用ABAQUS有限元分析软件，研究内置工字形CFRP型材方钢管混凝土构件在侧向冲击荷载作用下的受力性能。通过考虑动态响应下材料的应变率效应来计算材料强度，并建立有限元模型对冲击全过程、应力-应变关系以及构件的耗能状态进行研究。通过变换冲击能量、含钢率、剪跨比和材料强度等条件，对构件抗冲击性能进行参数分析。研究结果表明，内置CFRP工字型材使得构件具有更好的耗能和变形能力；随着冲击能量和剪跨比的增长，构件的跨中挠度增大，抵抗冲击所需的时间延长；冲击力峰值受混凝土强度影响甚微，但随着冲击能量 ...
李帼昌, 刘璐, 杨志坚
doaj
Journal of Advanced Nursing, Volume 76, Issue 2, Page 514-525, February 2020., 2020 Abstract Aim To investigate the long‐term psychological reactions and resilient process of the young survivors after a large‐scale burn disaster of the Formosa Color Dust Explosion in Taiwan. Design Longitudinal study with follow‐up interviews using standardized questionnaire during November 2015–June 2018.
Chia‐Yi Wu +5 more
wiley +1 more source
, 2023 光伏电池由于具有较高的光电转化效率，在沙漠等太阳能充足的地方被广泛应用。但在沙尘长期冲击的环境下，光伏电池内部结构易出现累积损伤，使光电转化效率大幅降低。因此，研究颗粒群冲击条件下光伏电池的力-电行为具有重要意义。基于分离式霍普金森压杆，发展了一种驱动较大尺寸颗粒群高速冲击的实验方法，并系统测量了不同冲击条件下，多晶硅光伏电池的损伤行为与光电转化性能衰减规律。研究结果表明，随着颗粒直径、冲击速度和数密度的增加，光伏电池的光电转换效率快速降低；颗粒冲击后光伏电池表现出三种典型的损伤模式 ...
黄晨光, 王易航, 吴先前
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